Patent ID: 7135841

Claim:
A circuit for voltage regulation, comprising: a switching circuit that is arranged to receive an input voltage and a ramp voltage and provide a regulated output voltage based on the input voltage and the ramp voltage; a feedback circuit that is arranged to receive the regulated output voltage and provide an error voltage; a Pulse Width Modulation (PWM) comparator circuit that is arranged to receive a ramp voltage and the error voltage and provide the PWM voltage based on a comparison of the ramp voltage and the error voltage; a ramp control circuit that is arranged to receive a sensed voltage based on a down-slope actual inductor current, a first timing signal, and a second timing signal, and to provide the ramp voltage to the PWM comparator; and a current sense circuit that is operable to sense a current across a synchronous switch of the switching circuit, and to provide the sensed voltage at a current sense node based on the sensed current, wherein the ramp control circuit includes: a switch that is coupled between the current sense node and a capacitor node, wherein the switch is operable to close if the synchronous switch is closed, and to open if the synchronous switch is open; a capacitor that is coupled to the capacitor node, wherein the capacitor voltage is provided by the capacitor at the capacitor node; a current source circuit that is operable to provide a current that is substantially proportional to a difference between the input voltage and the regulated output voltage; and an integrating feedback loop that is coupled to the current source circuit.