Abstract: A touch panel includes a first plurality of electrodes and a second plurality of electrodes. A plurality of transmitters generate a plurality of transmit signals by modulating a common sine wave signal with a set of orthogonal modulation signals, and drive each transmit signal onto a corresponding electrode of the first plurality of electrodes. Each transmit signal is generated by modulating the common sine wave signal with a unique orthogonal modulation signal of the set of orthogonal modulation signals. At least two of the plurality of transmit signals are not orthogonal. Each receiver of a plurality of receivers senses a receive signal on a corresponding electrode of the second plurality of electrodes and generates a set of correlation signals by correlating the receive signal with each transmit signal of the plurality of transmit signals. The sets of correlation signals are used to detect a touch event on the touch panel.

Abstract: The disclosure relates to a touch screen sensing system, example embodiments of which comprise: a touch screen panel having a plurality pairs of touch sensing electrodes (row1-Nrow, col1-Ncol) arranged in rows and columns extending across the panel; and a plurality of transceivers, each of the plurality of transceivers connected to send and receive sensing signals to and from a respective one of the plurality of touch sensing electrodes (row1-Nrow, col1-Ncol), wherein each one of the plurality of transceivers is configured to transmit a sensing signal including a range of frequencies over a signal bandwidth, the sensing signals being orthogonal to each other.

Abstract: A touch sensor controller including a line driver and a method of calibrating a line driver for a touch panel are described. The line driver is configured to be coupled to a row or column of a touch panel, the method includes providing a line drive current and providing a sense current related to the drive current. The sense current values are digitized and an overload status determined dependent on the digitized sense current values. The line driver is controlled to increase or decrease the line drive current dependent on the overload status.

Abstract: A method for display noise canceling in a touch sensing system includes measuring a first feedback voltage of a feedback node resistively coupled to a line voltage of a capacitive touch panel, the line voltage formed by a continuous wave output of an amplifier responsive to a reference voltage difference between the first feedback voltage and a reference voltage. A second feedback voltage is clamped to a first upper voltage threshold in response to a first voltage difference between the first feedback voltage and the reference voltage being greater than the first upper voltage threshold. The second feedback voltage is clamped to a first lower voltage threshold in response to the first voltage difference being less than the first lower voltage threshold.

Abstract: A touch screen is disclosed having a length and a height, and comprising interspaced and galvanically isolated first and second arrays of touch pads; wherein the first array of touch pads comprises a plurality of first strings of series-connected touch pads, each first string forming a drive line and extending in a first general direction; wherein the second array of touch pads comprises a plurality of second strings of series-connected touch pads, each second string forming a read line and extending in a second general direction, different to said first general direction; wherein the first general direction and the second general direction are each different from the length direction; and wherein the touch screen is configured for capacitive-based sensing which may be based on a change in a mutual capacitance between individual ones of the drive lines and individual ones of the read lines.

Abstract: A touch panel system that includes drivers for providing detection signals on a first plurality of electrodes of a touch panel where each detection signal includes one or more frequency signal components with each frequency signal component having a frequency and a phase offset. The detection signals includes at least three phase offsets for at least one frequency of the frequency signal components. Each detection signal has a unique frequency-phase offset combination of the one or more frequency signal components. The unique combinations allow for the determination of a touch at specific locations on the panel by sensing signals on a second set of electrodes.

Abstract: A voltage regulator utilizes an external pass transistor coupled between a supply voltage node and a regulated node. The voltage regulator includes an internal pass transistor that is coupled between the supply voltage node and the regulated node. A two-tap voltage divider between the regulated node and a ground node provides two feedback voltages. A first control loop that controls the external pass transistor receives the first feedback voltage and a second control loop that controls the internal pass transistor receives the second feedback voltage. At startup the control loops run concurrently but the first control loop is prioritized to reduce load current provided by the internal pass transistor at the end of startup. The voltage difference between the first and second feedback voltages ensures prioritization of the first control loop and the external pass transistor supplies most or all of the load current.

Abstract: A method for display noise canceling in a touch sensing system includes measuring a first feedback voltage of a feedback node resistively coupled to a line voltage of a capacitive touch panel, the line voltage formed by a continuous wave output of an amplifier responsive to a reference voltage difference between the first feedback voltage and a reference voltage. A second feedback voltage is clamped to a first upper voltage threshold in response to a first voltage difference between the first feedback voltage and the reference voltage being greater than the first upper voltage threshold. The second feedback voltage is clamped to a first lower voltage threshold in response to the first voltage difference being less than the first lower voltage threshold.

Abstract: A touch screen is disclosed having a length and a height, and comprising interspaced and galvanically isolated first and second arrays of touch pads; wherein the first array of touch pads comprises a plurality of first strings of series-connected touch pads, each first string forming a drive line and extending in a first general direction; wherein the second array of touch pads comprises a plurality of second strings of series-connected touch pads, each second string forming a read line and extending in a second general direction, different to said first general direction; wherein the first general direction and the second general direction are each different from the length direction; and wherein the touch screen is configured for capacitive-based sensing which may be based on a change in a mutual capacitance between individual ones of the drive lines and individual ones of the read lines.

Abstract: A touch panel system that includes drivers for providing detection signals on a first plurality of electrodes of a touch panel where each detection signal includes one or more frequency signal components with each frequency signal component having a frequency and a phase offset. The detection signals includes at least three phase offsets for at least one frequency of the frequency signal components. Each detection signal has a unique frequency-phase offset combination of the one or more frequency signal components. The unique combinations allow for the determination of a touch at specific locations on the panel by sensing signals on a second set of electrodes.

Abstract: A touch panel includes a first plurality of electrodes and a second plurality of electrodes. A plurality of transmitters generate a plurality of transmit signals by modulating a common sine wave signal with a set of orthogonal modulation signals, and drive each transmit signal onto a corresponding electrode of the first plurality of electrodes. Each transmit signal is generated by modulating the common sine wave signal with a unique orthogonal modulation signal of the set of orthogonal modulation signals. At least two of the plurality of transmit signals are not orthogonal. Each receiver of a plurality of receivers senses a receive signal on a corresponding electrode of the second plurality of electrodes and generates a set of correlation signals by correlating the receive signal with each transmit signal of the plurality of transmit signals. The sets of correlation signals are used to detect a touch event on the touch panel.

Abstract: A circuit of a system-on-chip for the transmission of an analog signal at a given transmission frequency modulated by a digital input signal coded in a number m of bits, includes 2m?1 unit cells each having a first block adapted to receive an activation voltage through an associated switch, and a second block with a first input path coupled to an output path of the first block, a second input path receiving a local oscillator signal, and an output path coupled to the output path of the circuit, with the switches each controlled as a function of the value of a bit of the digital input signal, the bit of index j of the digital input signal where j is between 0 and m?1, controlling the switches respectively associated with 2j unit cells.

Abstract: A circuit of a system-on-chip for the transmission of an analog signal at a given transmission frequency modulated by a digital input signal coded in a number m of bits, includes 2m?1 unit cells each having a first block adapted to receive an activation voltage through an associated switch, and a second block with a first input path coupled to an output path of the first block, a second input path receiving a local oscillator signal, and an output path coupled to the output path of the circuit, with the switches each controlled as a function of the value of a bit of the digital input signal, the bit of index j of the digital input signal where j is between 0 and m?1, controlling the switches respectively associated with 2j unit cells.