Sensor diagnostics for in-cell touch screen controller

Abstract

Sensor diagnostics for in-cell touch screen controllers are disclosed. Apparatuses, methods, and systems to detect the presence of faults such as shorts and / or opens within a touch sensitive display panel are described herein. In one implementation, a touch screen controller is disclosed that includes one or more receive channels, where each receive channel is configured to scan a corresponding group of sensors of a plurality of sensors. The touch screen controller can also include a plurality of multiplexers, each configured to selectively couple a respective sensor of the plurality of sensors to a corresponding receive channel or a reference voltage. The touch screen controller can also include a processing device configured to detect one or more shorts based on DC current sensing. The touch screen controller can also detect one or more opens based on AC current sensing of each of the one or more receive channels.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 977,923, filed on February 18, 2020, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure generally relates to touch- and / or presence-based display systems, and more specifically to display controllers with display sensor diagnostic capabilities. Background Technology

[0004] Capacitive sensing systems sense electrical signals generated on electrodes that reflect changes in capacitance. Such capacitance changes can indicate touch events, such as physical contact or proximity of an object to a specific electrode. An array of capacitive sensors operates by measuring the capacitance of capacitive sensors (e.g., electrodes) and evaluating the increment of capacitance indicating the touch or presence of a conductive object. When a conductive object (e.g., a finger, hand, or other object) touches or comes into close proximity to the capacitive sensor, the capacitance changes, and the conductive object is detected. The capacitance change can be measured by circuitry. The circuitry converts the signal corresponding to the measured capacitance of the capacitive sensors in the array into a digital value. The measured capacitance is typically received as a current or voltage that is integrated and converted into a digital value.

[0005] Capacitive sensors are widely used in modern customer applications, providing user interface options in existing products. Capacitive sensors can replace mechanical buttons, dials / knobs, and other similar mechanical user interface controls. Using capacitive sensors can replace the functions of complex mechanical switches and buttons, providing reliable operation under harsh conditions. Furthermore, the range of capacitive sensors can range from single buttons to large arrays of buttons arranged in the form of capacitive sensor arrays for touch sensing surfaces. Capacitive sensor arrays are ubiquitous in today's industrial and consumer markets. They can be found in automobiles, cellular phones, GPS devices, set-top boxes, cameras, computer screens, MP3 players, digital tablets, and more.

[0006] Two typical types of capacitance are commonly used in capacitive sensing: 1) mutual capacitance, where the capacitance sensing circuit measures the capacitance formed between two sensors coupled to the capacitance sensing circuit; and 2) self-capacitance, where the capacitance sensing circuit measures the capacitance of one sensor. Touch panels have distributed loads of both types (1) and (2) of capacitance, and some touch solutions sense both types of capacitance uniquely or in combination with their various sensing modes. Attached Figure Description

[0007] The embodiments are illustrated by way of example and not limitation in the accompanying drawings.

[0008] Figure 1 This is a block diagram illustrating a capacitive touchscreen display according to some embodiments of the present disclosure.

[0009] Figure 2 This is a block diagram illustrating a touchscreen controller according to some embodiments of the present disclosure.

[0010] Figures 3A to 3B This is a diagram illustrating a sensor array during various stages of short-circuit detection according to some embodiments of the present disclosure.

[0011] Figure 4 This is a diagram illustrating a touchscreen controller according to some embodiments of the present disclosure.

[0012] Figure 5 This is a diagram illustrating a sensor array during short-circuit detection according to some embodiments of the present disclosure.

[0013] Figure 6 This is a diagram illustrating half-cycle data of the receiving channel during short-circuit detection according to some embodiments of the present disclosure.

[0014] Figure 7 This is a block diagram illustrating a touchscreen display according to some embodiments of the present disclosure.

[0015] Figure 8 This is a flowchart of a method for detecting short circuits in a touchscreen display according to some embodiments of the present disclosure.

[0016] Figure 9 This is a flowchart of a method for detecting short circuits in a touchscreen display according to some embodiments of the present disclosure.

[0017] Figure 10 This is a flowchart of a method for detecting open circuits in a touchscreen display according to some embodiments of the present disclosure.

[0018] Figure 11 Programmable System-on-Chip (SoC) Implementation of the core architecture of a microcontroller. Detailed Implementation

[0019] In the following description, numerous specific details are set forth for illustrative purposes to provide a thorough understanding of this embodiment. However, it will be apparent to those skilled in the art that this embodiment can be practiced without these specific details. In other instances, well-known circuits, structures, and techniques are shown in block diagrams rather than in detail to avoid unnecessarily obscuring the understanding of this description.

[0020] The reference to "one embodiment" or "implementation" in the description means that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment. The phrase "in one embodiment" in various places throughout this description does not necessarily refer to the same embodiment.

[0021] Capacitive sensor arrays are ubiquitous in today's industrial and consumer markets. Capacitive sensing elements can replace the functionality of mechanical buttons, dials / knobs, and other similar mechanical user interface controls. However, capacitive sensing arrays can suffer from faults and defects. For example, a capacitive sensing array may suffer from short circuits, where multiple sensors are short-circuited on the panel itself or at the junction of the integrated circuit that implements the sensors. Another example of a fault is an "open circuit," which is a disconnect between sensor traces. Because these faults can affect the performance of touch-sensing displays, it is important to detect such faults, especially in environments such as automotive displays. Sensor diagnostic procedures must be able to execute while the display module is running and must not interfere with the displayed image during operation.

[0022] The structure of a touch-sensing display panel can include multiple layers, such as a cover glass, a color filter glass, an insulating component, a color filter, one or more polarizers, a liquid crystal (LCD) layer, a common layer (VCOM), a layer for implementing the display driver, and a layer for implementing the touchscreen controller. There are many ways to implement a display panel. For example, in an on-sell configuration, both top (TX & RX) sensing layers are above the color filter glass substrate but below the top polarizers. The LCD layer does not include display driver or touchscreen controller (capacitive sensing) functionality, and therefore requires a dedicated layer for the display driver or touchscreen controller. In a hybrid in-sell configuration, the structure includes a capacitive sensing layer above the color filter glass and a capacitive sensing layer below the color filter glass. The LCD layer can include touchscreen controller functionality, but the display driver functionality still requires a separate layer. In a true-in-sell configuration, the structure integrates the touchscreen controller and display driver functionality within the VCOM layer, and no additional layers are required.

[0023] The embodiments described herein are for detecting the presence of faults such as short circuits and / or open circuits within a touch-sensitive display panel. The display panel may include a touchscreen that includes a capacitive sensor array and a touchscreen controller operatively coupled to the touchscreen. The sensor array may include multiple capacitive sensors, and the touchscreen controller may be operatively coupled to the capacitive sensor array in any suitable configuration (e.g., truly embedded, surface-mount, hybrid embedded, etc.).

