The guarantee of the brightness of the glow, the efficiency and durability of LED sources is proper nutrition, which can be provided by special electronic devices - drivers for LEDs. They convert the AC voltage in the 220V network into the DC voltage of the set value. To understand what function the converters perform and what to look for when choosing them, an analysis of the main types and characteristics of devices will help.

The main function of an LED driver is to provide a constant current through the LED fixture. The value of the current flowing through the semiconductor crystal must correspond to the passport parameters of the LED. This will ensure the stability of the glow of the crystal and help to avoid its premature degradation. In addition, for a given current, the voltage drop will correspond to the value required for the p-n junction. You can find out the corresponding supply voltage of the LED using the current-voltage characteristic.

When lighting residential and office premises with LED lamps and fixtures, drivers are used, which are powered by 220V AC. In automotive lighting (headlights, DRL, etc.), bicycle headlights, portable lamps, DC power supplies are used in the range from 9 to 36V. Some low-power LEDs can be connected without a driver, but then a resistor must be added to the 220-volt network for connecting the LED.

The driver output voltage is indicated in the range of two final values, between which stable operation is ensured. There are adapters with an interval from 3V to several tens. To power a circuit of 3 series-connected white LEDs, each of which has a power of 1 W, you need a driver with output values ​​\u200b\u200bof U - 9-12V, I - 350 mA. The voltage drop for each die will be about 3.3V, for a total of 9.9V, which is within the range of the driver.

Main characteristics of converters

Before you buy a driver for LEDs, you should familiarize yourself with the main characteristics of the devices. These include output voltage, rated current and power. The output voltage of the converter depends on the magnitude of the voltage drop across the LED source, as well as on the connection method and the number of LEDs in the circuit. The current depends on the power and brightness of the emitting diodes. The driver must provide the LEDs with the current they need to maintain the required brightness.

One of the important characteristics of the driver is the power that the device produces in the form of a load. The choice of driver power is affected by the power of each LED device, the total number and color of the LEDs. The power calculation algorithm is that the maximum power of the device should not be lower than the consumption of all LEDs:

P = P(led) × n,

where P(led) is the power of a single LED source, and n is the number of LEDs.

In addition, a mandatory condition must be met, under which a power reserve of 25-30% would be provided. Thus, the value of the maximum power must not be less than the value (1.3 x P).

You should also take into account the color characteristics of the LEDs. After all, semiconductor crystals of different colors have a different voltage drop when a current of the same strength passes through them. So the voltage drop of a red LED at a current of 350 mA is 1.9-2.4V, then the average value of its power will be 0.75 W. For a green analog, the voltage drop is in the range from 3.3 to 3.9V, and at the same current, the power will be already 1.25 watts. This means that 16 red LED sources or 9 green ones can be connected to the 12V LED driver.

Useful advice! When choosing a driver for LEDs, experts advise not to neglect the maximum power value of the device.

What are the drivers for LEDs by device type

Drivers for LEDs are classified according to the type of device into linear and pulsed. Structure and typical scheme The driver for linear type LEDs is a current generator based on a p-channel transistor. Such devices provide smooth current stabilization under the condition of unstable voltage on the input channel. They are simple and cheap devices, but they are characterized by low efficiency, they generate a lot of heat during operation and cannot be used as drivers for high-power LEDs.

Pulse devices create a series of high-frequency pulses in the output channel. Their operation is based on the principle of PWM (pulse width modulation), when the average value of the output current is determined by the duty cycle, i.e. the ratio of the pulse duration to the number of repetitions. The change in the value of the average output current occurs due to the fact that the pulse frequency remains unchanged, and the duty cycle varies from 10-80%.

Due to the high conversion efficiency (up to 95%) and the compactness of the devices, they are widely used for portable LED designs. In addition, the efficiency of the devices has a positive effect on the duration of the functioning of autonomous power devices. Pulse-type converters are compact in size and have a wide range of input voltages. The disadvantage of these devices is the high level of electromagnetic interference.

Useful advice! You should purchase an LED driver at the stage of selecting LED sources, having previously decided on the LED circuit from 220 volts.

Before choosing a driver for LEDs, you need to know the conditions for its operation and the location of the LED devices. Pulse-width drivers, which are based on a single microcircuit, are miniature in size and are designed to be powered from autonomous low-voltage sources. The main application of these devices is car tuning and LED lights. However, due to the use of a simplified electronic circuit, the quality of such converters is somewhat lower.

Dimmable LED Drivers

Modern LED drivers are compatible with dimming devices semiconductor devices. The use of dimmable drivers allows you to control the level of illumination in the premises: reduce the intensity of the glow in the daytime, emphasize or hide individual elements in the interior, zone the space. This, in turn, makes it possible not only to rationally use electricity, but also save the resource of the LED light source.

Dimmable drivers come in two types. Some are connected between the power supply and LED sources. Such devices control the energy coming from the power supply to the LEDs. Such devices are based on PWM control, in which energy is supplied to the load in the form of pulses. The duration of the pulses determines the amount of energy from the minimum to the maximum value. Drivers of this type are mainly used for fixed voltage LED modules, such as LED strips, tickers, etc.

The driver is controlled using or PWM

Dimmable converters of the second type control the power supply directly. The principle of their operation is both in PWM regulation and in controlling the amount of current flowing through the LEDs. Dimmable drivers of this type are used for constant current LED fixtures. It is worth noting that when controlling LEDs using PWM control, negative effects on vision are observed.

Comparing these two control methods, it is worth noting that when adjusting the current through LED sources, not only a change in the brightness of the glow is observed, but also a change in the color of the glow. So, white LEDs emit a yellowish light at a lower current, and glow blue at an increase. When driving LEDs with PWM control, there are negative effects on vision and a high level of electromagnetic interference. In this regard, PWM control is used quite rarely, in contrast to current regulation.

LED driver circuits

Many manufacturers produce driver ICs for LEDs that allow you to power sources from low voltage. All existing drivers are divided into simple ones, made on the basis of 1-3 transistors, and more complex ones using special microcircuits with pulse-width modulation.

ON Semiconductor offers a wide range of ICs as the basis for drivers. They feature reasonable cost, excellent conversion efficiency, economy and low EMI. The manufacturer presents a UC3845 pulse type driver with an output current of up to 1A. On such a chip, you can implement a driver circuit for a 10W LED.

HV9910 (Supertex) electronic components are a popular driver IC due to its simple circuit resolution and low price. It has a built-in voltage regulator and outputs for dimming control, as well as an output for programming the switching frequency. The output current value is up to 0.01A. On this chip, it is possible to implement a simple driver for LEDs.

Based on the UCC28810 chip (produced by Texas Instruments), you can create a driver circuit for high-power LEDs. In such an LED driver circuit, an output voltage of 70-85V can be created for LED modules consisting of 28 LED sources with a current of 3 A.

Useful advice! If you are planning to buy superbright 10W LEDs, you can use a switching driver on the UCC28810 chip for designs of them.

Clare proposes the creation of a simple pulse-type driver based on the CPC 9909 chip. It includes a converter controller housed in a compact package. Due to the built-in voltage stabilizer, the converter can be powered from a voltage of 8-550V. Chip CPC 9909 allows you to operate the driver in a wide range of temperature conditions from -50 to 80°C.

How to choose a driver for LEDs

There is a wide range of LED drivers on the market from different manufacturers. Many of them, especially those made in China, have a low price. However, buying such devices is not always profitable, since most of them do not meet the declared characteristics. In addition, such drivers are not accompanied by a guarantee, and if a defect is found, they cannot be returned or replaced with high-quality ones.

So there is a possibility of acquiring a driver whose declared power is 50 W. However, in reality it turns out that this characteristic is of a non-permanent nature and such power is only short-term. In reality, such a device will work as a 30W LED driver or a maximum of 40W. It may also turn out that the filling will lack some of the components responsible for the stable operation of the driver. In addition, components of low quality and with a short service life can be used, which is essentially a marriage.

When buying, pay attention to the indication of the brand of the product. On a quality product, the manufacturer will be indicated, which will provide a guarantee and will be ready to be responsible for their products. It should be noted that the service life of drivers from trusted manufacturers will be much longer. The following is the estimated runtime of the drivers, depending on the manufacturer:

• driver from dubious manufacturers - no more than 20 thousand hours;
• average quality devices - about 50 thousand hours;
• converter from a proven manufacturer using quality components - over 70 thousand hours.

Useful advice! What quality will led driver- you choose. However, it should be noted that it is especially important to purchase a branded converter when it comes to using it for LED spotlights and high-power luminaires.

Calculation of drivers for LEDs

To determine the output voltage of an LED driver, you need to calculate the ratio of power (W) to current (A). For example, the driver has the following characteristics: power 3 W and current 0.3 A. The calculated ratio is 10V. Thus, this will be the maximum output voltage of this converter.

Related article:

Types. Connection diagrams for LED sources. Calculation of resistance for LEDs. Checking the LED with a multimeter. Do-it-yourself LED designs.

If it is necessary to connect 3 LED sources, the current of each of them is 0.3 mA at a supply voltage of 3V. Connecting one of the devices to the LED driver, the output voltage will be 3V and current 0.3 A. By assembling two LED sources in series, the output voltage will be 6V and current 0.3 A. Adding a third LED to the series chain, we get 9V and 0.3 A. With a parallel connection, 0.3 A will be equally distributed between the LEDs at 0.1 A. Connecting the LEDs to the device at 0.3 A at a current value of 0.7, they will get only 0.3 A.

This is the algorithm for the functioning of LED drivers. They deliver as much current as they are designed for. The method of connecting LED-devices in this case does not play a role. There are driver models that involve any number of LEDs connected to them. But then there is a limitation on the power of LED sources: it should not exceed the power of the driver itself. Drivers are available designed for a certain number of connected LEDs. They are allowed to connect a smaller number of LEDs. But such drivers have low efficiency, unlike devices designed for a specific number of LED devices.

It should be noted that drivers designed for a fixed number of emitting diodes are protected against emergencies. Such converters do not work correctly if you connect a smaller number of LEDs to them: they will flicker or not glow at all. Thus, if you connect voltage to the driver without an appropriate load, it will work unstably.

Where to buy LED drivers

You can buy an LED-driver at specialized points for the sale of radio components. In addition, it is much more convenient to get acquainted with the products and order the necessary product using the catalogs of the relevant sites. In addition, in online stores you can purchase not only converters, but also LED lighting devices and related products: control devices, connection tools, electronic components for repairing and assembling a driver for LEDs with your own hands.

Implementing companies present a huge range of drivers for LEDs, the technical characteristics and prices of which can be seen in the price lists. As a rule, product prices are indicative and are specified when ordering from the project manager. The range includes converters of various power and degree of protection, used for outdoor and indoor lighting, as well as for lighting and car tuning.

