A droop amplifier circuit for a DC-DC regulator including an amplifier, at
least one first resistive device, a second resistive device, a third
resistive device, and a first capacitive device. Each first resistive
device is coupled between an output inductor (phase node or current sense
node) and the amplifier's non-inverting input. The first capacitive
device is coupled between the regulator output and the amplifier's
output. The second resistive device is coupled between the regulator
output and the amplifier's inverting input. The third resistive device is
coupled between the amplifier's inverting input and output. A second
capacitive device may be coupled between the regulator output and the
amplifier's non-inverting input. A fourth resistive device may be coupled
in parallel with the second capacitive device. A relatively small, simple
and low performing amplifier is sufficient. Circuit area and power are
reduced, and low input offset voltage is more easily achieved.