## Can the led linear scheme do wide voltage?

Most of the nonlinear drivers belong to the on-off mode drivers. The working voltage range can be very wide, and the actual working voltage of LED can be unlimited or even higher than the actual working voltage. It can be isolated or non-isolated.

It mainly depends on the selection of cross-current drive scheme of LED driver power supply, now more and more power supplies are wide voltage input, mainly for the convenience of development and mass production, and will not develop new products because they are exported to different regions.

For the switching power supply, the input is 110v or 220v plus or minus 10%, which is called fixed voltage, and the input 80v~245v is called wide voltage. The same is true for led drivers. 220v input is called fixed voltage.

Wide voltage means that the product has a strong adaptability to voltage and can work normally under very different voltages. LED wide voltage can do 85-275V normal operation. There is no narrow voltage. If there is, it is a voltage with little difference between input and output. The voltage widths of other switching power supplies are between 110 and 265.

In general, the power supply of 5W high-power LED lamp uses constant current drive IC to work directly, and there are few parts. If isolation is needed, a general voltage-limited and constant-current isolated switching power supply should be used. Under normal full load, input AC 90V to 260V, DC output 36V, energy efficiency 0.72 is not difficult.

## How to better realize unidirectional linear dimming of LED lamp

1. Wide voltage inputLow voltage dimming the LED driver using LYTSwitch-7 IC has a voltage input range of 90V to 305V, and dimming can still be achieved under low voltage input.

2. The first kindThis dimming method completes the dimming of the LED lamp by modulating the LED driving current. Because the brightness of the LED chip is proportional to the LED driving current, soWe can control the light and shade of the LED lamp by adjusting the driving current of LED. The second kindThis dimming method is called imitation dimming method or linear dimming method.

3. Adjusting the position of the light is realized by adjusting the adjusting knob of the corresponding position behind the headlamp. The parts that need to be adjusted and the tools used in different models are different, depending on the specific model. Before adjusting, hit the headlights to the wall, and then observe whether the lights are offset or too high or too low.

## What are the commonly used led power drive schemes?

1. The driving mode of LED lamp power supply includes two types: the first constant current drive power supply.

2. The constant current source drive is the best LED driving mode, which is driven by the constant current source without the series current limiting resistor in the output circuit, and the current flowing through the LED is not affected by the change of the external power supply voltage, the ambient temperature and the discreteness of the LED parameters, so that the current can be kept constant and give full play to the excellent characteristics of LED.

3. Parallel drive: the advantage is that low voltage drive can be used, but more drive channels are needed. Series / parallel drive: when more backlight LED is used, series and parallel combined drive circuits are often used. the structure of this circuit has the advantages of both series and parallel LED drive circuits.

4. The driving mode of LED display screen can be divided into:\ x0d\ x0a constant voltage drive. LED display screen used to be driven by constant voltage. With the development of technology, constant voltage drive is gradually replaced by constant current drive. \ x0d\ x0a constant current drive.

5. Led driver mode 1: one constant voltage source supplies multiple constant current sources, and each constant current source supplies power to each led separately. This way, the combination is flexible, one led failure, does not affect the work of other led, but the cost will be slightly higher. The second driving mode of led drive power supply: direct constant current power supply, led series or parallel operation.