Abstract: A method for operating an electronic device, including: determining that a touchscreen is in a low frequency display (LFD) mode, determining whether a self-sensing scan was performed in a previous frame of a plurality of frames; after determining, a self-sensing scan was performed in the previous frame, determining a current duration of time corresponding to a current frame based on a previous duration of time corresponding to the previous frame, the previous frame being a frame immediately preceding the current frame; determining, whether the current duration of time is greater than the previous duration of time; and after determining that the current duration is greater than the previous duration, performing a self-sensing scan after the current duration of time, the current duration of time being measured from a beginning of the current frame, the current duration of time having a duration less than a duration of the current frame.

Abstract: A circuit includes a force driver to apply a force signal to a force node associated with a mutual capacitance to be sensed, and a charge to voltage converter having an input coupled to receive a sense signal from a sense node associated with the mutual capacitance to be sensed. The charge to voltage converter includes an integrator circuit to integrate the sense signal to sense the mutual capacitance, an input switch between the input of the charge to voltage converter and an input of the integrator circuit, and a reset switch between an output of the integrator circuit and the input of the integrator circuit. A control circuit controls generation of the force signal to alternate between at least two different frequencies and generates, for each half cycle of the force signal, a first signal for closing the input switch and a second signal for closing the reset switch.

Abstract: A method for operating an electronic device, the method including: displacing a rollable touchscreen to a first position along a first direction, a first side of the rollable touchscreen being mounted in a housing, the rollable touchscreen being configured to be rolled into or unrolled out of the housing along the first direction, detecting an active electrode at a first location on the rollable touchscreen, the active electrode being mounted in the housing, and determining the first position of the rollable touchscreen based on the first location, the first positing being indicative of a fractional amount of the rollable touchscreen outside the housing.

Abstract: A device includes a force driver applying a force signal to a force node associated with a mutual capacitance between the force node and a sense node. A sensing circuit receives a sense signal from the sense node associated with the mutual capacitance between the force node and the sense node, and generates an output indicative of the sensed mutual capacitance. A control circuit controls the generation of the force signal to alternate between at least two different frequencies by generating consecutive pulses, with a given pulse of the consecutive pulses at a first of the at least two different frequencies. In a first operating state, a next pulse immediately succeeding the given pulse is at a second of the at least two different frequencies, and in a second operating state the next pulse immediately succeeding the given pulse is at the first of the at least two different frequencies.

Abstract: An over-voltage protection circuit and methods of operation are provided. In one embodiment, a method includes monitoring a voltage at an output of a rectifier, a voltage at an output of a voltage regulator, or a combination thereof. The method further includes determining the over-voltage condition based on the monitoring; and in response to determining the over-voltage condition, regulating the voltage at the output of the rectifier in accordance with a voltage difference between the voltage at the output of the rectifier and the voltage at the output of the voltage regulator.

Abstract: A method of wirelessly transmitting power includes: causing a power transmission circuit to transmit, to a master power reception circuit, a portion of power it is capable of transmitting; adjusting operation of a slave power reception unit until a first rectified voltage produced by the master power reception circuit and a second rectified voltage produced by the slave power reception unit are equal; causing the power transmission circuit to transmit additional power to the slave power reception unit, resulting in the first and second rectified voltages being unequal; and adjusting operation of the slave power reception unit until the first and second rectified voltages are again equal. A dummy load is connected to the slave power reception unit prior to causing the power transmission circuit to transmit the additional power, and is disconnected once the first and second rectified voltages are equal.

Abstract: A method for operating an electronic device includes rotating a first portion of a flexible touchscreen with respect to a second portion of the flexible touchscreen around a folding axis; detecting, self-capacitances sensed in a folding area of the flexible touchscreen using a self-sensing scan, where a first side of the folding area is on the first portion of the flexible touchscreen and a second side of the folding area is on the second portion of the flexible touchscreen, and the first side and the second side are separated by a folding axis; determining, a current strength sensed by the flexible touchscreen in the folding area based on the self-capacitances in the folding area; and determining, a folding angle of the first portion of the flexible touchscreen with the second portion of the flexible touchscreen around the folding axis based on the current strength in the folding area.