[0024] This document describes apparatus, methods, and systems for detecting the presence of faults such as short circuits and / or open circuits within a touch-sensitive display panel. In one embodiment, a touchscreen controller is disclosed, comprising: one or more receiving channels, each configured to scan a corresponding sensor group among a plurality of sensors. The touchscreen controller also includes a plurality of multiplexers, each configured to selectively couple a corresponding sensor among the plurality of sensors to a corresponding receiving channel or a reference voltage. The touchscreen controller further includes processing means configured to: detect one or more short circuits using DC current sensing, and detect one or more open circuits based on AC current sensing of each of the one or more receiving channels.

[0025] Figure 1 This is a block diagram illustrating one embodiment of a touchscreen display 100. The touchscreen display 100 may include a touchscreen 105 and a touchscreen controller 120. The touchscreen 105 may be a display screen for displaying images and may include multiple layers having a cover glass, color filter, polarizer, liquid crystal, and a common layer (VCOM). A capacitive sensing array 110 may be implemented in the touchscreen 105. In some embodiments, the touchscreen controller 120 may be integrated into the VCOM layer of the touchscreen 105 and may be configured to measure capacitance from the capacitive sensing array 110. This configuration may be referred to as an "embedded" configuration because the touchscreen controller functionality is implemented entirely on the VCOM layer without requiring additional layers. The touchscreen controller 120 may integrate touchscreen controller and display driver functions together on a single chip. The touchscreen controller function may refer to sensing the touch or proximity of a conductive object, and the display driver function may refer to refreshing the image displayed on the touchscreen 105. In some embodiments, the touchscreen 105 (e.g., a touchscreen or touchpad) may be coupled to a host computing device 140. In some implementations, the capacitive sensing array 110 is a two-dimensional sensing array that uses the touchscreen controller 120 to detect touches on the touchscreen 105.

[0026] In some embodiments, the capacitive sensing array 110 includes electrodes 111(1) to 111(L) (where L is a positive integer) arranged in a two-dimensional matrix (also referred to as an XY matrix). The capacitive sensing array 110 is coupled to a touchscreen controller 120 via one or more analog buses 115 that transmit multiple signals. The capacitive sensing array 110 may be a multidimensional capacitive sensing array organized as rows and columns. In other embodiments, the capacitive sensing array 110 is an opaque capacitive sensing array (e.g., a PC touchpad). The capacitive sensing array 110 may be configured to have a flat surface profile. Alternatively, the capacitive sensing array 110 may have a non-flat surface profile. Alternatively, other configurations of the capacitive sensing array may be used. For example, instead of vertical columns and horizontal rows, the capacitive sensing array 110 may have a hexagonal arrangement, etc., as will be understood by those skilled in the art who benefit from this disclosure. In one embodiment, the capacitive sensing array 110 may be included in an ITO panel or a touchscreen panel.

[0027] In some embodiments, the touchscreen controller 120 may include one or more receive (RX) channels 125(1) to 125(N) to measure the charge on the electrode 111 (also referred to herein as a “sensor”). Various methods exist for measuring capacitance on the capacitance sensing array 110, such as self-capacitance sensing and mutual capacitance sensing. The RX channels 125 may be used with any suitable technique for measuring capacitance. For example, each RX channel 125 may include a relaxation oscillator or other device to measure capacitance, and a counter or timer to measure the oscillator output. Alternatively, each RX channel 125 may include an operational amplifier, a switch, and an integrator capacitor. Other capacitance sensing methods known to those skilled in the art may also be utilized. In one embodiment, the touchscreen controller 120 is manufactured by Cypress Semiconductor, San Jose, California. TM The company developed Cypress A series of microcontrollers. RX channel 125 measures a signal representing the self-capacitance of electrodes 111(1) to 111(L). The touchscreen controller 120 also includes converter circuitry (not shown), such as an analog-to-digital converter (ADC) that converts the measured signal into a digital value. The touchscreen controller 120 may also include software components for converting count values ​​(e.g., capacitance values) into touch detection decisions (also known as switch detection decisions) or relative magnitudes. It should be noted that various known methods exist for measuring capacitance, such as current-to-voltage phase shift measurement, resistor-capacitor charging timing, capacitive bridge voltage dividers, charge transfer, successive approximations, sum-decrement modulators, charge accumulation circuits, field effects, mutual capacitance, frequency shift, or other capacitance measurement algorithms. However, it should be noted that in some embodiments, the touchscreen controller 120 may evaluate other measurements to determine user interaction rather than evaluating the raw count relative to a threshold. For example, in a touchscreen controller 120 with a sum-decrement modulator, the touchscreen controller 120 evaluates the ratio of the output pulse width (i.e., density domain) rather than the raw count being above or below a specific threshold. It should be noted that the RX channel 125 can be a type of sensing channel that can be configured for different operating modes. For example, the RX channel 125 in self-capacitance mode is configured as a sensing channel for driving and sensing electrode 111 to measure the self-capacitance of the electrode relative to ground or any suitable reference voltage. Although embodiments of this disclosure have been discussed with respect to self-capacitance sensing, the RX channel 125 can also be configured as a sensing channel for mutual capacitance mode, in which the mutual capacitance between the first electrode (RX) and the second electrode (TX) is measured. Alternatively, the RX channel can be configured for both self-capacitance and mutual capacitance modes, in which self-capacitance and mutual capacitance can be measured simultaneously or sequentially.

[0028] Touchscreen controller 120 is configured to detect one or more touches on touchscreen 105. Touchscreen controller 120 can detect conductive objects, such as fingers, passive styluses, active styluses, or any combination thereof. As used herein, detecting a conductive object can refer to detecting the proximity of a conductive object to touchscreen 105 or actual physical contact between a conductive object and touchscreen 105. Touchscreen controller 120 can measure touch data on capacitive sensing array 110.

[0029] Sensor 111 may be an electrode made of a conductive material such as copper, while touchscreen 105 is an ITO panel. Sensor 111 may be configured to enable touchscreen controller 120 to measure self-capacitance, mutual capacitance, or any combination thereof. In another embodiment, touch data is a 2D capacitive image of capacitive sensing array 110. In one embodiment, when touchscreen controller 120 measures the mutual capacitance of touch sensing devices (e.g., capacitive sensing array 110), touchscreen controller 120 obtains a 2D capacitive image of the touch sensing devices and processes data for peak and position information. In another embodiment, touchscreen controller 120 obtains, for example, a capacitive touch signal dataset from sensing array 110, and finger detection firmware executed on touchscreen controller 120 identifies the dataset area indicating a touch, detects and processes peaks, calculates coordinates, or any combination thereof. The firmware uses the embodiments described herein to identify peaks. The firmware may calculate the precise coordinates of the obtained peaks. In one embodiment, the firmware may use a correlation algorithm to calculate the precise coordinates of the obtained peaks, which calculates a correlation coefficient for each possible angle and identifies the angle with the highest correlation coefficient as the location of the touch. The X / Y coordinates of the peak can describe the precise location of the touch, as described in detail elsewhere herein. Alternatively, other coordinate interpolation algorithms can be used to determine the coordinates of the obtained peak. The touchscreen controller 120 can report the precise coordinates and other information to a host computing device (not shown).

