Electronic ballasts with current and voltage feedback paths
 A power converter for providing high frequency current to a load such as a fluorescent lamp. A rectifier circuit provides DC power to a half-bridge inverter whose output is connected to one end of a resonant load circuit. One load connection is at the other end of the load circuit, and is connected to one AC-side terminal of the rectifier circuit to provide current feedback. A voltage feedback capacitor is connected between the other AC-side rectifier circuit terminal and the other load connection. The two feedback paths contribute equivalent components to charging current for a bulk capacitor for the DC power to the inverter. Excellent fluorescent lamp ballast performance is obtained with constant inverter frequency, and with either full bridge or voltage doubler embodiments. 
Philips Electronics North America Corporation
H H Y
H02M H05B Y02B
inventional inventional additional
Chin
Chang