Patent ID: 9612686
Date: 2017-04-04
CPC Classifications: G05F,G06F,H03K

Claim:
1. A sensor for providing an output signal that is a function of a sensed capacitance to which the sensor is connected through a connection node, the sensor comprising: a charger for repetitively applying first and second voltages to the connection node to charge the sensed capacitance to first and second charge values in first and second phases respectively; a sampler including at least a first current mirror for providing first and second sample current signals that are a function of the first and second charge values respectively; and an accumulator that comprises an accumulator capacitor for repetitively using the first and second sample current signals differentially in modifying a charge on the accumulator capacitor and providing an accumulator signal; wherein the accumulator signal is a progressive function of the sensed capacitance but cancels noise in the first and second sample current signals at frequencies less than a repetition rate of operation of the accumulator, and wherein the accumulator uses the accumulator signal to provide the output signal.