Fine dimming device and dimming control method for light emitting diode (LED) module

Abstract

The invention discloses a fine dimming device for a light emitting diode (LED) module. According to the device, a first pulse width modulation (PWM) signal output interface of the central processing unit (CPU) is connected with a signal input end of a first field-effect transistor; a signal output end of the first field-effect transistor is connected with a control end of the LED module through a current-limiting module; a second PWM signal output interface of the CPU is connected with a signal input end of a second field-effect transistor; and a signal output end of the second field-effect transistor is connected with the control end of the LED module. A dimming method comprises the following steps of: 1, judging whether luminosity corresponding to the light illumination which is required to be output by the LED module is greater than 5 percent of the maximum luminosity of the LED module; 2, if the luminosity is not greater than 5 percent of the maximum luminosity of the LED module, controlling the LED module to illuminate through a first PWM control signal by the CPU; and 3, if the luminosity is greater than 5 percent of the maximum luminosity of the LED module, controlling the LED module to illuminate after the first PWM control signal and the second PWM control signal which are sent by the CPU are superposed. According to the method, the ratio of the minimum illumination output to the maximum illumination output exceeds 1:10,000, so the dimming fineness of the LED module is guaranteed.

Description

technical field [0001] The invention relates to the technical field of stage lighting, in particular to an LED module fine dimming device and a dimming control method. technical background [0002] At present, the dimming method of high-power LED (Light Emitting Diode, light-emitting diode) module generally adopts PWM (Pulse Width Modulation, pulse width modulation) signal to control a field effect tube, and then the field effect tube drives the LED module to realize dimming. Light. Compared with traditional tungsten filament lamps, due to the fast reflection speed of LEDs, when the resolution of the PWM signal is low, it can be clearly felt that the dimming process of the LEDs has a gradual jump. When the resolution of the PWM signal is increased, the problem that the turn-on and turn-off time of the field effect transistor cannot meet the requirement exists again. Moreover, when the frequency of the PWM signal is low, the switching frequency of the FET will be within the...

AI Technical Summary

Problems solved by technology

When the resolution of the PWM signal is increased, the on-off time of the field effect transistor is difficult to meet the demand.

Moreover, when the frequency of the PWM signal is low, the switching frequency of the FET will be within the audio range

In the application environment of the performance stage, this phenomenon will produce uncomfortable noise, which cannot meet the application requirements in specific environments.

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