When choosing a driver, you should take into account the conditions of its use and the power consumption of the LED design. Therefore, it is necessary to purchase a driver before buying LEDs. So, before you buy a 12 volt LED driver, you need to take into account that it must have a power reserve of about 25-30%. This is necessary in order to reduce the risk of damage or complete failure of the device during a short circuit or power surges in the network. The cost of the converter depends on the number of devices purchased, the form of payment and delivery time.

The table shows the main parameters and dimensions of 12 volt voltage stabilizers for LEDs, indicating their estimated price:

Modification LD DC/AC 12 V	Dimensions, mm (h/w/d)	Output current, A	Power, W	price, rub.
1x1W 3-4VDC 0.3A MR11	8/25/12	0,3	1x1	73
3x1W 9-12VDC 0.3A MR11	8/25/12	0,3	3x1	114
3x1W 9-12VDC 0.3A MR16	12/28/18	0,3	3x1	35
5-7x1W 15-24VDC 0.3A	12/14/14	0,3	5-7x1	80
10W 21-40V 0.3A AR111	21/30	0,3	10	338
12W 21-40V 0.3A AR11	18/30/22	0,3	12	321
3x2W 9-12VDC 0.4A MR16	12/28/18	0,4	3x2	18
3x2W 9-12VDC 0.45A	12/14/14	0,45	3x2	54

Making drivers for LEDs with your own hands

Using ready-made microcircuits, radio amateurs can independently assemble drivers for LEDs of various capacities. To do this, you must be able to read electrical circuits and have the skills to work with a soldering iron. For example, you can consider several options for do-it-yourself LED drivers for LEDs.

The driver circuit for the 3W LED can be implemented based on the Chinese PowTech PT4115 chip. The microcircuit can be used to power LED devices above 1W and includes control units that have a sufficiently powerful transistor at the output. The PT4115 based driver is highly efficient and has a minimum of piping components.

Overview of PT4115 and technical parameters of its components:

• glow brightness control function (dimming);
• input voltage - 6-30V;
• output current value - 1.2 A;
• current stabilization deviation up to 5%;
• protection against load breaks;
• the presence of conclusions for dimming;
• efficiency - up to 97%.

The microcircuit has the following conclusions:

• for the output switch - SW;
• for the signal and supply section of the circuit - GND;
• for brightness control - DIM;
• input current sensor - CSN;
• supply voltage - VIN;

Do-it-yourself LED driver circuit based on PT4115

Driver circuits for powering LED devices with a dissipating power of 3 W can be made in two versions. The first assumes the presence of a power supply with a voltage of 6 to 30V. In another circuit, power is provided from an alternating current source with a voltage of 12 to 18V. In this case, a diode bridge is introduced into the circuit, at the output of which a capacitor is installed. It helps smooth out voltage fluctuations, its capacitance is 1000 microfarads.

For the first and second circuits, the capacitor (CIN) is of particular importance: this component is designed to reduce ripple and compensate for the energy stored in the inductor when the MOP transistor is turned off. In the absence of a capacitor, all the energy of the inductance through the semiconductor diode DSHB (D) will go to the supply voltage output (VIN) and cause a breakdown of the microcircuit relative to the power supply.

Useful advice! It must be taken into account that the connection of the driver for LEDs in the absence of an input capacitor is not allowed.

Given the number and how much the LEDs consume, the inductance (L) is calculated. In the LED driver circuit, an inductance should be selected, the value of which is 68-220 μH. This is evidenced by the technical documentation. A slight increase in the value of L can be allowed, but it should be taken into account that then the efficiency of the circuit as a whole will decrease.

As soon as voltage is applied, the amount of current passing through the resistor RS (acts as a current sensor) and L will be zero. Further, the CS comparator analyzes the potential levels before and after the resistor - as a result, a high concentration appears at the output. The current flowing into the load rises to a certain value controlled by RS. The current increases depending on the value of the inductance and the value of the voltage.

Assembling Driver Components

The piping components of the RT 4115 chip are selected according to the manufacturer's instructions. For CIN, a low impedance capacitor (low ESR capacitor) should be used, as the use of other analogues will adversely affect the efficiency of the driver. If the device is powered from a stabilized current unit, one capacitor with a capacity of 4.7 uF or more will be needed at the input. It is recommended to place it next to the chip. If the current is alternating, you will need to introduce a solid-state tantalum capacitor with a capacitance of at least 100 microfarads.

In the switching circuit for 3 W LEDs, it is necessary to install an inductor of 68 μH. It should be located as close as possible to the SW terminal. You can make your own coil. This will require a ring from a failed computer and a winding wire (PEL-0.35). Diode FR 103 can be used as diode D. Its parameters are: capacitance 15 pF, recovery time 150 ns, temperature from -65 to 150°C. It can handle surge currents up to 30A.

The minimum value of the resistor RS in the LED driver circuit is 0.082 ohms, the current is 1.2 A. To calculate the resistor, you need to use the current required by the LED. Below is the formula for the calculation:

RS = 0.1 / I,

where I is the rated current of the LED source.

The value of RS in the LED driver circuit is 0.13 ohms, respectively, the current value is 780 mA. If such a resistor cannot be found, several low-resistance components can be used, using the resistance formula for parallel and series connection in the calculation.

DIY driver layout for 10 watt LED

You can assemble a driver for a powerful LED yourself, using electronic boards from failed fluorescent lamps. Most often in such lamps the lamps burn out. Electronic board remains working, which allows you to use its components for homemade power supplies, drivers and other devices. To work, you may need transistors, capacitors, diodes, inductors (chokes).

A defective lamp must be carefully disassembled with a screwdriver. To make a driver for a 10W LED, you should use a fluorescent lamp with a power of 20W. This is necessary so that the throttle can withstand the load with a margin. For a more powerful lamp, you should either select the appropriate board, or replace the inductor itself with an analogue with a large core. For LED sources with lower power, you can adjust the number of turns of the winding.

Next, over the primary turns of the winding, it is necessary to make 20 turns of wire and use a soldering iron to connect this winding to the rectifier diode bridge. After that, you should apply voltage from the 220V network and measure the output voltage at the rectifier. Its value was 9.7V. The LED source consumes 0.83 A through the ammeter. The rating of this LED is 900 mA, however, in order to underestimate the current consumption, it will increase its resource. The assembly of the diode bridge is carried out by surface mounting.

The new board and diode bridge can be placed in the stand from the old table lamp. Thus, the LED driver can be assembled independently from available radio components from failed devices.

Due to the fact that LEDs are quite demanding on power sources, it is necessary to choose the right driver for them. If the converter is chosen correctly, you can be sure that the parameters of the LED sources will not deteriorate and the LEDs will last their specified period.

Today, probably, not a single apartment or private house can do without LED lighting. And street lighting is gradually changing to economical and durable LED-elements. But looking at today's topic of conversation, one asks - what does the driver have to do with it (from the English “driver” is translated that way)? This is the first question that comes to the mind of a person who is ignorant of the LED lighting device. In fact, without such a device, light diodes do not work with a voltage of 220 V. Today we will figure out what function the LED driver performs, how to connect this device and whether it is possible to make it yourself.

Read in the article:

Why do we need drivers for LEDs and what is it

The answer to the question, what is an LED driver, is quite simple. This is a device that stabilizes the voltage and gives it the characteristics that are needed for the operation of LED elements. To make it clearer, let's draw an analogy with the ballast of a fluorescent lamp, which also cannot work without additional equipment. The only difference is that the driver has a compact size and fits in the body of the light fixture. In fact, it can be called a stabilizing starting device or a frequency converter.

Where are stabilizing devices for LED elements used?

LED drivers for LEDs are used in various fields:

• street lights;
• household lighting lamps;
• LED strips and various lighting;
• office lamps with the form of fluorescent lamps.

Even car daytime running lights require the installation of such a device, but everything is much simpler here, you can get by with one resistor. And although the driver for an LED strip (for example) differs in characteristics from a light bulb voltage regulator, they perform the same function.

Working Principle of 220V LED Lamp Driver Circuit

The principle of operation of the device is to maintain a given current at the output voltage (regardless of its value). This is the difference from the stabilizing power supply, which is responsible for the voltage.

Considering the circuit, we see that the current, passing through the resistances, stabilizes, and the capacitor gives it the desired frequency. Then the rectifying diode bridge comes into play. We get a stabilized direct current on the LEDs, which is again limited by resistors.

Noteworthy Driver Features

The characteristics of the converters required in a particular case are determined based on the parameters of the LED consumers. The main ones are:

1. Driver Rated Power- this parameter must exceed the total power consumed by the light diodes that will be in its circuit.
2. Output voltage- depends on the magnitude of the voltage drop on each of the light diodes.
3. Rated current, which depends on the brightness of the glow and the power consumption of the element.

It's important to know! The voltage drop across an LED depends on its color. For example, if you can connect 16 red LEDs to a 12 V power supply, then the maximum number of green LEDs will be 9.

Separation of LED drivers by device type

Converters can be divided into two types - linear and pulse. Both types are applicable to light diodes, but the differences between them are noticeable both in cost and in technical characteristics.

Linear converters are characterized by simple design and low cost. But such drivers have a significant drawback - the ability to connect only low-power light elements. Part of the energy is spent on heat generation, which contributes to a decrease in the coefficient of performance (COP).

Pulse converters are based on the principle of pulse-width modulation (PWM) and during their operation, the magnitude of the output currents is determined by such a parameter as the duty cycle. This means that there is no change in the pulse frequency, but the duty cycle can vary by values ​​from 10 to 80%. Such drivers allow you to extend the life of light diodes, but they have one drawback. During their operation, it is possible to induce electromagnetic interference. Let's try to figure out what it threatens a person with a simple example.

A person living in an apartment or house has a pacemaker installed. At the same time, a chandelier was installed in a small room with many devices operating on impulse ice drivers for. In this case, the pacemaker may begin to malfunction. Of course, this is exaggerated and to create such strong interference, you need a lot of lamps that are less than a meter away from the pacemaker, but there is still a risk.

How to choose a driver for an LED: some nuances

Before purchasing a converter, calculate the power consumed by the LEDs. The rated power of the device must exceed this figure by 25 ÷ 30%. Also, the stabilizer must match the output voltage.

If hidden placement is planned, it is better to choose a converter without a case - the cost will be lower with the same technical characteristics.

Important! Drivers made in China usually do not meet the declared characteristics. Don't skimp on purchasing a "made in" converter. It is better to give preference to the Russian manufacturer.

How to connect LED elements to the converter: methods and diagrams

LEDs are connected to the driver in two ways - in series or in parallel. For example, let's take 6 LED emitters with a voltage drop of 2 V. When connected in series, you need a driver for 12 V and 300 mA. In this case, the glow will be even for all elements.

