Audio amplifier with offset voltage correction circuit - has very low cut-off frequency but can be fully integrated

摘要

The input signal (1) is fed via the input offset voltage element (9) to the non-inverting input of the main amplifier (2). The output (4) of the amplifier is fed back via a resistive network (10) and a summing element (8) to the inverting input. The other input to the summing element is provided by the offset correction circuit (20). The output signal is attenuated (21) and fed via a second offset voltage element (22) to the input of a trans conductor circuit (25). The output of the trans conductor is fed via a capacitive filter (28, 29) and a second attenuator (30) to the second input (31) of the summing element (8).