US Patent 9417739 High speed multi-touch touch device and controller therefor

A touch-sensitive device includes a touch panel, a drive unit, a sense unit, and a measurement unit. A touch applied to a node of the panel changes a capacitive coupling between two electrodes (a drive electrode and a sense electrode) of the touch panel. The drive unit delivers a drive signal, which may comprise one or more drive pulses, to the drive electrode. The sense unit couples to the sense electrode, and generates a response signal that includes a differentiated representation of the drive signal. The amplitude of the response signal is responsive to the capacitive coupling between the electrodes, and is measured to provide an indication of a touch at the node.