Patent ID: 8913033

Claim:
A circuit for measuring a mutual capacitance between electrodes disposed on a substrate, comprising: a drive circuit configured to generate a periodic pulse and to communicate the pulse to a drive electrode; and a sense circuit configured to measure a mutual capacitance between the drive electrode and a sense electrode at a point of intersection between the drive electrode and the sense electrode, wherein the sense circuit comprises: an integrator circuit with an input section that is in continuous electrical communication with the sense electrode for an amount of time required for measuring the mutual capacitance; a switch circuit with an input in electrical communication with an output of the integrator circuit and an output in electrical communication with a analog-to-digital converter, wherein the switch operates to momentarily communicate an output signal of the integrator circuit to the analog-to-digital converter at a first time that is prior to a falling edge of the pulse, and at a second time that is prior to a rising edge of the pulse to thereby sample a maximum value and a minimum value of the output signal; and computational logic configured to determine a difference between the maximum value and the minimum value to thereby determine a mutual capacitance between the drive electrode and the sense electrode.