Electronic ballast with inductive power feedback
A low frequency to high frequency power converter having a power feedback network from a high frequency voltage source to the low frequency input to a DC supply circuit for the high frequency voltage source. The network forms part of a feedback path which has an inductive impedance at one or more frequencies within the operational range of the high frequency source. In a fluorescent lamp ballast embodiment, feedback is from a load connection point through a path having at least an inductor and a capacitor in series. A low pass filter input to the DC supply circuit may have a shunt capacitor across the rectifier input. The feedback network may include a capacitor in series with the parallel combination of an inductor and a capacitor. In another embodiment the feedback inductor is a tapped inductor connected to the rectifier input, its two inductor portions having mutually exclusive periods of zero current flow.
Philips Electronics North American Corporation
H
H05B
inventional
Chin
Chang