Abstract: A power transmitter includes: a first switch coupled between a first node and a reference voltage node; a second switch configured to be coupled between a power supply and the first node; a coil and a capacitor coupled in series between the first node and the reference voltage node; a first sample-and-hold (S&H) circuit having an input coupled to the first node; and a timing control circuit configured to generate a first control signal, a second control signal, and a third control signal that have a same frequency, where the first control signal is configured to turn ON and OFF the first switch alternately, the second control signal is configured to turn ON and OFF the second switch alternately, and where the third control signal determines a sampling time of the first S&H circuit and has a first pre-determined delay from a first edge of the first control signal.

Abstract: A wireless power receiving circuit includes a transistor based rectifier receiving an AC input voltage, and control logic receiving an overvoltage signal. The control logic generates control signals for controlling turn on of transistors within the transistor based rectifier based upon the overvoltage signal so as to cause the transistor based rectifier to produce a rectified output voltage from the AC input voltage. A comparator compares the rectified output voltage to a reference voltage and asserts the overvoltage signal if the rectified output voltage is greater than the reference voltage. In response to assertion of the overvoltage signal, the control logic asserts the control signals to simultaneously turn on all transistors of the transistor based rectifier.

Abstract: A method for modulating a signal including operating a circuit in a first arrangement during a first operating interval and switching the circuit between the first arrangement and a second arrangement during a first modulation interval to vary a load on the circuit to produce a first amplitude shift keying (ASK) signal. The method further includes detecting a voltage on the circuit crossing a threshold level and operating the circuit in the second arrangement during a second operating interval. The method also includes switching the circuit between the second arrangement and the first arrangement during a second modulation interval to vary the load on the circuit to produce a second ASK signal.

Abstract: A circuit includes a tank capacitor coupled between first and second nodes, and a sense resistor having a first terminal coupled to the first node and a second terminal coupled to a regulator input. A switching circuit has first and second inputs coupled to the first and second terminals of the sense resistor. A gain stage has first and second inputs capacitively coupled to first and second outputs of the switching circuit. An analog-to-digital converter receives the output of the gain stage, and receives first and second differential voltages. A reference voltage generator has a temperature independent current source coupled to source current to a reference resistor, the first differential reference voltage being formed across the reference resistor. The reference resistor and sense resistor are located sufficiently close to one another on a single common substrate such that they remain at substantially a same temperature.

Abstract: An electronic device includes a touch screen for a touch sensitive display carried by a portable housing. The electronic device is configured to operate in a high detection threshold mode to determine whether an object is in contact with the touch sensitive display, and operate in a low detection threshold mode to determine whether the object is adjacent to the touch sensitive display, based on lack of detection of the object being in contact with the touch sensitive display. The electronic device is further configured to determine whether the object s in contact with a peripheral edge of the portable housing by determining whether the object is adjacent opposite sides of the touch sensitive display, based on detection of the object being adjacent to the touch sensitive display.

Abstract: In an example, a method of sensing on a touchscreen including a plurality of touch sensors arranged in rows and columns on the touchscreen is described. The method includes detecting a passive touch on the touchscreen and a positon of an active stylus; determining a plurality of locations across the touchscreen corresponding to the passive touch and a positon of the active stylus, where each of the plurality of locations corresponds to a location of one of the plurality of touch sensors. The method includes transmitting a first uplink signal to a first group of the plurality of locations including a first fraction of the plurality of locations; and transmitting a second uplink signal to a second group of the plurality of locations including a second fraction of the plurality of locations, the first uplink signal being different from the second uplink signal.

Abstract: An electronic device includes a pixel array having a plurality of rows with active imaging pixels, and at least one row with test pixels. Each of the test pixels includes a test voltage generation circuit generating a test voltage, a switching circuit receiving the test voltage and an image pixel output signal and passing the test voltage as output when in a test mode, a comparison circuit receiving the output from the switching circuit and an analog to digital conversion signal and asserting a counter reset signal when the output from the switching circuit and the analog to digital conversion signal are equal in voltage, and a counter beginning counting at a beginning of each test cycle within the test mode, stopping counting upon assertion of the counter reset signal, and outputting its count upon stopping counting. The count is proportional to the test voltage when in the test mode.

