Digital dimming control system for light-emitting diode (LED) and method thereof

Abstract

A digital dimming control system for a light-emitting diode (LED) comprises a main power circuit and an LED load, is provided with an external control input module and comprises a control module, a pulse width modulation (PWM) driving module, a digital to analog (D / A) conversion module, a feedback circuit and a comparator, wherein the control module comprises decoding unit, a driving control unit, a time keeping unit and a timing unit. The control module adjusts switching time of PWM driving waveforms by controlling the PWM driving module according to the requirements of the external control input module; on one hand, the driving control unit changes a voltage reference value Vref of the input end of the comparator through the D / A conversion module, and on the other hand, the driving control unit controls connection of PWM signals. The time keeping unit is used for calculating connection time of the PWM during every period, the timing unit is used for determining the switching time of the PWM, the driving control unit guarantees constancy of a switching period of the PWM driving module through the timing unit, and by comparing time Treal obtained by the time keeping unit and storage time Tstatic inside the driving control unit, the driving control unit adjusts the connection time of the PWM and achieves corresponding protection.

Description

technical field [0001] The invention relates to an LED dimming control system, in particular to an LED digital dimming control system and a method thereof. Background technique [0002] The dimming control system has developed from the original analog dimming and semi-digital dimming system to a mature full-digital dimming system. With the development of semiconductor technology, the application of full-digital dimming is also more extensive. In LED lighting, since the brightness of a light-emitting diode is determined by the current flowing through the diode, in the digital dimming control system, the power tube switch is controlled by controlling the duty cycle of the digital dimming signal, and then the average current flowing through the light-emitting diode is controlled. current, so as to achieve the purpose of dimming. In the dimming control system, according to the input control signal and the feedback signal, the purpose of dimming the LED is achieved by changing t...

AI Technical Summary

Problems solved by technology

In the dimming control system, according to the input control signal and the feedback signal, the purpose of dimming the LED is achieved by changing the current flowing through the output LED. To achieve this goal, complex digital dimming systems are usually required Advanced A / D, D / A conversion circuit, complex system, high cost, poor reliability

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