Self-adaptive closed-loop feedback control system and method for silicon resonance pressure sensor

Abstract

The invention provides a self-adaptive closed-loop feedback control system and method for a silicon resonance pressure sensor, and belongs to the technical field of MEMS pressure sensors. The system comprises a V / F conversion circuit, a silicon resonance pressure core body connected with the V / F conversion circuit, a C / V circuit connected with the silicon resonance pressure core body, a self-adaptive feedback control module and a differentiator which are respectively connected with the C / V circuit, and an AGC circuit connected with the differentiator, wherein the AGC circuit is connected with the self-adaptive feedback control module. Through self-adaptive feedback control, the-90-degree phase difference characteristic of a driving end signal and a detection end signal is met, it is guaranteed that the silicon resonance pressure sensor is not affected by the external environment temperature, the phase-shifting anti-interference capacity is met, and it is guaranteed that the silicon resonance pressure sensor always works in a resonance state; and the influence caused by frequency drift or amplitude fluctuation due to the influence of an external environment is reduced.

Description

technical field [0001] The invention belongs to the technical field of MEMS pressure sensors, and in particular relates to an adaptive closed-loop feedback control system and method for a silicon resonance pressure sensor. Background technique [0002] Silicon resonant pressure sensors are widely used in aerospace, meteorological monitoring, industrial measurement and control and other fields because of their small size, low power consumption, and high precision. Silicon resonant pressure sensors are mainly composed of silicon resonant pressure cores and peripheral closed-loop drive control circuits. [0003] Considering the measurement accuracy of the silicon resonant pressure sensor, a closed-loop control circuit is usually used to realize the drive and detection of the silicon resonant pressure core. When the external pressure changes cause the resonant frequency of the silicon resonant pressure core to change, the self-excited closed-loop control circuit can be faster. T...

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Problems solved by technology

However, this solution usually has the following limitations: First, due to the existence of non-ideal factors in the circuit, the resistors and capacitors contained in the phase shifter circuit have certain temperature drift characteristics, and their resistance and capacitance will vary with time. As the temperature changes, the phase shifting circuit has a -90° phase shifting characteristic at room temperature and cannot meet the -90° phase difference condition in a high and low temperature environment; secondly, in the case of mass production and processing, a single There are large differences in the resonant frequency and quality factor of the silicon resonant core of the structure, and the use of the AGC phase shifting circuit will greatly increase the workload of the matching test between the structure and the interface circuit and the difficulty of circuit debugging

Patents such as CN113765516A, CN108519498B, etc. all use phase-locked loop circuits to realize closed-loop control, and although phase-locked loop circuits can ensure that the phase difference is -90° through a phase detector and are not affected by the external environment, the analog phase-locked loop The complexity of the circuit is quite high, and it is difficult to realize it with discrete analog devices. In addition, the PLL circuit will have a frequency sweep and frequency locking process at the initial stage of power-on, which will greatly increase the start-up of the silicon resonant closed-loop circuit. vibration time

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