Patent ID: 8183787
Filing Date: 2012-05-22
Classification: H05B,Y02B

Abstract:
1. A power supply system comprising: a power converter operable for providing power to a light emitting diode (LED); a first switch coupled to said power converter and operable for adjusting said power to said LED, wherein said first switch has a gate, a source and a drain; and a controller coupled to said first switch and operable for controlling a state of said first switch, wherein said controller has a first control terminal for providing a gate voltage to said gate of said first switch, a second control terminal for providing a source voltage to said source of said first switch, and an input terminal for receiving a supply voltage via said source of said first switch, wherein said controller comprises a second switch coupled to said first switch, and comprises a control circuit coupled to said second switch and operable for controlling said state of said first switch by controlling a state of said second switch, and wherein said controller is operable for limiting said supply voltage within a predetermined maximum level by regulating said gate voltage to a preset level.