By connecting the emitters in parallel in a group of 3, we get the opportunity to use a 6 V converter, but already at 600 mA. The problem is that due to the uneven voltage drop, one line will glow brighter than the other.

We calculate the characteristics of the converter for LEDs

For an accurate calculation, we first determine the power consumption of the LEDs. After the issue is resolved with the connection diagram - will it be parallel or serial. The output voltage and rated power of the required converter will depend on this. This is all the work that needs to be done. Now, in an electrical engineering store or on an online resource, we select a driver according to the calculated indicators.

Good to know! When purchasing a converter, ask the seller for a certificate of conformity for the product. If it is missing, it is better to refrain from buying.

What is a dimmable LED driver

Dimmable is a driver for an LED lamp that supports changing the input current parameters and is able to change the output depending on this. This is achieved by changing the intensity of the glow of LED emitters. An example would be a remote controlled LED strip controller. If desired, it becomes possible to "dim" the lighting in the room, to give rest to the eyes. It is also appropriate if a child is sleeping in the room.

Dimming is performed from the remote control, or from a regular mechanical stepless switch.

Chinese converters - what is special about them

Chinese friends are famous for their ability to fake equipment so that it becomes impossible to use. The same can be said for drivers. When purchasing a Chinese device, be prepared for overstated specifications, low quality and a quick failure of the converter. If you are going to build the first LED-lamp in your life, practice and gain skills in radio electronics, such products are indispensable due to their low cost and ease of execution.

What affects the service life of converters

The reasons for the failure of the converter are:

1. Sudden power surges in the network.
2. High humidity if the device does not meet the degree of protection.
3. Temperature fluctuations.
4. Insufficient ventilation.
5. Increased dustiness.
6. Incorrect calculation of consumer power.

Any of these causes can be prevented or corrected. This means that it is in the power of the home master to extend the life of the stabilizing device.

PT4115 LED driver circuit with dimmer

We are talking about a Chinese manufacturer, which is an exception to the rule. A microcircuit, on the basis of which it is possible to assemble the simplest converter just by its production. The PT4115 microprocessor has good performance and is gaining popularity in Russia.

Related article:

If the lighting is LED and conventional regulators are not suitable, then they are installed, which are slightly different structurally and technically. Today we will figure out what they are, how to choose and even make such a device yourself.

The figure shows the simplest PT4115 driver circuit for LEDs, which a beginner can assemble House master no experience in electronics. Interesting in the chip is an additional output (DIM) that allows you to connect a dimmer (dimmer).

How to make a DIY LED driver

Any novice master can assemble an LED lamp driver circuit. But this will require accuracy and patience. From the first time, the stabilizing device may not work. To make it clearer to the reader how the work is done, we offer several simple schemes.

As you can see, there is nothing complicated in driver circuits for LEDs from a 220 V network. Let's try to consider step by step all the stages of work.

DIY step-by-step instructions for making a driver for LEDs

Photo example	Action to take
	To work, we need a regular power supply for the phone. It makes everything quick and easy.
	After disassembling the charger in our hands, we already have an almost complete driver for three one-watt LEDs, but it needs to be slightly modified.
	We solder a 5 kOhm limiting resistor, which is located near the output channel. It is he who prevents the charger from applying too much voltage to the cell phone.
	Instead of a limiting resistor, we solder a tuning resistor by setting the same 5 kOhm on it. Subsequently, add voltage to the required.
	3 LEDs of 1 W each are soldered to the output channel, connected in series, which will give us a total of 3 W.
	We find the input contacts and unsolder from the printed circuit board. We no longer need them...
	... and in their place we solder the power cord, through which 220 V will be supplied.
	If desired, you can put a 1 Ohm resistor in the gap, set all indicators with an ammeter. In this case, the attenuation range of the LEDs will be wider.
	After complete assembly, we check the performance. The output voltage is 5 V, the LEDs are not yet lit.
	By turning the knob on the resistor, we see how the LED elements begin to “flare up”.

Be careful. From such a converter, you can get a discharge not only of 220 V (from the power cord), but also a shock of about 450 V, which is rather unpleasant (tested on yourself).

Very important! Before you check the LED driver for performance and connect it to a power source, you should once again visually check the correctness of the assembled circuit. Electric shock is life threatening and flash from a short circuit can cause damage to the eyes.

Current converters for light diodes: where to buy and what is the cost

Such devices are purchased in electrical stores or on the Internet resources. The second option is more cost effective. In addition, many manufacturers offer free shipping. Consider some models with an input voltage of 220 V with specifications and prices as of December 2017.

A photo	Model	Protection class, IP	Output voltage, V	Power, W	Cost, rub.
	DFT-I-40- LD64	20	60-130	45	400
	ZF-AC LD49	40	40-70	54	450
	XS0812-12W PS12	20	24-44	12	200
	PS100 (open)	20	30-36	100	1100
	PF4050A PS50	65	27-36	50	500
	PF100W LD100	65	23-36	100	1000

Looking at the prices, we can say that the independent manufacture of a current converter is more suitable for those for whom it is only a hobby. You can buy such a device quite inexpensively.

Summarize

When choosing a current converter for LED lamps, you should carefully calculate everything. Any error can lead to a decrease in the service life of the purchased device. Despite the low cost of the stabilizer, it is rather unpleasant to constantly throw money away. Only in this case the driver will serve its due period. And when making it yourself, follow the rules of electrical safety and be careful and attentive when assembling the circuit.

We hope that the information provided today was useful to our reader. You can ask any questions in the discussion - we will definitely answer them. Write, ask, share your experience with other readers.

And finally, a short video on today's topic:

The standard PT4115 LED driver circuit is shown in the figure below:

The supply voltage should be at least 1.5-2 volts higher than the total voltage across the LEDs. Accordingly, in the supply voltage range from 6 to 30 volts, from 1 to 7-8 LEDs can be connected to the driver.

The maximum supply voltage of the microcircuit is 45 V, but operation in this mode is not guaranteed (better pay attention to a similar chip).

The current through the LEDs has a triangular shape with a maximum deviation from the average value of ±15%. The average current through the LEDs is set by a resistor and is calculated by the formula:

I LED = 0.1 / R

The minimum allowable value R = 0.082 Ohm, which corresponds to a maximum current of 1.2 A.

The deviation of the current through the LED from the calculated one does not exceed 5%, provided that the resistor R is installed with a maximum deviation from the nominal value of 1%.

So, to turn on the LED for constant brightness, we leave the DIM output hanging in the air (it is pulled up to the 5V level inside the PT4115). In this case, the output current is determined solely by the resistance R.

If a capacitor is connected between the DIM pin and ground, we will get the effect of smooth lighting of the LEDs. The time to reach maximum brightness will depend on the capacitance of the capacitor, the larger it is, the longer the lamp will flare up.

For reference: each nanofarad of capacitance increases turn-on time by 0.8 ms.

If you want to make a dimmable driver for LEDs with brightness control from 0 to 100%, then you can resort to one of two methods:

1. First way involves supplying a constant voltage in the range from 0 to 6V to the DIM input. In this case, the brightness adjustment from 0 to 100% is carried out at a voltage at the DIM pin from 0.5 to 2.5 volts. Increasing the voltage above 2.5 V (and up to 6 V) does not affect the current through the LEDs (the brightness does not change). On the contrary, a decrease in voltage to a level of 0.3V or lower leads to the shutdown of the circuit and its transfer to standby mode (the current consumption drops to 95 μA). Thus, it is possible to effectively control the operation of the driver without removing the supply voltage.
2. Second way implies a signal from a pulse-width converter with an output frequency of 100-20000 Hz, the brightness will be determined by the duty cycle (pulse duty cycle). For example, if the high level is held for 1/4 of the period, and the low level, respectively, 3/4, then this will correspond to a brightness level of 25% of the maximum. It must be understood that the frequency of the driver is determined by the inductance of the inductor and in no way depends on the dimming frequency.

The PT4115 LED driver circuit with a constant voltage dimmer is shown in the figure below:

This LED dimming scheme works great because the DIM pin inside the chip is "pulled up" to the 5V bus through a 200 kΩ resistor. Therefore, when the potentiometer slider is in its lowest position, a voltage divider of 200 + 200 kΩ is formed and a potential of 5/2=2.5V is formed at the DIM pin, which corresponds to 100% brightness.

How the scheme works

At the first moment of time, when the input voltage is applied, the current through R and L is zero and the output key built into the microcircuit is open. The current through the LEDs begins to gradually increase. The rate of current rise depends on the value of the inductance and the supply voltage. The in-circuit comparator compares the potentials before and after the resistor R and, as soon as the difference is 115 mV, a low level appears at its output, which closes the output switch.

Due to the energy stored in the inductance, the current through the LEDs does not disappear instantly, but begins to gradually decrease. The voltage drop across the resistor R also gradually decreases. As soon as it reaches a value of 85 mV, the comparator will again give a signal to open the output key. And the whole cycle repeats from the beginning.

If it is necessary to reduce the current ripple through the LEDs, it is allowed to connect a capacitor in parallel with the LEDs. The larger its capacitance, the more the triangular shape of the current through the LEDs will be smoothed out and the more it will become similar to a sinusoidal one. The capacitor does not affect the operating frequency or efficiency of the driver, but it does increase the settling time for the desired current through the LED.

Important assembly details

An important element of the circuit is the capacitor C1. It not only smooths out ripples, but also compensates for the energy accumulated in the inductor at the moment the output switch is closed. Without C1, the energy stored in the inductor will flow through the Schottky diode to the power rail and can cause a breakdown of the microcircuit. Therefore, if you turn on the driver without a capacitor shunting the power supply, the microcircuit is almost guaranteed to be covered. And the greater the inductance of the inductor, the more likely it is to burn the mikruha.

The minimum capacitance of the capacitor C1 is 4.7 uF (and when the circuit is powered by a pulsating voltage after the diode bridge, it is at least 100 uF).

The capacitor should be placed as close to the chip as possible and have the lowest possible ESR value (i.e. tantalum conduits are welcome).

It is also very important to responsibly approach the choice of the diode. It should have a low forward voltage drop, a short recovery time during switching, and stable parameters when boosted. temperature p-n transition to prevent an increase in leakage current.

In principle, you can take an ordinary diode, but Schottky diodes are best suited for these requirements. For example, STPS2H100A in SMD version (forward voltage 0.65V, reverse - 100V, pulse current up to 75A, operating temperature up to 156°C) or FR103 in DO-41 package (reverse voltage up to 200V, current up to 30A, temperature up to 150 °C). The common SS34s showed themselves very well, which you can pull from old boards or buy a whole pack for 90 rubles.

