Patent ID: 9267976
Filing Date: 2016-02-23
CPC Classification: G01D,G01R

Claim Text:
1. A circuit for sensing a differential capacitance, comprising: a first sensing terminal and a second sensing terminal connected to two terminals of the differential capacitance, respectively; a switching circuit connected to the first and second sensing terminals, being switched to make the two terminals of the differential capacitance connected to a high-voltage source or a low-voltage source or to perform charge transfer; a charge-storing circuit coupled to the switching circuit, storing charges transferred by the differential capacitance in response to switching of the switching circuit, to generate a first output voltage and a second output voltage related to capacitances at the two terminals of the differential capacitance; and an amplifier stage operative to generate a sensing value according to a difference between the first and second output voltages, the amplifier stage including: