Shenzhen Goodix Technology Co., Ltd.

Silicon Laboratories Inc.

Marvellworld Trade Ltd.

Chao Yang

Dazhi Wei

Mohamed M Elsayed

Matthew Powell

Xiaodong Wang

Brian Taylor Brunn

Rinaldo Castello

Gregory Takeo Uehara

Alessandro Venca

Fernando De Bernardinis

Ruoxin Jiang

Marc Leroux

Axel Thomsen

Praveen Kallam

Scott D Willingham

Marck Leroux

Techniques are described for low-noise self-capacitor sensing in a capacitive touch panel array integrated with a display panel. Each channel of the array has a self-capacitance (Ci) that changes responsive to presence or absence of a local touch event local. Each channel is read by an analog front-end (AFE) by using a locally noise-suppressed discharge current for a discrete discharge time to discharge Ci to obtain a discharge voltage level that differs with presence or absence of the local touch event, and outputting a voltage output for the channel based on the discharge voltage level by passively mixing at least the discharge voltage level to produce a pair of up-converted channel signals, sampling the pair of up-converted channel signals to obtain a differential voltage sample, and amplifying the differential voltage sample to generate the Vout as indicating absence or presence of the touch event local to the channel.

Low-noise self-capacitor sensing for capacitive touch panels

Techniques are described for using a multi-branch AC-mode bridge approach with global current rotation for self-capacitor sensing in a capacitive touch panel, such as integrated into a display of a touchscreen electronic device. K channels are coupled with K branches of a multi-branch AC-mode bridge to form K−1 pairs of channels for concurrent differential readout. K nominally identical sinusoidal input currents are generated based on an error signal, which is generated based on comparing a sinusoidal driver signal with feedback from one or more of the K branches. A unit current rotator rotates the K sinusoidal input currents to each of the branches, so that each branch current is formed by a rotating contribution from each of the sinusoidal input currents. Driving each branch with its branch current manifests a respective branch voltage, and differences between the branch voltages can be used to differentially sense pairs of channels.

Self-capacitor sensing using alternating-current-mode bridge with global current rotation for capacitive touch panels

Techniques are described for discrete-time self-capacitor sensing in a touch panel. The self-capacitor manifests a detectably different capacitance based on presence or absence of a local touch event on the touch panel. In a first time phase, embodiments charge a self-capacitor and initialize a ramp bias generator. In a second time phase, embodiments discharge the self-capacitor with a ramp-controlled current source that is biased by the ramp bias generator to produce a discharge current that transitions from high at the beginning of the second time phase to low at the end of the second time phase. By the end of the second phase, the remaining charge in the self-capacitor depends on presence or absence of a local touch event. Some embodiments convert the remaining charge to an amplified sense output for readout.

Self-capacitor sensing for capacitive touch panels

Techniques are described for using an alternating-current-mode (AC-mode) bridge for low-noise self-capacitor sensing in a capacitive touch panel array integrated with a display panel. Each channel of the array has a self-capacitance (Ci) that changes responsive to presence or absence of a local touch event local. Pairs of channels are read out differentially by coupling pairs of channels to branches of an AC-mode bridge. The AC-mode bridge includes current sources that drive each branch (and thereby each channel) with a sinusoidal current, manifesting a branch voltage on each branch based on the self-capacitance of the branch. The branch voltages are used to generate an output voltage. The sinusoidal current is controlled by comparing a driver signal with feedback from the branches, so that common-mode noise on the channels becomes a common-mode component of the sinusoidal currents and is rejected in the generation of the output voltage.

Self-capacitor sensing using alternating-current-mode bridge for capacitive touch panels

An image sensor includes image sensor cells generating an image signal in response to one or more control signals, and a first driver generating a first control signal. The first driver includes a first positive supply terminal connected to a first power supply node. The image sensor also includes a voltage generator generating a first voltage at the first power supply node, where the voltage generator includes charge pump cells to receive clock signals and to source charge to the first power supply node, a delay line including delay line elements generating clock signals, where a first charge pump cell receives a first clock signal generated by a first delay line element, where a second charge pump cell receives a second clock signal generated by a second delay line element, and where a delay between the first clock signal and the second clock signal is determined by the delay line.

Image sensor with delay line charge pump voltage generator

An image sensor includes a plurality of image sensor cells, each configured to generate or not generate an image signal in response to one or more control signals, and a first driver generating a first control signal. The first driver includes a first positive supply terminal connected to a first power supply node. The image sensor also includes a voltage generator generating a first voltage at the first power supply node, where the voltage generator includes a plurality of charge pump cells selectably sourcing charge to the first power supply node in response to one of multiple enable signals, and a charge pump cell quantity controller circuit generating the enable signals. Each enable signal is either in an active or inactive state, and each charge pump cell sources charge to the first power supply node in response to receiving an enable signal in an active state.