The inductance of the inductor depends on the output current (see table below). An incorrectly selected inductance value can lead to an increase in the power dissipated on the microcircuit and beyond the operating temperature range.

When overheated above 160°C, the microcircuit will automatically turn off and remain in the off state until it cools down to 140°C, after which it will start automatically.

Despite the available tabular data, it is allowed to mount a coil with an inductance deviation upwards from the nominal value. This changes the efficiency of the entire circuit, but it remains operational.

The inductor can be taken from the factory, or you can do it yourself from a ferrite ring from a burnt motherboard and a PEL-0.35 wire.

If the maximum autonomy of the device is important (portable lamps, lanterns), then, in order to increase the efficiency of the circuit, it makes sense to spend time on careful selection of the throttle. At low currents, the inductance must be larger to minimize current control errors due to the delay in switching the transistor.

The inductor should be located as close as possible to the SW terminal, ideally connected directly to it.

And finally, the most precise element of the LED driver circuit is the resistor R. As already mentioned, its minimum value is 0.082 ohms, which corresponds to a current of 1.2 A.

Unfortunately, it is not always possible to find a resistor of a suitable value, so it's time to recall the formulas for calculating the equivalent resistance when resistors are connected in series and in parallel:

• R last \u003d R 1 + R 2 + ... + R n;
• R pairs = (R 1 xR 2) / (R 1 + R 2).

By combining various switching methods, you can get the required resistance from several resistors at hand.

It is important to separate the board so that the Schottky diode current does not flow along the track between R and VIN, as this can lead to errors in measuring the load current.

The low cost, high reliability and stability characteristics of the PT4115 driver contribute to its widespread use in LED lamps. Almost every second 12-volt LED lamp with an MR16 base is assembled on a PT4115 (or CL6808).

The resistance of the current-setting resistor (in ohms) is calculated using exactly the same formula:

R = 0.1 / I LED[A]

A typical wiring diagram looks like this:

As you can see, everything is very similar to the LED lamp circuit with a PT4515 driver. Description of work, signal levels, features of the elements used and the layout of the printed circuit board are exactly the same as those, so it makes no sense to repeat.

CL6807 is sold at 12 rubles / pc, you just need to watch so that they do not slip soldered ones (I recommend taking it).

SN3350

SN3350 - another inexpensive chip for LED drivers (13 rubles / piece). It is almost a complete analog of PT4115 with the only difference that the supply voltage can range from 6 to 40 volts, and the maximum output current is limited to 750 milliamps (continuous current should not exceed 700 mA).

Like all the above microcircuits, SN3350 is a pulse step-down converter with output current stabilization function. As usual, the current in the load (and in our case, one or more LEDs act as a load) is set by the resistance of the resistor R:

R = 0.1 / I LED

In order not to exceed the value of the maximum output current, the resistance R should not be lower than 0.15 ohm.

The microcircuit is available in two packages: SOT23-5 (maximum 350 mA) and SOT89-5 (700 mA).

As usual, by applying a constant voltage to the ADJ pin, we turn the circuit into a simple adjustable driver for LEDs.

A feature of this microcircuit is a slightly different adjustment range: from 25% (0.3V) to 100% (1.2V). When the potential at the ADJ pin drops to 0.2V, the microcircuit goes into sleep mode with a consumption in the region of 60 μA.

Typical switching circuit:

For other details, see the chip specification (pdf file).

ZXLD1350

Despite the fact that this microcircuit is another clone, some differences in technical characteristics do not allow their direct replacement with each other.

Here are the main differences:

• the microcircuit starts already at 4.8V, but it enters normal operation only when the supply voltage is from 7 to 30 Volts (it is allowed to supply up to 40V for half a second);
• maximum load current - 350 mA;
• resistance of the output key in the open state - 1.5 - 2 Ohm;
• By changing the potential at the ADJ pin from 0.3 to 2.5V, you can change the output current (LED brightness) in the range from 25 to 200%. At a voltage of 0.2V for at least 100 µs, the driver goes into sleep mode with low power consumption (about 15-20 µA);
• if the adjustment is carried out by a PWM signal, then at a pulse repetition rate below 500 Hz, the range of brightness change is 1-100%. If the frequency is above 10 kHz, then from 25% to 100%;

The maximum voltage that can be applied to the dimming input (ADJ) is 6V. In this case, in the range from 2.5 to 6V, the driver outputs the maximum current, which is set by the current-limiting resistor. The resistor resistance is calculated in exactly the same way as in all of the above microcircuits:

R = 0.1 / I LED

The minimum resistance of the resistor is 0.27 ohms.

A typical switching circuit is no different from its counterparts:

It is IMPOSSIBLE to supply power to the circuit without capacitor C1 !!! At best, the chip will overheat and give out unstable characteristics. In the worst case, it will instantly fail.

More detailed specifications ZXLD1350 can be found in the datasheet for this chip.

The cost of the microcircuit is unreasonably high (), despite the fact that the output current is quite small. In general, strongly on the fan. I wouldn't contact.

QX5241

QX5241 is a Chinese analogue of MAX16819 (MAX16820), but in a more convenient package. Also available under the names KF5241, 5241B. It is marked "5241a" (see photo).

In one well-known store they are sold almost by weight (10 pieces for 90 rubles).

The driver works on exactly the same principle as all of the above (continuous step-down converter), however, it does not contain an output switch, therefore, an external field-effect transistor is required for operation.

You can use any N-channel MOSFET with suitable drain current and drain-to-source voltage. Suitable, for example, are: SQ2310ES (up to 20V !!!), 40N06, IRF7413, IPD090N03L, IRF7201. In general, the lower the opening voltage, the better.

Here are some key features of the QX5241 LED driver:

• maximum output current - 2.5 A;
• Efficiency up to 96%;
• maximum dimming frequency - 5 kHz;
• maximum operating frequency of the converter - 1 MHz;
• current stabilization accuracy through LEDs - 1%;
• supply voltage - 5.5 - 36 Volts (it works fine even at 38!);
• the output current is calculated by the formula: R = 0.2 / I LED

Read more in the specification (in English).

The LED driver on the QX5241 contains few details and is always assembled according to the following scheme:

The 5241 microcircuit is only available in the SOT23-6 package, so it is better not to approach it with a soldering iron for soldering pans. After installation, the board should be thoroughly washed from the flux, any obscure contamination can adversely affect the operation of the microcircuit.

The difference between the supply voltage and the total voltage drop across the diodes should be 4 volts (or more). If less, then there are some glitches in operation (current instability and throttle whistle). So take it with a margin. Moreover, the greater the output current, the greater the voltage margin. Although, perhaps, I just got an unsuccessful copy of the microcircuit.

If the input voltage is less than the total drop across the LEDs, then the generation fails. At the same time, the output field switch opens completely and the LEDs glow (naturally, not at full power, since the voltage is not enough).

AL9910

Diodes Incorporated has created one very interesting LED driver IC: the AL9910. It is curious in that its operating voltage range allows you to connect it directly to a 220V network (through a simple diode rectifier).

Here are its main characteristics:

• input voltage - up to 500V (up to 277V for a change);
• built-in voltage regulator for powering the microcircuit, which does not require a quenching resistor;
• the ability to adjust the brightness by changing the potential on the control leg from 0.045 to 0.25V;
• built-in overheating protection (activated at 150°С);
• operating frequency (25-300 kHz) is set by an external resistor;
• an external field-effect transistor is required for operation;
• Available in 8-legged SO-8 and SO-8EP cases.

The driver assembled on the AL9910 chip does not have galvanic isolation from the network, therefore it should be used only where direct contact with the circuit elements is impossible.

Probably everyone, even a novice radio amateur, knows that in order to connect an ordinary LED to a power source, you need only one resistor. But what if the LED is powerful? Watt so 10. How to be then?
I will show you how to make a simple driver for a powerful LED with just two components.

For the stabilizer-driver we need:
1. Resistor -.
2. Chip - LM317 -.

LM317 is a stabilizer chip. Great for designing regulated power supplies or drivers to power LEDs, as in our case.

Advantages of LM317

• The voltage stabilization range is from 1.7 (including the LED voltage - 3 V) to 37 V. An excellent characteristic for motorists: the brightness will not float at any speed;
• Output current up to 1.5, you can connect several powerful LEDs;
  The stabilizer has a built-in protection system against overheating and short circuit.
• The negative power supply of the LED in the switching circuit is taken from the power source, therefore, when attached to the car body, the number of mounting wires is reduced, and the body can play the role of a large heat sink for the LED.

High power LED driver circuit

I will connect a 3 watt LED. As a result, we will need to calculate the resistance for our LED. A 1 W LED consumes 350 mA, and a 3 W LED consumes 700 mA (you can see it in the datasheet). Chip LM317 - has a reference voltage of the stabilizer - 1.25 - this is a constant number. It must be divided by the current and get the resistance of the resistor. That is: 1.25 / 0.7 \u003d 1.78 ohms. We take the current in amperes. We choose the nearest resistor by resistance, since there are no resistors with a resistance of 1.78. We take 1.8 and assemble the circuit.

If the power of your LED exceeds 1 W, then the chip must be installed on a radiator. In general, the LM317 is rated for current up to 1.5.
You can power our circuit with a voltage of 3 to 37 volts. Agree, a solid range of nutrition is obtained. But the higher the voltage, the more the microcircuit heats up, keep this in mind.

Homemade driver for LEDs from a 220V network. Schemes of ice drivers

Do-it-yourself LED driver: simple diagrams with descriptions

The use of LEDs as light sources usually requires a specialized driver. But it happens that the necessary driver is not at hand, but you need to organize the backlight, for example, in a car, or test the LED for the brightness of the glow. In this case, you can make a driver for LEDs with your own hands.

How to make an LED driver

The diagrams below use the most common items that can be purchased at any radio shop. Assembly does not require special equipment - all the necessary tools are widely available. Despite this, with a careful approach, the devices work for a long time and are not much inferior to commercial samples.

Necessary materials and tools

In order to assemble a homemade driver, you will need:

• Soldering iron with a power of 25-40 watts. You can use more power, but this increases the risk of overheating of the elements and their failure. It is best to use a soldering iron with a ceramic heater and a non-flammable tip, because. an ordinary copper sting oxidizes rather quickly, and it has to be cleaned.
• Flux for soldering (rosin, glycerin, FKET, etc.). It is desirable to use a neutral flux - unlike active fluxes (orthophosphoric and hydrochloric acids, zinc chloride, etc.), it does not oxidize contacts over time and is less toxic. Regardless of the flux used, after assembling the device, it is better to wash it with alcohol. For active fluxes, this procedure is mandatory, for neutral ones - to a lesser extent.
• Solder. The most common is low-melting tin-lead solder POS-61. Lead-free solders are less harmful when inhaled during soldering, but have a higher melting point with less fluidity and a tendency to degrade the weld over time.
• Small pliers for bending the leads.
• Nippers or side cutters for biting the long ends of leads and wires.
• Installation wires in isolation. Stranded is best copper wires section from 0.35 to 1 mm2.
• Multimeter for voltage control at nodal points.
• Insulating tape or heat shrink tubing.
• A small fiberglass breadboard. A 60x40 mm board will suffice.

