Abstract: A touch sensor circuit includes a plurality of drive/receive circuits and a drive signal generation circuit. The drive/receive circuits drive and receive signals from a multi-touch sensor. A drive/receive circuit includes an analog to digital conversion (ADC) circuit and a digital to analog conversion (DAC) circuit. The ADC circuit includes a first input to receive a sensor signal on an electrode of the multi-touch sensor. The sensor signal includes a drive signal component and a receive signal component. The ADC circuit includes a second input to receive an analog reference signal from the drive signal generation circuit. The ADC circuit generates a digital signal based on the analog reference signal and the sensor signal. The DAC circuit converts the digital signal into the drive signal component and the receive signal component is representative of an impedance on the electrode detected and is indicative of a touch proximal to the electrode.

Abstract: Circuitry, systems, and methods are provided that can acquire touch sensor data simultaneously for different modes of, for example, self, mutual, and pen, and with simultaneous sampling of the different channels. Drive/receive circuitry and methods of driving and receiving sensor electrode signals are provided that allow digital I/O pins to be used to interface with touch sensor electrodes using external passive filter components. Drive/receive circuitry is provided employing voltage following sigma-delta A/D coverts that are adapted to both drive and sense touch sensor signals on multiple frequencies simultaneously. This circuitry may be operated in modes to sense various combinations of mutual, self, and pen touch signals simultaneously. While capacitive multi-touch sensors are preferred, the circuits and methods herein are useful with many other types of touch sensors as well.