Patent ID: 7843149

Claim:
A light dimming device for compact fluorescent lamp, comprising: a rectifying circuit for rectifying an AC current signal into a zero crossing voltage signal and outputting the zero crossing voltage signal to a current limiting circuit; a current limiting circuit for limiting a current level of the zero crossing voltage signal to obtain a current limited zero crossing voltage signal and sending the current limited zero crossing voltage signal to a voltage regulating and filtering circuit and a first comparator; the voltage regulating and filtering circuit for regulating the current limited zero crossing voltage signal and sending the regulated current limited signal to a reference voltage generating circuit and a current controller; the reference voltage generating circuit for generating a reference voltage signal upon receiving the regulated current limited signal and sending the reference voltage signal respectively to the first comparator and a second comparator; the current controller for controlling the amount of a charging current of a capacitor; the first comparator for outputting a low voltage level signal to the capacitor to discharge the capacitor after receiving the zero crossing voltage signal and the reference voltage signal, thereby letting the capacitor to output a discharging signal to the second comparator; the second comparator for outputting a drive signal to the drive circuit to turn on a power switch after receiving the discharging signal and the reference voltage signal, thereby transferring the discharging signal of the capacitor to a filter circuit; the filter circuit for converting the discharging signal of the capacitor into a steady DC current signal and transferring the DC current signal to the compact fluorescent lamp so as to let the compact fluorescent lamp generate light of different luminance according to the amount of the DC current signal.