US Patent 9151792 High-voltage, high-sensitivity self-capacitance sensing

Apparatuses and methods of high-voltage capacitance-sensing circuits are described. One apparatus includes a capacitance-sensing circuit coupled to a capacitive-sense array of electrodes. The capacitance-sensing circuit includes a self-capacitance sensing channel, a first voltage source (e.g., a low-voltage drive source) to drive a reference voltage, and a second voltage source (e.g., high-voltage drive source) to drive a sensing voltage. The sensing voltage is greater in magnitude than the reference voltage. The capacitance-sensing circuit also includes 1) a first set of switches to selectively couple the self-capacitance sensing channel or the second voltage source to a sensing electrode of the capacitance-sensing array; and 2) a second set of switches to selectively couple the first voltage source or the second voltage source to a shielding electrode of the capacitance-sensing array.