Importance

Loading Importance Indicators...

Abstract

An amplifier circuit comprises an amplifier for amplifying an input signal and outputting the amplified signal to an external device. A power supply provides a supply voltage to the amplifier. The nature or type of external device (for example line-load or headphones) is determined by measuring a parameter related to the supply voltage. The parameter may be the time taken for the supply voltage to fall or rise a predefined threshold value. Alternatively, the measured parameter may be a voltage drop or voltage rise over a predetermined period of time. Both of these parameters give an indication as to the rate of change of the supply voltage with time, which provides an indication of the nature of the load. Processing circuitry may be provided for calibrating the rate of change of the supply voltage with time, based on the input signal.

First Claim