Self-stabilization zero amplifying circuit and method for improving gain stability of amplifying circuit

Abstract

The invention provides a self-stabilization zero amplification circuit and a method for improving gain stability of the amplification circuit, the circuit comprises a main amplification unit, a first auxiliary self-stabilization zero amplification unit and a second auxiliary self-stabilization zero amplification unit, and the first auxiliary self-stabilization zero amplification unit and the second auxiliary self-stabilization zero amplification unit both have a zero setting state and an amplification state. In each clock period, the first auxiliary self-stabilization zero amplification unit and the second auxiliary self-stabilization zero amplification unit alternately work in an amplification state, and the gain of the main amplification unit is kept stable while it is ensured that the offset voltage of the main amplification unit is stably counteracted. Through the structural design of the two auxiliary self-stabilization zero amplification units and in combination with control of clock signals, the two auxiliary self-stabilization zero amplification units alternately work in an amplification state in each clock period, it is guaranteed that the offset voltage of the main amplification unit is stably offset, and the gain of the main amplification unit is kept stable; and spurious signals generated at the output end due to gain error change can be avoided.

Description

technical field [0001] The invention relates to the technical field of integrated circuit design, in particular to an auto-zero amplifying circuit and a method for improving the gain stability of the amplifying circuit. Background technique [0002] In recent years, with the rapid development of intelligent sensing systems represented by the Internet of Things (IOT), the application of sensor products has increased significantly, such as temperature sensors, pressure sensors, infrared photoelectric sensors, etc. It is getting weaker and weaker, and a high-gain operational amplifier circuit is required to amplify the signal, so the requirements for the accuracy of the post-amplifier are also getting higher and higher. The input offset voltage is an important index to characterize the accuracy of the operational amplifier. If the offset voltage is too large, there will be a large DC voltage offset in the output of the operational amplifier. This offset voltage is one of the ma...

AI Technical Summary

Problems solved by technology

However, there are still problems in the actual use of the traditional auto-zero amplifier: only a set of auxiliary amplifier circuits are used, which work in the zeroing state and the amplifying state respectively, and the amplification of the first signal cannot be realized in the zeroing state, while the analog The first signal is generally a continuous signal. If the first signal changes during the zeroing period, it will not be reflected to the output, resulting in an error signal generated by the second signal during the zeroing and amplification period; offsetting the voltage of the input offset It is stored on the holding capacitor. In order to achieve a stable offset offset voltage, the holding capacitor needs to be very large. It can only be connected with an external capacitor, which increases the complexity of peripheral use and is not conducive to the miniaturization design of the circuit.

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