What is the role of the LED power supply, driver, transformer, and what is the difference

The LED driver is actually a switching power supply, which generally has the role of soft start and constant current. For 220V power supply, a switching power supply with an isolation transformer is used because the voltage needs to be greatly reduced. If it is used for 12 volt and 24 volt power supply, there is generally no need for a transformer.

To put it simply, a complete LED circuit includes a power supply, a drive circuit, and LED components. The function of the transformer is to use the mains transformer as the power supply for the driving circuit. The driver circuit is used to control the LED, control the LED on and off, and how to turn on and off.

LEDs are light-emitting diodes, which are very small light sources, and their power supply is also powered by others. If it is an LED LCD, the power transformer and driver board of each manufacturer are different.

First of all, the power supply, of course, is the driver for power supply, which is used to install the software, so that the system can recognize the transformer, which is used to adapt to the voltage

The nature of the use of power supplies and transformers is similar. Driver, mainly refers to the LED drive circuit and installation software and drivers.

The whole is a switching power supply. A transformer is a part of a switching power supply that is used for energy conversion.

They are all integrated, the transformer is a part of the power supply, which plays the role of voltage reduction, and the power supply is controlled by the drive, so as to control the various states of the LED light emitting tube. You don't understand what you are asking, I don't know what you want to know?

The difference between voltage drive and current drive:

1. Different driving modes:

Voltage driven, the output voltage is fixed; The current is driven, and the output current is constant.

2. The requirements for the load are different:

Voltage driven, it is strictly forbidden to completely short circuit the load; Current driven, it is strictly forbidden to completely open the load.

3. The requirements for the circuit are different

Voltage drive, you need to add a suitable resistor to drive the circuit; The current drive can directly drive the circuit.

The intermediate circuit that is located between the main circuit and the control circuit and amplifies the signal of the control circuit is the driving circuit. LED driver refers to the power trimming electronics that drive LED light emitting or LED module components to work properly.

Difference 1:

In terms of voltage:

The input voltage is basically a definite value, increasing the current can change the brightness, and decreasing the current can reduce the brightness, so it is determined to be a current-type device.

Difference 2: From the current aspect:

When the voltage is low, it doesn't even light up. When the current is very small, it is determined to be a voltage-type device.

Difference 3: From the aspect of receptivity:

Whether the external characteristics of the device change significantly when it accepts a change in voltage input, or when it accepts a change in current input, its external characteristics change a lot.

I think this is how we can understand the difference between voltage drive and current drive. When a device accepts a change in voltage input, its external characteristics change a lot, or when it accepts a change in current input, its external characteristics change a lot. If the change is large, it can be counted as that type of device.

For example, the input voltage of a light-emitting diode is basically a certain value, and increasing the current can change the brightness, and decreasing the current can reduce the brightness, so it is determined to be a current-type device. Another example is the gas neon sign, which is not even bright when the voltage is low. When the current is very small, it is determined to be a voltage-type device.

FYI.

The single-chip microcomputer pin can be programmed to control the output high and low levels, which are voltage outputs;

The current will only appear after the external device is connected.

When the output of the microcontroller is low, the external device is allowed to sink current into the pins of the microcontroller, and the general reference value is 16mA;

When the output of the microcontroller is high, the external device is allowed to pull out the current from the pins of the microcontroller, which is less than 1mA.

Single-chip microcomputer, only such a large capacity, if it cannot meet the power demand of external devices, it needs voltage drive or current drive.

Even if the driver is not added, a "pull-up resistor" is usually added to compensate for the disadvantage of "weak high-level output current".

Let's explain the driver of the LED.

Voltage drive means that the driving power supply of the LED is the power supply that outputs constant voltage, and then the current changes according to the different loads. Because LED is a current-type device, if a constant voltage drive is used, a series resistor is required to limit the current. This drive method is generally only suitable for low-power LED lights.

Current drive means that the driving power supply of LED is the power supply that outputs constant current, and then outputs different voltages according to the voltage required by the load, but the current is constant. Of course, it is also to ensure constant current within a certain voltage range, which is not unconditional. This constant current drive is more energy-saving than constant voltage drive, but the cost is relatively high, and it is mostly used for high-power LED lights.

Voltage is to amplify the voltage, and current drive is to amplify the current.

Do you know the three working states of the transistor: common emitter - amplification current and voltage but the voltage is reversed; Common base - only amplify the voltage; Co-collector - only amplify the current;

LED can be driven with a general triode, which requires both voltage and current

Summary. The insulated transformer can effectively suppress electromagnetic interference, and the cost of the <> control type is between the inductance type and the variable capacitance type. <>

At the same time, the LED driver will use other components, oh, <>

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Such as diodes, capacitors, resistors, op amps, transistors, rectifier diodes, etc., <> the above chips and components can prevent LED from being damaged by power failure or overvoltage, <> and reduce the heating of LED lamps, reduce noise and accurately adjust the brightness of LED lamps. <>

Is there a transformer in the LED driver power supply?

