At present, the most commonly used LED dimming power supplies are: LEDTriac dimming power supplies, LED 0/1-10V dimming power supplies, and PWM dimming power supplies. The other working principle of dimming is to achieve the LED dimming function by controlling the output of current, voltage and frequency.一，LEDTriac dimming power supply
一，LEDTriac dimming power supply
LED Triac dimming power supply Thyristor dimming has been applied to incandescent lamps and energy-saving lamp dimming methods earlier, and is currently the most widely used dimming method for LED dimming. Its working principle is to produce a tangential output voltage waveform after cutting the input voltage waveform through the conduction angle. Applying the principle of tangential direction can reduce the effective value of the output voltage, thereby reducing the power of ordinary loads (resistive loads). The advantages of thyristor dimming are higher working efficiency and stable performance.
二，LED 0/1-10V dimming power supply
The LED 0/1-10V dimming power supply is designed with a control chip. When connected to a 0-10V dimmer, the output current of the power supply can be changed by the 0-10V voltage change to adjust the brightness of the light. For example, when the 0-10V dimmer is modulated to 0V (minimum value), the current drops to 0A, and the brightness of the light is off (equivalent to the function of a switch). When the 0-10V dimmer is modulated to 10V (minimum value), the output current will also reach 100% of the power output, and the brightness will be adjusted to 100% (the output voltage is unchanged). And 0-10V dimming Not the same, the 1-10V dimmer is 1-10V. When the resistance dimmer is adjusted to 1V (minimum), the current to change the output is 10%, and the brightness will be adjusted to 10%; if it reaches 10V (maximum), the output current will also reach 100% of the power output, brightness It will also be 100% (the output voltage is constant). Remarks: 1-10V has no switch function, and the lamp cannot be adjusted to the lowest shutdown function.
三，PWM dimming power supply
PWM dimming power digital dimming, also known as PWM dimming, is used to turn on and off the LED through the PWM wave 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. PWM adjusts the brightness by adjusting the ratio of light and dark time. In a PWM cycle, because the human eye flickers the light within 100Hz, the perceived brightness is a cumulative process, that is, the proportion of the bright time in the entire cycle The bigger, the brighter the human eye feels. However, for some high-frequency sampling devices, such as high-frequency sampling cameras, it is possible that the image of the LED is captured when the LED is dark during sampling.