Microchip Technology Incorporated
Reference Noise Rejection Improvement Based on Sample and Hold Circuitry

Abstract:

A touch controller may include a measurement circuit, configured to receive a signal from an active channel in a proximity sensor, and to sample and hold the signal to measure the signal. The touch controller may include a driven shield buffer. The touch controller may include a voltage reference circuit configured to generate a divided voltage reference, provide the divided voltage reference to the measurement circuit, and drive the divided voltage reference through a switched circuit to the driven shield buffer to hold channels in the proximity sensor during measurement of the active channel.