CIRCUITS AND METHODS FOR DRIVING A LIGHT SOURCE

摘要

A circuit includes a bridge circuit, a converter, and a controller. The bridge circuit receives power from first and second power lines of a switch and generates a rectified voltage. The switch is capable of operating in a first state in which the switch conducts power to the first power line but not the second power line, a second state in which the switch conducts power to the second power line but not the first power line, and a third state in which the switch conducts power to both the first and second power lines. The converter converts the rectified voltage to an output voltage to drive a light source, and controls a current through the light source according to a driving signal. The controller monitors the operation state of the switch and generates the driving signal based on the operation state to control brightness/dimming of the light source.

主权项

1. A circuit for driving a light source, said circuit comprising:
a bridge circuit coupled to a switch through a first power line and a second power line, and configured to receive power from said first and second power lines and generate a rectified voltage, wherein said switch operates in a plurality of operation states comprising a first state, a second state, and a third state, wherein in said first state said switch conducts power to said first power line but not said second power line, wherein in said second state said switch conducts power to said second power line but not said first power line, and wherein in said third state said switch conducts power to both said first and second power lines; a converter coupled to said bridge circuit and configured to convert said rectified voltage to an output voltage to drive said light source, and control a current through said light source according to a driving signal; and a controller coupled to said converter and configured to monitor said operation state of said switch and generate said driving signal based on said operation state to control the light level of said light source.