1. No LED chromatogram shift will occur, because the LED always works between the full amplitude current and 0.

2. It has a very high dimming accuracy, because the pulse waveform can be controlled to a very high precision, so it is easy to achieve a precision of one ten thousandth.

3. Even if the light is dimmed in a wide range, there will be no flicker. Because the working conditions of the constant current source wi not be changed, problems such as overheating are less likely to occur.

Although the LED PWM dimming method has many advantages, the following two issues need to be paid attention to:

1. The choice of pulse frequency, because the LED is in a fast switching state, if the working 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.

2. It is necessary to eliminate the whistling sound caused by dimming. It is possible to hear a slight sound during dimming. There are two ways to solve this problem. One is to increase the switching frequency above 20kHz, out of the range of human hearing. Another method is to find out the sound-producing device and deal with it.