Ripple Generation In Buck Regulator Using Fixed On-Time Control To Enable The Use of Output Capacitor Having Any ESR

摘要

A buck switching regulator formed on an integrated circuit and receives an input voltage and provides a switching output voltage on a switch output node using a fixed on-time, minimum off-time feedback control scheme. The buck switching regulator includes a first capacitor and a first resistor formed on the integrated circuit where the first capacitor and the first resistor are connected in series between the switch output node and a feedback voltage node, and a second capacitor coupled between the DC output voltage node and the feedback voltage node. 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 where the magnitude of the ripple voltage signal is a function of the capacitance value of the second capacitor.