Apple Inc.

Invensense, Inc.

Texas Instruments Corporation

Du Chen

Christoph Horst Krah

Baris Cagdaser

Stanley Bo-Ting Wang

Derek Keith Shaeffer

Hasan Akyol

Vadim M Tsinker

Kemal Safak Demirci

Pablo Moreno Galbis

Chang Yong Kang

An electronic device can be configured to operate in a plurality of operating modes to generate various stimulation signals for touch sensing operations. Switching circuitry can selectively couple one or more stimulation circuits to touch stimulation circuitry to reduce electromagnetic interference generated during transitions between the plurality of operating modes. The electronic device can transition from a stimulation phase to a termination phase at an arbitrary time, unconstrained by integration time requirements of accompany touch sensing circuitry.

System and method of power management for touch and display supplies in multiple power domains

A power management circuit can comprise a direct-current-to-direct-current (DC-DC) converter and a guard buffer. The guard buffer can be referenced to a system ground and configured to generate a guard ground. The power management circuit can comprise a supply capacitor coupled to the DC-DC converter that can be referenced to system ground in a first mode and referenced to the guard ground in a second mode. A regulator can be coupled to the DC-DC converter and referred to system ground in the first mode, and decoupled and referred to guard ground in the second mode. The DC-DC converter can generate a first voltage in the first mode and a second voltage in the second mode, the second voltage greater than the first.

Some touch screens can be formed by at least partially integrating touch sensing circuitry into a display pixel stackup. In some examples, noise can be introduced into touch sensor panel measurements, for example, from display data lines of a display device proximate to the touch sensor panel. In some examples, rows or columns of touch electrodes can be split and a first portion of the touch sensor panel can be stimulated to measure capacitance and noise and a second portion of the touch sensor panel can be unstimulated and measure noise. In some examples, both the first and the second portions of the touch sensor panel can be stimulated using orthogonal stimulation codes. In some examples, measurements from the first and/or second portions of the touch sensor panel can be subtracted from measurements from the other portion of the touch sensor panel to eliminate or reduce common mode noise.

Common mode noise mitigation for integrated touch screens

A circuit includes a sensor and a half-bridge circuit. The sensor includes a first sensor capacitor and a second sensor capacitor, where capacitances of the first sensor capacitor and the second sensor capacitor change in opposing directions responsive to receiving a physical signal. The sensor generates a plurality of sensor signals according to the physical signal, the plurality of signals including a common mode injection and a plurality of differential signals. The half-bridge circuit includes a first half-bridge capacitor and a second half-bridge capacitor, where capacitances of the first half-bridge capacitor and the second half-bridge capacitor compensate for the common mode injection of the plurality of sensor signals. The sensor and the half-bridge circuit are coupled to a plurality of sense nodes configured to output the plurality of differential signals.

Half-bridge circuit for a sensor

A system includes a sensor device, a circuit driving he sensor device at a drive frequency, a receiver, and a low pass filter. The sensor device is configured to change its electrical characteristics in response to external stimuli. The sensor device generates a modulated signal proportional to the external stimuli. The receiver is configured to receive the modulated signal and further configured to demodulate the modulated signal to generate a demodulated signal. The demodulation signal has a guard band. The receiver consumes power responsive to receiving the modulated signal. The low pass filter is configured to receive the demodulated signal and further configured to generate a sensor output.

Continuous-time sensing apparatus

A method and system for measuring displacement of a structure is disclosed. The method and system comprise providing a first capacitance and providing a second capacitance. The first and second capacitances share a common terminal. The method and system further include determining a difference of the inverses of the value of the first and second capacitances when the structure is displaced. The first capacitance varies in inverse relation to the displacement of the structure.

Linear capacitive displacement sensor

A circuit utilizes a MOS device in a triode mode of operation and includes a biasing circuit and a MOS device. The MOS device has a drain, a source, and a gate terminal, and is coupled to the biasing circuit. The source terminal, drain terminal, and gate terminal each has a potential and the drain and the source terminals have a resistance. The biasing circuit couples the drain and source terminals of the MOS device to the gate terminal of the MOS device. The biasing circuit couples a DC potential to the gate terminal to adjust the resistance between the source and drain terminals of the MOS device. The resistance between the source and drain terminals is a non-linear function of voltage potentials at the source and drain terminals. The biasing circuit reduces the non-linearity of the resistance between the drain and source terminals by modulating the potential at the gate terminal by a combination of source and drain terminal potentials.

Cancellation of dynamic offset in MOS resistors

Active resistive circuitry (A,A, or) includes a first current divider circuit () having an input () coupled to a first signal (V). The first current divider circuit () includes a first amplifier () having a first input (&#x2212;) coupled to the first signal (V). A symmetrically bilateral first bidirectional circuit (M,M; R) is coupled between the first input (&#x2212;) of the first amplifier () and an output () of the first amplifier (), and functions as a feedback circuit of the first amplifier (). A symmetrically bilateral second bidirectional circuit (M,M; R) is coupled between the output () of the first amplifier () and an output () of the first current divider circuit ().

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Saratoga, CA, United States of America

Du Chen