Patent ID: 6605990
Filing Date: 2003-08-12
Classification: H03F

Abstract:
A balanced transformer-less amplifier with output terminals for establishing a DC-connection to a load, said balanced transformed-less amplifier comprising an offset detection system for detecting a differential DC-offset across the output terminals, characterized in that said offset detection system comprises:an analog-to-digital converter for converting a signal voltage across the output terminals into a digital signal; a counter coupled to the analog-to-digital converter for intergrating the digital signal during a predetermined period of time, said counter forming a counting result; evaluation means coupled to the counter for evaluating the counting result of said counter; and a digital-to-analog converter coupled to an output of the evaluation means for generating analog correction signal, said analog correction signal being applied to an input of the amplifier for counteracting the DC-offset across the output terminals, characterized in that the analog-to-digital converter is a sigma-delta modular generating a 1-bit digital representation of the signal voltage across the output terminals of the amplifier.