Patent ID: 9019012
Filing Date: 2015-04-28
Classification: H03F

Abstract:
1. A Class-D amplifier circuit for amplifying an input signal comprising: an output stage comprising a plurality of switches operable to provide a plurality of output states comprising at least a positive output state and a negative output state; control circuitry configured to receive a first signal based on the input signal and produce a digital control signal, wherein the digital control signal is used to determine the switch state of the output stage; a digital integrator configured to receive a feedback signal indicative of the output state of the output stage, to sample said feedback signal at a sample rate, and to produce an integrated output signal indicating the difference in number of instances of the positive output state and the negative output state; correction circuitry for subtracting the integrated output signal from the input signal to produce a signal from which the first signal is derived so as to provide correction for any D.C. offset; and wherein said feedback signal is derived from the signal path of the amplifier upstream of the output stage.