Texas Instruments Incorporated
Capacitance measuring system and method

Abstract:

A system operable between a charging mode and a transferring mode for measuring capacitance of a capacitive sensor, includes a switching unit configured to, in a first phase of the charging mode, arrange the capacitive sensor to be charged by a first supply voltage from a first end of the capacitive sensor until a voltage difference between the first end and an opposite second end of the capacitive sensor reaches a first predetermined voltage, and in a second phase of the charging mode, disconnect the first end of the capacitive sensor from the first supply voltage and couple the second end of the capacitive sensor (10) to a second supply voltage to raise a voltage at the first end of the capacitive sensor to a second predetermined voltage.