Patent ID: 7250773

Claim:
A circuit for detecting a difference in capacitance between a first capacitor and a second capacitor provided in a sensor, comprising: a first oscillator configured to generate a first oscillating signal having frequency responsive to the first capacitor; a second oscillator configured to generate a second oscillating signal having frequency responsive to the second capacitor; a first counter coupled to said first oscillator to output a first count responsive to said first oscillating signal; a second counter coupled to said second oscillator to output a second count responsive to said second oscillating signal; an oscillation circuit configured to generate a drive signal for driving the sensor to cause harmonic motion to the first capacitor and the second capacitor; a control circuit configured to output a timing signal indicative of directions of the harmonic motion in response to the drive signal; and an operation circuit coupled to said first counter, said second counter, and said control circuit to obtain an annular rate applied to the sensor in response to the first count, the second count, and the timing signal.