Abstract: In accordance with an embodiment, a method of operating a piezoelectric transducer configured to transduce mechanical vibrations into transduced electrical signals at a pair of sensor electrodes includes stimulating a resonant oscillation of the piezoelectric transducer by applying at least one pulse electrical stimulation signal to the pair of sensor electrodes; detecting, at the pair of sensor electrodes, at least one electrical signal resulting from the stimulated resonant oscillation, wherein the at least one electrical signal resulting from the stimulated resonant oscillation oscillates at a resonance frequency of the piezoelectric transducer; measuring a frequency of oscillation of the at least one electrical signal resulting from the stimulated resonant oscillation to obtain a measured resonance frequency of the piezoelectric transducer; and tuning a stopband frequency of a notch filter coupled to the piezoelectric transducer to match the measured resonance frequency of the piezoelectric transducer.

Abstract: A method includes: displaying, an image on a display by sequentially displaying a plurality of frames of the image, the plurality of frames including a first frame and second frame; performing a first noise sampling scan at a plurality of frequencies at a first time location within a first frame; determining a first frequency from the plurality of frequencies with the lowest noise; performing a first mutual sensing scan at the first frequency; performing, a second noise sampling scan at the plurality of frequencies at a second time location within a second frame of the plurality of frames, the second time location being a different frame location than the first time location; determining a second frequency from the plurality of frequencies with the lowest noise, the second frequency being different from the first frequency; and performing, a second mutual sensing scan at the second frequency.

Abstract: A wireless power receiver includes a rectifier with first and second inputs coupled to first and second terminals of a receiver coil, and having a first output coupled to ground and a second output at which a rectified voltage is produced. A first switch is coupled between the second input and ground, and is controlled by a first gate voltage generated at a first node. A second switch is coupled between the first node and ground, and is controlled by a second gate voltage. The first gate voltage closes the first switch to couple the second input to ground when the rectified voltage is less than a threshold voltage, boosting the rectified voltage. The second gate voltage closes the second switch to cause the second gate voltage to be pulled to ground when the rectified voltage is greater than the threshold voltage, limiting the boosting of the rectified voltage.

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: Disclosed herein is a wireless power reception system that utilizes a switched capacitor DC-DC voltage converter to charge a load. Current sensing circuits described herein enable the measurement of the input current to the switched capacitor DC-DC voltage converter while being relatively insensitive to temperature variation. Voltage/current sensing circuits described herein enable the selective measurement of load voltage, high side load current, and low side load current. One of the current sensing circuits may be used together with one of the voltage/current sensing circuits in a single device, or the current sensing circuits and voltage/current sensing circuits may be used separately in different devices.

Abstract: A device includes an analog to digital converter configured to convert voltages into a digital signal by sampling the voltages at a fixed sampling time; a first multiplier configured to multiply the digital signal with in-phase coefficients, the in-phase coefficients generated to produce a demodulated in-phase signal at a demodulation signal frequency; a first adder configured accumulate the demodulated in-phase signal to output in-phase magnitude values; a second multiplier configured to multiply the digital signal with quadrature coefficients, the quadrature coefficients generated to produce a demodulated quadrature signal at the demodulation signal frequency; and a second adder configured to accumulate the demodulated quadrature signal to output quadrature magnitude values.

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 bridge rectifier is controlled by control circuitry to act a “regtifier” which both regulates and rectifies without the use of a traditional voltage regulator. To accomplish this, the gate voltages of transistors of the bridge that are on during a given phase may be modulated to dissipate excess power. Gate voltages of transistors of the bridge that are off during the given phase may alternatively or additionally be modulated to dissipate excess power. The regtifier may act as two half-bridges that each power a different voltage converter, with those voltage converters powering a battery. The voltage converters may be switched capacitor voltage converters that switch synchronously with switching of the two half-bridges as they perform rectification.

Abstract: A bridge rectifier and associated control circuitry collectively form a “regtifier” which rectifies an input time varying voltage and regulates the rectified output voltage produced without the use of a traditional voltage regulator. 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). 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. This modulation is based upon both a voltage feedback signal and a current feedback signal.

