Closed-loop driving circuit for micromechanical resonance structure

Abstract

The invention discloses a closed-loop driving circuit for a micromechanical resonance structure, which is an alternating-current automatic gain control closed-loop self-excited driving circuit mainly comprising an amplitude limiting circuit 7, a band-pass filter 8, an automatic gain control loop 9 and a phase compensating circuit 12. The automatic gain control loop 9 adjusts the gain of a loop and the phase compensating circuit 12 adjusts the phase of the loop so as to separate the gain adjustment and the phase adjustment, avoid the coupling influence between the gain adjustment and the phase adjustment and facilitate the debugging of the circuit; and the introduction of the amplitude limiting circuit 7 and the band-pass filter 8 enlarges the linear working range of the circuit, even if an I / V converter 5 detects high output signals, the signals are limited in a certain amplitude through the amplitude limiting circuit 7, and the noise signals are filtered through the band-pass filter 8 so that the feedback driving signals are limited at a resonance frequency and instable resonance caused by introducing nonlinear signals into the circuit is avoided.

Description

technical field [0001] The invention relates to a closed-loop driving circuit, in particular to a closed-loop driving circuit for a micromechanical resonant structure. Background technique [0002] With the development of microelectromechanical system technology, micromechanical resonant structures based on mechanical resonance principles can be used in microsensors, microactuators and microresonators, such as resonant pressure sensors, vibrating micromechanical gyroscopes and scanning micromirrors. Among them, the common electrode variable capacitance micromechanical resonant structure is one of the major categories. The common feature of this type of micromechanical resonant structure is composed of a pair of capacitors or multiple pairs of capacitors with a common electrode 1, refer to figure 1 shown. Usually, the common electrode 1 is a movable resonant structure, and the fixed electrode I2 and the fixed electrode II3 are used as fixed structures. And in the resonant ...

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Problems solved by technology

[0005] The purpose of the present invention is: in order to overcome the mutual coupling influence of gain adjustment and phase adjustment in the debugging process of the closed-loop drive circuit in the prior art, it is difficult to debug; the dynamic range of the circuit signal is small, and the shortcoming of the closed-loop self-excited oscillation of the resonant structure cannot be effectively realized , while avoiding the introduction of nonlinear signals in the closed-loop drive circuit, causing unstable resonance of the resonant structure, the present invention proposes a new closed-loop drive circuit for micro-mechanical resonant structures

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