[0030] In one embodiment, the operation of the touchscreen controller 120 can be implemented using on-board firmware. In other embodiments, they can be implemented in hardware or software. For example, the operation of the touchscreen controller 120 can be stored as instructions in a memory 135 located separately from the touchscreen controller 120 (e.g., because high-voltage display driver processing is incompatible with known flash memory technology), and the touchscreen controller 120 can execute the instructions to perform its functions. For example, the touchscreen controller 120 may include one or more processing devices 130 (for ease of illustration, in...). Figure 1 A single processing device (shown in the diagram) executes instructions in memory 135 to perform functions. The processing device 130 may receive signals from RX channel 125 and determine the state of the capacitive sensing array 110, such as whether an object (e.g., a finger) is detected on or near the sensing array 110 (e.g., determining the presence of an object), determining the position of the object on the sensing array (e.g., determining the position of the object), tracking the motion of the object, or other object-related information detected at the touch sensor. The processing device 130 may be any suitable central processing unit (CPU).

[0031] In another embodiment, the touchscreen controller 120 may send raw or partially processed data to the host computing device 140 instead of performing the operations of the processing device 130 within the touchscreen controller 120. The host computing device 140 (hereinafter referred to as "host 140") may include logic that performs some or all of the operations of the processing device 130. The operation of the decision logic may be implemented in firmware, hardware, software, or a combination thereof. The host 140 may include a high-level application programming interface (API) in an application that performs routines on received data, such as sensitivity difference compensation, other compensation algorithms, baseline update routines, startup and / or initialization routines, interpolation operations, or scaling operations. The operations described with respect to the processing device 130 may be implemented in the logic, applications, or other hardware, software, and / or firmware of the host 140. The host 140 may also include non-sensing action hardware or software that can be used to process data and / or receive / send data from / to the host. For example, additional components (e.g., keyboard, keypad, mouse, trackball, LED, display or other peripheral devices) can be implemented to operate together with the touch screen controller 120 and the capacitive sensing array 110.

[0032] In one embodiment, the sensors 111 are configured as rows and columns, respectively. It should be noted that the rows and columns of the sensors 111 can be configured by the touchscreen controller 120 as individual electrodes for self-capacitance measurement. The touchscreen controller 120 can configure the electrodes 111 as receiving electrodes for self-capacitance sensing via, for example, a multiplexer, and configure one or more electrodes as blocking electrodes. In some embodiments, the touchscreen controller 120 may also configure some of the electrodes 111 to be driven by a shielding signal.

[0033] In some embodiments, the touchscreen 105 may include a plurality of touchscreen controllers 120, all of which may be located on a common carrier substrate, such as an integrated circuit (IC) die substrate or a multi-chip module substrate, together with the capacitive sensing array 110. In these embodiments, a first touchscreen controller 120 may act as a master controller and may be used to scan specific sensors of the capacitive sensing array 110, and other touchscreen controllers 120X may act as slave controllers to scan the remaining sensors of the capacitive sensing array 110.

[0034] The description of the touchscreen controller 120 can be generated and compiled for incorporation into an integrated circuit. For example, behavioral-level code describing the touchscreen controller 120 or portions thereof can be generated using hardware description languages ​​such as VHDL or Verilog and stored on a machine-accessible medium (e.g., CD-ROM, hard disk, floppy disk, etc.). Furthermore, behavioral-level code can be compiled into register-transfer-level (“RTL”) code, netlists, or even circuit layouts and stored on a machine-accessible medium. Behavioral-level code, RTL code, netlists, and circuit layouts can represent various levels of abstraction describing the touchscreen controller 120.

[0035] In one embodiment, the touchscreen display 100 is used in a tablet computer. Alternatively, the electronic device can be used in other applications, such as a laptop computer, a mobile handheld device, a personal data assistant (“PDA”), a keyboard, a television, a remote control, a monitor, a handheld multimedia device, a handheld media (audio and / or video) player, a handheld gaming device, a point-of-sale signature input device, an e-book reader, a global positioning system (“GPS”), or a control panel. The embodiments described herein are not limited to touchscreens or touch sensor panels implemented in laptops, but can be used in other capacitive sensing implementations, such as touch sensor sliders (not shown) or touch sensor buttons (e.g., capacitive sensing buttons). In one embodiment, these sensing devices include one or more capacitive sensors or other types of capacitive sensing circuitry. The operations described herein are not limited to laptop pointer operations, but can include other operations such as lighting control (dimmer), volume control, graphic equalizer control, speed control, or other control operations requiring gradual or discrete adjustments. It should also be noted that these capacitive sensing implementations can be used in conjunction with non-capacitive sensing elements, including but not limited to selection buttons, sliders (e.g., display brightness and contrast), scroll wheels, multimedia controls (e.g., volume, track advance, etc.), handwriting recognition, and numeric keypad operation.

[0036] For reference Figures 2 to 9As discussed in further detail, the touchscreen controller 120 can provide the ability to detect various types of faults during the operation of the touchscreen display 100. One example of a fault might be a "short circuit," where two or more sensors are short-circuited on the panel itself or at the junction of the integrated circuit implementing the sensors. Another example of a fault is an "open circuit," where a disconnection occurs between sensor traces. Open circuits can be found at various locations, either on the board included with the IC or on the display panel itself. The fault detection provided is effective during operation of the display and can prevent distortion or interruption of the image display during operation. As used herein, a "scan" of an electrode or sensor can refer to (in self-capacitance mode) receiving channels driving sensors to measure the capacitance of the sensor relative to ground or any suitable reference voltage. Furthermore, a "touch scan" of a sensor array can refer to obtaining (e.g., "scanning") capacitance measurements from each sensor in the array to detect the presence or proximity of a conductive object. Therefore, a touch scan of a sensor array can include multiple scans of the various electrodes or sensors included in the sensor array.

[0037] Figure 2 A Touch and Display Driver Integration (TTDI) controller (hereinafter referred to as "Touchscreen Controller 200") using the special multiplexing structure shown is illustrated. Touchscreen Controller 200 can be... Figure 1A more detailed representation of the touchscreen controller 120 is shown below. Each RX channel 201 can address (e.g., connect to) M different sensors (M sensors forming a sensor group), such that each RX channel 201 can address a corresponding sensor group. There can be N RX channels 201, forming N sensor groups, such that the ratio of RX channels to the total number of sensors is N:L = 1:M (e.g., 1:6). A common layer (VCOM) generator 202 drives the sensor 205 by generating DC levels frame-by-frame during the display refresh interval. A mask generator 203 can be a programmable arbitrary waveform generator. During the capacitance sensing time window, the mask generator 203 can apply a copy of the waveform of the sensor 205 driven by the RX channel 201 (referred to as a compensation signal) to the display's gate line and data lines, as well as to unused sensors 205. More specifically, the mask generator 203 can match the phase and amplitude of the waveform generated by the RX channels 201, such that the capacitance seen by each RX channel 201 is minimized. Otherwise, parasitic coupling is formed between each RX channel 201, unused sensor 205, display gate line, and data line. The touchscreen controller 200 may also include a memory 207 and a processing device 206, the memory 207 including instructions for performing the scanning method described below, and the processing device 206 for executing the instructions. In some embodiments, the instructions for performing the scanning method described below may be implemented as firmware within the processing device 206. In other embodiments, the memory 207 may reside on a separate device and may be communicatively coupled to the processing device 206. The touchscreen controller 200 may also include components such as analog-to-digital converters (ADCs), which, for ease of illustration, have been removed from [the original text]. Figure 2 These components have been omitted.

