Patent ID: 6700331
Filing Date: 2004-03-02
Classification: H05B,Y02B

Abstract:
A control circuit for varying the intensity of illumination of a fluorescent lamp having first and second filaments comprising:(a) a DC supply for rectifying a low frequency alternating supply voltage having first and second rectified voltage terminals; (b) a triggerable pulse source connected between the first and second rectified voltage terminals of the DC supply, said pulse source being triggered from a blocking state to a conducting state when the amplitude of the applied supply voltage exceeds a predetermined voltage; (c) a self-oscillating multi-vibrator connected to the pulse source adapted to provide energy at the resonant frequency of said control circuit; and (d) an output voltage doubler including at least one inductive element to provide an alternating current voltage output to the fluorescent lamp which is substantially greater than the supply voltage, said output voltage doubler including first and second diodes connected across the first and second filaments of the fluorescent lamp, respectively, and in being series with said inductive element.