Low emission touch controller

Abstract

This invention provides a low-emission touch controller. The technology relating to a low-emission touch controller in an in-cell touch display system is described. An in-cell touch controller includes a signal generator circuit configured to generate a sensing signal according to a sensing function, the sensing signal comprising a windowed sine wave. The controller generates a transition signal to cause the in-cell touch display to transition between a display function and a sensing function. The controller drives the sensing signal and the transition signal on a common voltage (VCOM) layer of electrodes during a touch scan interval. During the display function interval, an integrated display driver is configured to drive a first signal on the VCOM layer of electrodes during the display function interval.

Description

[0001] Related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 960,474, filed January 13, 2020, the entire contents of which are incorporated herein by reference. Background Technology

[0003] Touch sensors are used to detect the presence and location of objects or their proximity within the touch-sensing area of ​​a touch sensor. For example, a touch-sensing circuit system can detect the presence and location of a touch object near a touch sensor positioned in relation to a display screen. Many different types of touch sensors exist. Types of touch sensors can include resistive touch sensors, surface acoustic wave touch sensors, capacitive touch sensors, inductive touch sensors, etc. Different touch sensors can detect different types of objects.

[0004] Most touch sensing applications require high sensitivity to support thick overlays on the touch sensor, operation of the touch sensor with gloves, or hover recognition over long distances in noisy conditions such as those caused by nearby liquid crystal displays (LCDs), inductive load switching, or radio emissions. Furthermore, the emission of touch sensors is limited, which restricts the excitation energy required for the touch sensor to achieve a sufficient signal-to-noise ratio (SNR). Summary of the Invention

[0005] According to the present invention, a method is provided, the method comprising: driving a first signal on a common voltage VCOM layer of electrodes of an in-cell touch display according to a display function during a display function interval by an in-cell touch controller; generating a second signal according to a sensing function by the in-cell touch controller, wherein the second signal comprises a windowed sine wave; generating a transition signal by the in-cell touch controller to cause the in-cell touch display to transition between the display function and the sensing function; and driving the second signal and the transition signal on the VCOM layer during a touch scan interval by the in-cell touch controller.

[0006] According to the present invention, an in-cell touch controller is provided, the in-cell touch controller comprising: an integrated display driver configured to drive a first signal on a common voltage VCOM layer of electrodes of an in-cell touch display according to a display function during a display function interval; and a touch driver including a sensing channel and a signal generator circuit. The signal generator circuit is configured to: generate a second signal according to a sensing function, wherein the second signal includes a windowed sine wave; generate a transition signal to cause the in-cell touch display to transition between the display function and the sensing function; and drive the second signal and the transition signal on the VCOM layer during a touch scan interval.

[0007] According to the present invention, a system is provided, the system including an in-cell touch display and an in-cell touch controller. The in-cell touch display includes a common voltage VCOM layer for electrodes, the VCOM layer being configured to operate in relation to a display function during a first interval and in relation to a sensing function during a second interval. The in-cell touch controller is coupled to the in-cell touch display, wherein the in-cell touch controller includes a first sensing channel and a first signal generator circuit. The first signal generator circuit is configured to: generate a sensing signal according to the sensing function, wherein the sensing signal includes a windowed sine wave; generate a transition signal to cause the in-cell touch display to transition between the display function and the sensing function; and drive the sensing signal and the transition signal on the VCOM layer during the second interval. Attached Figure Description

[0008] The disclosure is illustrated by way of example rather than limitation in the accompanying drawings.

[0009] Figure 1A It is a block diagram of an in-cell touch display and an in-cell touch controller having an integrated display driver, according to at least one embodiment.

[0010] Figure 1B It is a block diagram of an implementation of a stacked display with separate touch controllers and display drivers.

[0011] Figure 2 A plurality of touch unit cells of an in-cell touch display according to at least one embodiment are shown.

[0012] Figure 3 Multiple common voltage (VCOM) electrodes of an in-cell touch display according to at least one embodiment are shown.

[0013] Figure 4It is a waveform diagram of a signal used for display function during a display function interval and a waveform diagram of a signal used for sensing function during a touch scan interval, according to at least one embodiment.

[0014] Figure 5 It is a functional diagram of a signal generator circuit with a sigma-delta modulator (SDM) according to at least one embodiment.

[0015] Figure 6 This is a waveform diagram showing an output signal having a combined scan signal and a transition signal according to at least one embodiment.

[0016] Figure 7 It is a functional block diagram of a signal generator circuit having a sigma-delta modulator (SDM) and a digitally controlled potentiometer according to at least one embodiment.

[0017] Figure 8 This is a waveform diagram showing an output signal having a separate scan signal and a transition signal according to at least one embodiment.

[0018] Figure 9 It is a spectrum diagram showing a comparison of the spectra of the separate scan signal and transition signal according to at least one embodiment with the combined scan signal and transition signal.

[0019] Figure 10A It is a block diagram of the analog output stage circuit of a signal generator circuit according to at least one embodiment.

[0020] Figure 10B It is a block diagram of an analog output stage circuit, a reference generator, and a shielded driver according to at least one embodiment.

[0021] Figure 11 This is a flowchart of a method for operating a touch controller within a unit according to at least one embodiment.

[0022] Figure 12 This is a flowchart of a method for operating a touch controller within a unit using separate scan signals and transition signals, according to at least one embodiment.

[0023] Figure 13 This is a flowchart of a method for operating a touch controller within a unit using a combination of scan signals and transition signals, according to at least one embodiment.

[0024] Figure 14A This is a schematic diagram of a system having an in-cell touch controller coupled to a simplified in-cell touch display, according to at least one embodiment.

[0025] Figure 14BDuring the display function according to at least one embodiment Figure 14A A schematic diagram of the system.

[0026] Figure 14C During the touch scanning function according to at least one embodiment Figure 14A A schematic diagram of the system.

[0027] Figure 15 This is a schematic diagram of a system having an in-cell touch controller coupled to an in-cell touch display according to at least one embodiment.

[0028] Figure 16 A multiplexer configuration for scanning several sensors using a single RX channel, according to at least one embodiment, is shown. Detailed Implementation

[0029] The following description illustrates numerous specific details, such as examples of specific systems, components, methods, etc., to provide a good understanding of the various implementations of the techniques described herein for a touch controller with high touch performance and low emission. High touch performance can mean that the touch controller can meet stringent emission customer requirements while providing high-performance touch sensing such as touch, glove, optional hover, waterproofing, etc. The touch controller can provide touch sensing with high touch performance, such as that provided in an in-cell display panel, within a short scan cycle. An in-cell display panel is a panel with Touch and Display Driver Integration (TDDI), where both the underlying display driver and touch sensor are physically located in a single integrated circuit. An in-cell touch panel can be a panel in which the same panel elements (e.g., a VCOM layer) are used for both touch sensing and display functions. The in-cell panel works with TDDI circuitry, where an integrated circuit combines the display driver and touch scanning circuitry. The TDDI circuitry is attached to the in-cell display panel, making the display itself a single piece of glass with built-in thin-film transistors (TFTs) and gate-in-panel circuitry.

[0030] For low emissions in conventional stacked touch controllers (e.g., for automotive applications), two common approaches exist, including Multiphase Self-Capacitance (MPSC). The MPSC method uses multiphase excitation and sensing modes to sense self-capacitance. This method performs poorly in terms of temperature drift, high sensitivity to displays (e.g., LCDs), and radio frequency (RF) noise. In particular, the MPSC method has poor noise suppression for LCD noise and external noise because all sensing electrodes of the panel are connected together during the sensing phase, acting as a large antenna for sensing noise from various sources. The other approach is the Floating Ground (FGND) method, in which the entire sensing front-end circuitry floats with the sensed signal waveform, compared to device or system grounding. The FGND method offers excellent sensing and water resistance, but the circuitry can be expensive for multi-channel current isolation or high-voltage level transitions. Common methods are not suitable for applications with stringent customer requirements regarding emissions, such as in-cell touch controllers in automation applications. High in-cell panel capacitance, which cannot be easily compensated for using the MPSC method and input current, is highly sensitive to changes in the drive voltage of the shielding electrodes (panel gate lines and source lines). Direct application of the FGND method in in-cell design would require floating analog front-end circuitry. This could be difficult to implement in a small die with integrated display driver circuitry, as it would require high-speed data isolation or level shifting. Furthermore, the standard single-electrode, self-capacitance method with a rectangular excitation signal (i.e., a square wave signal) cannot be used due to its high radiated emissions caused by higher harmonics exceeding permissible emission limits.