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: An embodiment method for operating an electronic device includes transmitting, from a controller, a tearing effect (TE) signal to a touchscreen over a first period of time, the first period of time occurring during a first frame and having a duration that is shorter than a period of the first frame, the TE signal being configured to restrict image data from being displayed on the touchscreen during the first period of time; displaying the first frame of a plurality of frames of the image data on a display of the touchscreen over a second period of time within the period of the first frame other than during the first period of time; and detecting, at the controller, a first touch by performing a first self-sensing scan during the first period of time.

Abstract: The present disclosure is directed to a contactless card including an actuation security structure that is actuated to provide authorization in accessing identifying information on an integrated circuit within the contactless card. In at least one embodiment, the actuation security structure includes a pair of conductive layers and a pair of electrodes. Ends of the pair of conductive layers overlap respective ones of the pair of electrodes. The ends of the pair of conductive layers are at and in a first elastically deformable region and the respective ones of the pair of electrodes are at and in a second elastically deformable region. An owner of the contactless card may provide authorization to access the identification information on the contactless card by applying force to both the first and second elastically deformable regions inward resulting in the ends of the conductive layers moving into electrical communication with the pair of electrodes.

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: In an example, a display device includes a rollable display including a display side and an opposite non-display side. The rollable display includes a conductive material with a pattern disposed on the non-display side. The device includes a housing configured to house the rollable display and configured to roll in and roll out the rollable display along a first direction, and a capacitive sensor including a transmitter and a receiver electrode disposed within the housing and configured to sense the pattern.

Abstract: A wireless power-reception system has a bridge rectifier with two high-side and two low-side transistors, linked to input-nodes and sense-resistors. During a first phase, a control circuit activates certain transistors for rectification, producing an output voltage, while modulating a gate voltage of a non-activated low-side transistor to dissipate excess power and regulate the output voltage. During a first given number of occurrences of the first phase, the control circuit determines the current through the low-side transistor having its gate voltage modulated based upon a voltage across a first sense resistor coupled between that low-side transistor and ground. During a second given number of occurrences of the first phase, the control circuit determines the current delivered to the load based upon a voltage across the first sense resistor and a voltage across a second sense resistor coupled between the other low-side transistor and ground.

Abstract: A method for operating a wireless charging transmitter includes switching, by the wireless charging transmitter, an operating mode of a full bridge inverter of the wireless charging transmitter from a first mode to a second mode; and changing, by the wireless charging transmitter, an operating point of the wireless charging transmitter from a first operating point associated with the first mode to a second operating point associated with the second mode, the second operating point being selected to dampen a change in a rectifier voltage of a wireless charging receiver inductively coupled to the wireless charging transmitter.

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: An integrated circuit is provided having an active circuit. A heating element is adjacent to the active circuit and configured to heat the active circuit. A temperature sensor is also adjacent to the active circuit and configured to measure a temperature of the active circuit. A temperature controller is coupled to the active circuit and configured to receive a temperature signal from the temperature sensor. The temperature controller operates the heating element to heat the active circuit to maintain the temperature of the active circuit in a selected temperature range.

Abstract: A method for operating an electronic device includes a touchscreen controller determining based on a frequency of a vertical synchronization signal (Vsync), whether a first display frame includes an idle time, the idle time being a duration of time remaining in the first display frame after an image displayed on a display of the electronic device is updated during the first display frame. The method further includes in response to determining that the first display frame includes the idle time, the touchscreen controller transmitting an uplink signal in the first display frame, the uplink signal being transmitted during the idle time of the first display frame.

Abstract: In an embodiment, a method includes performing a calibration of a first touch cell of a touch screen, where performing the calibration includes: receiving a first code associated with the first touch cell; receiving a second code associated with the first touch cell; determining whether there is an indication of a touch of the touch screen based on the first and second codes; generating a raw code based on the first or second codes; receiving a third code associated with the first touch cell; determining whether the third code matches the raw code; and in response to determining that there is no indication of a touch of the touch screen based on the first and second codes, and that the third code matches the raw code, updating a calibration code associated with the first touch cell based on the raw code or the third code.