Image sensor with charge pump cell quantity control

An image sensor includes ADCs, each including a comparator receiving a ramp signal and an image signal, and generating a comparator output. Each ADC also includes a counter ceasing to change a digital count value in response to a change in the comparator output. The digital count value has a first resolution. Each ADC also includes a delay line circuit including a delay line generating a first digital value encoding a duration of a period of the counter clock and generating a second digital value encoding a first portion of the period of the counter clock. Each ADC also includes a delay to digital circuit generating a digital output value based on the first and digital values. The digital output value encodes a second value of the ramp signal, where the digital count value has a second resolution that is greater than the first resolution.

Image sensor having high resolution analog to digital converter

An image sensor includes image sensor cells, each configured to generate an image signal in response to control signals. The image sensor also includes an ADC to receive the image signals of the image sensor cells, and a first driver to generate one or more first control signals for a first image sensor cell, where the first driver includes a first negative supply terminal. The image sensor also includes a first multiplexor to selectively connect the first negative supply terminal of the first driver to one of a plurality of power supply nodes, and a second driver to generate one or more second control signals for a second image sensor cell, where the second driver includes a second negative supply terminal. The image sensor also includes a second multiplexor to selectively connect the second negative supply terminal of the second driver to one of the power supply nodes.

Image sensor row driver negative supply connections

An image sensor includes a controller and a plurality of pixel clusters. Each of the pixel clusters includes a plurality of pixels coupled to a reset transistor, a floating diffusion node, a source follower, and a select transistor. Each pixel of a pixel cluster includes a photodiode, and a transfer transistor having a first terminal coupled to the photodiode, a second terminal coupled to the floating diffusion node, and a gate. The controller is configured to apply a transfer control signal to the gate of the transfer transistor in response to a pixel operation, the transfer control signal being one of a positive voltage level, a negative voltage level, and a ground voltage level.

Two level TX low control for simultaneous improved noise and dark current

A charge pump system including charge pump circuitry, a charge pump controller, and current limit circuitry. The charge pump circuitry has an input coupled to a supply input node and has an output for developing a drive voltage. The charge pump controller controls the charge pump circuitry to increase the drive voltage above a supply voltage provided to the supply input node. The current limit circuitry limits current through the charge pump circuitry to a limited current level that is less than a maximum current level during a current limit mode to reduce current spikes at the nodes of the charge pump system that may generate EMI. A current mirror may be used as the current limit circuitry to directly limit current through switches of the charge pump circuitry. The timing of the charge pump switches may also be modified such as inserting strategic delays to reduce the current spikes.

Charge pump system with electromagnetic interference mitigation

An apparatus includes an integrated circuit, which includes a processor core, a plurality of input/output (I/O) circuits, and a plurality of over voltage tolerant (OVT) circuits. Each I/O circuit is associated with an I/O pad and is associated with an OVT circuit of the plurality of OVT circuits. At least one of the OVT circuits includes a passive circuit, which is adapted to receive a pad voltage from the associated I/O pad; receive a supply voltage of the associated I/O circuit; and based on a relationship of the received pad voltage relative to the received supply voltage, selectively couple a gate of a transistor of the associated I/O circuit to the pad voltage to inhibit a leakage current.

Over voltage tolerant circuit

A quantizer including passive summers, dynamic comparators and a clock generator. Each passive summer samples the input voltages and a reference voltage scaled by one of multiple graduated gains, and subtracts the scaled reference voltage from the sum of the input voltages. The graduated gains divide a predetermined voltage range into multiple voltage subranges, each between sequential pairs of the passive summers. The dynamic comparators compare each sequential pair of passive summer output voltages according to multiple splitting ratios and provide corresponding quantization bits. The dynamic comparators are activated in groups to reduce comparator kickback. Each dynamic comparator recharges the passive summer output voltages coupled to its inputs back to their initial voltage values to reduce kickback residual. The passive summers eliminate the need for a resistor string to generate the reference voltages. Staggered activation and comparator recharging replace preamplifiers used to suppress kickback and kickback residuals.

Low power quantizer with passive summers and interpolated dynamic comparators

In some embodiments, a method may include receiving an input signal at an input stage of a circuit and amplifying the input signal using an amplifier of the circuit to produce a level-shifted output signal. The method may further include selectively controlling switches of an active load coupled to the input stage based on the level-shifted output signal to turn off current flow between transitions in the input signal.

Level-shifter circuit for low-input voltages

In one embodiment, an apparatus includes an upconversion unit configured to upconvert a baseband signal to a radio frequency (RF) signal. A plurality of baluns for a plurality of wireless bands are provided. Multiplexing circuitry is coupled to the plurality of baluns where the upconversion unit is coupled to each balun through the multiplexing circuitry. The multiplexing circuitry is configured to multiplex the radio frequency signal from the upconversion unit to one of the plurality of baluns based on a wireless band being used.

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Austin, TX, United States of America

Chao Yang