Integratable capacitive touch sensing circuit through charge sharing

Abstract

An integratable capacitive touch sensing circuit through charge sharing is provided, including a charge sharing circuit, voltage-controlled oscillator, reference frequency generator, switch clock generator and frequency compare circuit; wherein charge sharing circuit further including a sensing capacitor, touch capacitor, share capacitor, charging switch, charge sharing switch and discharging switch, for sharing charge from charged sensing capacitor with discharged share capacitor through charge sharing to accumulate voltage on share capacitor. The capacitance of share capacitor is adjustable for applications generating different sensing capacitance. The charging switch, charge sharing switch and discharging switch are controlled by non-overlapping clocks. Prolonging close duration of charging switch and minimizing close duration of charge sharing switch and discharging switch can minimize interference from ambient noise. The charge sharing circuit finishes charge sharing in a clock cycle and voltage of share capacitor are linear to sensing capacitance and touch capacitance.

Dependencies are inferred from the claim text.