Abstract: An electronic device described herein includes a touch screen for a touch sensitive display carried by a portable housing. The electronic device is configured to operate in a high detection threshold mode to determine whether an object is in contact with the touch sensitive display, and operate in a low detection threshold mode to determine whether the object is adjacent to the touch sensitive display, based on lack of detection of the object being in contact with the touch sensitive display. The electronic device is further configured to determine whether the object is in contact with a peripheral edge of the portable housing by determining whether the object is adjacent opposite sides of the touch sensitive display, based on detection of the object being adjacent to the touch sensitive display.

Abstract: A receiver circuit includes a rectifier operable in full-, half-synchronous and asynchronous modes. A measurement circuit, with method, provides for real-time power measurement within the rectifier. The measurements are made based on the average output current from the rectifier delivered to the load and measurements sampled over time of the instantaneous voltage at each input/output node of the rectifier. Equivalent resistance in the rectifier is determined from the measurements and power dissipation calculated from the determined equivalent resistance and the average output current. The instantaneous voltages are synchronously captured through high-voltage AC coupling in order to detect the voltage drop across each element of the rectifier. The sensed voltages are amplified in the low voltage domain and converted by a high-speed analog-to-digital converter in order to produce data useful in computing equivalent resistance values.

Abstract: A system comprising includes a wireless power receiver generating a rectified voltage. A low dropout regulator (LDO) generates a first regulated output voltage from the rectified voltage, during a first phase. A first switch couples the first regulated output voltage to a voltage output node during the first phase. During a second phase, the LDO generates a second regulated output voltage from the rectified voltage. A switching regulator generates a third regulated output voltage during the second phase. A second switch couples the third regulated output voltage to the voltage output node during the second phase. During a third phase, the LDO is disabled, while the switching regulator continues to generate the third regulated output voltage. The first switch opens during the third phase while the second switch remains closed.

Abstract: Disclosed herein is a bridge rectifier and associated control circuitry collectively forming a “regtifier”, capable of both rectifying an input time varying voltage as well as regulating the rectified output voltage produced. To accomplish this, the gate voltages of transistors of the bridge rectifier that are on during a given phase may be modulated via analog control (to increase the on-resistance of those transistors) or via pulse width modulation (to turn off those transistors prior to the end of the phase). Alternatively or additionally, the transistors of the bridge rectifier that would otherwise be off during a given phase may be turned on to help dissipate excess power and thereby regulate the output voltage. A traditional voltage regulator, such as a low-dropout amplifier, is not used in this design.

Abstract: An electronic device includes a test voltage generation circuit to generate a test voltage as a function of a regulator voltage, and a switching circuit to receive the test voltage and an image pixel output signal, and to pass the test voltage as output when in a test mode. A comparison circuit receives the output from the switching circuit and an analog to digital conversion signal, and asserts a counter reset signal when the output from the switching circuit and the analog to digital conversion signal are equal in voltage. A counter begins counting at a beginning of each test cycle within the test mode, stops counting upon assertion of the counter rest signal, and outputs its count upon stopping counting. The count is proportional to the test voltage when in the test mode.

Abstract: A strain gauge includes first and second substrates spaced apart from one another. A first flexible printed circuit board portion is in contact with a top side of the first and second substrates, and has a first Wheatstone bridge formed therein. The first flexible printed circuit board portion positions the first Wheatstone bridge such that two resistors of the first Wheatstone bridge are positioned to span from the top side of the first substrate to the top side of the second substrate. A second flexible printed circuit board portion is in contact with a bottom side of the first and second substrates, and has a second Wheatstone bridge formed therein. The second flexible printed circuit board positions the second Wheatstone bridge such that two resistors of the second Wheatstone bridge are positioned to span from the bottom side of the first substrate to the bottom side of the second substrate.