Patent ID: 8174855
Filing Date: 2012-05-08
Classification: G05F,H02M,Y02B

Abstract:
1. A power factor correction integrated circuit housed in an integrated circuit package for controlling a boost converter circuit having an input inductor coupled in series with a boost rectifier between a rectified AC line input voltage and a DC bus voltage, on a DC bus, the rectified AC line input voltage provided by a rectifier coupled to an AC line input voltage to be power factor corrected, the integrated circuit comprising: a first input circuit sensing the DC bus voltage, said first input circuit integrated into said integrated circuit; a second input circuit sensing current through the inductor and determining when the current through the inductor discharges to substantially zero current, a power switch coupled between a common connection of the inductor and boost rectifier and a return line of said DC bus for allowing said inductor to be charged by current from said rectified AC line input voltage when said power switch is turned on; an over-current sensing circuit for detecting an over-current condition without an external current sense resistor; and a control circuit comprising a feedback circuit comparing said DC bus voltage to a fixed reference voltage for turning OFF said power switch for a period of time to maintain said DC bus voltage at a desired level; the feedback circuit comprising an operational transconductance amplifier which sinks or sources a current to an external capacitor coupled to a PFC Error Amplifier; said control circuit further operating so that when said inductor current is substantially zero, said power switch is turned ON forcing current through said inductor and charge said inductor, thereby forcing the current in said inductor to follow said rectified AC line input voltage and achieve power factor correction of said AC line input voltage; said power switch being contained within said integrated circuit package.