Cypress Semiconductor Corporation

Parade Technologies, Ltd.

Kaveh Hosseini

Roman Ogirko

Paul M Walsh

Viktor Kremin

Timothy John Williams

Denis Ellis

Brendan Lawton

Erhan Hancioglu

Jaskarn Singh Johal

Onur Ozbek

Gabriel Rowe

Andriy Maharyta

Jonathan R Peterson

Kofi Makinwa

Andrew C Page

Rajiv Singh

Dermot MacSweeney

Saravanan Murugesan

Gerard Baldwin

Rishi Raghav Bacchu

A capacitance-sensing circuit may include a channel input associated with measuring a capacitance of a unit cell of a capacitive sense array. The capacitance-sensing circuit may also include a capacitive hardware baseliner that is coupled to the channel input. The capacitive hardware baseliner generates a baseline current based on a time constant of the channel input associated with the measuring of the capacitance of the element of the capacitive sense array using the programmable baseline resistor. The capacitive hardware baseliner provides the baseline current at the channel input to provide a charge for a sense capacitor. A change in the charge of the sense capacitor is provided by the baseline current indicating a presence of a tough object proximate to the element.

Providing a baseline capacitance for a capacitance sensing channel

A capacitance-sensing circuit may include a channel input associated with measuring a capacitance of a unit cell of a capacitive sense array. The capacitance-sensing circuit may also include a capacitive hardware baseliner that is coupled to the channel input. The capacitive hardware baseliner includes a programmable baseline resistor, and a buffer with an input coupled to the programmable baseline resistor and an output coupled to the channel input. The capacitive hardware baseliner generates a baseline current based on a time constant of the channel input associated with the measuring of the capacitance of the element of the capacitive sense array using the programmable baseline resistor. The capacitive hardware baseliner provides the baseline current at the channel input to provide a charge for a sense capacitor. A change in the charge of the sense capacitor is provided by the baseline current indicating a presence of a touch object proximate to the element.

A capacitance-sensing circuit may include a plurality of channel inputs associated with measuring a capacitance of a unit cell of a capacitive sense array. The capacitance-sensing circuit may also include a baseliner component that is coupled to the plurality of channel inputs. The baseliner component may generate a baseline compensation signal using a capacitive circuit and may provide the baseline compensation signal to each of the plurality of channel inputs of the capacitive sense array.

Generating a baseline compensation signal based on a capacitive circuit

A method includes providing a differential signal and generating an in-phase component of the differential signal and a quadrature component of the differential signal. The method further includes generating an output signal representing a capacitance value using the in-phase component and the quadrature component.

Capacitive fingerprint sensor with quadrature demodulator and multiphase scanning

A capacitance sensing circuit may include a charge to digital converter, coupled to a signal receiver channel, to receive a signal from a capacitive sense array. The capacitance sensing circuit may also include a baseline compensation signal generator, coupled to the signal receiver channel, to provide a baseline compensation signal in an opposite phase of the signal to the signal receiver channel.

Baseline compensation for capacitive sensing

A circuit, system, and method for measuring capacitance are described. A current may be received at an input of a conversion circuit. The current may be converted to a voltage signal which may be used to create a negative feedback current to the input of the conversion circuit and which may be demodulated digitally to provide a static digital output representative of a capacitance.

Delta modulator receive channel for capacitance measurement circuits

A fingerprint sensing circuit, system, and method is disclosed. The fingerprint sensor maybe include a plurality of inputs coupled to a plurality of fingerprint sensing electrodes and to an analog front end. The analog front end may be configured to generate at least one digital value in response to a capacitance of at least one of the plurality of fingerprint sensing electrodes. Additionally, the analog front end may include a quadrature demodulation circuit to generate at least one demodulated value for processing by a channel engine. The channel engine may generate a capacitance result value that is based, in part, on the demodulated value and is stored in a memory.

A capacitance-sensing circuit may include a channel input associated with measuring a capacitance of a unit cell of a capacitive sense array. The capacitance-sensing circuit may also include a capacitive hardware baseliner that is coupled to the channel input. The capacitive hardware baseliner may generate a baseline current using a baseline capacitor and may provide the baseline current to the channel input.

A method for compensating for panel capacitance the associated current is proposed, wherein the mutual capacitances of a capacitance sensing array are selectively coupled to drive voltages and to a self capacitance under test.

Tunable baseline compensation scheme for touchscreen controllers

Embodiments of a capacitance sensing system including an integrating amplifier and methods for operating the same to provide a higher slew rate and bandwidth are described. In one embodiment, the integrating amplifier comprises an input stage including an inverting input coupled to an electrode of a capacitor to sense a capacitance and a non-inverting input coupled to a reference potential, and an output stage including a compensating capacitor coupled to an output. The compensating capacitor comprises two smaller capacitors coupled in parallel and a switching element configured to open when the integrating amplifier is operated in a RESET mode decoupling one of the two smaller capacitors from the output to decrease capacitance of the compensating capacitor.

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Cork, Ireland

Kaveh Hosseini