Patent ID: 8493331

Claim:
A system for determining an amount of touch at each of a plurality of locations of touch sensor circuitry, the system comprising: touch sensor circuitry having a plurality of drive lines and a plurality of sense lines; and an integrated circuit coupled to the touch sensor circuitry, including driver logic that generates a plurality of different sets of stimulation signals and applies the sets sequentially to the plurality of drive lines such that the stimulation signals in each set are applied simultaneously to the plurality of drive lines, the stimulation signals in each set including stimulation signals of different frequencies; a plurality of sense channels, each sense channel receiving a sense signal from a different sense line of the touch sensor circuitry during application of each set of stimulation signals to the drive lines, wherein each sense signal includes a composite signal based on a plurality of stimulation signals in the applied set; a demodulation section that demodulates each sense signal with demodulation signals at demodulation frequencies corresponding to the stimulation frequencies in the corresponding applied set, wherein each sense signal is demodulated with multiple demodulation signals to produce multiple demodulated values, each demodulated value including a composite value based on touch information of a plurality of locations of the touch sensor circuitry; and a calculation section that calculates, based on a plurality of the demodulated values produced over a plurality of sequential applications of sets of stimulation signals, an amount of touch at each of the plurality of locations of the touch sensor circuitry.