As the LED display technology continues to mature, the requirement of large LED screen is becoming higher and higher, from monochrome to color. LED experts introduce the below two kinds of control methods to adjust the brightness of large LED display:
1- Another means of controlling the brightness of large LED display is the pulse width modulation (PWM), using the human eye can feel the change of frequency, using pulse width modulation method to realize gray scale control, which is periodic change light pulse width (duty cycle), only the light cycle repeatedly short enough (i.e., the refresh frequency is high enough), the human eye is feeling less than glowing pixels are shaking. Due to the pulse width modulation is more suitable for digital control, so is the development use. Common method is to adopt the microcomputer to provide LED display mode. Now almost all of the LED display is adopted PWM to control the gray level.
2- Current through the LED is a kind of change, common LED tube allows continuous mission at around 20 ma current, besides red LEDs have saturation phenomenon, the rest of the LED brightness basically proportional to the flow of electric current. But this kind of adjusting method is simple. With the gradual improvement requirements for the large LED display, more and more not adapt to the rapid precise modulation, accept a modulation method in common use.