[0031] As described above, most touch sensing applications require high sensitivity, such as for glove touch or hover sensing. As described herein, implementations can provide enhanced immunity to external noise by using windowed sine waves and client transition waveforms between the display function interval and the sensing interval. However, it will be apparent to those skilled in the art that at least some implementations can be practiced without these specific details. In other instances, to avoid unnecessarily obscuring the techniques described herein, well-known components, elements, or methods are not described in detail or presented in a simple block diagram format. Therefore, the specific details set forth below are merely exemplary. Specific implementations may differ from these exemplary details and may still be considered within the spirit and scope of this disclosure.

[0032] This article describes various implementations of capacitive sensing techniques utilizing in-cell touch displays with low emission. Implementations of in-cell touch controllers can provide low emission to meet stringent emission requirements, such as those found in demanding automotive customer environments, while offering high-performance touch sensing for touch sensing, glove-enabled touch sensing, hover touch sensing, and waterproofing within short scan cycles (e.g., 100 to 200 microseconds) provided by the in-cell touch display. It should be noted, however, that in in-cell systems, there is no display noise because sensing is performed in quiet intervals when no display transitions occur. High touch performance and low emission can be provided by using any combination of the following techniques: a windowed sinusoidal waveform for the sensing signal, which reduces emission; a custom transition waveform between display and sensing functions, which also reduces emission; a combined sensing and transition waveform (display / scan mode transition) to support touch sensing during the transition, which reduces emission, provides a scan result with a longer scan time, and provides a better signal-to-noise ratio (SNR) for touch sensing; a signal generator that uses a multi-stage sigma-delta modulator with dynamic element matching to generate the scan waveform, which reduces implementation cost because it eliminates the need for precision components such as resistors, capacitors, or current sources that may be perfectly matched; phase adjustment of the sensing channel signal relative to the shielding signal, which reduces uncompensated capacitance, reduces noise, and provides a better SNR; a floating capacitor for the gate driver power supply and a lower phase delay DC (DC) offset for the gate driver, which provides design simplicity and lower cost; and other aspects as described herein. SNR can be a numerical value that indicates the degree to which touch signals are separated from noise.

[0033] Implementations may provide a touch sensing unit (also referred to as a touch sensor) that can be used in conjunction with a capacitive sensing circuitry system to detect different types of objects. In one implementation, the sensing unit may be used for mutual capacitance sensing or self-capacitance sensing. In one implementation, as described in more detail herein, the capacitive sensing circuitry system (also referred to herein as a “capacitive sensing circuitry system” or a “sensing circuitry system”) may use a capacitive touch sensing channel in such a way that it is capable of measuring the capacitance of a sensing element (e.g., a single electrode related to ground potential or a single electrode between a receiving (RX) electrode and a transmitting (TX) electrode). The sensing circuitry system may also be configured to detect the inductance of the sensing element, for example, to detect ferrous and nonferrous metal objects adjacent to the sensing unit using inductive sensing techniques. Examples of devices that can use capacitive sensing include, but are not limited to: automobiles, home appliances (e.g., refrigerators, washing machines, etc.), personal computers (e.g., laptops, notebook computers, etc.), mobile computing devices (e.g., tablets, tablet computers, e-reader devices, etc.), mobile communication devices (e.g., smartphones, cellular phones, personal digital assistants, messaging devices, handheld computers, etc.), connectivity and charging devices (e.g., hubs, docking stations, adapters, chargers, etc.), audio / video / data recording and / or playback devices (e.g., cameras, voice recorders, handheld scanners, monitors, etc.), wearable devices, and other similar electronic devices.

[0034] The references to "implementation," "one implementation," "example implementation," "some implementations," and "various implementations" in the specification mean that a specific feature, structure, step, operation, or characteristic described in connection with one or more implementations is included in at least one implementation of this disclosure. Furthermore, the phrases "implementation," "one implementation," "example implementation," "some implementations," and "various implementations" appearing in multiple places in the specification do not necessarily refer to the same one or more implementations.

[0035] The specification includes references to the accompanying drawings, which form part of the detailed description. The drawings illustrate embodiments according to exemplary practices. These embodiments, which may also be referred to herein as “examples,” are described in sufficient detail to enable those skilled in the art to practice embodiments of the claimed subject matter described herein. Embodiments may be combined, other embodiments may be utilized, or structural, logical, and electrical changes may be made without departing from the scope and spirit of the claimed subject matter. It should be understood that the embodiments described herein are not intended to limit the scope of the subject matter, but rather to enable those skilled in the art to practice, make, and / or use the subject matter.

[0036] Figure 1A This is a block diagram of an in-cell touch display 100 and an in-cell touch controller 102 with an integrated display driver according to at least one embodiment. The in-cell touch display 100 includes a protective glass 104 and a display with an integrated touch sensor 106, and has multiple layers. One of the layers is a common voltage (VCOM) layer that provides a dual function. The VCOM layer provides a VCOM voltage to the display elements for display functions during display intervals and acts as an electrode for the touch sensor for sensing functions during scan intervals. The display with the integrated touch sensor 106 may be a thin-film transistor (TFT) liquid crystal display (LCD). A TFT LCD includes a VCOM layer with electrodes. The in-cell touch controller 102 includes: an integrated display driver that drives the in-cell touch display 100 during display function intervals; and a sensing circuitry that performs touch scanning during touch scan intervals. The in-cell touch controller 102 may also aggregate touch data from other devices (e.g., slave devices) and may perform touch coordinate calculations or other operations. The in-cell touch controller 102 may include a Touch and Display Driver Integration (TDDI), in which both the underlying display driver and the touch sensor circuitry are physically located within a single integrated circuit (also referred to as a chip). The in-cell touch display 100 may include Gate-in-Panel (GIP) technology, which integrates gate driver circuitry within the in-cell touch display 100 itself. As described in more detail below, the in-cell touch controller 102 includes a signal generator circuit (also referred to as a SINEGEN block) that provides a windowed sine wave (sine wave) for sensing the signal. For example, a combination of Direct Digital Synthesis (DDS) and sigma-delta modulation can be used to generate a variable-density data stream, which is then converted to an analog signal using a low-pass filter (LPF). The SINEGEN block can be any combination of discrete components, gate circuitry, logic circuitry, digital signal processing (DSP) function blocks, etc. DDS is a method for generating a sine wave or other waveform signal with good frequency resolution. The operation of DDS can be performed by DDS circuitry. DDS circuits can be any combination of discrete components, gate circuit systems, logic circuit systems, DSP function blocks, etc. The following is about... Figure 5 and Figure 7The example DDS circuit is illustrated and described using a signal generator circuit. The windowed sine waveform used for the sensing signal can reduce emissions, for example, by narrowing the frequency peak width. A custom transition waveform between the display and sensing functions reduces emissions. In some cases, combined sensing and transition waveforms (display / scan mode transition) can support touch sensing during the transition, which reduces emissions, provides scan results with longer scan times, and provides a better signal-to-noise ratio (SNR) for touch sensing. The signal generator circuit of the in-cell touch controller 102 can utilize a multi-stage sigma-delta modulator with dynamic element matching to generate the scan waveform. The in-cell touch controller 102 can also provide phase adjustment of the sensing channel signal relative to the shielding signal to reduce uncompensated capacitance, reduce noise, and provide a better SNR. The in-cell touch display 100 can use a floating capacitor for the gate driver power supply and a lower phase delay DC offset for the gate driver.

[0037] The touch industry has evolved from Figure 1B The stacked touch technology shown (also known as hybrid on-cell touch technology) is transferred to Figure 1A In-unit touch display technology.

[0038] Figure 1B This is a block diagram of a stacked display 150 having a separate touch controller 152 and a display driver 154. The stacked display 150 includes a protective glass 156, a touch sensor 158, and a display 160.

