A closed-loop drive circuit for microgyroscopes with high amplitude stability

A common closed-loop driving scheme was improved to enhance the control precision of microgyroscope. Based on the theory of self-oscillation, the loop gain was calculated in a closed-loop driving system in which the phase angle and gain are decoupled. Furthermore the circuit parameters were optimized through the comparisons of the amplitude-frequency characteristics in different situations. After the optimization, the driving forces were able to be controlled by only one variable, which made the circuit debugging much more easier. Experimental results showed that the standard deviation of the amplitude and frequency were improved from 1.029 V and 0.014 6 Hz to 0.793 V and 0.003 3 Hz, respectively. It proved that the presented circuit scheme could improve the stability of drive frequency and the amplitude effectively.