An amplifier capable of driving an analog load is provided. The
amplifier can be constructed and arranged to operate as at least one circuit selected from the group consisting of a
class D amplifier,
voltage regulator, audio
amplifier,
servo amplifier,
servo control,
digital control,
switching power supply, and
switching power amplifier. The amplifier comprises a sigma
delta modulator (SDM), a
pulse processing circuit, an output stage, and a
feedback loop. The SDM produces a plurality of
noise-shaped output pulses based upon an input
signal (e.g., an analog input
signal) to the amplifier and an
error signal. The
pulse processing circuit processes at least a portion of the plurality of
noise-shaped output pulses to ensure that each of the
noise-shaped output pulses in the portion contains an amount of energy that is as close as possible to the amount of energy in the other pulses. The output stage is coupled to the
pulse processing circuit and has first state wherein the output stage provides analog noise-shaped output energy pulses to a load and a second state where the output energy delivered is essentially zero. The
feedback loop is coupled between the output stage and the SDM. The
feedback loop samples the energy provided to the load during the first state by measuring the load during the second state and generates an
error signal based on the difference between the sampled portion of the noise-shaped output pulses and the input
signal to the amplifier.