[0039] The in-cell touch display 100 can offer customers and display manufacturers many advantages over the stacked display 150. For example, compared to the stacked display 150, the in-cell touch display 100 can have: higher brightness at the same backlight power, less reflection in direct sunlight (due to fewer layers in the stack), higher display image contrast due to less internal reflection, true black levels when the display is off (no visible metal bridges), reduced panel bezel area (because there is no sensing electrode wiring at the perimeter), thinner overall stack, simpler supply chain (because the entire system comes from a single supplier), and lower solution cost (the sensing panel has no additional bending and fewer layers).

[0040] In one embodiment, the in-cell touch controller 102 includes an integrated display driver and a touch driver. The integrated display driver is configured to drive a first signal on the common voltage (VCOM) layer of the electrodes of the in-cell touch display according to the display function during a display function interval. Because the display driver and the touch driver can be part of a single integrated circuit, the display driver is considered to be integrated into the in-cell touch controller 102. Additionally, it should be noted that, as described herein, a gate driver can be integrated into the in-cell touch display 100. The touch driver includes a sensing channel and signal generator circuitry. The signal generator circuitry can be configured to generate a second signal according to the sensing function. The second signal includes a windowed sine wave. The signal generator circuitry generates a transition signal (also referred to herein as a display / scan mode transition or display / scan mode change). The transition signal is configured to cause the in-cell display to switch between a display function and a sensing function. The signal generator circuitry is also configured to drive the second signal and the transition signal on the VCOM layer during a touch scan interval.

[0041] In another embodiment, the touch driver is further configured to combine the transition signal and the second signal into a combined output signal during the touch scan interval and drive the combined output signal on the VCOM layer to support sensing functionality during transition to or from display functionality. The touch driver may include direct digital synthesis (DDS) circuitry for windowing sine wave generation or other pre-programmed signal waveform generation, as described in more detail below. For example, in one embodiment, the DDS circuitry includes a plurality of functional blocks, including: a phase accumulator; a first adder; a phase-to-amplitude converter including a lookup table (LUT); a multiplier; a sigma-delta modulator (SDM); and a low-pass filter (LPF). In another embodiment, the DDS circuitry is used in conjunction with a digitally controlled potentiometer.

[0042] Figure 2A plurality of touch unit cells 202 of an in-cell touch display 200 according to at least one embodiment are shown. The in-cell touch display 200 may be similar to the in-cell touch display 100 described above, and a more detailed view of the display 100 may be shown. The in-cell touch display 200 includes a plurality of touch unit cells 202, each of which includes segmented VCOM electrodes 204, which can provide a VCOM voltage during the display function of the in-cell touch display 200 and provide a scan signal (e.g., a self-capacitance signal or a sensing signal) during the sensing function of the in-cell touch display 200. Metal lines from each of the segmented VCOM electrodes may be disposed under a black mask of the in-cell touch display 200. The in-cell touch display 200 also includes a plurality of display elements 206. The display elements 206 may be organized into a set of elements of three different colors and a plurality of sets of each segmented VCOM electrode 204. As described herein, a gate driver may be integrated into the in-cell touch display 200, such as Figure 2 The diagram shows coupling to rows and individual columns. Although not in... Figure 2 As shown, but it should be noted that the gate driver (e.g., GIP circuitry) forms the row signal for the TFT transistor gate, such as... Figure 2 As shown, the column signals (data lines) originate from the touch controller within the unit (e.g., TDDI circuitry). As mentioned above regarding... Figure 1A As described, the in-unit touch controller can use the segmented VCOM electrodes 204 for display and sensing functions.

[0043] Figure 3 A plurality of VCOM electrodes 302 of an in-cell touch display 300 according to at least one embodiment are shown. The VCOM electrodes 302 are coupled to sensor row lines 304, sensor column lines 306, and touch path lines 308. The sensor row lines 304 may be from an in-cell touch controller (…). Figure 3 The gate signal (not shown) provides a path (labeled as the gate path). Sensor column line 306 can provide a path (labeled as the data / source path) for the source signal from the in-cell touch controller. Touch path line 308 can provide a path for the sensing signal between each of the plurality of VCOM electrodes 302 and the in-cell touch controller used for sensing functions.

[0044] like Figure 3As shown, due to the large coupling capacitance between the VCOM layer and the underlying TFT transistor with connected gate and source lines, in-cell touch panels typically employ a single-electrode, self-capacitance (SE-SC) approach for touch sensing with active shielding. The phase and amplitude of the shielding signal used for active shielding are typically equal to the sensing signal, but a DC offset may be required to provide an appropriate level to the in-panel TFT transistors to prevent leakage current to the touch path 308 coupled to the RX channel and to prevent image quality degradation due to touch sensor operation. The in-cell touch controller described herein can provide phase and amplitude modulation of both the shielding and sensing signals.

[0045] Because the touch sensor and display driver functions are integrated into the in-cell touch display, the in-cell touch controller has a shorter scan interval compared to touch controllers used in stacked displays. For example, the typical scan burst length in an in-cell touch display can be between 100 and 200 microseconds, with a burst repetition period of approximately 1.6 milliseconds, while the scan time budget for a stacked display can be up to the entire report cycle (e.g., 8 milliseconds for an application with a typical report rate of 120Hz). The following is about... Figure 4 This is used to illustrate and describe the display function intervals and touch scan intervals of the touch controller within the unit.

[0046] Figure 4 This is a waveform diagram 400 of signals used for display functions during a display function interval and for sensing functions during a touch scan interval, according to at least one embodiment. Waveform diagram 400 includes a single display frame 402 at 60 Hz, totaling approximately 16.66 milliseconds. At the beginning of display frame 402, a vertical sync (VSYNC) signal 404 is asserted. After the VSYNC signal 404 is asserted, touch scan interval 406 and display function interval 408 may alternate multiple times during display frame 402. As shown in an exploded view of one of the touch scan intervals 406, a horizontal sync (HSYNC) signal 410 is asserted, and a sensing signal 412 is applied to the VCOM electrode of the touch display within the cell. Additionally, a first shield signal 414 is applied to the source line of the integrated display driver, and a second shield signal 416 is applied to the gate line of the integrated display driver. As described herein, the phase and amplitude of the first shield signal 414 and the second shield signal 416 may be equal to the sensing signal 412, but with some DC offset. Figure 4 As shown, these signals have sinusoidal waveforms. Sine waveforms can be generated by signal generator circuits, such as those described below. Figures 5 to 8 The signal generator circuits shown generate the signals. It should be noted that, for ease of explanation, in... Figure 4 The signal does not show the windowing.

[0047] At the end of the touch scan interval 406, the HSYNC signal 410 is de-asserted, and the VCOM voltage 412 is applied to the VCOM electrode. Signals 420 (e.g., -7V to +7V) and 422 (e.g., -16V to +16V, depending on the LCD panel technology) are applied to the source and gate lines, respectively, for display functionality. In this example, the touch scan interval 406 can be approximately 200 microseconds, and the display function interval 408 can be approximately 633 microseconds. Alternatively, other interval lengths are possible for a given display frame.

[0048] It can be generated by the touch controller within the unit. Figure 4 The signal, where the in-cell touch display includes an integrated gate driver, also known as a gate-in-panel (GIP) circuit. There are several challenges for in-cell touch controllers, such as those listed in Table 1 below.

[0049] Table 1 - Key Challenges of In-Unit Touch Controllers

[0050]

[0051]

[0052] The various aspects of this disclosure address these challenges by using a combination of techniques as described in Table 2.

[0053] Table 2 - Technologies used for in-cell touch controllers

[0054]

[0055]

[0056] As described above, one technique in implementing an in-cell touch controller is a low-distortion sine wave source (SINEGEN), referred to herein as a signal generator circuit. The signal generator circuit maintains low system emissions and enables implementations to meet stringent customer emission requirements. The signal generator circuit can be implemented in existing semiconductor processing used for high-voltage display driver implementations. The signal generator circuit can generate a low-distortion windowed sine wave signal. The signal generator circuit can provide a transition between sensing functionality (touch scanning) and display functionality. In some cases, the signal generator circuit can also support scanning during the transition. The signal generator circuit can handle high panel loads. The signal generator circuit can implement features such as those described below. Figure 5The DDS method is shown and described. In some cases, a smooth scan-display function transition reduces the emission of a wideband panel, while a windowed sine sensing waveform results in narrowband emission, where the emission peak is outside the customer's emission limit, such as 100 kHz.