[0038] Each multiplexer 204 can couple a corresponding sensor 205 to an RX channel 201 corresponding to a sensor group in which the corresponding sensor 205 is part. More specifically, each multiplexer 204 can selectively couple a sensor 205 simultaneously to the corresponding RX channel 201, VCOM generator 202, and shield generator 203, or to ground (GND). In some embodiments, each multiplexer 204 can selectively couple a sensor 205 simultaneously to the corresponding RX channel 201, VCOM generator 202, and shield generator 203, or to a programmable DC source (e.g., shield generator 203). In this way, each RX channel 201 can be coupled to and sequentially scanned to each sensor 205 in the sensor group of the RX channel 201. Hereinafter, the RX channel 201 is addressed by index i = [1; N]. In the following text, multiplexer 204 and sensor 205 are addressed by two indices (i,j), where the first index i defines the RX channel index to which the corresponding multiplexer and sensor can be connected (i = [1; N]), and the second index j defines the sensor index within the i-th sensor group to which the corresponding multiplexer and sensor belong (j = [1; M]). When RX channel 201(1) is coupled to sensor 205(1,1) via multiplexer 204(1,1), multiplexers 204(1,2) to 204(1,M) can couple sensors 205(1,2) to 205(1,M) to GND (or a programmable DC source). Similarly, when RX channel 201(1) is coupled to sensor 205(1,2) via multiplexer 204(1,2), other multiplexers 204(1,1) to 204(1,M) besides 204(1,2) can couple other sensors 205(1,1) to 205(1,M) besides 205(1,2) to GND or a programmable DC source. Both GND and the programmable DC source can be referred to as examples of reference voltages.

[0039] In some implementations, the touchscreen controller 200 can perform short-circuit detection using DC current sensing between a sensor connected to the RX channel and a ground sensor. A short circuit creates a current path from the enabled RX channel to GND, which affects the ADC conversion results. Conventional surface-mount short-circuit testing techniques require scanning each sensor (with the rest grounded). Therefore, if the embedded panel includes 960 sensors, the short-circuit test would require 960 scans using conventional techniques.

[0040] Figure 3AThe first stage of a DC current sensing method according to an embodiment of the present disclosure is shown, wherein a touchscreen controller 200 can detect a short circuit within a sensor group. The touchscreen controller 200 can execute M scan sets, each of the M scan sets using (scanning) all RX channels of RX channels 201 in parallel. During each of the M scan sets, at the moment of scanning, only one sensor 205 in each sensor group (in...) Figure 3A The sensor 205 (indicated by the shadow sensor 205) is connected to the corresponding RX channel 201. For example, in sensor group 1, sensor 205(1,1) can be connected to RX channel 201(1) via the corresponding multiplexer 204(1,1). Unused sensors 205(1,2)-205(1,M) (indicated by the shadow sensor 205) are connected to the corresponding RX channel 201. Figure 3A The sensors (indicated by the unshaded sensor 205) are connected to GND via their respective multiplexers 204. The touchscreen controller 200 can perform a DC scan, so no AC excitation can be applied to the connected sensors 205(1,1). The specific potential of the connected sensor 205(1,1) is different from the GND (or programmable DC level) of the unused sensors 205(1,2) to 205(1,M), and this voltage difference forms a current path that creates a detectable leakage current. The touchscreen controller 200 can perform the remaining M scan sets in a similar manner, sequentially connecting each RX channel 201 to a different sensor 205 in the sensor group each time. The touchscreen controller 200 can perform each of the M scan sets in this way and then check the ADC readings to determine if they are within the manufacturing tolerance range. If the measured data exceeds the manufacturing tolerance range limit, the touchscreen controller 200 can report a test failure.

[0041] Figure 3B The second stage of the DC current sensing method is illustrated, in which a touchscreen controller 200 can detect short circuits between sensor groups. The touchscreen controller 200 can sequentially perform N scans, where for each scan, a single channel 201 is connected to all sensors 205 in the corresponding sensor group. For example, in the first scan, RX channel 201(1) can be connected to sensors 205(1,1) through 205(1,M), and unused sensors (e.g., sensors 205 on any other RX channels 201(2) through 201(N)) are connected to GND (or a programmable DC source). The touchscreen controller 200 can perform each of the N scans in this manner and then check the ADC readings to determine if the ADC readings are within manufacturing tolerances. If the measurement data exceeds the manufacturing tolerance limits, the FW reports a test failure.

[0042] As can be seen, for an embedded panel with 960 sensors, and a touchscreen controller 200 with 160 RX channels (N=160) and a 1:6 MUX ratio (M=6), the required number of scans can be given as M+N=6+160=166. Therefore, compared to traditional testing techniques that require M×N=6×160=960 scans, the testing time can be reduced by approximately M times.

[0043] In some implementations, if the grounding of an unused sensor affects the image on the display, the touchscreen controller can drive the unused sensor (and any other nodes defining parasitic capacitance as seen by the receiving channel 201) with a programmable constant voltage generated by the shielding generator 203, instead of grounding the unused sensor. The touchscreen controller 200 can modulate the compensation signal of the shielding generator 203 such that the difference in ADC readings between the normal and damaged sensors is detectable and algorithmically determined. In some implementations, the touchscreen controller 200 can use an intermediate voltage close to the touch scan reference voltage for the compensation signal.

[0044] As can be seen, short-circuit testing and diagnostics using DC current sensing do not require additional hardware, but they cannot be performed as part of a standard touch scan and require a separate diagnostic scan.

[0045] The second short-circuit test method utilizes a separate (programmable or constant) DC offset voltage for each detection channel. Using a separate DC offset voltage allows short-circuit diagnostics to be performed in parallel during the scan. Figure 4 It shows Figure 2 The touchscreen controller 200, and more specifically shown Figure 2 The RX channel 201 has an offset voltage source for short-circuit testing. For example... Figure 4 As can be seen, the offset voltage source on each RX channel is different (e.g., Voff1≠Voff2≠Voff3≠Voff4), and therefore, although the drive signal for each RX channel 201 is the same, the measured waveform seen at each RX channel 201 will also have different DC components. Thus, the DC offset at each RX channel will be individualized. Leakage resistance (or short circuit) between the individual sensors causes DC current between sensors connected to different offset voltage sensing channels and / or causes DC current between sensor 205 connected to the offset voltage channel and sensor 205 connected to the shield generator 203. This DC current causes half-cycle data imbalance ( Figure 6(As shown in the diagram), and short circuits can be detected by calculating the half-cycle imbalance value. Touch response (ideally) has no effect on data imbalance. It should be noted that the DC offset value of each RX channel 201 should be small enough to prevent any impact on the displayed image.

