An electrostatic stiffness type silicon microresonant acceleration sensor chip

Abstract

The invention provides a static stiffness type silicon micro resonance acceleration sensor chip. The sensor chip comprises two clamped vibration beams, driving comb tooth capacitor fixing pole plates, detection parallel plate capacitor fixing pole plates and a mass block. The mass block is arranged between the two clamped vibration beams, a set of parallel pole plates on the clamped vibration beams and one set of parallel pole plates on the mass block form a parallel plate capacitor for introducing static stiffness to the clamped vibration beams, and the other set of parallel pole plates on the clamped vibration beams and the detection parallel plate capacitor fixing pole plates form a detection parallel plate capacitor. In the process of working, the clamped vibration beams conduct double-side driving and form closed loop resonance through the detection parallel plate capacitor and a driving circuit, direct-current bias voltages are exerted between parallel plate capacitance pole plates between the clamped vibration beams and the mass block, and then the additional static stiffness is introduced to the clamped vibration beams. When acceleration effect exists, the mass block is shifted to enable the static stiffness of one clamped vibration beam to be increased, the resonant frequency of one clamped vibration beam is reduced, the static stiffness of the other clamped vibration beam is decreased, resonant frequency of the other clamped vibration beam is increased, and the resonance frequency difference and the acceleration of the two clamped vibration beams form direct ratios. The sensor outputs the frequency difference of the two clamped vibration beams, and the chip has the advantages of being strong in capacity of resisting disturbance, high in precision, convenient to use and the like.

Description

technical field [0001] The invention relates to an electrostatic stiffness type silicon micro-resonance acceleration sensor chip. Background technique [0002] If the vibrator is connected to one plate of the parallel plate capacitor and there is a DC bias voltage V between the plates of the parallel plate capacitor b , the vibration of the vibrator will cause the electrostatic force between the parallel plates to change, and there is an electrostatic force component proportional to the vibration displacement, which is equivalent to introducing an additional electrostatic stiffness to the vibrator , where ε is the dielectric constant, A is the effective area of ​​the parallel plate capacitor, g 0 is the parallel-plate capacitance gap corresponding to the equilibrium position. If the inertial force of the mass block under the action of acceleration changes g 0 , the electrostatic stiffness will change, thereby changing the resonant frequency of the vibrator, and the accel...

AI Technical Summary

Problems solved by technology

In this way, the driving comb capacitor can only drive the vibrating beam on one side, and cannot realize the bilateral driving of the vibrating beam. The parallel plate capacitance of electrostatic stiffness is introduced, so that the impact on electrostatic stiffness needs to be considered when designing the resonant frequency detection circuit of the vibrating beam

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