Patent ID: 7068095

Claim:
An amplifier circuit, comprising: an input configured to receive a useful signal to be amplified; an output configured to tap off or output an amplified version of the useful signal; a differential amplifier comprising a first input connected to the input of the amplifier circuit, a second input coupled to the output of the amplifier circuit, and an output; a comparator comprising a first input connected to the output of the differential amplifier, and a second input configured to receive a periodic signal; an output stage comprising an input coupled to an output of the comparator, an output coupled to the amplifier output, and a supply connection for receiving a supply voltage; and a signal generator connected to the second input of the comparator and configured to provide the periodic signal at an amplitude which is proportional to the supply voltage at the output stage, the signal generator configured as a phase locked loop to regulate a frequency of the periodic signal based on a reference clock.