Broadcom Corporation

Synaptics Corporation

David A Sobel

Sumant Ranganathan

John S Walley

Jeyhan Karaoguz

Jeremy Roberson

Tianhao Li

Pieter Vorenkamp

Monika Gupta

Peijun Shan

Joseph Kurth Reynolds

Stephen L Morein

Adam L Schwartz

Tom W Kwan

Damien Berget

Augustine Kuo

Robert M Lukas

Federico Santiago Cattivelli

Satish Vithal Joshi

Glen Weaver

Qiang Fu

Xin Dai

Kirk Hargreaves

Eric Scott Bohannon

David Hoch

Tetsuo Tanemura

Tracy Scott Dattalo

Derek Solven

Vladan Petrovic

John Weinerth

Pi Sheng Chang

Xinyu Yu

Farzaneh Shahrokhi

Fang Lin

Kerrynn Jacques De Roche

Bob Lukas

Jeff Lukanc

Ian Atkinson

A system and method for synchronizing multiple integrated circuit (IC) chips for an input device having a display device integrated with a capacitive sensing device. A first one of the IC chips is a master IC chip and a second one of the IC chips is a slave IC chip. The master IC chip is configured to transmit synchronization signals to and from the slave IC chip, such that capacitive frames are acquired by each of the IC chips at substantially the same time, the initiation of the sensing signals is synchronized for each of the IC chips and the clock signals of the slave IC chips are synchronized with the clock signal of the master IC chip.

System and method for synchronizing sensing signals of integrated circuit chips

A force sensing device includes a first force sensor and a second force sensor. The first force sensor is configured to output a first force resulting signal and includes a first strain gauge coupled to a first voltage source and a first trace. The first force sensor further includes a second strain gauge coupled to a second voltage source and the first trace. The second force sensor is configured to output a second force resulting signal having a polarity opposite that of the first force resulting signal. The second force sensor includes a first strain gauge coupled to the second voltage source and a second trace, and a second strain gauge coupled to the first voltage source and the second trace.

Force sensing input device utilizing strain gauges

Embodiments disclosed herein generally relate to electronic devices, and more specifically, to a waveform generation circuit for input devices. One or more embodiments provide a new waveform generator for an integrated touch and display driver (TDDI) and methods for generating a waveform for capacitive sensing with a finely tunable sensing frequency. A waveform generator includes accumulator circuitry, truncation circuitry, and saturation circuitry. The accumulator circuitry is configured to accumulate the phase increment value based on a clock signal, and output the accumulated phase increment value. The truncation circuitry configured to drop one or more bits of the accumulated phase increment value to output a truncated value. The saturation circuitry is configured to compare the truncated value to a saturation limit and output a signal corresponding to accessed data samples.

Waveform generation circuit for finely tunable sensing frequency

A processing system includes a sensor module configured to receive first and second signals from first and second sensor electrodes, respectively, and generate a combination signal. The processing system further includes a determination module configured to determine, using the first sensor electrode, an absolute capacitive coupling to an input object; determine, using the first and second sensor electrodes, a transcapacitive coupling; determine a ratio of the absolute to transcapacitive coupling; determine, using the combination signal, in absence of a predetermined low ground mass state, and when the ratio fails to exceed a predetermined threshold, first positional information regarding a location of the input object; and determine, when the ratio fails to exceed the predetermined threshold and in presence of the predetermined low ground mass state, second positional information regarding the location of the input object in the sensing region using an absolute capacitive scan.

Transcapacitive and absolute capacitive sensing profiles

An input device is configured to detect signals from of an input object. Examples include acquiring a first signal on a first sensor electrode of the input device; acquiring a second signal on a second sensor electrode of the input device; combining the first signal and the second signal to produce a combined signal; demodulating the combined signal to determine an in-phase component of the combined signal and a quadrature component of the combined signal; and combining the in-phase component and the quadrature component to determine signal magnitude information.

Touch controller with signal combining and simultaneous I/Q demodulation

Embodiments described herein include an input device with a plurality of capacitive sensor electrodes configured to receive a signal. The input device also includes a processing system coupled to the plurality of capacitive sensor electrodes. The processing system includes an analog front end (AFE). The AFE includes an anti-aliasing filter comprising a continuous time analog infinite impulse response (IIR) filter configured to filter out interference from the received signal at frequencies higher than a signal frequency of the processing system to produce an anti-aliased signal. The AFE also includes a charge integrator configured to integrate the anti-aliased signal.

