Sensor side charge cancellation
AssigneeSynaptics Incorporated
InventorsJonathan Losh, Don Speck
Life of this patent
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Abstract
An input device includes a receiver electrode, a transmitter electrode and a processing system coupled to the receiver electrode and transmitter electrode. The processing system is configured to transmit a transmitter signal with the transmitter electrode during a first time period, inject a charge onto the receiver electrode during a second time period, and receive a resulting signal from the receiver electrode during a third time period. The resulting signal includes effects corresponding to the injected charge. The second time period and the third time period are non-overlapping.
Claims20
An input device comprising:
- a plurality of transmitter electrodes;
- a receiver electrode, wherein the receiver electrode is configured to be capacitively coupled to the plurality of transmitter electrodes;
- and
- a processing system coupled to the receiver electrode and the plurality of transmitter electrodes, the processing system configured to:
- transmit a transmitter signal with a first transmitter electrode of the plurality of transmitter electrodes during a first time period,
- inject a charge onto the receiver electrode during a second time period, and
- receive a resulting signal with the receiver electrode during a third time period, wherein the resulting signal comprises effects corresponding to the injected charge and the transmitter signal and wherein the second time period and the third time period are non-overlapping.
A processing system comprising:
- a transmitter module coupled to a transmitter electrode and configured to transmit a transmitter signal with the transmitter electrode during a first time period,
- a compensation circuit coupled to a receiver electrode and configured to inject a charge onto the receiver electrode during a second time period;
- and
- a receiver module coupled to the receiver electrode, the receiver electrode configured to be capacitively coupled to the transmitter electrode, the receiver module is configured to receive a resulting signal with the receiver electrode during a third time period, wherein the resulting signal comprises effects corresponding to the injected charge and the transmitter signal, and wherein the second time period and the third time period are non-overlapping.
A method comprising:
- transmitting a transmitter signal on a transmitter electrode during a first time period;
- injecting, during a second time period, a charge onto a receiver electrode, the receiver electrode capacitively coupled to the transmitter electrode;
- receiving a resulting signal from the receiver electrode during a third time period, wherein the resulting signal comprises effects corresponding to the transmitter signal and the injected charge and wherein the second time period and the third time period are non-overlapping;
- and
- determining positional information for an input object based on the resulting signals.
Dependencies are inferred from the claim text.