Patent ID: 6411161
Filing Date: 2002-06-25
Classification: H03F

Abstract:
An AC coupling circuit for receiving an output signal from a signal processing circuit having a first differential amplifier which has an inverting input and a non-inverting input, and for transmitting the output signal to a stage subsequent to the signal processing circuit as an AC signal, the first differential amplifier receiving an input signal with a predetermined potential and a signal with a reference potential to differentially amplify the signals, the AC coupling circuit comprising:a CR circuit including a resistor and a capacitor; and a feedback circuit including a second differential amplifier for detecting a potential difference between a node of a stage previous to the CR circuit and a node of a stage subsequent to the CR circuit with reference to the potential of the node of the subsequent stage to the CR circuit to amplify the potential difference, the feedback circuit feeding back the amplified potential difference to the non-inverting input of the first differential amplifier of the signal processing circuit.