Breadboard made of textolite for quick installation

Diagram of a simple driver for a 1W LED

One of the simplest circuits for powering a high-power LED is shown in the figure below:

As you can see, in addition to the LED, it includes only 4 elements: 2 transistors and 2 resistors.

In the role of the regulator of the current passing through the led, here is a powerful field-effect n-channel transistor VT2. Resistor R2 determines the maximum current passing through the LED, and also works as a current sensor for transistor VT1 in the feedback circuit.

The more current passes through VT2, the more voltage drops on R2, respectively, VT1 opens and lowers the voltage at the gate of VT2, thereby reducing the LED current. Thus, stabilization of the output current is achieved.

The circuit is powered from a constant voltage source of 9 - 12 V, current not less than 500 mA. The input voltage must be at least 1-2 V greater than the voltage drop across the LED.

Resistor R2 should dissipate 1-2 watts of power, depending on the required current and supply voltage. Transistor VT2 - n-channel, rated for a current of at least 500 mA: IRF530, IRFZ48, IRFZ44N. VT1 - any low power bipolar npn: 2N3904, 2N5088, 2N2222, BC547, etc. R1 - with a power of 0.125 - 0.25 W with a resistance of 100 kOhm.

Due to the small number of elements, assembly can be carried out by surface mounting:

Another simple driver circuit based on the LM317 linear controlled voltage regulator:

Here, the input voltage can be up to 35 V. The resistance of the resistor can be calculated using the formula:

where I is the current strength in amperes.

In this circuit, the LM317 will dissipate significant power with a large difference between the supply voltage and the LED drop. Therefore, it will have to be placed on a small radiator. The resistor must also be rated for at least 2 watts.

This scheme is more clearly discussed in the following video:

This shows how to connect a powerful LED using batteries with a voltage of about 8 V. With a voltage drop across the LED of about 6 V, the difference is small, and the microcircuit heats up slightly, so you can do without a heatsink.

Please note that with a large difference between the supply voltage and the drop on the LED, it is necessary to put the microcircuit on a heat sink.

Power driver circuit with PWM input

Below is a diagram for powering high-power LEDs:

The driver is based on a dual comparator LM393. The circuit itself is a buck-converter, that is, a pulsed step-down voltage converter.

Driver Features

• Supply voltage: 5 - 24 V, constant;
• Output current: up to 1A, adjustable;
• Output power: up to 18W;
• Output short circuit protection;
• The ability to control the brightness using an external PWM signal (it will be interesting to read how to adjust the brightness of the LED strip through a dimmer).

Operating principle

Resistor R1 with diode D1 form a reference voltage of about 0.7 V, which is additionally regulated by a variable resistor VR1. Resistors R10 and R11 serve as current sensors for the comparator. As soon as the voltage on them exceeds the reference, the comparator will close, thus closing a pair of transistors Q1 and Q2, and those, in turn, will close the transistor Q3. However, the inductor L1 at this moment tends to resume the passage of current, so the current will flow until the voltage across R10 and R11 becomes less than the reference, and the comparator again does not open transistor Q3.

The pair Q1 and Q2 acts as a buffer between the output of the comparator and the gate of Q3. This protects the circuit from false positives due to interference on the gate of Q3, and stabilizes its operation.

The second part of the comparator (IC1 2/2) is used for additional dimming with PWM. To do this, a control signal is applied to the PWM input: when TTL logic levels (+5 and 0 V) ​​are applied, the circuit will open and close Q3. The maximum signal frequency at the PWM input is about 2 kHz. This input can also be used to turn the device on and off using the remote control.

D3 is a Schottky diode, rated up to 1 A. If you can't find the Schottky diode, you can use a switching diode, such as FR107, but the output power will then be slightly reduced.

The maximum output current is adjusted by selecting R2 and including or excluding R11. This way you can get the following values:

• 350mA (1W LED): R2=10K, R11 disabled,
• 700mA (3W): ​​R2=10K, R11 connected, 1 ohm nominal,
• 1A (5W): R2=2.7K, R11 connected, nominal 1 ohm.

Within narrower limits, the adjustment is made by a variable resistor and a PWM signal.

Building and configuring the driver

Driver components are mounted on a breadboard. First, the LM393 chip is installed, then the smallest components: capacitors, resistors, diodes. Then transistors are placed, and lastly a variable resistor.

It is better to place elements on the board in such a way as to minimize the distance between the connected pins and use as few wires as jumpers as possible.

When connecting, it is important to observe the polarity of the diodes and the pinout of the transistors, which can be found in technical description to these components. Diodes can also be checked with a multimeter in resistance measurement mode: in the forward direction, the device will show a value of about 500-600 ohms.

To power the circuit, you can use an external DC voltage source of 5-24 V or batteries. Batteries 6F22 ("crown") and others have too little capacity, so their use is not advisable when using powerful LEDs.

After assembly, you need to adjust the output current. To do this, LEDs are soldered to the output, and the VR1 engine is set to the lowest position according to the diagram (checked with a multimeter in the “ringing” mode). Next, we apply a supply voltage to the input, and by rotating the VR1 knob we achieve the required brightness of the glow.

Item List:

Conclusion

The first two of the considered circuits are very simple to manufacture, but they do not provide protection against short circuits and have a rather low efficiency. For long-term use, the third circuit on the LM393 is recommended, as it does not have these disadvantages and has more power output adjustment capabilities.

ledno.ru

220V LED driver circuit

The advantages of LED paws have been discussed repeatedly. The abundance of positive feedback from users of LED lighting willy-nilly makes you think about Ilyich's own light bulbs. Everything would be nice, but when it comes to costing the conversion of an apartment to LED lighting, the numbers are a little “strain”.

To replace an ordinary 75W lamp, there is a 15W LED bulb, and a dozen of such lamps need to be changed. With an average cost of about $ 10 per lamp, the budget is decent, and the risk of acquiring a Chinese “clone” with a life cycle of 2-3 years cannot be ruled out. In light of this, many are considering the possibility of self-manufacturing these devices.

The theory of powering LED lamps from 220V

The most budget option can be assembled with your own hands from these LEDs. A dozen of these little ones cost less than a dollar, and are as bright as a 75W incandescent bulb. Putting everything together is not a problem, but you can’t connect them directly to the network - they will burn out. The heart of any LED lamp is the power driver. It depends on how long and well the light bulb will shine.

To assemble a 220 volt LED lamp with our own hands, let's look at the power driver circuit.

Network parameters significantly exceed the needs of the LED. In order for the LED to be able to work from the network, it is required to reduce the voltage amplitude, current strength and convert the AC voltage to DC.

For these purposes, a voltage divider with a resistor or capacitive load and stabilizers are used.

LED Light Components

A 220 volt LED lamp circuit will require a minimum number of available components.

• LEDs 3.3V 1W - 12 pcs.;
• ceramic capacitor 0.27uF 400-500V - 1 pc.;
• resistor 500kΩ - 1MΩ 0.5 - 1W - 1 sh.t;
• 100V diode - 4 pcs.;
• electrolytic capacitors for 330uF and 100uF 16V, 1 pc.;
• voltage regulator for 12V L7812 or similar - 1 pc.

Making a 220V LED driver with your own hands

The 220 volt ice driver circuit is nothing more than a switching power supply.

As a homemade LED driver from a 220V network, consider the simplest switching power supply without galvanic isolation. The main advantage of such schemes is simplicity and reliability. But be careful when assembling, since such a circuit does not have a limit on the output current. The LEDs will take their prescribed one and a half amps, but if you touch the bare wires with your hand, the current will reach ten amperes, and such a current shock is very noticeable.

The simplest driver circuit for 220V LEDs consists of three main stages:

• Voltage divider on capacitance;
• diode bridge;
• voltage stabilization stage.

The first stage is the capacitance on the capacitor C1 with a resistor. The resistor is necessary for the self-discharge of the capacitor and does not affect the operation of the circuit itself. Its value is not particularly critical and can be from 100kΩ to 1MΩ with a power of 0.5-1W. The capacitor is necessarily not electrolytic for 400-500V (effective peak voltage of the network).

When a half-wave of voltage passes through a capacitor, it passes current until the plates are charged. The smaller its capacity, the faster the full charge. With a capacity of 0.3-0.4 μF, the charging time is 1/10 of the half-wave period of the mains voltage. In simple terms, only a tenth of the incoming voltage will pass through the capacitor.

The second stage is a diode bridge. It converts AC voltage to DC. After cutting off most of the voltage half-wave by the capacitor, we get about 20-24V DC at the output of the diode bridge.

The third stage is a smoothing stabilizing filter.

A capacitor with a diode bridge acts as a voltage divider. When the voltage in the network changes, the amplitude at the output of the diode bridge will also change.

To smooth out the voltage ripple, we connect an electrolytic capacitor in parallel with the circuit. Its capacity depends on the power of our load.

In the driver circuit, the supply voltage for the LEDs must not exceed 12V. As a stabilizer, you can use the common element L7812.

The assembled circuit of the 220 volt LED lamp starts working immediately, but before connecting to the network, carefully insulate all bare wires and solder points of the circuit elements.

Driver option without current stabilizer

There are a huge number of driver circuits for LEDs from a 220V network on the network that do not have current stabilizers.

The problem of any transformerless driver is the ripple of the output voltage, and therefore the brightness of the LEDs. A capacitor installed after the diode bridge partially copes with this problem, but does not completely solve it.

There will be a ripple with an amplitude of 2-3V on the diodes. When we install a 12V regulator in the circuit, even taking into account the ripple, the amplitude of the incoming voltage will be above the cutoff range.

Voltage diagram in a circuit without a stabilizer

Diagram in a circuit with a stabilizer

Therefore, a driver for diode lamps, even assembled by oneself, will not be inferior in terms of pulsation to similar units of expensive factory-made lamps.

As you can see, assembling a driver with your own hands is not particularly difficult. By changing the parameters of the circuit elements, we can vary the values ​​of the output signal over a wide range.

If you have a desire to assemble a 220 volt LED spotlight circuit based on such a circuit, it is better to convert the output stage to 24V with an appropriate stabilizer, since the output current of the L7812 is 1.2A, this limits the load power to 10W. For more powerful light sources, you need to either increase the number of output stages, or use a more powerful stabilizer with an output current of up to 5A and install it on a radiator.

svetodiodinfo.ru

How to choose a led driver, led driver

The most optimal way to connect to 220V, 12V is to use a current stabilizer, an LED driver. In the language of the alleged enemy, "led driver" is written. By adding the desired power to this request, you can easily find a suitable product on Aliexpress or Ebay.

