Patent ID: 8674605
Filing Date: 2014-03-18
Classification: H05B

Abstract:
1. A driver circuit to drive a solid state light source, comprising: a rectifier circuit configured to receive an AC input voltage and provide an unregulated DC voltage; an energy storage element coupled to the rectifier circuit; a switch, wherein the switch is configured to close so as to couple a portion of the unregulated DC voltage to the energy storage element, and wherein the switch is configured to open so as to transfer energy from the energy storage element to provide a DC output voltage to drive the solid state light source; a power factor controller circuit configured to provide an output signal to control the switch; a current bleeder circuit coupled to the rectifier circuit, the current bleeder circuit configured to provide a supply voltage to the power factor controller circuit within a nominal operating range and to maintain a current flow associated with the AC input voltage, wherein the current flow exceeds a predetermined threshold; a constant off-time controller circuit configured to provide a switching frequency control signal to the power factor controller circuit; and an electromagnetic interference (EMI) filter configured to reduce EMI noise generated by the driver circuit.