[0046] Figure 5 A short-circuit test sequence using a separate offset voltage for each RX channel 201 is shown. The touchscreen controller 200 can initiate touch scans of the sensors 205 (e.g., to detect capacitance values ​​from the sensors). More specifically, the touchscreen controller 200 can initiate a first scan set in which the first sensor of each available RX channel 201 (corresponding to the sensor group for each available RX channel 201) is scanned in parallel (the sensor scanned in each scan is shaded; different shade colors and patterns represent different offset voltages of the RX channels), while the remaining sensors are masked. During this first scan set, each RX channel 201 can generate a sample during excitation. Each RX channel 201 generates one sample for each half-cycle of excitation (e.g., ...). Figure 6 As shown). Figure 6 As can be seen, the half-cycle can alternate between odd and even numbers. (Return to reference) Figure 5 Subsequently, the touchscreen controller 200 can execute a second scan set, in which the second sensor of each available RX channel 201 is scanned in parallel while the remaining sensors are masked. Similarly, each RX channel 201 can generate one sample for each half-cycle of the excitation. In this way, the touchscreen controller 200 can iteratively execute M scan sets, where M is the number of sensors in the sensor group.

[0047] When accumulating touch information from sensor 205 during scanning, the values ​​of even-numbered samples and odd-numbered samples (half a cycle) are summed and added together. Therefore, the touch response count for a specific sensor on scanning RX channel 201 is calculated as follows:

[0048] T 数据 =∑N 偶数 +∑N 奇数 Short circuit detection is based on DC leakage current, which is given as the difference between even-numbered and odd-numbered sample values. Therefore, the DC leakage current used to scan a specific sensor on RX channel 201 is calculated as follows:

[0049] DC 数据 =∑N 偶数 -∑N 奇数

[0050] Figure 6Figure 600 shows half-cycle data for RX channels 201(1) and 201(2) (with different voltage offsets) under three different conditions (no short circuit, channel-to-channel sensor short circuit, and channel-to-shielded sensor short circuit). Figure 5 In this context, shaded sensors can indicate sensors that are not shielded during the scan (e.g., connected to their respective RX channels 201 and excited by a drive signal), while unshaded sensors are those that are shielded during the scan. Ideally (e.g., without short circuits), the half-cycle data counts for both RX channels 201(1) and RX channels 201(2) can be symmetrical, as shown in the “No Short Circuit” diagram. As used herein, the half-cycle data for RX channel 201 can be symmetrical if the odd and even samples are intrinsically similar in magnitude within a certain predetermined level of deviation. As can be seen in the “No Short Circuit” diagram, the samples of the odd and even half-cycles (half-cycle data) are symmetrical with respect to RX channels 201(1) and RX channels 201(2).

[0051] In contrast, the "channel-to-channel" diagram shows that the half-cycle data of RX channel 201(1) and RX channel 201(2) are asymmetrical, thus indicating a channel-to-channel sensor short circuit (by... Figure 6 The leakage resistance (RL) is shown as an indication. This asymmetry may be caused by the difference in the DC component of the drive signal of each of the RX channels in RX channel 201(1) and RX channel 201(2). As discussed above, the touchscreen controller 120 can compare the difference between half-cycle data of any appropriate number of consecutive samples of RX channel 201(1) with a predetermined deviation threshold, and if the difference exceeds the threshold, it can be determined that a channel-to-channel sensor short circuit has been detected (if RX channel 201(2) also has asymmetric half-cycle data).

[0052] The “Channel to Shield” diagram indicates that when there is a short circuit between the unshielded sensor (connected to RX channel 201(1)) and the shielded sensor (connected to RX channel 201(1)), the short circuit is caused by… Figure 6 The leakage resistance (R) shown LThe half-cycle data of RX channels 201(1) and RX channels 201(2) at the indicated time. Compared to the waveform of the sensor driven by the RX channel, all shielded sensors are driven by the same waveform, which has the same AC component and different DC components (generated by the offset voltage source). As shown in the "Channel to Shield" diagram, this may result in asymmetry in the half-cycle data. As can be seen in the "Channel to Shield" diagram, the half-cycle data of RX channel 201(1) is asymmetrical, while the half-cycle data of RX channel 201(2) is symmetrical. This indicates a short circuit between the unshielded sensor driven by RX channel 201(1) and the shielded sensor (e.g., the sensor being scanned and the unscanned sensor). The symmetrical half-cycle data generated by RX channel 201(2) indicates that the sensor driven by RX channel 201(2) is neither short-circuited to the shielded sensor nor short-circuited to the unshielded sensor.

[0053] In some implementations, the use of a separate DC offset voltage for short-circuit testing and diagnostics can be combined with associated double sampling. The touchscreen controller 200 can be used to switch the DC offset of each RX channel on and off. In this way, the touchscreen controller 200 can calculate the imbalance of each sensor data half-cycle twice, once when the DC offset is on and once when the DC offset is off. For example, refer to... Figure 4 The touchscreen controller 200 can first scan the first sensor of each available RX channel in parallel, while masking the remaining sensors. However, during this first scan, the touchscreen controller 200 can perform a first scan of the first sensor 205(1,1), in which the DC offset (Voff1) is bypassed, and calculate the half-cycle data imbalance of RX channel 201(1). Then, the touchscreen controller 200 can perform a second scan of the first sensor 205(1,1), in which Voff1 is active, and again calculate the half-cycle data imbalance of RX channel 201(1). The touchscreen controller 200 can then determine the difference between the imbalance value when Voff1 is active and the imbalance value when Voff1 is bypassed. The touchscreen controller 200 performs this scanning method in parallel for the first sensor of each available RX channel 201. If the magnitude of the difference in the imbalance values ​​of any sensor is greater than a predetermined threshold, the touchscreen controller 200 can determine which sensors are experiencing a short circuit. Then, the touchscreen controller 200 performs this scanning method in parallel on the second sensor of each available RX channel 201 until M scans have been performed (i.e., each sensor has been scanned in this manner). Imbalance changes can correspond to leak detection.

[0054] This concept allows for the elimination of any internal data imbalance in the RX channel, such as due to positive / negative IDAC current mismatch, attenuator defects, etc. More specifically, during actual operation, even the even / odd samples of half-cycle data used for the RX sensing channel are not ideally symmetrical, even in the absence of a short-circuited sensor. Due to manufacturing variations (such as poor matching of the positive / negative baseline-compensated iDAC source, poor matching of attenuator gain for the positive / negative current direction, and / or poor matching of the positive / negative charge-balanced iDAC source, etc.), the RX channel gain and / or offset may differ with respect to the positive and negative polarities of the input sensing current. This results in an inherent sampling asymmetry (internal data imbalance). Although calibration processes exist that allow minimizing internal imbalance, some finite values ​​remain. This residual imbalance value can be diagnosed as a false short circuit by the FW (touchscreen controller 200). However, the use of correlated double sampling techniques (taking two readings using Voff1 on and off and obtaining the difference) eliminates the internal data imbalance value from the measurement. Therefore, the imbalance data caused only by a short circuit is retained in the difference count:

[0055] (1) Voff1 is turned off. Here, the ADC sample contains information about the internal imbalance.