Hello, yes, Hongqing withered <>

The LED driver is usually a single-switch AC-DC conversion power supply device with a built-in transformer<>

Its circuit structure and characteristics are more positive than the power supply, <>

There are mainly inductance type, variable capacity type, insulation transformer, control type, etc. Among <>, inductive drivers are the most commonly used, <>

The structure is simple and the cost is low. <>

The disguise drive stupid device can suppress the influence of the recoil wave of tung seepage better than the local gear ridge, the stability of the <> is better, and the equipment cost is higher. <>

Insulated transformers can effectively suppress electromagnetic interference Oh, <>

The cost of the control type is between the inductance type and the variable capacity type. At the same time, the LED driver will use other components, oh, <>

That is, electronic components, <>

Such as diodes, capacitors, resistors, op amps, sock transistors, rectifier diodes, etc., <> the above chips and components can prevent LED from being damaged by power outages or overvoltages, <> and reduce the heat of LED lamps, reduce noise and accurately adjust the brightness of LED lamps. <>

The LED drive power supply uses a switching transformer, which is a switching power supply with a switching transformer.

In addition to the voltage conversion function of ordinary transformer, it also has the functions of insulation isolation and power transmission, which is generally used in switching power supply and other occasions involving high-frequency circuits.

Similar to the transformer used for switching power supply, it is a high-frequency transformer.

Ordinary transformers can be as long as the power and current are sufficient, and there are no special requirements

Generally speaking, LED driver is also a kind of switching power supply, but it has several particularities, and it is also the commonality of this kind of switching power supply, so it is customary to classify it as LED driver. The peculiarities of these points are:

1. Its voltage output is a multiple, that is, the form of voltage output is, but at most it is generally not exceeded, because after exceeding this number, when the LED is turned on, it will be possible to instantly burn the last LED due to the poor uniformity of the product. And this voltage is not constant, but changes with the change of load to achieve the purpose of constant current.

2. Its output current is constant, and the ideal circuit is that no matter how the characteristic curve of the LED changes, the current of the driving power supply remains unchanged. However, limited to the accuracy of the component, there will still be a small amount of change, and this change is also an important parameter to judge whether the drive circuit is excellent, the function of LED conduction and voltage is a nonlinear "three-stage" relationship, so it is very important to maintain a constant current.

3. Its startup is a soft start. Due to the very poor consistency of LEDs and the instantaneous change in the activity of the internal PN junction when it is turned on, the LED driver is generally designed to be soft-start to avoid this defect.

4. Its circuit requirements are the simplest, because many times, the circuit is required to be installed in a small space to match the convenience of LED lighting, so the circuit should be as simple as possible, which can also save costs and reduce energy consumption.

5. It generally does not require isolation, because many products are similar to the structure of ordinary lights, and the safety aspect can be similar to that of lighting, but this Article 5 is an "optional reading item", we should not misunderstand when we understand, because some drivers still need to be isolated, this feature is only applicable to our current popular circuits, and may not be suitable for future circuit development needs.

To sum up, it can be considered that it is characterized by soft start, constant current, step voltage, and simple circuit.

Here is another point: it is not right to emphasize constant current from the side of people, but not to mention the voltage, because the concept of constant current has nothing to do with voltage, for example, a power supply, if it is only a constant current of 30V output, then when you open the circuit, its voltage is 30V, at this time, if you connect the LED, then this component that works directly with the PN junction will be burned before the reaction of the most accurate circuit, because any circuit needs to have a reaction time, and the working device in the circuit is a semiconductor. The PN junction of the crowd can only react after the power supply gives a sampling signal, and the PN junction of the LED starts to work directly, so its "response" is faster than the "many PN junctions in the circuit", and it is burned in advance! Of course, there are special occasions to use this kind of driver, but the driver of this LED does not allow the output to open the circuit, to be precise, "the output is not allowed to open and then connect the LED".Therefore, at the same time of constant current, we need to add the concept of voltage, not to mention that it is more conducive to understanding the on-on function curve of LED.

The so-called power supply refers to the first power supply, and the output voltage can be measured by the meter. The so-called driver is a kind of power conversion circuit, which converts a certain fixed form of power supply into another power supply of different voltages or different forms (referring to AC or DC) to supply electrical appliances with specific power supply needs. So the drive becomes a power supply itself when it is connected to the power supply.

LED, the abbreviation of light emittingdiode in English, is also known as light-emitting diode. Its basic structure is an electroluminescent semiconductor material, which is a solid-state semiconductor device that can directly convert electricity into light. It is placed on a shelf with leads, and then sealed with epoxy resin around it to protect the internal core, so the LED has good shock resistance.

The heart of an LED is a semiconductor wafer with one end attached to a bracket, one end is the negative electrode, and the other end is connected to the positive electrode of the power supply, so that the entire wafer is encapsulated by epoxy resin.

There is not much difference between the two in principle, but the LED driver IC integrates more functions in order to cater to the characteristics of LED lighting, even if the ordinary power driver IC can achieve those functions, but the circuit is more complex.

The LED driver IC is not much related to the circuit design scheme, it is only related to the total power that needs to drive the LED, that is, this IC has a maximum driving power, and if it exceeds this power, it will be replaced by another IC. This power range is possible, but the design of the power supply circuit is related to the design of the LED circuit, and the driving power supply must be designed in a targeted manner. This topic is too big, and you can understand it differently when I say this, so get familiar with it slowly.