Capacitance measurement circuit and method therefor

摘要

A capacitance measurement circuit includes an operation amplifier; a reference capacitor having a first terminal coupled to a first input terminal of the operation amplifier and a second terminal selectively coupled to a first or second reference voltage; a sensor capacitor having a first terminal coupled to a second input terminal of the operation amplifier and a second terminal selectively coupled to the first or second reference voltage; an approximation unit having an output terminal and an input terminal coupled to an output terminal of the operation amplifier; a conversion unit having an output terminal and an input terminal coupled to the output terminal of the approximation unit; and a coupling capacitor having a first terminal coupled to the first or second input terminal of the operation amplifier and a second terminal coupled to the output terminal of the conversion unit.