[0056] (2) Voff1 is turned on. Here, the ADC sample contains data with internal imbalance plus imbalance caused by short circuit.

[0057] If the difference between (2) and (1) is taken, only the unbalanced data caused by short circuits is retained.

[0058] As can be seen, using a separate DC offset voltage for short-circuit testing and diagnostics allows short-circuit testing to be performed simultaneously with touch scanning (e.g., as part of touch scanning) and eliminates the need for a separate diagnostic scan. However, additional hardware in the form of a programmable DC offset source for each RX channel 201 is required to implement an individualized DC offset voltage for each RX channel 201.

[0059] Figure 2The touchscreen controller 200 can also be used to detect open circuits in the sensor 205. When testing for an open circuit, the touchscreen controller can utilize AC current sensing. The presence of an open circuit can alter the baseline capacitance seen by the sensing RX channel 201, and thus change the ADC conversion result. Open circuit testing and detection can be performed during manufacturing and operation. For surface-mount panels, a combination of self-capacitance and mutual capacitance (Cp / Cm) scans is used to detect open circuits. ADC readings for a self-capacitance sensing mode with disconnected electrodes may differ significantly from typical manufacturing tolerances, and / or ADC readings for a mutual capacitance sensing mode at a crossroads formed by disconnected electrodes may differ significantly from typical manufacturing tolerances. For in-wall panels, open circuit detection can be performed during LCD optical manufacturing time testing. During such manufacturing testing, a floating VCOM sensor disconnected from the touchscreen controller 200 may cause distortion of the test image pattern.

[0060] During in-display panel operation, open-circuit testing and detection can be performed using capacitance sensing. However, during the scanning of sensor 111 (e.g., the capacitance sensing time window), shielding generator 203 can apply a compensation signal (e.g., a copy of the waveform of sensor 205 driven by RX channel 201) to the display's gate lines and data lines (see [link to relevant documentation]). Figure 7 This runtime active shielding technique eliminates baseline capacitance from the ADC readings, thus concealing potential open circuits within acceptable panel non-uniformity ranges. Therefore, baseline capacitance must be restored to make the system sensitive to open circuits. Figure 7 A touchscreen panel 105 (as a truly in-line panel) is shown, having gate TFT lines and data (source) TFT lines driven by a touchscreen controller 200. Baseline recovery (fully or partially) can be performed during operation of the touchscreen panel 105 in the following manner:

[0061] • The touchscreen controller 200 can change the amplitude of the compensation signal applied to the gate TFT line and / or data TFT line. Figure 7 The goal is to make the amplitude of the compensation signal waveform different from the amplitude of the waveform generated by the RX channel 201.

[0062] • The touch screen controller 200 can change the phase of the compensation signal applied to the gate TFT line and / or data TFT line so that the phase of the compensation signal waveform is different from the phase of the waveform generated by the RX channel 201.

[0063] • The touchscreen controller 200 can change both the amplitude and phase of the shielding signal applied to the gate TFT line and / or data TFT line.

[0064] The touchscreen controller 200 maintains identical compensation signals for both the sensor lines and gate lines, and only modulates / modulates the compensation signals for the data TFT lines. The gate lines open the TFT structure and can change the charge on the storage capacitors of individual TFT pixels. During baseline capacitance recovery, it is important not to introduce any distortion into the displayed image. Therefore, without altering the compensation signals for the gate lines and sensor lines, the integrity of the displayed image can be maintained.

[0065] After the baseline capacitance (Cp) recovers, the touchscreen controller 200 can verify that the ADC reading is within the normal operating range limits. If the measured data exceeds the operating range limits, the touchscreen controller 200 reports a test failure. The touchscreen controller 200 can use reference data from a panel known to have no open / short circuits to establish limits on the operating range for comparative purposes.

[0066] Figure 8 This is a flowchart of a short-circuit detection method 800 according to some embodiments of the present disclosure. Method 800 can be executed by processing logic, which may include hardware (e.g., circuitry, dedicated logic, programmable logic, processor, processing device, central processing unit (CPU), system-on-chip (SoC), etc.), software (e.g., instructions that run / execute on the processing device), firmware (e.g., microcode), or a combination thereof. For example, method 800 can be executed by a touchscreen controller 200 that executes short-circuit detection firmware.

[0067] Also refer to Figure 2 , Figure 3A and Figure 3B At box 805, the touchscreen controller can be configured for DC current sensing. The touchscreen controller 200 can execute M scan sets, each of which uses (scans) all RX channels of RX channel 201 in parallel. During each of the M scan sets, at the moment of scanning, only one sensor 205 in each sensor group (in...) Figure 3A The shadow sensor 205 (indicated in the image) is connected to the corresponding RX channel 201. At block 810, the touchscreen controller 200 can connect the j-th sensor 205 (i,j) in each i-th group (in the image) to the corresponding RX channel 201. Figure 3A The sensor 205 (indicated by the shadow sensor 205) is connected to its corresponding i-th RX channel 201(i), and at block 815, a scan of each connected sensor 205 can be performed. The touchscreen controller 200 can perform a DC scan, so no AC excitation can be applied to the connected sensor 205. Unused sensor 205 (indicated by the shadow sensor 205) is connected to its corresponding i-th RX channel 201(i), and at block 815, a scan of each connected sensor 205 can be performed. Figure 3AThe sensors 205 (indicated by the unshaded sensor 205) are connected to GND via their respective multiplexers 204. At block 820, the touchscreen controller 200 can determine whether the measurements from the scan are within manufacturing tolerances. More specifically, the connected sensors 205 have a specific potential at GND (or a programmable DC level) different from the unused sensors 205, and this voltage difference forms a current path that creates a leakage current that can be detected and compared to the manufacturing tolerance range. The touchscreen controller 200 can perform the remaining M scan sets (until j ≥ M, as shown in block 825) in a similar manner, sequentially connecting each RX channel 201 to a different sensor 205 in the sensor group each time until each sensor 205 has been scanned. The touchscreen controller 200 can perform each of the M scan sets in this manner and then check the ADC readings to determine whether they are within manufacturing tolerances. If the measurement data of any sensor 205 exceeds the manufacturing tolerance range limit, the touchscreen controller 200 can report a test failure.

[0068] Then, the touchscreen controller 200 can begin the second stage of the DC current sensing method, wherein the touchscreen controller 200 can detect short circuits between sensor groups. The touchscreen controller 200 can sequentially execute N scan sets, wherein for each scan set, a single channel 201 is connected to all sensors 205 in the corresponding sensor group (in... Figure 3B (Indicated by shadow sensor 205). At box 830, the i-th RX channel 201(i) can be connected to all sensors 205(i,1) to 205(i,M) in its corresponding i-th sensor group (in... Figure 3B (Indicated by shadow sensor 205), and unused sensors (e.g., on any other RX channel 201, in...) Figure 3BThe sensor 205 (indicated by the shadowless sensor 205) is connected to GND (or a programmable DC source). For example, in the first scan set, RX channel 201(1) may be connected to sensors 205(1,1) through 205(1,M) (e.g., sensors in sensor group 1). At block 835, the touchscreen controller 200 may subsequently perform a scan of each connected sensor, and at block 840, the ADC reading may be checked to determine if the ADC reading is within the manufacturing tolerance range. If the measurement data exceeds the manufacturing tolerance range limit (i.e., the query at block 840 is false), the FW reports a test failure. At block 845, the touchscreen controller 200 may perform each scan set in N scan sets in this manner (until i>N) until each sensor 205 has been scanned. If the measurement data of all sensors are within the manufacturing tolerance range limit (i.e., the query at block 840 is true for each of the N scans), the touchscreen controller 200 may report that the test has passed.

