Patent AT-E401694-T1: [Translated] HIGH DUTY RATIO OFFSET VOLTAGE COMPENSATION FOR OPERATIONAL AMPLIFIER

A circuit arrangement comprising an input amplifier stage (31) with two inputs (36, 37) and an output (34) being connectable to an input (35) of an output amplifier stage (32). The circuit furthermore comprises a comparator (33) with a first input (41), a second input (42) and a comparator output (44), a feedback capacitor (43) connected to an offset tuning input (45) of the input amplifier stage (31), and a plurality of switches (S1, S2) that are controllable by switching signals (V1, V2) to allow the circuit to be switched from a first phase to a second phase. During the first phase (1), the output (34) and the input (35) are separated by a first one of the switches (S2) and the two inputs (36, 37) are connected via a second one of the switches (S1). The first input (41) of the comparator (33) is connected to the output (34) of the input amplifier stage (31) and the second input (42) of the comparator (33) is connected to the input (35) of the output amplifier stage (32) such that via the comparator output (44) a charge on the feedback capacitor (43), and hence the voltage at the offset tuning input (45) is altered and an offset of the input amplifier stage (31) is corrected.