Back to results
US 11,442,586 B2Granted
Canceling unwanted capacitive effects in a capacitive touch measurement, and related systems, methods, and devices
AssigneeMicrochip Technology Incorporated
InventorAnders Vinje
Life of this patent
Estimating the term…
Abstract
The embodiments of the present disclosure relate generally to systems and methods for canceling mutual capacitive effects in a capacitive touch measurement, and more specifically, implementing a driven shield using rail-to-rail voltage.
Claims9
A capacitive touch circuitry, the circuitry comprising:
- an electrode circuitry;
- a driven shield circuitry to:
- drive one or more inactive electrodes of the electrode circuitry at a first reference voltage rail for a first period of time;
- and
- drive one or more inactive electrodes of the electrode circuitry in a generally increasing or decreasing manner between the first reference voltage rail and a second reference voltage rail for a second period of time, and at least in part thereby induce cancelling mutual capacitance effects at an active sense electrode;
- a sensing circuitry to drive an active drive electrode and at least in part thereby induce self-capacitance effects at the active sense electrode;
- a self-capacitance sensing circuitry to provide one or more measurable signals that are indicative of the induced cancelling mutual capacitance effects and the induced self- capacitance effects;
- and
- a measurement circuitry to:
- combine a first and second measurement values, the first measurement value corresponding to a measurable signal generated during the first period of time and the second measurement value corresponding to a measurable signal generated during the second period of time;
- and
- obtain a self-capacitance measurement.
9 more elements
A microcontroller package, comprising:
- a number of programmable input/output (I/O) pins;
- a touch controller to generate a first voltage at one or more programmable I/O pins associated with inactive drive lines and inactive sense lines during a measurement acquisition cycle, the measurement acquisition cycle comprising a positive pre-charge measurement phase and a negative pre-charge measurement phase, wherein providing the shield voltage comprises:
- holding the one or more programmable I/O pins associated with inactive drive lines and inactive sense lines to a first voltage rail during one of the positive pre-charge measurement phase and the negative pre-charge measurement phase;
- and
- driving the one or more programmable I/O pins associated with inactive drive lines and inactive sense lines from the first voltage rail to a second voltage rail during the other one of the positive pre-charge measurement phase and the negative pre-charge measurement phase;
- and
- a digital control bus operatively coupled to the touch controller.
4 more elements
Dependencies are inferred from the claim text.