[0069] Figure 9 This is a flowchart of a short-circuit detection method 900 according to some embodiments of the present disclosure. Method 900 can be executed by processing logic, which may include hardware (e.g., circuitry, dedicated logic, programmable logic, processor, processing device, central processing unit (CPU), system-on-chip (SoC), etc.), software (e.g., instructions that run / execute on the processing device), firmware (e.g., microcode), or a combination thereof. For example, method 900 can be executed by a touchscreen controller 200 that executes short-circuit detection firmware.

[0070] Also refer to Figure 4 , Figure 5 and Figure 6 At box 905, the touchscreen controller 200 can activate an offset voltage source on each RX channel, and each offset voltage source can be different (e.g., Voff1 ≠ Voff2 ≠ Voff3 ≠ Voff4). Therefore, although the drive signal (AC component) for each RX channel 201 is the same, the measured waveform seen at each RX channel 201 will have a different DC component. Leakage resistance (or short circuit) between the individual sensors causes DC current between sensors connected to different offset voltage sensing channels and / or causes DC current between sensor 205 connected to the offset voltage channel and sensor 205 connected to the shield generator 203. This DC current causes half-cycle data imbalance ( Figure 6 (As shown in the diagram), and short circuits can be detected by calculating the half-cycle imbalance value. Touch response (ideally) has no effect on data imbalance. It should be noted that the DC offset value of each RX channel 201 should be small enough to prevent any impact on the displayed image.

[0071] At box 910, the touchscreen controller 200 can initiate a touch scan of sensor 205 (e.g., to detect capacitance values). More specifically, the touchscreen controller 200 can initiate a first scan set, wherein a first sensor of each available RX channel 201 (corresponding to a sensor group for each available RX channel) is scanned in parallel (the sensor scanned in each scan is in...). Figure 5 The one designated as the shadow sensor is in the middle, while the other sensors are shielded (in...). Figure 5 (Indicated by a shadowless sensor). During this first scan set, each RX channel 201 can generate a sample during excitation. Each RX channel 201 generates one sample for each half-cycle of excitation (e.g., ...). Figure 6 As shown). Figure 6 As can be seen, the half-cycles can alternate between odd and even numbers. (Return to reference) Figure 5 Subsequently, the touchscreen controller 200 can execute a second scan set, in which the second sensor of each available RX channel 201 is scanned in parallel while the remaining sensors are masked. Similarly, each RX channel 201 can generate one sample for each half-cycle of the excitation. In this way, the touchscreen controller 200 can iteratively execute M scan sets, where M is the number of sensors in the sensor group. At block 915, the touchscreen controller 200 can determine the half-cycle imbalance of each sensor 205.

[0072] At block 920, the touchscreen controller 200 can deactivate the offset voltage source on each channel, and at block 925, another touch scan can be run. At block 930, the touchscreen controller 200 can determine the half-cycle imbalance of each sensor 205 and calculate the change in imbalance for each sensor 205 (the difference between the half-cycle imbalance with offset voltage and the half-cycle imbalance without offset voltage). At block 940, the touchscreen controller 200 can determine whether the difference in half-cycle imbalance for each sensor 205 is greater than or less than a threshold difference. If the difference in half-cycle imbalance for all sensors 205 is less than the threshold, the touchscreen controller 200 can report a successful test and no short circuit detected. If the difference in half-cycle imbalance for any sensor 205 is greater than the threshold, the touchscreen controller 200 can determine that a short circuit has been detected and report the test as a failure.

[0073] Figure 10This is a flowchart of a method 1000 for detecting open circuits according to some embodiments of this disclosure. Method 1000 can be executed by processing logic, which may include hardware (e.g., circuitry, dedicated logic, programmable logic, processor, processing device, central processing unit (CPU), system-on-chip (SoC), etc.), software (e.g., instructions that run / execute on the processing device), firmware (e.g., microcode), or a combination thereof. For example, method 1000 can be executed by a touchscreen controller 200 that executes open circuit detection firmware.

[0074] Also refer to Figure 7 At box 1005, the touchscreen controller can configure itself for AC current sensing. The presence of an open circuit can alter the baseline capacitance seen by the RX channel 201, and thus change the ADC conversion result. Open circuit testing and detection can be performed during manufacturing and operation. For surface-mount panels, a combination of self-capacitance and mutual capacitance (Cp / Cm) scans is used to detect open circuits. ADC readings for a self-capacitance sensing mode with disconnected electrodes may differ significantly from typical manufacturing tolerances, and / or ADC readings for a mutual capacitance sensing mode at a crossroads formed by disconnected electrodes may differ significantly from typical manufacturing tolerances. For in-wall panels, open circuit detection can be performed during LCD optical manufacturing time testing. During such manufacturing testing, a floating VCOM sensor disconnected from the touchscreen controller 200 may cause distortion of the test image pattern.

[0075] During in-display panel operation, open-circuit testing and detection can be performed using capacitance sensing. However, during the scanning of sensor 111 (e.g., the capacitance sensing time window), shielding generator 203 can apply a compensation signal (e.g., a copy of the waveform of sensor 205 driven by RX channel 201) to the display's gate lines and data lines (see [link to relevant documentation]). Figure 7 This runtime active shielding technology eliminates baseline capacitance from the ADC readings, thereby concealing potential open circuits within acceptable panel non-uniformity ranges. Therefore, at box 1010, the touchscreen controller 200 can restore the baseline capacitance to make the system sensitive to open circuits. Figure 7 A touchscreen panel 105 (as a truly in-line panel) is shown, having gate TFT lines and data (source) TFT lines driven by a touchscreen controller 200. Baseline recovery (fully or partially) can be performed during operation of the touchscreen panel 105 in the following manner:

[0076] • The touchscreen controller 200 can change the amplitude of the compensation signal applied to the gate TFT line and / or data TFT line. Figure 7 The goal is to make the amplitude of the compensation signal waveform different from the amplitude of the waveform generated by the RX channel 201.

[0077] • The touch screen controller 200 can change the phase of the compensation signal applied to the gate TFT line and / or data TFT line so that the phase of the compensation signal waveform is different from the phase of the waveform generated by the RX channel 201.

[0078] • The touchscreen controller 200 can change both the amplitude and phase of the shielding signal applied to the gate TFT line and / or data TFT line.

