Patent ID: 6611169
Filing Date: 2003-08-26
Classification: H03F

Abstract:
An apparatus for amplifying an audio signal, comprising:a regulated switching power supply adapted to produce a positive and negative rail voltages in relation to a midpoint voltage, the regulated switching power supply including a peak current mode control system using a voltage error amplifier adapted to receive a feedback signal; an audio frequency amplifier electrically connected to the midpoint and rail voltages of the regulated switching power supply and adapted to receive and amplify the audio signal; a feedback generator connected between at least one rail and the midpoint voltage, the feedback generator adapted to proportionally divide the voltage between the midpoint voltage and the rail voltage to generate the feedback signal and a reference voltage; and a rail overvoltage detection circuit connected to the feedback generator and at least one rail voltage, the rail overvoltage detection circuit adapted to detect an overvoltage on the at least one rail voltage and adjust the feedback generator's reference voltage to control the feedback signal such that the regulated switching power supply will adjust the at least one rail voltage.