[0057] Figure 5 This is a functional block diagram of a signal generator circuit 500 having a DDS circuit 530 and a sigma-delta modulator (SDM) 502, according to at least one embodiment. The DDS circuit 530 includes a phase accumulator 504, dithering circuits 506 and 516, a first adder 508, a phase-to-amplitude converter 510 including a lookup table (LUT), a multiplier 512, the SDM 502, and a low-pass filter (LPF) 514. The phase accumulator 504 sums a phase value 501, such as an initial phase, stored in a phase control register (PCR) each clock cycle to obtain an accumulated phase value 503. The phase accumulator 504 can provide feedback on the current value to be summed at a frequency set by the frequency control register (FCR). The dithering circuits 506 and 516 generate a dithered signal 505. The dithered signal 505 can be generated based on pseudo-random numbers from a pseudo-random source 516. The first adder 508 adds the accumulated phase value 503 to the jitter signal 505 to obtain the phase signal 507. The phase-to-amplitude converter 510 uses a lookup table (LUT) to convert the phase signal 507 into an amplitude signal 509. The lookup table operation converts the phase signal into a selective waveform. Depending on the values ​​pre-programmed into the LUT, this conversion can be linear or non-linear. The multiplier 512 multiplies the amplitude signal 509 with a windowed signal 511 to obtain a windowed sine wave 513. The windowed signal 511 can be generated by a window generator 518. The window generator 518 can be implemented using the Tukey window function or other window functions.

[0058] In this embodiment, the signal generator circuit 500 includes a transient signal generator 520 and a second adder 522. The transient signal generator 520 generates a transient signal 521, and the second adder 522 combines the transient signal 521 and a windowed sine wave 513 into a combined signal 515, which is fed to the SDM 502. Combining the transient signal 521 with the windowed sine wave 513 provides a display / scan function transition using a signal profile, such as a Tukey window.

[0059] SDM 502 can be a multi-stage SDM with differential or single-ended output 517. SDM 502 converts the input numerical data in the combined signal 515 into a density-modulated stream. As described in more detail below, the differential output 517 is passed to LPF 514, which filters the differential output 517 to obtain an output signal 519, which is passed to the analog output stage.

[0060] As described above, the signal generator circuit includes an SDM in the digital domain. In another embodiment, a signal generator circuit such as the following can be used... Figure 7 The digitally controlled potentiometer shown and described.

[0061] Figure 6 This is a waveform diagram showing an output signal 600 having a combined scan signal and a transition signal according to at least one embodiment. The output signal 600 corresponds to... Figure 5 The output signal 519. As described above, the output signal 600 includes both a sensing signal and a transition signal. The sensing signal is used for the sensing function. The transition signal is the signal that switches between the display function and the sensing function. In some unit panels, there may be different levels for the display function and the sensing function, and the transition signal can switch between different levels.

[0062] During operation, the in-cell touch controller uses signal generator circuitry 500 to drive output signal 600 during touch scan interval 602. Because output signal 600 combines sensing and transition signals, the in-cell touch controller can support sensing during the transition between display and sensing functions. In other words, by combining sensing and transition signals, the duration of the scanning function during touch scan interval 602 can be extended.

[0063] In another embodiment, during operation, the in-cell touch controller uses signal generator circuitry 500 to drive a first portion of the transition signal during a first segment of the touch scan interval and a second portion of the transition signal during a second segment of the touch scan interval. The in-cell touch controller also drives a sensing signal (also referred to herein as a second signal) during a third segment of the touch scan interval, which follows the first segment and precedes the second segment. In another embodiment, the transition signal may be driven only in the first segment, while the sensing signal is driven in the second segment following the first segment (e.g., at the beginning of the touch scan interval). In yet another embodiment, the transition signal may be driven only in the first segment, while the sensing signal is driven in the second segment preceding the first segment (e.g., at the end of the touch scan interval).

[0064] Figure 7This is a functional block diagram of a signal generator circuit 700 having a DDS circuit 530, an SDM 502, and a digitally controlled potentiometer 702 according to at least one embodiment. The DDS circuit 500 is similar to the signal generator circuit 500 indicated by similar reference numerals. However, instead of adding the transition signal 521 and the windowed sine wave 513 by the second adder 522 as performed in the signal generator circuit 500, the signal generator circuit 700 passes the windowed sine wave 513 to the SDM 502, and the SDM 502 converts the input numerical data in the windowed sine wave 513 into a density-modulated stream as a differential output 517. The differential output 717 is passed to an LPF 514, which filters the differential output 717 to obtain an analog output signal 719. The digitally controlled potentiometer 702 receives the output signal 719 and the transition signal 721 from the transition signal generator 720. The transition signal 721 provides a display / scan function transition using signal contours such as a Tukey window. The center pin of the digitally controlled potentiometer 702 is controlled by a control signal to output an output signal 723 based on the transition signal 721 from the transition signal generator 720 or the output signal 719 from the LPF 514. In one embodiment, the center pin of the digitally controlled potentiometer 702 acts as the summation point of the LPF output and VCOM, and the output signal 723 transitions gradually between the LPF output and VCOM under the control of the signal generator circuit 700. This transition is controlled by the transition data generator. In one embodiment, the signal generator circuit 700 can operate like a DJ attenuator for the digitally controlled potentiometer 702 to provide a smooth transition. The output signal 723 is passed to an analog output stage, which is described in more detail below.

[0065] Figure 8 This is a waveform diagram showing an output signal 800 having separate scan and transition signals according to at least one embodiment. The output signal 800 corresponds to... Figure 7 The output signal 723. As described above, the output signal 800 includes a separate sensing signal and a transition signal. The sensing signal is used for sensing functions. The transition signal is used to switch between display functions and sensing functions, and between sensing functions and display functions.

[0066] During operation, the in-cell touch controller uses signal generator circuitry 700 to drive a first portion 802 of the transition signal during a first segment 808 of the touch scan interval and a second portion 804 of the transition signal during a second segment 810 of the touch scan interval. The in-cell touch controller also drives a sensing signal 806 (also referred to herein as a second signal) during a third segment 812 of the touch scan interval, which follows the first segment 808 and precedes the second segment 810. In another embodiment, the transition signal may be driven only in the first segment 808, while the sensing signal 806 may be driven in the third segment 812, which follows the first segment 808 (e.g., at the beginning of the touch scan interval). In another embodiment, the transition signal may be driven only in the second segment 810, while the sensing signal 806 may be driven in the third segment 812, which precedes the second segment 810 (e.g., at the end of the touch scan interval).

[0067] Figure 9 This is a spectrum diagram 900 showing a comparison of the spectra of separate scan and transition signals 902 and combined scan and transition signals 904 according to at least one embodiment. The graph 900 shows that, as indicated by the approximately 3dB stronger touch signal of the combined scan and transition signals 904 and the combined scan and transition signals 904 having a narrower peak width of approximately 10dB at some frequencies due to the longer total pulse train duration, combining the transition signal (the mode that combines transition and scan) with the scan signal can achieve a longer scan pulse train duration.

[0068] Figure 10A This is a block diagram of an analog output stage circuit 1000 of a signal generator circuit according to at least one embodiment. The analog output stage circuit 1000 includes a level shifter 1002, a buffer 1004, a programmable LPF 1006 with programmable bandwidth, and an output analog buffer and attenuator 1008. The level shifter 1002 receives input signals (input data (Din) and inverted balanced data (Dinb)) and transforms the input signals between different levels according to different domain signals. The level shifter 1002 outputs the level-shifted signal to the buffer 1004. The buffer 1004 is powered by a low-noise power supply VDDL. The digital logic is powered by a potentially noisy VCCD power supply. The LPF 1006 has two strings of equal-value resistors and simultaneously performs multi-stage SDM density-to-analog conversion and low-pass filtering by means of other passive components.

