Patent ID: 6864642
Filing Date: 2005-03-08
Classification: H05B,Y02B

Abstract:
1. A fluorescent lamp electronic ballast comprising: a PFC stage providing an essentially level output DC voltage; a DC to DC flyback converter receiving the PFC stage output DC voltage and including a flyback transformer connected to a diode/capacitor combination, and including a switch used to switch the flyback transformer to produce a flyback waveform that is rectified by the diode and results in an essentially level high voltage DC output at the capacitor; a commutator circuit receiving the high voltage DC output and converting the high voltage DC output to an AC signal for operating the fluorescent lamp; and a current sensor for sensing a DC lamp current from the output of the flyback converter and providing a current sense signal to the flyback converter, wherein the flyback converter switch is controlled based on the current sense signal to control the DC lamp current.