Patent ID: 8164275
Filing Date: 2012-04-24
Classification: H02M,H05B

Abstract:
1. A drive circuit comprising: a DC/DC converter including a switch, an input terminal, and an output terminal, wherein the input terminal is coupled to an output of a voltage rectifier and the output terminal is coupled to a load; an outer control loop having an input coupled to the load, wherein an output voltage of the outer control loop represents a comparison between a load current and a reference voltage; a multiplier configured to multiply the outer control loop output voltage with a sample of the voltage rectifier output and provide an output current; a current amplifier configured to provide an output representative of a comparison between an input line current sample and the multiplier output current; a comparator configured to provide a modulated output based on the current amplifier output and a sawtooth reference signal, wherein the modulated output drives the switch; and an upper voltage limit loop having an output terminal 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.