Patent ID: 8085563

Claim:
A controller operably connected to generate a drive signal for a converter circuit that converts a rectified alternating current (AC) input voltage to a direct current (DC) output voltage, the controller comprising: a pulse width modulator (PWM) connected to generate the drive signal based on a voltage feedback signal and a current feedback signal; an outer feedback loop that monitors the output voltage of the converter circuit and generates in response the voltage feedback signal provided to a first input of the PWM; and an inner feedback loop that monitors an AC input current drawn by the converter circuit and generates in response the current feedback signal provided to a second input of the PWM, the inner feedback loop comprising: an amplifier having a first input connected to receive a feedback signal representing the monitored AC input current, a second input, and an output; and a fault protection and clamp circuit connected to monitor the current feedback signal provided to the second input of the PWM and to detect fault conditions associated with the converter circuit, wherein in response to an over-voltage condition in the current feedback signal or a detected fault condition the fault protection and clamp circuit clamps the current feedback signal provided to the second input of the PWM to a reference value and provides the reference value in feedback to the amplifier.