Abstract: A method for operating a display includes receiving a horizontal synchronization (HSYNC) signal from a display driver of the display, the HSYNC signal including a plurality of pulses; measuring a parameter of the HSYNC signal within a frame; and initiating a touch scan on a touch sensing panel of the display based on the measured parameter.

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: 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: A data demodulating circuit includes a sensing circuit sensing a power signal applied to a coil at first and second times, and outputting an analog value representing a difference in voltage of the power signal at the first and second times. An analog-to-digital converter digitizes the analog value output by the analog voltage differential sensing circuit to produce a digital code. A compensation circuit, over a period of time, compares a present value of the digital code to a first value of the digital code during the period, and subtracts a given value from the present value of the digital code if the present value is greater than the first value but add the given value to the present value of the digital code if the present value is less than the first value. An accumulator accumulates output of the compensation circuit, and a filter filters output of the accumulator.

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: A method of differential self-capacitance measurement is used to enhance a signal-to-noise ratio of sense lines in a touch panel display, thereby improving touch sensor accuracy. The differential self-capacitance measurement is implemented for a touch panel using charge sharing between adjacent sense lines of the touch panel matrix. Sequential differential self-capacitance measurements can be compared with one another by computing the difference |CS1?CS2|?|CS2?CS1| to sense a change caused by an intervening event. By scanning the entire touch panel matrix, events can be tracked across the touch panel.

Abstract: An electronic device disclosed herein includes a display layer generating display noise based on scanning thereof, and a sensing layer including a plurality of sense lines. A common voltage layer is coupled to the display layer and the sensing layer, with the common voltage layer capacitively coupling the display noise from the display layer to the each of the plurality of sense lines of the sensing layer via a different parasitic impedance. An amplitude of the display noise seen at an input to each sense line is a function of a location of that sense line. The electronic device includes a plurality of compensation impedances, with each compensation impedance coupled to a different one of the plurality of sense lines. Each of the plurality of compensation impedances has an impedance value such that an amplitude of the display noise at an output of each sense line is substantially equal.

Abstract: A method of differential self-capacitance measurement is used to enhance a signal-to-noise ratio of sense lines in a touch panel display, thereby improving touch sensor accuracy. The differential self-capacitance measurement is implemented for a touch panel using charge sharing between adjacent sense lines of the touch panel matrix. Sequential differential self-capacitance measurements can be compared with one another by computing the difference |CS1?CS2|?|CS2?CS1| to sense a change caused by an intervening event. By scanning the entire touch panel matrix, events can be tracked across the touch panel.

Abstract: An electronic device disclosed herein includes a display layer generating display noise based on scanning thereof, and a sensing layer including a plurality of sense lines. A common voltage layer is coupled to the display layer and the sensing layer, with the common voltage layer capacitively coupling the display noise from the display layer to the each of the plurality of sense lines of the sensing layer via a different parasitic impedance. An amplitude of the display noise seen at an input to each sense line is a function of a location of that sense line. The electronic device includes a plurality of compensation impedances, with each compensation impedance coupled to a different one of the plurality of sense lines. Each of the plurality of compensation impedances has an impedance value such that an amplitude of the display noise at an output of each sense line is substantially equal.

Abstract: A touch panel includes capacitive sensing electrodes and a touch controller operates in a first operating mode to detect a touch location on the touch panel. In a second operating mode, the touch controller transmits a modulated data signal through the touch panel to an active stylus. Each electrode is driven by a line driver circuit. A control circuit selectively actuates first ones of the line driver circuits to pass the modulated data signal to corresponding first ones of the electrodes which do not pass through a region of the touch panel associated with the location of the detected touch. Simultaneously, the control circuit selectively actuates second ones of the line driver circuits, different from said first ones of the line driver circuits, to ground corresponding second ones of the electrodes which do pass through the region of the touch panel associated with the location of the detected touch.

Abstract: An electronic device may include a first controller associated with some channels of a digitizer having channels configured to receive a signal from a stylus, and with each channel having a direction. A second controller may be associated with channels of the digitizer not associated with the first controller. The first controller may scan for the signal at each channel associated with the first controller, and based on acquisition of the signal at a given channel associated with the first controller, calculate a property of the signal. The first controller may send the calculated property and the direction of the given channel to the second controller. The first controller and the second controller may scan for the signal at each channel having the direction of the given channel, at acquisition intervals based upon the calculated property.

Abstract: A touch panel includes capacitive sensing electrodes and a touch controller operates in a first operating mode to detect a touch location on the touch panel. In a second operating mode, the touch controller transmits a modulated data signal through the touch panel to an active stylus. Each electrode is driven by a line driver circuit. A control circuit selectively actuates first ones of the line driver circuits to pass the modulated data signal to corresponding first ones of the electrodes which do not pass through a region of the touch panel associated with the location of the detected touch. Simultaneously, the control circuit selectively actuates second ones of the line driver circuits, different from said first ones of the line driver circuits, to ground corresponding second ones of the electrodes which do pass through the region of the touch panel associated with the location of the detected touch.

Abstract: An electronic device may include a first controller associated with some channels of a digitizer having channels configured to receive a signal from a stylus, and with each channel having a direction. A second controller may be associated with channels of the digitizer not associated with the first controller. The first controller may scan for the signal at each channel associated with the first controller, and based on acquisition of the signal at a given channel associated with the first controller, calculate a property of the signal. The first controller may send the calculated property and the direction of the given channel to the second controller. The first controller and the second controller may scan for the signal at each channel having the direction of the given channel, at acquisition intervals based upon the calculated property.

Abstract: A voltage regulator circuit includes a differential amplifier stage. The gate terminal of a first n-channel MOSFET is coupled to an output of the differential amplifier stage. A resistor is coupled between the drain terminal and gate terminal of the first n-channel MOSFET. The drain terminal of the first n-channel MOSFET drives the gate of a second n-channel MOSFET whose drain terminal is at the input of a current mirror circuit. An output of the current mirror circuit forms the regulated voltage output. A feedback circuit is coupled between the regulated voltage output and one input of the voltage regulator circuit. Another input of the voltage regulator circuit is configured to receive a reference voltage.

Abstract: In one embodiment, a semiconductor circuit for coupling a first node to a second node includes a first transistor having a first terminal coupled to the first node, a second terminal coupled to the second node, and a control terminal coupled to a control node. The circuit also includes a level shifting circuit having a series diode for coupling a bulk terminal of the first transistor to the control node, and a supply coupling circuit coupled between a first power supply node and the control node.

Abstract: In one embodiment, a semiconductor circuit for coupling a first node to a second node includes a first transistor having a first terminal coupled to the first node, a second terminal coupled to the second node, and a control terminal coupled to a control node. The circuit also includes a level shifting circuit having a series diode for coupling a bulk terminal of the first transistor to the control node, and a supply coupling circuit coupled between a first power supply node and the control node.