Principle of LED DimmablePower Supply

2020-04-29 00:36:34

LED dimming is an important part of the use of light today, people have long been dissatisfied with the light is only used for lighting. We found that through LED dimming, lights can produce multiple functions. Such as color changes, such as creating a more comfortable environment, such as adjusting the brightness of lights, etc., as well as reducing unnecessary electric light, to further achieve the purpose of energy saving and emission reduction, these can be achieved by dimming, and Most LED dimming is dimming by controlling the power supply. Today we will talk about the dimming principle of several LED dimmable power supplies.

Digital dimming, also known as PWM dimming, turns on and off LEDs through PWM waves to change the conduction time of the forward current to achieve the effect of brightness adjustment. PWM dimmable is a kind of dimming technology applied in LED dimming products which is more mainstream at present. This method is based on the characteristic that the human eye is not sensitive enough to the brightness flicker, so that the load LED is bright and dark. If the frequency of light and dark exceeds 100 Hz, what the human eye sees is the average brightness, not the LED flickering. The basic principle of pwm dimming, in fact, in the actual application of the product, it can be understood that a MOS switch is connected in series in the load of the LED, and the anode of the string of LEDs is powered by a constant current source. Then use a PWM signal to the gate of the MOS tube to quickly switch the string of LEDs to achieve dimming.

The power supply is designed with a control chip. When a 0-10V dimmer is connected, the output current of the power supply is changed through 0-10V voltage change, and the light is reduced. For example: when the 0-10V dimmer is modulated to 0V, the current drops to 0 , The brightness of the light is also off (with a switch function), when the 0-10V dimmer is adjusted to 10V, the output current will also reach 100% of the power output, and the brightness will also be 100%. (The output voltage is unchanged of).

Triac dimming has been applied to incandescent lamps and energy-saving lamps dimming methods earlier, and is also the most widely used dimming method for LED dimming. Its working principle is to generate a tangential output voltage