• 1. Features of Chinese
• 2. Service life
• 3. LED driver for 220V
• 4. RGB driver for 220V
• 5. Assembly module
• 6. Driver for LED lights
• 7. Power supply for led strip
• 8. DIY LED driver
• 9. Low voltage
• 10. Brightness adjustment

Features of Chinese

Many people like to buy from the largest Chinese market, Aliexpress. The prices and range are amazing. LED driver is most often chosen due to low cost and good performance.

But with the appreciation of the dollar, it became unprofitable to buy from the Chinese, the cost was equal to the Russian one, while there is no guarantee and the possibility of exchange. For cheap electronics, the characteristics are always overestimated. For example, if a power of 50 watts is indicated, at best this is the maximum short-term power, and not constant. Rated will be 35W - 40W.

In addition, they save a lot on the filling in order to reduce the price. In some places, there are not enough elements that ensure stable operation. The cheapest components are used, with a short service life and low quality, so the rejection rate is relatively high. As a rule, components operate at the limit of their parameters, without any margin.

If the manufacturer is not specified, then he does not need to be responsible for the quality and a review about his product will not be written. And the same product is produced by several factories in different configurations. For good products, the brand must be indicated, which means that he is not afraid to be responsible for the quality of his products.

One of the best is the MeanWell brand, which values ​​the quality of its products and does not produce junk.

Life time

Like any electronic device, the LED driver has a service life that depends on the operating conditions. Branded modern LEDs already work up to 50-100 thousand hours, so the power fails earlier.

Classification:

1. consumer goods up to 20.000 hours;
2. medium quality up to 50.000 hours;
3. up to 70.000h power supply on high-quality Japanese components.

This indicator is important in calculating the payback in the long term. There is enough consumer goods for domestic use. Although the miser pays twice, and in LED spotlights and fixtures, this works great.

LED driver 220V

Modern LED drivers are constructively implemented on a PWM controller, which can very well stabilize the current.

Main parameters:

1. rated power;
2. operating current;
3. number of connected LEDs;
4. Power factor;
5. stabilizer efficiency.

Cases for outdoor use are made of metal or impact-resistant plastic. When the case is made of aluminum, it can act as a cooling system for the electronics. This is especially true when filling the case with a compound.

The marking often indicates how many LEDs can be connected and what power. This value can be not only fixed, but also in the form of a range. For example, it is possible to connect LEDs 12 220 from 4 to 7 pieces of 1W. It depends on the design electrical circuit LED driver.

RGB driver 220V

Three-color RGB LEDs differ from single-color ones in that they contain crystals of different colors red, blue, green in one package. To control them, each color must be lit separately. For diode tapes, an RGB controller and a power supply are used for this.

If a power of 50W is indicated for an RGB LED, then this is the total for all 3 colors. To find out the approximate load on each channel, we divide 50W by 3, we get about 17W.

In addition to powerful led drivers, there are also 1W, 3W, 5W, 10W.

Remote controls (DU) are of 2 types. With infrared control, like a TV. With radio control, the remote control does not need to be directed to the signal receiver.

Assembly module

If you are interested in an ice driver for assembling an LED spotlight or lamp with your own hands, then you can use the led driver without a case.

If you already have a current regulator for LEDs that is not suitable for current strength, then it can be increased or decreased. Find the PWM controller chip on the board, on which the characteristics of the led driver depend. It contains the marking by which it is necessary to find the specifications for it. The documentation will indicate a typical switching scheme. Typically, the output current is set by one or more resistors connected to the legs of the microcircuit. If you change the value of the resistors or set the variable resistance according to the information from the specifications, then you can change the current. Just do not exceed the initial power, otherwise it may fail.

Driver for LED lights

There are slightly different requirements for the power supply of street lighting equipment. When designing street lighting, it is taken into account that the LED driver will work in conditions from -40 ° to + 40 ° in dry and humid air.

The ripple factor for luminaires can be higher than for indoor use. For street lighting, this indicator becomes irrelevant.

When operating outdoors, complete tightness of the power supply is required. There are several ways to protect against moisture ingress:

1. filling the entire board with sealant or compound;
2. block assembly using silicone seals;
3. placement of the LED driver board in the same volume with the LEDs.

Max Level protection is IP68, referred to as "Waterproof LED Driver" or "waterproof electronic led driver". The Chinese do not guarantee water resistance.

In my practice, the declared level of protection against moisture and dust does not always correspond to the real one. In some places, there may not be enough seals. Pay attention to the input and output of the cable from the case, there are samples with a hole that is not closed with sealant or in another way. Water through the cable will be able to flow into the housing and then evaporate in it. This will cause corrosion on the board and exposed parts of the wires. This will greatly reduce the life of the spotlight or lamp.

Power supply for led strip

LED strip works on a different principle, it requires a stabilized voltage. The current-setting resistor is installed on the tape itself. This facilitates the connection process, you can connect a segment of any length ranging from 3cm to 100m.

Therefore, power for the LED strip can be made from any 12V power supply from consumer electronics.

Main parameters:

1. the number of volts at the output;
2. rated power;
3. degree of protection against moisture and dust
4. Power factor.

DIY led driver

The simplest do-it-yourself driver can be made in 30 minutes, even if you do not know the basics of electronics. As a voltage source, you can use a power supply from consumer electronics with a voltage of 12V to 37V. Particularly suitable is the power supply from a laptop, which has 18 - 19V and power from 50W to 90W.

You will need a minimum of details, they are all shown in the picture. A radiator for cooling a powerful LED can be borrowed from a computer. Surely somewhere at home in the pantry you have old spare parts from the system unit gathering dust. It is best suited from the processor.

To find out the value of the required resistance, use the current regulator calculator for the LM317.

Before making a led driver 50W with your own hands, you should look a little, for example, there is one in every diode lamp. If you have a faulty light bulb that has a fault in the diodes, then you can use the driver from it.

Low voltage

We will analyze in detail the types of low-voltage ice drivers operating from voltages up to 40 volts. Our Chinese brothers in mind offer many options. On the basis of PWM controllers, voltage stabilizers and current stabilizers are produced. The main difference is that the module with the ability to stabilize the current has 2-3 blue regulators on the board, in the form of variable resistors.

The PWM parameters of the microcircuit on which it is assembled are indicated as the technical characteristics of the entire module. For example, the outdated but popular LM2596, according to specifications, holds up to 3 Amperes. But without a heatsink, it can only handle 1 amp.

More modern version with improved efficiency, this is an XL4015 PWM controller rated at 5A. With a miniature cooling system, it can work up to 2.5A.

If you have very powerful ultra-bright LEDs, then you need a led driver for LED fixtures. Two radiators cool the Schottky diode and the XL4015 chip. In this configuration, it is capable of operating up to 5A with voltage up to 35V. It is desirable that it does not work in extreme conditions, this will significantly increase its reliability and service life.

If you have a small lamp or a pocket spotlight, then a miniature voltage regulator is suitable for you, with a current of up to 1.5A. Input voltage from 5 to 23V, output up to 17V.

Brightness control

To control the brightness of the LED, you can use compact LED dimmers, which have recently appeared. If its power is not enough, then you can put a larger dimmer. Usually they work in two ranges for 12V and 24V.

You can control it using an infrared or radio remote control (DU). They cost from 100 rubles per simple model and from 200 rubles a model with a remote control. Basically, such remotes are used for 12V diode tapes. But it can be easily put to a low-voltage driver.

Dimming can be analog in the form of a rotary knob and digital in the form of buttons.

led-obzor.ru

LED DRIVER

We will look at a really simple and inexpensive high power LED driver. The circuit is a constant current source, which means it keeps the brightness of the LED constant no matter what power you use. If a resistor is enough to limit the current of small super-bright LEDs, then a special circuit is needed for powers above 1 watt. In general, it is better to power the LED in this way than with a resistor. The proposed led driver is ideal especially for high-power LEDs, and can be used for any number and configuration of them, with any type of power supply. As a test project, we took a 1 watt LED element. You can easily change the driver elements for use with more powerful LEDs, for different types of power supply - PSU, batteries, etc.

Specifications of led driver:

Input voltage: 2V to 18V - Output voltage: 0.5V less than input voltage (0.5V drop across FET) - Current: 20 amps

Details on the diagram:

R2: approximately 100 ohm resistor

R3: resistor is selected

Q2: small NPN transistor (2N5088BU)

Q1: large N-channel transistor (FQP50N06L)

LED: Luxeon 1-watt LXHL-MWEC

Other driver elements:

An adapter transformer is used as a power source, you can use batteries. To power one LED 4 - 6 volts is enough. That's why this circuit is handy, that you can use a wide variety of power supplies and it will always shine the same way. A heatsink is not required as there is about 200 mA of current flowing. If more current is planned, you must install an LED element and transistor Q1 on a heatsink.

Choice of resistance R3

The LED current is set with R3, it is approximately equal to: 0.5 / R3

Power dissipation in resistor approx: 0.25 / R3

In this case, the current is set to 225 mA with R3 at 2.2 ohms. R3 has a power of 0.1W, so a standard 0.25W resistor is fine. Transistor Q1 will work up to 18V. If you want more, you need to change the model. Without heatsinks, the FQP50N06L can only dissipate about 0.5W - enough for 200mA of current with a 3V difference between the power supply and the LED.

Functions of transistors in the circuit:

Q1 is used as a variable resistor. - Q2 is used as a current sensor and R3 is a set resistor that causes Q2 to close when increased current flows. The transistor creates feedback, which continuously monitors the current parameters and keeps it exactly at the set value.

This circuit is so simple that it makes no sense to assemble it on printed circuit board. Just connect the leads of the parts by surface mounting.

Forum on powering various LEDs

elwo.ru

Drivers for LED bulbs.