Continuous time anti-alias filter for capacitive touch sensing

An input device including: a first in-phase touch sensing block including: an analog mixer configured to mix a resulting signal associated with a capacitive sensor electrode with a local oscillator (LO) signal; an analog to digital converter (ADC) configured to convert an output of the analog mixer into a digital signal; and a first decimation filter configured to determine an in-phase component of an interference at a frequency of the LO signal based, at least in part, on the digital signal; and a first quadrature interference detection block including: a second decimation filter configured to determine a quadrature component of the interference at the frequency.

Interference detection

An example circuit includes: a filter configured to process a digital signal through at least one stage; and a coefficient generator circuit configured to generate coefficients for the at least one stage of the filter. The coefficient generator circuit includes: a lookup-table (LUT) configured to output a differential sequence; an up-sampling holder circuit configured to up-sample and hold the differential sequence to generate an up-sampled differential sequence; and an accumulator configured to integrate the up-sampled differential sequence to generate the coefficients.

Coefficient generation for digital filters

A processing system for an input device, the processing system including: a sensor module coupled to sensor circuitry and configured to: initiate a current beacon period including a plurality of timeslots by broadcasting a current beacon signal to a plurality of active pens; receive, during a first timeslot, a first downstream packet from a first active pen transceiver; and receive, during a second timeslot, a second downstream packet from a second active pen transceiver; and a determination module configured to: determine an attribute of a first active pen including the first active pen transceiver from at least the first downstream packet.

Active pen with bidirectional communication

An example circuit includes: a plurality of analog-to-digital converters (ADCs) receiving a respective plurality of analog signals and outputting a respective plurality of digital signals; a coefficient generator circuit outputting a coefficient signal; and a plurality of decimation filters each including a first input that receives a respective one of the plurality of digital signals and a second input that receives the coefficient signal, each of the plurality of decimation filters including a finite impulse response (FIR) filter having a multiplier and a single accumulator.

Decimation filtering in systems having parallel analog-to-digital converter channels

Adaptive reconfiguration of a capacitive touch controller is implemented by estimating the interference spectrum of the signal received by the touch controller. The spectrum of the received signal is used to determine a desired frequency, and the touch panel transmitter is configured to use that desired frequency. The spectrum of the received signal is also used to determine an desired filter transfer function. A filter in the touch panel received signal path is configured to use that desired filter transfer function. The adaptive reconfiguration is focused on improving the signal to noise ratio of the received signal without the need for shielding the touch panel, performing additional scans of the touch panel, or using components that operate at higher power levels.

Interference estimation and adaptive reconfiguration of a capacitive touch controller

Provided are systems and methods for providing enhanced touch sensing. One system providing enhanced touch sensing includes a multi-mode touch screen and a processor configured to apply at least one test signal to a sense element of the multi-mode touch screen, detect at least one return signal from the sense element, and then determine a relative position of an object corresponding to the at least one return signal, the multi-mode touch screen being capable of sensing the first object using first and second detection modes. One multi-mode touch screen comprises a multi-mode multi-touch touch screen. One processor is configured to apply an adaptive test signal to a sense element of a touch screen.

Systems and methods for providing enhanced touch sensing

Systems and methods are provided that allow a touch sensor, such as a mutual capacitive touch panel, to switch from an operative transmit (TX) frequency at which the mutual capacitive touch panel is driven to an alternative TX frequency. When switching to an alternative TX frequency, an alternative baseline capacitance value corresponding to the alternative TX frequency may be utilized to determine whether a touch event has occurred on the mutual capacitive touch panel. Frame scans can be repeatedly performed at the operative TX frequency and the alternative TX frequency in rapid succession, and an average difference of the frame scans can be calculated and utilized to generate the alternative baseline capacitance value which may be insensitive to sudden ambient changes and moving touch events affecting the mutual touch capacitive panel.

Baseline recalculation after frequency reconfiguration of a mutual capacitive touch controller

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San Francisco, CA, United States of America

David A Sobel