Patent ID: 7482793
Filing Date: 2009-01-27
Classification: H02M

Abstract:
1. A buck switching regulator formed on an integrated circuit and receiving an input voltage, the buck switching regulator controlling a first switch and a second switch using a fixed on-time, minimum off-time feedback control scheme to drive a switch output node for generating a switching output voltage, the switch output node being coupled to an LC filter circuit external to the integrated circuit to generate a regulated output voltage having a substantially constant magnitude on an output node, the regulated output voltage being fed back to the buck switching regulator to a voltage divider for generating a feedback voltage on a feedback voltage node, the buck switching regulator comprising: a first capacitor and a first resistor formed on the integrated circuit of the buck switching regulator, the first capacitor and the first resistor being connected in series between the switch output node and the feedback voltage node; and a second capacitor coupled between the output node and the feedback voltage node, wherein the first capacitor and the first resistor generate a ripple voltage signal being related to the switching output voltage and provide the ripple voltage signal to the feedback voltage node for use in the fixed on-time, minimum off-time feedback control scheme, the magnitude of the ripple voltage signal being a function of the capacitance value of the second capacitor.