Patent ID: 8446135

Claim:
A control circuit for a ripple regulator system having a high-side device and a low-side device being coupled to each other by a phase node and controlled by a pulse width modulation (PWM) signal to control an inductor current to charge an output capacitor for generating an output voltage, the control circuit comprising: an error comparator having two input terminals to receive a reference voltage and a feedback voltage related to the output voltage, respectively, and an output terminal to provide a comparison signal; a PWM controller connected to the error comparator, responsive to the comparison signal to trigger the PWM signal; a ripple generation circuit operative to generate a ripple signal in-phase and synchronous with the inductor current for one of the two input terminals of the error comparator; and an offset cancellation circuit connected to the ripple generation circuit and the error comparator, operative to extract a ripple information proportional to an amplitude of the ripple signal from the ripple generation circuit, to generate an offset cancellation signal supplied to the error comparator to improve an offset of the output voltage caused by the ripple signal.