[0069] Using a programmable LPF 1006 and an output analog buffer and attenuator 1008, the analog output stage circuit 1000 generates a low-distortion signal 1010 over a wide range of output frequencies and output voltages, rather than enabling the processing of panels operating at various frequencies and voltages.

[0070] In some implementations, supplementary components may be present; for example, synchronization logic may be part of a level shifter that resamples the SDM data stream and can simultaneously align multiple SDM level changes to mitigate the effects of different signal routing times. In another implementation, the logic may include dynamic element matching (DEM) logic that shuffles multiple data levels in real time, thereby enabling excellent spurious-free dynamic range (SFDR) by means of components with large tolerances—e.g., resistors with a 10% tolerance in the LPF. Bias sources can provide bias current for operational amplifiers (as part of the LPF) and analog buffers / attenuators. Common-mode voltage sources (VCMs) can generate a DC offset (common-mode voltage, such as half of VDDL) for the LPF, enabling the system to operate from a unipolar supply. Design-for-Test (DTF) circuitry is capable of performing individual block characterization tests during chip sample characterization or as part of a batch production test procedure. 2:1 multiplexers can accept vref-ext signals. For example, when customers do not have strict transmission requirements for consumer or certain industrial electronic products, vref-ext signals can be used to switch rectangular signal excitation schemes.

[0071] Figure 10B This is a block diagram of an analog output stage circuit 1000, a reference generator 1050, and a shield driver 1052 according to at least one embodiment. In this embodiment, the reference generator 1050 generates a reference signal to the analog output stage circuit 1000. This reference signal can also be applied to the shield driver 1052, which compares the reference signal with an output signal 1054 (VDDL) from a level shifter 1002 of the analog output stage circuit 1000.

[0072] As described herein, aspects of this disclosure can provide substantial improvements or advantages over other solutions by offering lower solution costs (smaller footprint, lower power consumption) compared to high-speed digital-to-analog converters (DACs) that achieve high performance at high cost. This can be achieved by using low-cost sine wave generation techniques described herein, such as multi-stage sigma-delta modulation with dynamic element matching. As described herein, aspects of this disclosure can provide substantial improvements or advantages over other solutions by using signal windowing techniques—for example, for VCOM signals, using sufficiently smooth and sufficiently long (e.g., 20 microseconds or longer) transitions between display and sensing functions—resulting in lower radiated emissions. As described herein, aspects of this disclosure can provide substantial improvements or advantages over other solutions by combining touch pulse trains and VCOM transitions within a single waveform. As described herein, aspects of this disclosure can provide substantial improvements or advantages over other solutions by providing highly adjustable—including gain adjustment, LPF cutoff frequency adjustment, etc.—low-distortion analog output circuitry. Analog output circuits can have high power supply rejection ratios (PSRR) to tolerate power supply noise. As described herein, aspects of this disclosure can provide substantial improvements or advantages over other solutions by generating shielded GIP circuit power supplies with the aid of storage capacitors to eliminate the need for additional regulators.

[0073] Figure 11 This is a flowchart of a method 1100 for operating an in-cell touch controller according to at least one embodiment. Method 1100 can be performed by processing logic including hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, etc.), software, firmware, or a combination thereof. In one embodiment, method 1100 can be performed by any circuitry described herein. In one embodiment, method 1100 is performed by the in-cell touch controller 102 of FIG1. ​​In another embodiment, by… Figure 5 Signal generator circuit 500 or Figure 7 The signal generator circuit 700 performs method 1100. In another embodiment, method 1100 is performed by a device including a capacitive touch sensing channel and a processing device coupled to the capacitive touch sensing channel.

[0074] Return to reference Figure 11Method 1100 begins with the processing logic driving a first signal on the common voltage (VCOM) layer of the electrodes of the touch display within the cell according to the display function during a display function interval (box 1102). The processing logic generates a second signal according to the sensing function (box 1104). The second signal includes a windowed sine wave. The processing logic generates a transition signal to switch the display within the cell between the display function and the sensing function (box 1106). The processing logic drives the second signal and the transition signal on the VCOM layer during a touch scan interval (box 1108), and method 1100 ends.

[0075] In another embodiment, the processing logic combines the transition signal and the second signal into a combined output signal. To drive the second signal and the transition signal, the processing logic drives the combined output signal on the VCOM layer during the touch scan interval to support sensing functionality during transition to or from display functionality.

[0076] In another embodiment, the processing logic for driving the second signal and the transition signal drives the transition signal during a first segment of the touch scan interval and drives the second signal during a second segment of the touch scan interval, the second segment being after the first segment.

[0077] In another embodiment, the processing logic for driving the second signal and the transition signal drives the transition signal during a first segment of the touch scan interval and drives the second signal during a second segment of the touch scan interval, the first segment being after the first segment.

[0078] In another embodiment, the processing logic for driving the second signal and the transition signal drives a first portion of the transition signal during a first segment of the touch scan interval, drives a second portion of the transition signal during a second segment of the touch scan interval, and drives the second signal during a third segment of the touch scan interval, the third segment being after the first segment and before the second segment.

[0079] In another embodiment, the processing logic generates a second signal by modulating a windowed sine wave using SDM. In yet another embodiment, the processing logic combines the transition signal and the second signal into a combined signal, and generates a combined output signal by modulating the combined signal using SDM in the digital domain. The processing logic generates an analog output signal based on the combined output signal. To drive the second signal and the transition signal, the processing logic drives the analog output signal on the VCOM layer during the touch scan interval.

[0080] In one implementation, at block 1104, the processing logic generates a second signal to obtain a digital output signal by modulating a windowed sine wave using SDM in the digital domain, and generates the second signal based on the digital output signal using a digitally controlled potentiometer.

[0081] In another embodiment, the processing logic uses SDM to modulate a windowed sine wave in the digital domain to obtain a digital output signal. The digital output signal and the transition signal are combined into a combined output signal, and a digitally controlled potentiometer is used to generate the combined output signal based on this combined output signal. To drive the second signal and the transition signal, the processing logic drives the combined output signal.

[0082] In one implementation, generating a windowed sine wave includes: processing logic summing the phase values ​​in each clock cycle to obtain an accumulated phase value; the processing logic generating a jitter signal based on pseudo-random numbers and adding the accumulated phase value and the jitter signal to obtain a phase signal; and the processing logic using a LUT to convert the phase signal into an amplitude signal and multiplying the amplitude signal by the windowed signal to obtain the windowed sine wave.

[0083] In another embodiment, to combine the transition signal and the second signal into a combined output signal, the processing logic sums the phase values ​​in each clock cycle to obtain an accumulated phase value. The processing logic generates a jitter signal based on pseudo-random numbers and adds the accumulated phase value and the jitter signal to obtain the phase signal. The processing logic uses a LUT to convert the phase signal into an amplitude signal and multiplies the amplitude signal by a windowed signal to obtain a windowed sine wave. The processing logic adds the windowed sine wave and the transition signal to obtain the combined output signal.

[0084] In another embodiment, to combine the transition signal and the second signal into a combined output signal, the processing logic sums the phase values ​​each clock cycle to obtain an accumulated phase value. The processing logic generates a jitter signal based on pseudo-random numbers and adds the accumulated phase value to the jitter signal to obtain the phase signal. The processing logic uses a LUT to convert the phase signal into an amplitude signal and multiplies the amplitude signal by a windowed signal to obtain a windowed sine wave. The processing logic modulates the windowed sine wave in the digital domain using SDM to obtain a digital output signal. The processing logic combines the digital output signal with the transition signal to obtain the combined output signal. To drive the second signal and the transition signal, the processing logic uses a digitally controlled potentiometer to output the combined output signal.

[0085] As described in this article, SINEGEN can be part of an in-unit touch controller and can be used in two supported configurations: in one configuration, as follows regarding Figure 12As shown and described, the display function – touch scan transition and scan – are separated in time; in another configuration, as follows regarding Figure 13 As shown and described, touch scanning is combined with mode-changing transitions.

[0086] Figure 12 This is a flowchart of a method 1200 for operating an in-cell touch controller using separate scan and transition signals according to at least one embodiment. Method 1200 can be executed by processing logic including hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, etc.), software, firmware, or a combination thereof. In one embodiment, method 1200 can be executed by any circuitry described herein. In one embodiment, method 1200 is executed by the in-cell touch controller 102 of FIG1. ​​In another embodiment, by… Figure 5 Signal generator circuit 500 or Figure 7 Method 1200 is executed by a signal generator circuit 700. In another embodiment, method 1200 is executed by a device including a capacitive touch sensing channel and a processing device coupled to the capacitive touch sensing channel.

