PWM dimming is currently a mainstream dimming technology used in LED dimming power supply products. In the circuit of the analog signal, the brightness change of the lamp is controlled by the digital output. Compared with traditional analog signal dimming, this dimming method has many advantages.

  The basic principle of pwm dimming led driver can be understood as connecting a MOS switch tube in the LED load, and the anode of this string of LEDs is powered by a constant current source. Then a PWM signal is applied to the gate of the MOS tube to quickly switch the string of LEDs to achieve dimming. The advantages of pwm dimming are very obvious, with the following points:

  First,pwm dimming, accurate dimming.

  Precision dimming is a significant feature common to digital signal dimming, because PWM dimming uses pulse waveform signals with high precision.

  Second, pwm dimming, no color cast.

  In the entire dimming range, because the LED current is either at the maximum value or turned off, the average current of the LED is changed by adjusting the pulse duty cycle, so this solution can avoid color shift during the current change.

  Third, pwm dimming, with a large adjustable range.

  PWM dimming frequency is generally 200Hz (low frequency dimming) to more than 20kHz (high frequency dimming).

  Fourth, pwm dimming, no stroboscopic.

  As long as the PWM dimming frequency is higher than 100 Hz, no LED flicker will be observed. Because the LED is in a fast switching state, if the operating frequency is very low, the human eye will feel flicker. In order to make full use of the residual visual phenomenon of the human eye, its operating frequency should be higher than 100 Hz, preferably 200 Hz.