Feedback control circuit and LED driving circuit

摘要

A feedback control circuit, adapted to control a converting circuit to transform an input power into an output voltage for driving an LED module. The feedback control circuit comprises a detection circuit, a PWM circuit, a PWM logic control circuit and a PWM control circuit. The detection circuit is coupled to at least one LED string of the LED module and generates at least one detection signal. The PWM circuit comprises a capacitance, a charging circuit and a discharging circuit, and determines a capacitance voltage of the capacitance to increase, decrease, or maintain. The PWM logic control circuit compares a level of the least one detection signal with a high reference level and a low reference level to control the PWM circuit to adjust the capacitance voltage. The PWM control circuit controls the converting circuit to execute the power transformation in response to the capacitance voltage of the capacitance.

主权项

1. A feedback control circuit, adapted to control a converting circuit to execute a power transformation for driving an LED module, wherein the LED module has at least one LED string connected in parallel, the feedback control circuit comprising:
a detection circuit, coupled to the LED strings of the LED module, and generating at least one detection signal in response to a state of the least one LED string; a PWM circuit, comprising a capacitance, a charging circuit and a discharging circuit, wherein the charging circuit and the discharging circuit determines a capacitance voltage of the capacitance to increase, decrease or maintain according to a set of control signals; a PWM logic control circuit, executing a logical operation on a dimming signal and compared results of a level of the at least one detection signal with a high reference level and a low reference level, and generating the set of the control signals in response to the logical operation, wherein the high reference level is higher than the low reference level; and a PWM control circuit, controlling the converting circuit to execute the power transformation in response to the capacitance voltage of the capacitance, wherein the PWM circuit determines the capacitance voltage of the capacitance to increase, decrease or maintain according to the set of the control signals when the dimming signal represents that the LED module lights.