Class D amplifiers and methods of amplification wherein a load is
periodically coupled to a positive power supply connection through a
first switch or a negative power supply connection through a second
switch for a period responsive to an input signal. A third switch couples
the load to a circuit ground connection during times when the load is not
coupled to either the positive or the negative power supply connection.
This provides a load current recirculation path through the ground
connection, which together with the inductance of the load, tends to
maintain the load current when both the first and second switches are
open. Loads such as speakers may be directly connected to the amplifier
output, or may be coupled to the amplifier output through a filter.
Various exemplary control methods, including use of feedback, are
disclosed.