Crystal oscillation sensor amplification circuit for bypass capacitance compensation and method for performing bypass capacitance compensation by utilizing amplification circuit

Abstract

The invention relates to acrystal oscillation sensor amplification circuit for bypass capacitance compensation and a method for performing bypass capacitance compensation by utilizing the amplification circuit, relating to a technology for bypass capacitance compensation of crystal oscillation sensors. The problems that resonance is influenced by bypass capacitance in the crystal oscillation sensor and a method for compensating the bypass capacitance does not exist can be solved. The crystal oscillation sensor and two variable-capacitance diodes are sequentially connected between two wiring terminals at the secondary side of a transformer in serial; a public end of the crystal oscillation sensor and one variable-capacitance diode is connected to an operational amplifier; cathodes of the two variable-capacitance diodes are connected; a driving signal is loaded to the primary side of the transformer; reverse bias voltage is provided for the two variable-capacitance diodes, so that the output signal of the operational amplifier is zero; and the value of the reverse bias voltage is controlled through a digital control system. According to the invention, the bypass capacitance of the crystal oscillation sensor can be precisely compensated, so that influence of the bypass capacitance in the crystal oscillation sensor to the resonance is eliminated; and thus, the amplification circuit is applicable to precisely compensating the bypass capacitance of the crystal oscillation sensor with various resonant frequencies.

Description

technical field [0001] The invention relates to the compensation technology of the shunt capacitor of a crystal oscillator sensor. Background technique [0002] Crystal sensor has advantages that traditional cantilever beam sensors cannot match, such as high Q value, self-excitation and self-detection function, large elastic coefficient so that "kick contact" phenomenon will not occur, so it is widely used as a scanning probe Microscope sensor. Using the piezoelectric effect of the crystal oscillator, the vibration of the cantilever is converted into an electrical signal and detected by the preamplifier, so the preamplifier plays a vital role in the signal detection process of the crystal oscillator sensor. However, the bypass capacitance of the crystal oscillator sensor in the preamplifier circuit will affect the resonance, resulting in asymmetry of the resonance curve, resonance frequency shift, and phase shift corresponding to the resonance point. At present, there is no...

AI Technical Summary

Problems solved by technology

[0003] The present invention aims to solve the problem that the bypass capacitance in the crystal oscillator sensor affects the resonance, resulting in the asymmetry of the resonance curve, the shift of the resonance frequency and the phase shift corresponding to the resonance point, and the lack of a method for compensating the bypass capacitance, thereby providing a bypass Circuit capacitance compensation crystal oscillator sensor amplifying circuit and method for bypass capacitance compensation using the amplifying circuit

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