Analog signal processing circuit

Abstract

The invention discloses an analog signal processing circuit, which comprises a differential amplifier, a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a first capacitor and a second capacitor, wherein the differential amplifier comprises a first input end, a second input end and an output end; an external analog signal passes through the first switch and the second switch in turn to be connected with the first input end; the second input end is grounded; the upper polar plate of the first capacitor is connected between the first switch and the second switch, and the lower polar plate of the first capacitor is grounded; the third switch is connected between the first input end and the output end of the differential amplifier in series; the upper polar plate of the second capacitor is connected with the first input end, and the lower polar plate of the second capacitor is grounded in series through the fourth switch; the lower polar plate of the second capacitor is connected with the output end in series through the fourth switch; the first switch, the third switch and the fourth switch are turned on in a signal acquisition phase; and the second switch and the fifth switch are amplified in a hold amplification phase.

Description

technical field [0001] The invention relates to the field of mixed signal systems, in particular to an analog signal processing circuit. Background technique [0002] In a mixed-signal system, an analog signal processing circuit is usually required to collect and amplify the analog signal, and then send it to the signal processing system for subsequent processing; the above-mentioned analog signal processing circuit usually includes a differential amplifier, because there is a difference between the positive and negative input terminals of the differential amplifier. Inherent offset, even if the input signal is zero, the output will have an offset output, which is an obvious defect; therefore, an analog signal processing circuit with input offset voltage cancellation becomes the first choice. [0003] An existing analog signal processing circuit with offset voltage correction function such as figure 1 As shown, it includes switches S1, S2, S3, S4, S5, S6, S7, compensation c...

AI Technical Summary

Problems solved by technology

[0006] The technical problem to be solved by the present invention is: the input terminal of the differential amplifier in the prior art is susceptible to the influence of parasitic capacitance during operation, and while meeting the requirements of high gain accuracy, it is inevitable to waste the area of ​​the chip

Images