[0087] Return to reference Figure 12 Method 1200 begins with the processing logic configuring parameters of the touch controller within the unit (e.g., a touch subsystem (TSS) including the TX channel, SINEGEN, and various supplementary logic circuits, such as operating frequency, windowing mode, and scan slot duration) (box 1202). The processing logic configures a channel multiplexer for a given scan slot (box 1204). The processing logic waits for a synchronization signal from the display driver (box 1206). The processing logic generates a display / scan mode transition signal (box 1208). The processing logic begins scanning the pulse train (box 1210) and collects scan data (box 1212). The processing logic generates a scan / display mode transition signal (box 1214). The processing logic continues the display function (box 1216). Method 1200 can be repeated by returning to box 1208 for the next scan window.

[0088] In this embodiment, the display / scan mode switching signal at block 1208 and the scan / display mode switching signal at block 1214 are separated from the scan signal in the scan pulse train at block 1210.

[0089] Figure 13This is a flowchart of a method 1300 for operating an in-cell touch controller using combined scanning and transition signals according to at least one embodiment. Method 1300 can be executed by processing logic including hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, etc.), software, firmware, or a combination thereof. In one embodiment, method 1300 can be executed by any circuitry described herein. In one embodiment, method 1300 is executed by the in-cell touch controller 102 of FIG1. ​​In another embodiment, by… Figure 5 Signal generator circuit 500 or Figure 7 Method 1300 is executed by a signal generator circuit 700. In another embodiment, method 1300 is executed by a device including a capacitive touch sensing channel and a processing device coupled to the capacitive touch sensing channel.

[0090] Return to reference Figure 13 Method 1300 begins with the processing logic configuring parameters of the touch controller (e.g., TSS / SINEGEN) within the cell, such as operating frequency, windowing mode, and scan slot duration (box 1302). The processing logic configures a channel multiplexer for a given scan slot (box 1304). The processing logic waits for a synchronization signal from the display driver (box 1306). The processing logic combines the scan signals in the scan burst to generate a display / scan mode transition signal (box 1308). The processing logic collects scan data (box 1310). The processing logic combines the scan signals in the scan burst to generate a scan / display mode transition (box 1312). The processing logic continues the display function (box 1314). Method 1300 can be repeated by returning to box 1308 for the next scan window.

[0091] In this embodiment, the display / scan mode transition signal at block 1308 and the scan / display mode transition signal at block 1312 are combined with the scan signal in the scan burst. In methods 1200 and 1300, in addition to the mode transition and scan burst source, Figure 12 Operate sequentially or in Figure 13 Aside from simultaneous or concurrent operations, the sequence of operations is similar.

[0092] like Figures 12 to 13As indicated, since fewer parallel sensing channels can exist compared to the number of electrodes on the panel, an input multiplexer can be used to process multiple panel sensors. For some in-cell touch controllers, the ratio between the number of electrodes and the number of physically parallel capacitive sensing channels can be approximately 4:1 to 10:1. Multiple RX channels can be configured for multiple parallel self-capacitance sensing to perform sensor scanning functions during touch scan intervals. In some implementations, two synchronously operating SINEGEN blocks can be used to drive, for example, in... Figures 14A to 14C and Figure 15 The image shows two separate sections of the touch display within the unit.

[0093] Figure 14A This is a schematic diagram of a system 1400 according to at least one embodiment, the system 1400 having an in-cell touch controller 1402 coupled to a simplified version of an in-cell touch display 1400. Figure 14A A simplified structure of the in-cell touch controller element is shown. For ease of description, this simplified structure includes a smaller number of sensing pads (electrodes in the VCOM layer) and only one RX channel. In other embodiments, the number of sensing channels can be more than one, and in some cases, the number of sensing channels may be substantially higher, for example, from 50 to 200. The in-cell touch controller 1402 can be similar to the above description with respect to Figures 1 to 1402. Figure 13 The described in-cell touch controller. In this embodiment, the in-cell touch controller 1402 includes a first SINEGEN circuit 1406. The first SINEGEN circuit 1406 can generate sensing signals and transition signals, or a combination of sensing-transition signals, for a first portion of the in-cell touch display 1404. In one embodiment, as Figure 14C As shown, the first SINEGEN circuit 1406 is configured to generate a sensing signal according to a sensing function. The sensing signal includes a windowed sine wave. Furthermore, the first SINEGEN circuit 1406 generates a transition signal to cause at least a first portion of the touch display 1404 within the cell to transition between a display function and a sensing function. The first SINEGEN circuit 1406 drives the sensing signal and the transition signal on the VCOM layer during a touch scan interval. In another embodiment, the first SINEGEN circuit 1406 combines the transition signal and the sensing signal into a combined output signal and drives the combined output signal on the VCOM layer during a touch scan interval to support the sensing function during transition to or from the display function.

[0094] like Figure 14AAs shown, system 1400 includes the following functional blocks: an inner panel of the unit with four sensors labeled A through D; a single SINEGEN source; a shielded buffer (external or internal, depending on the implementation); a 4-to-1 receive channel multiplexer; a shielded / VCOM multiplexer with arbitrary switch control; a single receive (RX) channel; a VCOM source, which is an adjustable DC source; a GIP circuit (as part of the inner panel of the unit); a parallel data line source; a regulated power supply for the GIP circuit, providing DC voltages VGHO_REG and VGLO_REG; and an external tank capacitor C. T1 C T2 ; and analog switches SW1 to SW8 to switch between display mode and touch scan mode. System 1400 can have two time-alternating functions, such as Figure 14B The display functions shown and such Figure 14C The touch scanning function (also referred to as the sensing function in this document) is shown. These functions can be staggered in time. See the timing diagram. Figure 4 It includes display and touch functions.

[0095] Figure 14B It is according to at least one embodiment during the display function Figure 14A A schematic diagram of System 1400. In this function, the RX channel is disconnected from the sensing pad, and VCOM is generated using a VCOM DC source. The panel's GIP circuitry is powered by VGHO and VGLO sources, respectively. External tank capacitor C T1 and C T2 Accordingly, it is charged from the DC voltages VGHO and VGLO. Parallel panel data signals are fed into the data lines using the data generation source. The SINEGEN block is turned off, therefore no signal is generated.

[0096] Figure 14C This is according to at least one embodiment during the touch scanning function. Figure 14A A schematic diagram of System 1400. In this function, the SINEGEN block is activated and generates a scan pulse train. The VCOM source is disconnected and can be turned off when needed to save power. With the help of the RX multiplexer, one of the sensors is connected to the sensing channel. Because the sensing channel acts as a unity-gain voltage buffer for the reference signal, the sensing channel reference input is driven by the SINEGEN output, so the sensing pad has the same level as the SINEGEN output.

[0097] The shielding signal is provided to the remaining three sensors (B, C, D) on the panel. Therefore, in this configuration, all touch sensors remain at the same potential, and the sensor capacitances to the gate lines and data lines are shielded (disabled). The data generator is turned off, and the SINEGEN output signal is also provided to the data lines. Note: In some implementations, the data lines may remain floating during touch scan functionality, depending on the LCD panel.

[0098] The internal panel GIP circuitry is powered by a floating power supply that provides an AC voltage with the same amplitude and phase as the sensor pads, and the internal panel GIP circuitry is driven by SINEGEN data lines. The floating power supply is located between two tank-circuit capacitors C. T1 and C T2 This is achieved with the help of [unclear - likely referring to a specific technology or mechanism], where the bottom terminals of the two tank circuit capacitors are driven by the SINEGEN output. Note: During the display function state, these capacitors are pre-charged to VGHO and VGLO levels, and the DC voltage variation during the scan cycle due to GIP circuit power consumption is not significant and has no impact on either scan performance or display function. For the gate driver floating power supply implementation, other implementations can use different implementations, such as summing amplifiers / buffers.

