A Capacitance-Voltage Conversion Circuit for Mems Capacitive Sensor

Abstract

The invention provides a capacitance-voltage conversion circuit for a MEMS capacitive sensor, comprising: a voltage excitation source, a common-mode charge controller, and a charge-voltage conversion module; wherein, the charge-to-voltage conversion module includes: a first-stage differential amplifier, a first-stage differential amplifier, a Two-stage differential amplifier, gain error corrector, active noise canceller and charge feedback unit, because after the first-stage differential amplifier amplifies the set-up noise signal of the parasitic capacitance of the preset capacitance sensor, there are some parts connected to the first-stage differential amplifier. The source noise canceller can absorb the set-up noise signal, and the gain error corrector connected to the active noise canceller and the second-stage differential amplifier respectively can correct the gain errors generated by the first-stage differential amplifier and the second-stage differential amplifier. Corrected, thereby improving gain accuracy while reducing noise, resulting in a significant increase in energy efficiency.

Description

technical field [0001] The invention belongs to the technical field of MEMS capacitive sensors, in particular to a capacitance-voltage conversion circuit for MEMS capacitive sensors. Background technique [0002] MEMS (Micro Electro-Mechanical System, Micro-Electro-Mechanical System) capacitive sensor technology, as an important branch in the field of MEMS research and manufacturing, has developed rapidly in recent years in the fields of miniaturization, multi-functionalization, and intelligence. Micro-capacitive sensors are the most representative of micro-mechanical pressure gauges and accelerometers. They have the advantages of small size, low cost, light weight and low power consumption. They have been widely used in motion sensing, security alarm, attitude control and other fields. application. [0003] With the continuous improvement of semiconductor technology and the trend of shrinking device size, the requirements for the accuracy and power consumption of the MEMS ...

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Problems solved by technology

[0003] With the continuous improvement of semiconductor technology and the continuous reduction of device size, the requirements for the accuracy and power consumption of MEMS capacitive sensor interface circuits are getting higher and higher. However, the noise deterioration caused by parasitic capacitance effects is becoming more and more significant.

The capacitance-voltage conversion circuit of the MEMS capacitive sensor in the related art, due to the existence of the position noise generated by the parasitic capacitance and the output noise of the operational amplifier, causes the signal to deteriorate and cannot meet the signal-to-noise ratio requirement

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