电容式微机械陀螺调理电路

电容式微机械陀螺的驱动电压比敏感信号大4个数量级以上,而且敏感电容很小,敏感电容与驱动电容之间的杂散耦合电容往往只比敏感电容小2个数量级,因此产生驱动电压严重干扰敏感信号问题。电容式微陀螺有2个振动自由度,2个振动自由度的机械耦合也严重干扰敏感信号。本文提出一种调理电路方案,该方案利用电容式微陀螺振动的惯性,对其进行不连续驱动,在敏感信号达到最大值时进行积分采样,并且在采样时关闭驱动电压的方法,有效地减少了干扰。在往复运动的固定相位点进行信号采样,也有利于减缓机械耦合干扰,此方法比常规连续波相敏检测的方法的信噪比有了明显的改善。

Conditioning circuit of capacitive micromachined gyroscope

The driving voltage is nearly ten thousand times larger than the detected signal in capacitive micromachined gyroscope. But the detecting capacitance is small, it is only nearly one hundred times larger than the parasitic coupling capacitance, so the driving voltage greatly disturbs the detected signal. Capacitive micromachined gyroscope has two degrees of vibration freedom, the mechanical coupling between them greatly disturbs the detected signal. This paper presents a conditioning circuit, which uses the inertia of capacitive micromachined gyroscope oscillation to discontinuously drive the microgyroscope. When sensitive signal reaches the maximum value, integral sampling is performed and the driving voltage is cut off, which effectively decreases the interference. Sampling in the fixed-phase point of reciprocating movement also benefits decreasing the interference from mechanical coupling. Comparing with ordinary continuous wave phase-sensitive detection, this method has significantly improved the signal to noise ratio.