A small laboratory on the topic “which driver is better?” Electronic or on capacitors as a ballast? I think everyone has their own niche. I will try to consider all the pros and cons of both schemes. Let me remind you the formula for calculating ballast drivers. Maybe someone is interested? I will build my review on a simple principle. First, I will consider drivers on capacitors as a ballast. Then I'll look at their electronic counterparts. Well, at the end of the comparative conclusion. And now let's get down to business. We take a standard Chinese light bulb. Here is her diagram (slightly improved). Why improved? This circuit will fit any cheap Chinese light bulb. The difference will be only in the ratings of the radio components and the absence of some resistances (in order to save money).
There are light bulbs with missing C2 (very rare, but it happens). In such bulbs, the ripple coefficient is 100%. Very rarely put R4. Although the resistance R4 is simply necessary. It will be instead of a fuse, and will also soften the starting current. If it is not in the diagram, it is better to put it. The current through the LEDs determines the value of capacitance C1. Depending on what current we want to pass through the LEDs (for do-it-yourselfers), we can calculate its capacitance using formula (1).
I wrote this formula many times. I repeat. Formula (2) allows you to do the opposite. With its help, you can calculate the current through the LEDs, and then the power of the light bulb, without having a wattmeter. To calculate the power, we still need to know the voltage drop across the LEDs. You can measure with a voltmeter, you can just count (without a voltmeter). It's easy to calculate. The LED behaves in the circuit like a zener diode with a stabilization voltage of about 3V (there are exceptions, but very rare). When LEDs are connected in series, the voltage drop across them is equal to the number of LEDs multiplied by 3V (if 5 LEDs, then 15V, if 10 - 30V, etc.). Everything is simple. It happens that circuits are assembled from LEDs in several parallels. Then it will be necessary to take into account the number of LEDs in only one parallel. Let's say we want to make a light bulb with ten 5730smd LEDs. According to passport data, the maximum current is 150mA. Let's calculate the bulb for 100mA. There will be power reserve. According to formula (1) we get: C \u003d 3.18 * 100 / (220-30) \u003d 1.67 μF. The industry does not produce such a capacity, even the Chinese one. We take the nearest convenient one (we have 1.5 μF) and recalculate the current according to formula (2). (220-30)*1.5/3.18=90mA. 90mA*30V=2.7W. This is the wattage of the light bulb. Everything is simple. In life, of course, it will be different, but not by much. It all depends on the real voltage in the network (this is the first minus of the driver), on the exact capacity of the ballast, the real voltage drop across the LEDs, etc. Using formula (2), you can calculate the power of light bulbs already purchased (already mentioned). The voltage drop across R2 and R4 can be neglected, it is negligible. You can connect a lot of LEDs in series, but the total voltage drop should not exceed half the mains voltage (110V). When this voltage is exceeded, the light bulb reacts painfully to all changes in voltage. The more it exceeds, the more painful it reacts (this is friendly advice). Moreover, beyond these limits, the formula works inaccurately. Can't calculate exactly. That's a very big plus for these drivers. The power of the light bulb can be adjusted to the desired result by selecting the C1 container (both homemade and already purchased). But then there was a second disadvantage. The circuit has no galvanic isolation from the network. If you poke anywhere on the light bulb with an indicator screwdriver, it will show the presence of a phase. It is strictly forbidden to touch with your hands (a light bulb included in the network). Such a driver has almost 100% efficiency. Losses only on diodes and two resistances. It can be made within half an hour (quickly). You don't even need to charge a fee. I ordered these capacitors: aliexpress.com/snapshot/310648391.html aliexpress.com/snapshot/310648393.html These diodes are: aliexpress.com/snapshot/6008595825.html

But these schemes have another serious drawback. These are pulsations. Ripple with a frequency of 100 Hz, the result of rectifying the mains voltage.
Different light bulbs will have slightly different shapes. It all depends on the size of the filter capacity C2. The larger the capacitance, the smaller the humps, the less ripple. It is necessary to look at GOST R 54945-2012. And there it is written in black and white that ripples with a frequency of up to 300 Hz are harmful to health. There is also a formula for calculation (Appendix D). But that's not all. It is necessary to look at Sanitary norms SNiP 23-05-95 "NATURAL AND ARTIFICIAL LIGHTING". Depending on the purpose of the room, the maximum allowable ripple is from 10 to 20%. Nothing in life just happens. The result of the simplicity and cheapness of light bulbs is obvious. It's time to move on to electronic drivers. Here, too, not everything is so cloudless. This is the driver I ordered. This is a link to it at the beginning of the review.
Why did you order this one? Will explain. I wanted to “collective farm” lamps on 1-3W LEDs myself. Selected for price and features. I would be satisfied with a driver for 3-4 LEDs with a current of up to 700mA. The driver must include a key transistor, which will unload the driver control chip. To reduce the RF ripple, a capacitor should be placed at the output. First minus. The cost of such drivers (US $ 13.75 / 10 pieces) differs more from ballast ones. But here's a plus. Stabilization currents of such drivers are 300mA, 600mA and higher. Ballast drivers never dreamed of such a thing (I do not recommend more than 200mA). Let's look at the specifications from the seller: ac85-265v" that everyday household appliances." load after 10-15v; can drive 3-4 3w led lamp beads series 600mA But the output voltage range is small (also a minus). A maximum of five LEDs can be connected in series. In parallel, you can pick up as much as you like. LED power is calculated by the formula: Driver current multiplied by the voltage drop across the LEDs [number of LEDs (from three to five) and multiplied by the voltage drop across the LED (about 3V)]. Another big disadvantage of these drivers is high RF interference. Some instances hear not only FM radio, but also the reception of digital TV channels disappears during their operation. The conversion frequency is several tens of kHz. But protection, as a rule, no (from interference).
Under the transformer is something like a "screen". Should reduce interference. It is This driver that almost does not fonit. Why they glow, it becomes clear if you look at the voltage waveform on the LEDs. Without capacitors, the Christmas tree is much more serious!
At the output of the driver, there should be not only an electrolyte, but also ceramics to suppress high-frequency interference. Expressed his opinion. It usually costs one or the other. Sometimes it doesn't cost anything. It happens in cheap light bulbs. The driver is hidden inside, making a claim will be difficult. Let's see the diagram. But I'll warn you, it's introductory. I applied only the main elements that we need for creativity (to understand "what's what").

There is an error in the calculations. By the way, at low powers, the device also twists. And now let's calculate the pulsations (the theory at the beginning of the review). Let's see what our eyes see. I connect a photodiode to the oscilloscope. Two pictures combined into one for ease of perception. The light on the left is off. On the right, the light is on. We look at GOST R 54945-2012. And there it is written in black and white that ripples with a frequency of up to 300 Hz are harmful to health. And we have about 100Hz. It's bad for the eyes.
I got 20%. It is necessary to look at Sanitary norms SNiP 23-05-95 "NATURAL AND ARTIFICIAL LIGHTING". Can be used, but not in the bedroom. And I have a corridor. You can not watch SNiP. And now let's see another option for connecting LEDs. This is a wiring diagram for an electronic driver.
Total 3 parallels of 4 LEDs. Here is what the wattmeter shows. 7.1W active power.
Let's see how much comes to the LEDs. I connected an ammeter and a voltmeter to the output of the driver.
Let's calculate the pure LED power. P \u003d 0.49A * 12.1V \u003d 5.93W. Everything that is missing, the driver took over. Now let's see what our eye sees. The light on the left is off. On the right, the light is on. The pulse repetition frequency is about 100 kHz. We look at GOST R 54945-2012. And there it is written in black and white that only pulsations with a frequency of up to 300 Hz are harmful to health. And we have about 100 kHz. It's harmless to the eyes.

Looked at everything, measured everything. Now I will highlight the pros and cons of these circuits: Cons of light bulbs with a capacitor as a ballast compared to electronic drivers. -During operation, it is categorically impossible to touch the elements of the circuit, they are under phase. -It is not possible to achieve high LED currents, because this requires large capacitors. And an increase in capacitance leads to large inrush currents that spoil the switches. - Large pulsations of the light flux with a frequency of 100 Hz require large filter capacitances at the output. Pluses of light bulbs with a capacitor as a ballast compared to electronic drivers. + The scheme is very simple, does not require special skills in the manufacture. + The output voltage range is fantastic. The same driver will work with one and with forty series-connected LEDs. Electronic drivers have a much narrower output voltage range. + The low cost of such drivers, which literally consists of the cost of two capacitors and a diode bridge. + You can make your own. Most parts can be found in any shed or garage (old TVs, etc.). + You can adjust the current through the LEDs by selecting the ballast capacitance. + Indispensable as an initial LED experience, as the first step in mastering LED lighting. There is another quality that can be attributed to both pluses and minuses. When using similar circuits with illuminated switches, the LEDs of the light bulb are illuminated. For me personally, this is more of a plus than a minus. I use it everywhere as a duty (night) lighting. I deliberately do not write which drivers are better, each has its own niche. I posted as much as I know. He showed all the pros and cons of these schemes. The choice, as always, is yours. I just tried to help. That's all! Good luck everyone.

mysku.ru

How to choose an LED driver - types and main characteristics

LEDs have become very popular. The main role in this was played by the LED driver, which maintains a constant output current of a certain value. We can say that this device is a current source for LED devices. Such a current driver, working together with the LED, ensures a long service life and reliable brightness. An analysis of the characteristics and types of these devices allows you to understand what functions they perform and how to choose them correctly.

What is a driver and what is its purpose?

Driver for LED is electronic device, at the output of which D.C. after stabilization. In this case, it is not a voltage that is formed, but a current. Devices that stabilize the voltage are called power supplies. The output voltage is indicated on their case. 12 V power supplies are used to power LED strips, LED strips and modules.

The main parameter of the LED driver, with which it can provide the consumer for a long time at a certain load, is the output current. As a load, individual LEDs or assemblies of similar elements are used.

The LED driver is usually powered by a 220 V mains voltage. In most cases, the operating output voltage range is from three volts and can reach several tens of volts. To connect six 3W LEDs, you will need a driver with an output voltage of 9 to 21 V, rated at 780 mA. With its versatility, it has a low efficiency, if you include a minimum load on it.

When lighting in cars, headlights of bicycles, motorcycles, mopeds, etc., portable lamps are equipped with a constant voltage supply, the value of which varies from 9 to 36 V. You can not use a driver for LEDs with low power, but in such cases, it will be necessary to introduce an appropriate resistor into the 220 V supply network. Despite the fact that in household switches this element is used, it is rather problematic to connect the LED to a 220 V network and rely on reliability.

Key Features

The power that these devices are capable of delivering under load is an important indicator. Do not overload it, trying to achieve maximum results. As a result of such actions, the drivers for the LEDs or the LED elements themselves may fail.

The electronic filling of the device is affected by many reasons:

• device protection class;
• elemental component that is used for assembly;
• entry and exit parameters;
• manufacturer's brand.

The manufacture of modern drivers is carried out using microcircuits using pulse-width conversion technology, which include pulse converters and current-stabilizing circuits. PWM converters are powered from 220 V, have a high class of protection against short circuits, overloads, as well as high efficiency.

Specifications

Before purchasing a converter for LEDs, you should study the characteristics of the device. These include the following options:

• output power;
• output voltage;
• rated current.

