Patent ID: 6762643
Filing Date: 2004-07-13
Classification: H03F

Abstract:
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), 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) in allow the circuit arrangement to the switched from a firm phase to a second phase, wherein during the first phase,the output (34) of the input amplifier stage (31) and the input (35) of the output amplifier stage (32) are separated by a first one of the switches (S2), the two inputs (36, 37) of the input amplifier stage (31) 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.