Dimmable LED drive circuit with passive bleeder resistor to stabilize dimming operation and improve power factor

摘要

A dimmable LED drive circuit having a passive bleeder resistor for stabilizing dimming operation and improving power factor, comprising: a dimming circuit (100) for performing phase cutting operation of an AC voltage to provide a phase cut AC voltage in response to a dimming input ; a bridge rectifier (110) that provides an input voltage by performing a rectifying operation of the phase-cut AC voltage; a passive leakage resistance circuit (120) connected between the input voltage and a ground and comprising a charge path, a discharge path and a capacitor, the charge path having a series connection of a diode (121) and a first resistor (122), the discharge path a second Resistor (124), the charge path and the discharge path form a parallel connection path, wherein the parallel connection network is connected in series with the capacitor (123) and the second resistor (124) has a resistance which is greater than that of the first capacitor (122) ; and a power converter (130) for converting the input voltage to an output current for an LED load (240).