A Class D audio amplifier including a gain stabilization feedback loop in
which volume control is achieved by varying the bus voltage. Changes in
the bus voltage are compensated for by complementary changes in the gain
of a compensation element in feedback loop so the signal level at the
output of the Class D stage can be adjusted independent of the feedback.
A digital attenuator can be employed ahead of the amplifier to shift the
effective gain of the amplifier output to provide additional volume
control range.