Patent ID: 8686702

Claim:
A controller for a current mode switching power supply that uses at least one power switch and an inductor to generate an output voltage, the controller comprising: a clock circuit configured to generate a periodic clock signal; an error amplifier configured to generate an error signal that is representative of a difference between a signal representative of the output voltage and a reference voltage; a peak current threshold circuit configured to generate a peak current threshold signal indicative of a peak current that should be reached in the inductor during each cycle of the periodic clock signal that has a level that is based on the error signal; a switch control circuit configured to generate a switch control signal that is configured to regulate the voltage output by closing and then opening the at least one power switch during each cycle of the periodic clock signal, the timing of the opening being based on the peak current threshold signal; and a slope compensation circuit configured to provide negative slope compensation that causes the switch control circuit to delay opening the at least one power switch during each cycle of the periodic clock signal in an amount that decreases with increasing duty cycles of the switch control signal.