Patent ID: 8319507

Claim:
A method for sensing a load current that flows from an amplifier into a load of the amplifier, the method comprising: obtaining a voltage drop across internal impedance of the amplifier; and computing the load current using the internal impedance and the voltage drop across the internal impedance, wherein obtaining the voltage drop across the internal impedance comprises: generating a digital input voltage using a digital signal source; converting the digital input voltage into an analog input voltage using a digital-to-analog converter; applying the analog input voltage to the amplifier and generating an analog output voltage; converting the analog output voltage into a digital output voltage using an analog-to-digital converter; multiplying the digital input voltage by a gain factor of the amplifier to produce a voltage product using a digital signal processing module; and calculating the voltage drop across the internal impedance as a voltage difference between the digital output voltage and the voltage product using the digital signal processing module.