A buck switching regulator formed on an integrated circuit receives an input voltage and provides a switching output voltage on a switch output node using a constant on-time, variable off-time feedback control loop. The buck switching regulator includes an amplifier comparing a feedback voltage to a reference voltage and generating an output voltage on an output terminal, a first capacitor and a first resistor connected in series between the switch output node and the output terminal of the amplifier, and a second capacitor coupled between the DC output voltage node and the output terminal of the amplifier. The first capacitor and the first resistor generate a ripple voltage signal which is injected onto the output terminal of the amplifier for use in the constant on-time, variable off-time feedback control scheme. The magnitude of the ripple voltage signal is a function of the capacitance value of the second capacitor.