Dimming analysis of LED dimming power supply

LED dimming is to adjust the current supplied to the LED luminous tube to achieve the purpose of dimming brightness. LED has strict requirements on supply voltage and current, too high voltage and current will seriously reduce its service life.

At present, the commonly used LED dimming power supply include: triac dimming, 0-10V dimming power supply, PWM dimming power supply, DALI dimming and DMX dimming. The working principle of dimming is to achieve LED dimming function by controlling the output of current, voltage and frequency.

1. Triac dimming

It has been applied to the dimming method of incandescent lamps and energy-saving lamps earlier, and it is also a kind of dimming method that is widely used in LED dimming.

Its working principle is to produce a tangential output voltage waveform after cutting the input voltage waveform through the conduction angle. Using the principle of tangential direction, the effective value of the output voltage can be reduced, thereby reducing the power of the ordinary load (resistive load). The advantages of thyristor dimming are higher working efficiency and stable performance.

2. 0-10V dimming

The 100W 0-10V dimming power supply is designed with a control chip. When the 0-10V dimmer is connected, the output current of the power supply can be changed through the 0-10V voltage change to adjust the brightness of the light.

3. PWM dimming

PWM dimming, also known as digital dimming, uses PWM waves to turn on and off the LED to change the conduction time of the forward current to achieve the effect of brightness adjustment. This method is based on the fact 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 brightness and darkness exceeds 100Hz, the average brightness is seen by the human eye, not the LED flickering.