Patent ID: 9705458
Date: 2017-07-11
CPC Classifications: H02M,H03F,H03G

Claim:
1. An audio amplifier circuit for providing an output signal to an audio transducer, the audio amplifier circuit comprising: a power amplifier having an audio input for receiving an audio input signal, an audio output for providing the output signal, and a pair of power supply rail connections; a power supply for providing a power supply voltage across the pair of power supply rail connections of the power amplifier, wherein the power supply has a control input for controlling the power supply voltage, whereby power consumption of the power amplifier is reduced when a magnitude of the audio input signal is reduced; a control circuit for providing a control signal to the control input of the power supply in conformity with an indication of the magnitude, so that the control signal causes the power supply to increase the power supply voltage when the indication of magnitude indicates that clipping may occur in the output signal; and a gain control circuit for decreasing the magnitude of the audio input signal in conformity with the indication of the magnitude for a predetermined period until the power supply has increase the power supply voltage, so that the clipping is prevented.