Patent ID: 7436126
Filing Date: 2008-10-14
Classification: H05B,Y10S

Abstract:
1. A switching circuit for a ballast, comprising: a resonant circuit, formed by a capacitor and a transformer connected in series to operate a lamp, wherein said transformer has a first winding connected in series with said lamp, and a second winding and a third winding of said transformer respectively generate a first control signal and a second control signal in response to a switching current of said resonant circuit; a first switch, coupled to said resonant circuit to supply a first voltage to said resonant circuit, wherein said first switch is controlled by a first switching signal; a second switch, coupled to said resonant circuit to supply a second voltage to said resonant circuit, wherein said second switch is controlled by a second switching signal; a first control circuit, coupled to generate said first switching signal in response to said first control signal; and a second control circuit, coupled to generate said second switching signal in response to said second control signal.