| 摘要 |
A solid state light source driver circuit, system and method are provided. The driver circuit includes a rectifier circuit, an energy storage element coupled thereto, a current bleeder circuit coupled thereto, and a switch. The rectifier circuit receives AC input and provides unregulated DC voltage. The switch closes to couple some of the unregulated DC voltage to the energy storage element, and opens to transfer energy to drive the light source. A power factor controller circuit provides an output signal to control the switch. The current bleeder circuit provides supply voltage to the power factor controller circuit within a range and maintains a current flow associated with the AC input that exceeds a predetermined threshold. A constant off-time controller circuit provides a switching frequency control signal to the power factor controller circuit. An EMI filter reduces generated EMI noise.
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