Patent ID: 6392475
Filing Date: 2002-05-21
Classification: H03F

Abstract:
An offset compensator in a differential amplifier circuit for driving a load, comprising:an input stage that receives an input voltage; a differential amplifier that includes a non-inversion input terminal, an inversion input terminal and an output stage, wherein the non-inversion and inversion input terminals receive a differential input voltage and the output stage generates an output voltage in accordance with the differential input voltage; a capacitor coupled to the non-inversion input terminal; a first switch coupled between the input stage and the capacitor, wherein the first switch is controlled by a first control signal and selectively couples the input stage to the capacitor; a second switch coupled between the input stage and the non-inversion input terminal, wherein the second switch is controlled by a second control signal and selectively couples the input stage to the non-inversion input terminal; and a third switch coupled between the output stage and the capacitor, wherein the third switch is controlled by the second control signal and selectively couples the output stage to the capacitor, wherein offset detection and compensation of a single input signal is performed in first to fourth intervals, and wherein logic values of the first and second control signals are determined in the first to fourth intervals.