Multi-touch sensor and electrostatic pen digitizing system utilizing simultaneous functions for improved performance
First Claim
1. Driver and receiver circuitry for a sensor, the circuitry comprising:
- multiple drive/receive circuits, a drive/receive circuit of the multiple drive/receive circuits includes;
a voltage-following sigma-delta analog to digital converter (ADC) circuit that includes a first input coupled to receive a sensor drive signal, a second input coupled to an electrode of the sensor, and an output; and
a sigma-delta digital to analog converter (DAC) circuit includes a converter input and a converter output, the converter input coupled to the output of the voltage-following sigma-delta ADC circuit; and
an output filter having a filter input coupled to the converter output and a filter output coupled to the second input of the voltage-following sigma-delta ADC circuit and to the electrode of the sensor;
drive signal generation circuitry coupled to generate the sensor drive signal that includes at least one of a mutual analog sensor signal at a first frequency and a self analog sensor signal at a second frequency that is different from the first frequency; and
wherein the drive/receive circuit is configured to drive and sense the electrode in accordance with at least one of the self analog sensor signal and the mutual analog sensor signal.
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Accused Products
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.
23 Citations
21 Claims
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1. Driver and receiver circuitry for a sensor, the circuitry comprising:
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multiple drive/receive circuits, a drive/receive circuit of the multiple drive/receive circuits includes; a voltage-following sigma-delta analog to digital converter (ADC) circuit that includes a first input coupled to receive a sensor drive signal, a second input coupled to an electrode of the sensor, and an output; and a sigma-delta digital to analog converter (DAC) circuit includes a converter input and a converter output, the converter input coupled to the output of the voltage-following sigma-delta ADC circuit; and an output filter having a filter input coupled to the converter output and a filter output coupled to the second input of the voltage-following sigma-delta ADC circuit and to the electrode of the sensor; drive signal generation circuitry coupled to generate the sensor drive signal that includes at least one of a mutual analog sensor signal at a first frequency and a self analog sensor signal at a second frequency that is different from the first frequency; and wherein the drive/receive circuit is configured to drive and sense the electrode in accordance with at least one of the self analog sensor signal and the mutual analog sensor signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A drive/receive circuit comprising:
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a voltage-following sigma-delta analog to digital converter (ADC) circuit that includes a first input coupled to receive a sensor drive signal, a second input coupled to a sensor, and an output; a sigma-delta digital to analog converter (DAC) circuit that includes a converter input and a converter output, the converter input coupled to the output of the voltage-following sigma-delta ADC circuit; and an output filter having a filter input coupled to the converter output and a filter output coupled to the second input of the voltage-following sigma-delta ADC circuit and to the sensor; and the voltage-following sigma-delta ADC being configured to generate an output signal based on the sensor drive signal received via the first input and a feedback signal coupled to the second input from the filter output. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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Specification