Modulating a reference voltage to preform capacitive sensing
First Claim
1. An input device, comprising:
- a plurality of sensor electrodes; and
a processing system, comprising;
a sensor module configured to operate the plurality of sensor electrodes for capacitive sensing;
a reference voltage modulator configured to modulate reference voltage rails of the processing system while the input device is in a low power state; and
a receiver configured to simultaneously acquire resulting signals from the sensor electrodes for detecting an input object while modulating the reference voltage rails, wherein the receiver and the sensor electrodes are coupled to a common electrical node, wherein the processing system is configured to switch the input device from the low power state to an active state based on the acquired resulting signals.
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Accused Products
Abstract
This disclosure generally provides an input device that includes a reference voltage modulator that modulates reference voltage rails when performing capacitive sensing. In one embodiment, reference voltage rails are coupled to a DC power source which provides power to operate a panel that includes a display screen integrated with a touch sensing region. Before performing capacitive sensing, the input device may isolate the DC power source from the reference voltage rails and use the reference voltage rails to modulate the rails—e.g., VDD and VGND. The input device may include a receiver that simultaneously acquires resulting signals from a plurality of display and/or sensor electrodes when modulating the reference voltage rails. The resulting signals can then be processed to determine if an input object is interacting with the input device.
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Citations
31 Claims
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1. An input device, comprising:
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a plurality of sensor electrodes; and a processing system, comprising; a sensor module configured to operate the plurality of sensor electrodes for capacitive sensing; a reference voltage modulator configured to modulate reference voltage rails of the processing system while the input device is in a low power state; and a receiver configured to simultaneously acquire resulting signals from the sensor electrodes for detecting an input object while modulating the reference voltage rails, wherein the receiver and the sensor electrodes are coupled to a common electrical node, wherein the processing system is configured to switch the input device from the low power state to an active state based on the acquired resulting signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A processing system, comprising:
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a sensor module configured to drive a plurality of sensor electrodes for capacitive sensing; a reference voltage modulator configured to modulate reference voltage rails of the processing system while an input device comprising the processing system is in a low power state, wherein, before modulating the reference voltage rails, the processing system is configured to electrically disconnect the reference voltage rails from at least one DC power supply; and a receiver configured to simultaneously acquire resulting signals using the sensor electrodes for detecting an input object while modulating the reference voltage rails, wherein the receiver and the sensor electrodes are coupled to a common electrical node, wherein the processing system is configured to switch the input device from the low power state to an active state based on the acquired resulting signals. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28)
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29. An input device, comprising:
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a plurality of sensor electrodes, each sensor electrode comprising at least one common electrode of a display device, wherein the sensor electrodes are disposed in a matrix array on a common plane; and a processing system, comprising; a sensor module configured to operate the plurality of sensor electrodes for capacitive sensing; a reference voltage modulator configured to modulate reference voltage rails of the processing system while the input device is in a low power state; and a receiver configured to acquire resulting signals using the sensor electrodes for detecting an input object while modulating the reference voltage rails, wherein the receiver and the sensor electrodes are coupled to a common electrical node, wherein the processing system is configured to wake up the input device from the low power state based on the acquired resulting signals. - View Dependent Claims (30)
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31. A method, comprising:
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driving a capacitive sensing signal on a plurality of sensor electrodes in an input device; electrically disconnecting reference voltage rails from at least one DC power supply; after electrically disconnecting the reference voltage rails, modulating the reference voltage rails while the input device is in a low power state; simultaneously acquiring resulting signals using the sensor electrodes at a receiver for detecting an input object while modulating the reference voltage rails, wherein the receiver and the sensor electrodes are coupled to a common electrical node; and switching the input device from the low power state to an active state based on the acquired resulting signals.
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Specification