[0099] Given that there are far fewer sensing RX channels in the display than in the sensing pad, we need to use the same sensing channels in series to scan different sensors. Each sensor is scanned in a different sensing time slot, triggered by the HSYNC signal (see the main patent application). Figure 4 In this simplified example, we have four sensors scanned through a single sensing channel (multiplexing ratio of 4:1), but in a typical cell panel, the multiplexing ratio is approximately 1:8 to 1:10.

[0100] The sensing channels are connected alternately to the individual sensors, one at a time, and with the help of a VCOM / masked multiplexer, the shielded signal is provided to the remaining three sensors.

[0101] Figure 15This is a schematic diagram of a system 1500 according to at least one embodiment, the system 1500 having an in-cell touch controller 1502 coupled to an in-cell touch display 1504. The in-cell touch controller 1502 may be similar to the in-cell touch controller described above with respect to Figures 1 to 14. In this embodiment, the in-cell touch controller 1502 includes two SINEGEN circuits 1506 and 1508. The first SINEGEN circuit 1506 can generate a sensing signal and a transition signal, or a combined sensing-transition signal, for a first portion of the in-cell touch display 1504. The second SINEGEN circuit 1508 can generate a sensing signal and a transition signal, or a combined sensing-transition signal, for a second portion of the in-cell touch display 1504. In one embodiment, the first SINEGEN circuit 1506 is configured to generate a sensing signal according to a sensing function. The sensing signal includes a windowed sine wave. Furthermore, the first SINEGEN circuit 1506 generates a transition signal to cause at least a first portion of the in-cell touch display 1504 to transition between a display function and a sensing function. The first SINEGEN circuit 1506 drives a sensing signal and a transition signal on the VCOM layer during the touch scan interval. In another embodiment, the first SINEGEN circuit 1506 combines the transition signal and the sensing signal into a combined output signal and drives the combined output signal on the VCOM layer during the touch scan interval to support the sensing function during transition to or from display function. The second SINEGEN circuit 1508 is configured to generate a second sensing signal according to the sensing function. The second sensing signal includes a windowed sine wave. The second SINEGEN circuit 1508 generates a second transition signal to cause at least a second portion of the touch display 1504 within the cell to transition between display function and sensing function. The second SINEGEN circuit 1508 drives the second sensing signal and the second transition signal on the VCOM layer during the touch scan interval. The first SINEGEN circuit 1506 and the second SINEGEN circuit 1508 operate synchronously. In another embodiment, the second SINEGEN circuit 1508 combines the second sensing signal and the second transition signal into a combined output signal, and drives the combined output signal on the VCOM layer during the touch scan interval to support sensing functionality during transition to or from display functionality. Given the very narrow (2mm) and long (e.g., 35mm) TTDI chip, these two SINEGEN blocks can be used for precise phase and amplitude adjustments on a large in-cell panel and also simplify the overall chip layout.

[0102] An external high-power buffer 1510 can be used to shield signals(s). For example, two storage capacitors can be used to generate AC-shielded GIP circuit signals during the touch scan interval. During display functions, a voltage regulator can be used to generate GIP power (e.g., VGHO_REG, VGLO_REG). A VCOM source 1512 can be used to provide VCOM levels to the in-cell touch display 1504. Unlike stacked touch sensors within a display, the in-cell panel itself can include an array of TFT transistors on the glass of the in-cell touch display 1504 and built-in GIP drivers 1514, 1516. The in-cell touch display 1504 has a glass panel with integrated sensors (electrodes). As described above, the in-cell touch controller 1502 can include an input multiplexer 1518 to couple electrodes to a receiver (RX) channel that measures charge and converts the charge into a digital value for further processing, such as touch coordinates, gesture recognition, etc.

[0103] System 1500 may include one or more TDDI chips (including the in-cell touch controllers described herein). When multiple in-cell touch controllers are present, one may operate as the master touch controller to initiate the scanning function and provide synchronization signals to the other slave touch controllers. The master controller may scan certain panel areas, while the remaining areas may be scanned by the slave controller(s). In some cases, touch data originates from and is processed locally by the master in-cell touch controller, thus eliminating the need for an external central processing unit (CPU) for touch coordinates. In other cases, the touch controller(s) may offload these calculations to another processing element, where a single master touch controller collects and processes data in parallel from multiple TDDI chips. This separation may offer several design advantages, such as using high-voltage CMOS technology for the TDDI chips and low voltage for the CPU chips.

[0104] As mentioned above, such as Figure 16 As shown, the sensing channels are connected alternately to the individual sensors, one at a time, and with the help of the VCOM / masked multiplexer, the shielded signal is provided to the remaining three sensors.

[0105] Figure 16 A multiplexer configuration 1600 for scanning several sensors using a single RX channel, according to at least one embodiment, is shown. In a common embodiment, a typical panel's HSYNC pulse (see...) is used... Figure 4A scan of a sensor is triggered by a single HSYNC pulse. In other implementations (display panels that can accept long scan intervals), more than one (e.g., two) sensors can be scanned in series with each HSYNC pulse. In this case, the TDDI chip's internal state machine performs seamless sensor switching. When scanning more than one sensor in a single time slot, only one window pulse train is required, which allows for a stronger touch signal and a reduced peak width at the panel's emission center.

[0106] In the above description, certain parts are presented in detail based on the algorithms and symbolic representations of operations on data bits within computer memory. These algorithmic descriptions and representations are the means by which those skilled in the art of data processing most effectively communicate the essence of their work to others skilled in the art. Here, and generally, an algorithm is conceived as a self-consistent sequence of steps leading to a desired result. These steps are those that require physical manipulation of physical quantities. Typically, although not always necessary, these quantities take the form of electrical or magnetic signals that can be stored, transmitted, combined, compared, and otherwise manipulated. Primarily for general reasons, it has sometimes proven convenient to refer to these signals as bits, values, elements, symbols, characters, items, numbers, etc.

[0107] However, it should be remembered that all these terms and similar terms should be associated with appropriate physical quantities and are merely convenient labels applied to those quantities. Unless otherwise stated, it is apparent from the above discussion that, throughout the description, discussions using terms such as “determine,” “allocate,” “dynamically allocate,” “redistribute,” “ignore,” “reassign,” “detect,” “execute,” “polling,” “register,” “monitor,” etc., refer to the actions and processes of a computing system or similar electronic computing device that will be represented as physical (e.g., electronic) quantities within the registers and memories of the computing system, manipulated and converted into other data similarly represented as physical quantities within the computing system's memory or registers or other such information storage, transmission, or display devices.

[0108] The terms “example” or “exemplary” are used herein to mean as an example, instance, or illustration. Any aspect or design described herein as “example” or “exemplary” is not necessarily to be construed as being more preferred or advantageous than other aspects or designs. Rather, the use of the terms “example” or “exemplary” is intended to present concepts in a specific manner. As used in this application, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless otherwise stated or clear from the context, “X includes A or B” is intended to mean any natural inclusion arrangement. That is, if X includes A; X includes B; or X includes both A and B, then “X includes A or B” is satisfied in any of the above cases. Additionally, unless otherwise stated or clear from the context that a singular form is involved, the articles “a” and “an” as used in this application and the appended claims should generally be construed as meaning “one or more.” Furthermore, unless described to indicate the same embodiment, the use of the terms “implementation” or “an embodiment” or “implementation” throughout the text is not intended to indicate the same implementation or implementation.

[0109] The embodiments described herein may also relate to devices for performing the operations described herein. Such devices may be specifically constructed for a desired purpose, or they may comprise a general-purpose computer selectively activated or reconfigured by a computer program stored in a computer. Such computer programs may be stored in a non-transitory computer-readable storage medium, such as, but not limited to, any type of disk (including floppy disks, optical disks, CD-ROMs, and magneto-optical disks), read-only memory (ROM), random access memory (RAM), EPROM, EEPROM, magnetic cards or optical cards, flash memory, or any type of medium suitable for storing electronic instructions. The term "computer-readable storage medium" should be understood to include a single medium or multiple media (e.g., a centralized or distributed database and / or associated cache memory and server) storing one or more sets of instructions. The term "computer-readable medium" should also be considered to include any medium capable of storing, encoding, or carrying a set of instructions executable by a machine and enabling the machine to perform any one or more methods of this embodiment. Therefore, the term "computer-readable storage medium" should be understood to include, but is not limited to, solid-state memory, optical media, magnetic media, and any medium capable of storing a set of instructions that can be executed by a machine and enabling the machine to perform any one or more methods of this embodiment.

