DRIVE CIRCUIT FOR HIGH-BRIGHTNESS LIGHT EMITTING DIODES

摘要

A drive circuit includes a DC/DC converter, an outer control loop providing an output voltage representing a comparison between a load current and a reference voltage, a multiplier multiplying the outer control loop output voltage with a sample of the rectified output and provide an output current, a current amplifier comparing an input line current sample and the multiplier output current, a comparator driving the switch with a modulated output based on the current amplifier output and a sawtooth reference, and an upper voltage limit loop having an output in electrical communication with the outer control loop output, wherein the outer control loop output voltage is impacted by the upper voltage limit loop output during a zero load scenario. The drive circuit also includes a line voltage transformer and a lightning suppression circuit coupled to the voltage rectifier output.