LED driver connection diagram

The output voltage is affected by the connection scheme to the power source, the number of LEDs in it. The value of the current proportionally depends on the power of the diodes and the brightness of their radiation. The LED driver must supply as much current to the LEDs as needed to ensure constant brightness. It is worth remembering that the power of the required device must be more consumed by all the LEDs. It can be calculated using the following formula:

P(led) is the power of one LED element;

n is the number of LED elements.

To ensure long-term and stable operation of the driver, the power reserve of the device should be 20-30% of the nominal one.

When performing the calculation, the color factor of the consumer should be taken into account, as it affects the voltage drop. Different colors will have different meanings.

Best before date

LED drivers, like all electronics, have a certain service life, which is strongly influenced by operating conditions. LED elements made by well-known brands are designed to work up to 100,000 hours, which is much longer than power supplies. According to the quality, the calculated driver can be classified into three types:

• low quality, with working capacity up to 20 thousand hours;
• with average parameters - up to 50 thousand hours;
• converter, consisting of components of well-known brands - up to 70 thousand hours.

Many do not even know why pay attention to this parameter. This will be needed to select a device for long-term use and further payback. For use in domestic premises, the first category is suitable (up to 20 thousand hours).

How to choose a driver?

There are many types of drivers used for LED lighting. Most of the presented products are made in China and do not have the required quality, but stand out at the same time with a low price range. If you need a good driver, it is better not to chase cheap Chinese-made ones, since their characteristics do not always match the declared ones, and they rarely come with a guarantee. There may be a defect on the microcircuit or a quick failure of the device, in which case it will not be possible to exchange for a better product or return the funds.

The most commonly chosen option is a 220V or 12V frameless driver. Various modifications allow them to be used for one or more LEDs. These devices can be selected for organizing research in the laboratory or conducting experiments. For phyto-lamps and domestic use, drivers for LEDs located in the housing are chosen. Frameless devices win in terms of price, but lose in terms of aesthetics, security and reliability.

Types of drivers

Devices that power LEDs can be conditionally divided into:

• impulse;
• linear.

Pulse-type devices produce many high-frequency current pulses at the output and operate on the PWM principle, their efficiency is up to 95%. Pulse converters have one significant drawback - strong electromagnetic interference occurs during operation. To ensure a stable output current, a current generator is installed in the linear driver, which plays the role of an output. Such devices have a low efficiency (up to 80%), but at the same time they are technically simple and inexpensive. Such devices cannot be used for high power consumers.

From the above, we can conclude that the power supply for LEDs should be chosen very carefully. An example is a fluorescent lamp, which is supplied with a current exceeding the norm by 20%. There will be practically no changes in its characteristics, but the performance of the LED will decrease several times.

lampagid.ru

Schemes for connecting LEDs to 220V and 12V

Let's consider ways to turn on medium power LED diodes to the most popular ratings of 5V, 12 volts, 220V. Then they can be used in the manufacture of color music devices, signal level indicators, smooth switching on and off. I've been going to make a smooth artificial dawn for a long time in order to follow the daily routine. In addition, dawn emulation allows you to wake up much better and easier.

Read about connecting LEDs to 12 and 220V in the previous article, all methods are considered from complex to simple, from expensive to cheap.

• 1. Types of schemes
• 2. Designation on the diagram
• 3. Connecting the LED to a 220v network, diagram
• 4. DC connection
• 5. The simplest low voltage driver
• 6. Drivers powered from 5V to 30V
• 7. Turn on 1 diode
• 8. Parallel connection
• 9. Serial connection
• 10. RGB LED connection
• 11. Turn on COB diodes
• 12. Connecting SMD5050 to 3 crystals
• 13. LED strip 12V SMD5630
• 14. RGB LED Strip 12V SMD5050

Schema types

There are two types of LED connection scheme, which depend on the power source:

1. constant current LED driver;
2. power supply with stabilized voltage.

In the first option, a specialized source is used, which has a certain stabilized current, for example, 300mA. The number of connected LED diodes is limited only by its power. A resistor (resistance) is not required.

In the second variant, only the voltage is stable. The diode has a very low internal resistance, if it is turned on without ampere limitation, it will burn out. To turn on, you must use a current-limiting resistor. The calculation of the resistor for the LED can be done on a special calculator.

The calculator takes into account 4 parameters:

• voltage drop on one LED;
• rated operating current;
• the number of LEDs in the circuit;
• the number of volts at the output of the power supply.

If you are using inexpensive Chinese-made LED elements, then most likely they will have a wide range of parameters. Therefore, the actual Ampere value of the circuit will be different and an adjustment of the set resistance will be required. To check how large the spread of parameters is, you need to turn everything on sequentially. We connect the power of the LEDs and then lower the voltage until they barely glow. If the characteristics differ greatly, then part of the LED will work brightly, part dimly.

This leads to the fact that on some elements electrical circuit the power will be higher, because of this they will be more heavily loaded. There will also be increased heating, increased degradation, lower reliability.

Designation on the diagram

For designation on the diagram, the above two pictograms are used. Two parallel arrows indicate that it shines very strongly, the number of bunnies in the eyes cannot be counted.

Connecting an LED to a 220v network, diagram

To connect to a 220 volt network, a driver is used, which is a source of stabilized current.

The driver circuit for LEDs is of two types:

1. simple on the quenching capacitor;
2. full-fledged using stabilizer chips;

Assembling a driver on a capacitor is very simple, it requires a minimum of parts and time. The voltage of 220V is reduced by a high-voltage capacitor, which then straightens and stabilizes a little. It is used in cheap LED lamps. The main disadvantage is high level pulsations of light that are bad for health. But this is individual, some do not notice it at all. It is also difficult to calculate the circuit due to the spread of the characteristics of electronic components.

A complete circuit using dedicated chips provides better stability at the output of the driver. If the driver copes well with the load, then the ripple factor will be no higher than 10%, and ideally 0%. In order not to make a driver with your own hands, you can take it from a faulty light bulb or lamp if the problem was not with the power supply.

If you have a more or less suitable stabilizer, but the current strength is less or more, then it can be corrected with a minimum of effort. Find the specifications for the chip from the driver. Most often, the number of amperes at the output is set by a resistor or several resistors located next to the microcircuit. By adding more resistance to them or removing one of them, you can get the required current strength. The only thing you can not exceed the specified power.

DC voltage connection

1. 3.7V - batteries from phones;
2. 5V - charging device with USB;
3. 12V - car, cigarette lighter, consumer electronics, computer;
4. 19V - blocks from laptops, netbooks, monoblocks.

The simplest low voltage driver

The simplest current regulator circuit for LEDs consists of a linear LM317 chip or its analogues. The output of such stabilizers can be from 0.1A to 5A. The main disadvantages are low efficiency and strong heating. But this is offset by the maximum ease of manufacture.

Input up to 37V, up to 1.5 Amps for the case indicated in the picture.

To calculate the resistance that sets the operating current, use the current regulator calculator on the LM317 for LEDs.

Drivers powered from 5V to 30V

If you have a suitable power source from any household appliances, then it is better to use a low-voltage driver to turn it on. They are up and down. Boosting even from 1.5V will make 5V to make the LED circuit work. Stepping down from 10V-30V will make it lower, for example 15V.

They are sold in a large assortment from the Chinese, the low-voltage driver differs in two regulators from a simple Volt stabilizer.

The real power of such a stabilizer will be lower than indicated by the Chinese. At the parameters of the module, they write the characteristics of the microcircuit and not the entire structure. If there is a large radiator, then such a module will pull 70% - 80% of the promised one. If there is no radiator, then 25% - 35%.

Models based on the LM2596 are especially popular, which are already quite outdated due to low efficiency. They also get very hot, so without a cooling system they do not hold more than 1 Ampere.

More efficient XL4015, XL4005, the efficiency is much higher. Without a cooling radiator, they can withstand up to 2.5A. There are quite miniature models on the MP1584 measuring 22mm by 17mm.

Turn on 1 diode

The most commonly used are 12 volts, 220 volts and 5V. Thus, low-power LED lighting of 220V wall switches is made. In the factory standard switches most often a neon lamp is placed.

Parallel connection

When connected in parallel, it is desirable to use a separate resistor for each series diode circuit in order to obtain maximum reliability. Another option is to put one powerful resistance on several LEDs. But if one LED fails, the current on the remaining ones will increase. As a whole, it will be higher than the nominal or specified value, which will significantly reduce the resource and increase heating.

The rationality of the applications of each method is calculated based on the requirements for the product.

Serial connection

Serial connection when powered by 220V is used in filament diodes and LED strips for 220 volts. In a long chain of 60-70 LEDs, 3V drops on each, which allows you to connect directly to high voltage. Additionally, only a current rectifier is used to obtain plus and minus.

Such a connection is used in any lighting engineering:

1. led lamps for home;
2. led lamps;
3. New Year's garlands for 220V;
4. led strip 220.

Home lamps usually use up to 20 LEDs connected in series, the voltage on them is about 60V. The maximum quantity is used in Chinese corn bulbs, from 30 to 120 pieces of LED. Corns do not have a protective flask, so the electrical contacts on which up to 180V are completely open.

Be careful if you see a long daisy chain, and they don't always have a ground connection. My neighbor grabbed the corn with his bare hands and then recited fascinating poems from bad words.

RGB LED connection

Low-power three-color RGB LEDs consist of three independent crystals in one package. If 3 crystals (red, green, blue) are turned on at the same time, we will get white light.

Each color is controlled independently by the RGB controller. The control unit has ready-made programs and manual modes.

Turn on COB diodes

The connection schemes are the same as for single-chip and three-color LEDs SMD5050, SMD 5630, SMD 5730. The only difference is that instead of 1 diode, a serial circuit of several crystals is included.

Powerful LED matrices are composed of many crystals connected in series and in parallel. Therefore, power is required from 9 to 40 volts, depending on the power.

Connecting SMD5050 to 3 crystals

SMD5050 differs from ordinary diodes in that it consists of 3 white light crystals, therefore it has 6 legs. That is, it is equal to three SMD2835 made on the same crystals.

When connected in parallel using a single resistor, the reliability will be lower. If one of the crystals fails, then the current through the remaining 2 increases. This leads to accelerated burnout of the remaining ones.

When using a separate resistance for each crystal, the above disadvantage is eliminated. But at the same time, the number of resistors used increases by 3 times and the LED connection diagram becomes more complicated. Therefore, it is not used in LED strips and lamps.

LED Strip 12V SMD5630

A good example of connecting an LED to 12 volts is an LED strip. It consists of sections of 3 diodes and 1 resistor connected in series. Therefore, you can cut it only in the indicated places between these sections.

LED strip RGB 12V SMD5050

The RGB tape uses three colors, each is controlled separately, a resistor is placed for each color. You can cut only at the indicated place so that each section has 3 SMD5050 and it can connect to 12 volts.

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LED driver circuits