[0110] The methods and demonstrations presented herein are not inherently related to any particular computer or other device. Various general-purpose systems can be used with the programs taught herein, or it may prove convenient to construct more specialized devices to perform the required method steps. The necessary structures for various such systems will be presented in the following description. Furthermore, this embodiment is described without reference to any particular programming language. It will be understood that the teachings of the embodiments described herein can be implemented using a variety of programming languages.

[0111] To provide a good understanding of some embodiments of this disclosure, the foregoing description sets forth numerous specific details, such as examples of particular systems, components, methods, etc. It should be understood that the foregoing description is intended to be illustrative and not restrictive. Many other embodiments will become apparent to those skilled in the art upon reading and understanding the foregoing description. Therefore, the scope of this disclosure should be determined by reference to the appended claims and the full scope of their equivalents.

Claims

1. A method for operating a touch controller within a unit, comprising: The touch controller within the unit drives a first signal on the common voltage VCOM layer of the electrodes of the touch display within the unit according to the display function during the display function interval; The touch controller within the unit generates a second signal based on the sensing function, wherein the second signal includes a windowed sine wave; The touch controller within the unit generates a transition signal to cause the touch display within the unit to switch between the display function and the sensing function; and The second signal and the transition signal are driven on the VCOM layer by the touch controller within the unit during the touch scan interval.

2. The method of claim 1, further comprising combining the conversion signal and the second signal into a combined output signal, wherein, Driving the second signal and the transition signal includes: driving the combined output signal on the VCOM layer during the touch scan interval to support the sensing function during transition to or from the display function.

3. The method according to claim 1, wherein, The driving signals for the second signal and the transition signal include: The transition signal is driven during the first segment of the touch scan interval; and The second signal is driven during a second segment of the touch scan interval, wherein the second segment follows the first segment.

4. The method according to claim 1, wherein, The driving signals for the second signal and the transition signal include: The transition signal is driven during the first segment of the touch scan interval; and The second signal is driven during a second segment of the touch scan interval, wherein the first segment follows the first segment.

5. The method according to claim 1, wherein, The driving signals for the second signal and the transition signal include: A first portion of the transition signal is driven during a first segment of the touch scan interval; The second portion of the transition signal is driven during the second segment of the touch scan interval; and The second signal is driven during a third segment of the touch scan interval, wherein the third segment is after the first segment and before the second segment.

6. The method of claim 1, further comprising generating the second signal by modulating the windowed sine waveform using a sigma-delta modulator (SDM).

7. The method according to claim 1, further comprising: The transition signal and the second signal are combined into a combined signal; as well as A combined output signal is generated by modulating the combined signal using a sigma-delta modulator (SDM) in the digital domain. as well as An analog output signal is generated based on the combined output signal, wherein driving the second signal and the transition signal includes driving the analog output signal on the VCOM layer during the touch scan interval.

8. The method according to claim 1, wherein, Generating the second signal includes: The windowed sine waveform is modulated using a sigma-delta modulator (SDM) in the digital domain to obtain a digital output signal; and The second signal is generated using a digitally controlled potentiometer based on the digital output signal.

9. The method according to claim 1, further comprising: The windowed sine waveform is modulated using a sigma-delta modulator (SDM) in the digital domain to obtain a digital output signal; as well as The digital output signal and the conversion signal are combined into a combined output signal; as well as A digitally controlled potentiometer generates a combined output signal based on the combined output signal, wherein driving the second signal and the transition signal includes driving the combined output signal.

10. The method according to claim 1, wherein, Generating the windowed sine waveform includes: The phase value is accumulated by summing the phase values ​​in each clock cycle using a phase accumulator. The jitter signal is generated by a jitter circuit based on pseudo-random numbers; The accumulated phase value is added to the jitter signal to obtain the phase signal; The phase signal is converted into an amplitude signal using a lookup table (LUT); and The amplitude signal is multiplied by the windowed signal to obtain the windowed sine waveform.

11. The method according to claim 2, wherein, Combining the transformation signal and the second signal into the combined output signal includes: The phase value is accumulated by summing the phase values ​​in each clock cycle using a phase accumulator; The jitter signal is generated by a jitter circuit based on pseudo-random numbers; The accumulated phase value is added to the jitter signal to obtain the phase signal; The phase signal is converted into an amplitude signal using a lookup table (LUT). Multiplying the amplitude signal by the windowed signal yields the windowed sine waveform; and The windowed sine waveform and the transformation signal are added together to obtain the combined output signal.

12. The method according to claim 2, wherein, Combining the transformation signal and the second signal into the combined output signal includes: The phase value is accumulated by summing the phase values ​​in each clock cycle using a phase accumulator. The jitter signal is generated by a jitter circuit based on pseudo-random numbers; The accumulated phase value is added to the jitter signal to obtain the phase signal; The phase signal is converted into an amplitude signal using a lookup table (LUT). Multiplying the amplitude signal by the windowed signal yields the windowed sine waveform; and The windowed sine waveform is modulated using a sigma-delta modulator (SDM) in the digital domain to obtain a digital output signal; and The digital output signal and the transition signal are combined to obtain the combined output signal, wherein driving the second signal and the transition signal includes outputting the combined output signal using a digitally controlled potentiometer.

13. An in-unit touch controller, comprising: An integrated display driver is configured to drive a first signal on the common voltage VCOM layer of the electrodes touching the display within the cell, according to the display function, during a display function interval; as well as A touch driver includes a sensing channel and a signal generator circuit, wherein the signal generator circuit is configured to: A second signal is generated based on the sensing function, wherein the second signal includes a windowed sine waveform; Generate a transition signal to cause the touch display within the unit to switch between the display function and the sensing function; and The second signal and the transition signal are driven on the VCOM layer during the touch scan interval.

14. The in-unit touch controller according to claim 13, wherein, The touch driver is also configured to: The conversion signal and the second signal are combined into a combined output signal; and The combined output signal is driven on the VCOM layer during the touch scan interval to support the sensing function during transition to or from the display function.

15. The in-unit touch controller according to claim 13, wherein, The touch driver includes a direct digital synthesis (DDS) circuit.

16. The in-unit touch controller according to claim 15, wherein, The DDS circuit includes multiple functional blocks, which include: Phase accumulator; First adder; A phase-to-amplitude converter, which includes a lookup table (LUT); Multiplier; Sigma-Delta Modulator (SDM); and Low-pass filter (LPF).

17. The in-unit touch controller according to claim 13, wherein, The touch driver includes a direct digital synthesis (DDS) circuit and a digitally controlled potentiometer.

18. A system having an in-unit touch controller, comprising: The unit includes a touch display comprising a common voltage VCOM layer for electrodes, the common voltage VCOM layer being configured to operate in relation to a display function in a first interval and in relation to a sensing function in a second interval. as well as An in-unit touch controller coupled to the in-unit touch display, wherein the in-unit touch controller includes a first sensing channel and a first signal generator circuit, the first signal generator circuit being configured to: A sensing signal is generated based on the sensing function, wherein the sensing signal includes a windowed sine waveform; Generate a transition signal to cause the touch display within the unit to switch between the display function and the sensing function; and During the second interval, the sensing signal and the transition signal are driven on the VCOM layer.

19. The system according to claim 18, wherein, The first signal generator circuit is further configured to combine the transition signal and the sensing signal into a combined output signal, and to drive the combined output signal on the VCOM layer during the second interval to support the sensing function during transition to or from the display function.

20. The system according to claim 18, wherein, The touch controller within the unit includes: Second sensing channel; and The second signal generator circuit is configured to: A second sensing signal is generated based on the sensing function, wherein the second sensing signal includes a windowed sine waveform; Generate a second transition signal to cause the touch display within the unit to switch between the display function and the sensing function; and During the second interval, the second sensing signal and the second transition signal are driven on the VCOM layer, wherein the first signal generator circuit and the second signal generator circuit operate synchronously.

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