[0079] The touchscreen controller 200 maintains identical compensation signals for both the sensor lines and gate lines, and only modulates / modulates the compensation signals for the data TFT lines. The gate lines open the TFT structure and can change the charge on the storage capacitors of individual TFT pixels. During baseline capacitance recovery, it is important not to introduce any distortion into the displayed image. Therefore, by not altering the compensation signals for the gate lines and sensor lines, the integrity of the displayed image can be maintained.

[0080] After the baseline capacitance (Cp) is restored, the touchscreen controller 200 can perform a touch scan at box 1015 and verify at box 1020 whether the ADC reading (raw count) is within the normal operating range limits. If the measured data exceeds the operating range limits, the touchscreen controller 200 reports a test failure. The touchscreen controller 200 can use reference data from a panel known to have no open / short circuits to establish limits on the operating range for comparative purposes.

[0081] Figure 11 This demonstrates the ability to perform sensor short-circuit and open-circuit detection as previously disclosed. An implementation of the core architecture 1100 of the controller or processing element, for example, is provided by Cypress Semiconductor, Inc. (San Jose, California). Used in the product series. In one embodiment, the core architecture 1100 includes a microcontroller 1102. The microcontroller 1102 includes a CPU (Central Processing Unit) core 1104 (which may correspond to...). Figure 1 Processing device 130 or Figure 2 The processing device 206 includes a flash program memory 1106, a DOC (on-chip debug) 1108, a prefetch buffer 1110, a dedicated SRAM (static random access memory) 1112, and a special function register 1114. In one embodiment, the DOC 1108, prefetch buffer 1110, dedicated SRAM 1112, and special function register 1114 are coupled to a CPU core 1104 (e.g., CPU core 1006), while the flash program memory 1106 is coupled to the prefetch buffer 1110.

[0082] The core architecture 1100 may also include a CHub (core hub) 1116, which includes a bridge 1118 and a DMA controller 1120 coupled to the microcontroller 1102 via a bus 1122. The CHub 1116 provides the primary data and control interface between the microcontroller 1102 and its peripherals (e.g., peripheral devices) and memory and the programmable core 1124. The DMA controller 1120 can be programmed to transfer data between system elements without burdening the CPU core 1104. In various implementations, each of these sub-components of the microcontroller 1102 and the CHub 1116 may differ depending on the choice or type of CPU core 1104. The CHub 1116 may also be coupled to a shared SRAM 1126 and an SPC (System Performance Controller) 1128. A dedicated SRAM 1112 is independent of the shared SRAM 1126 accessed by the microcontroller 1102 via the bridge 1118. CPU core 1104 accesses dedicated SRAM 1112 without going through bridge 1118, thereby enabling local register and RAM accesses to occur simultaneously with DMA access to shared SRAM 1126. Although referred to herein as SRAM, in various other embodiments, these memory modules can be any suitable type of various (volatile or non-volatile) memory or data storage modules.

[0083] In various embodiments, the programmable core 1124 may include various combinations of sub-components (not shown), including but not limited to digital logic arrays, digital peripherals, analog processing channels, globally routed analog peripherals, DMA controllers(multiple), SRAM and other suitable types of data memory, I / O ports, and other suitable types of sub-components. In one embodiment, the programmable core 1124 includes GPIO (General Purpose I / O) and EMIF (Extended Memory Interface) blocks 1130, programmable digital blocks 1132, programmable analog blocks 1134, and special function blocks 1136, each configured to implement one or more functions of the sub-components. In various embodiments, the special function block 1136 may include dedicated (non-programmable) function blocks and / or include one or more interfaces to the dedicated function blocks, such as USB, crystal oscillator drivers, JTAG, etc.

[0084] The programmable digital block 1132 may include a digital logic array, which comprises an array of digital logic blocks and associated wiring. In one embodiment, the digital block architecture includes a UDB (Universal Digital Block). For example, each UDB may include ALU functionality and CPLD functionality.

[0085] In various implementations, one or more UDBs of the programmable digital block 1132 can be configured to perform various digital functions, including, but not limited to, one or more of the following: a basic I2C slave device; an I2C master device; an SPI master or SPI slave device; a multi-wire (e.g., 3-wire) SPI master or slave device (e.g., MISO / MOSI multiplexed on a single pin); timers and counters (e.g., a pair of 8-bit timers or counters, a 16-bit timer or counter, an 8-bit capture timer, etc.); PWM (e.g., a pair of 8-bit PWMs, a 16-bit PWM, an 8-bit dead-time PWM, etc.); a level-sensitive I / O interrupt generator; a quadrature encoder; a UART (e.g., half-duplex); a delay line; and any other suitable type of digital function or combination of digital functions that can be implemented in multiple UDBs.

[0086] In other implementations, groups of two or more UDBs can be used to implement additional functionality. For illustrative purposes only and not as a limitation, multiple UDBs can be used to implement the following functions: I2C slave devices that support hardware address detection and the ability to process complete transactions without CPU core (e.g., CPU core 1104) intervention and help prevent forced clock stretching on any bit in the data stream; I2C multi-master devices that can include slave options in a single block; arbitrary length PRS or CRC (up to 32 bits); SDIO; SGPIO; digital correlators (e.g., with up to 32 bits, 4x oversampling, and support for configurable thresholds); LINbus interfaces; incremental sum modulators (e.g., for Class D audio DACs with differential output pairs); I2S (stereo); LCD drive control (e.g., a UDB can be used to implement L...). The CD drive block provides timing control and display RAM addressing; full-duplex UART (e.g., 7-bit, 8-bit, or 9-bit, with 1 or 2 stop bits and parity, and RTS / CTS support), IRDA (transmit or receive); capture timer (e.g., 16-bit, etc.); dead-time PWM (e.g., 16-bit, etc.); SMbus (including SMbus grouping formatting in software using CRC); brushless motor drive (e.g., to support 6 / 12-step commutation); automatic baud rate detection and generation (e.g., automatically determining the baud rate for a standard rate from 1200 baud to 115200 baud and generating the required clock to generate the baud rate after detection); and any other suitable type of digital function or combination of digital functions that can be implemented in multiple UDBs.

[0087] Programmable analog block 1134 may include analog resources, including but not limited to comparators, mixers, PGAs (programmable gain amplifiers), TIAs (transimpedance amplifiers), ADCs (analog-to-digital converters), DACs (digital-to-analog converters), voltage references, current sources, sample-and-hold circuits, and any other suitable type of analog resources. Programmable analog block 1134 can support a variety of analog functions, including but not limited to analog routing, LCD driver I / O support, capacitance sensing, voltage measurement, motor control, current-to-voltage conversion, voltage-to-frequency conversion, differential amplification, optical measurement, sensing position monitoring, filtering, voice coil driving, magnetic card reading, acoustic Doppler measurement, echo ranging, modem transmit and receive encoding, or any other suitable type of analog function.

[0088] The embodiments described herein can be used in various designs of mutual capacitance sensing systems, self-capacitance sensing systems, or combinations of both. As will be understood by those skilled in the art who benefit from this disclosure, the embodiments described herein are not dependent on a particular capacitance sensing solution and can also be used with other sensing solutions, including optical sensing solutions.

[0089] Numerous details have been set forth in the foregoing description. However, it will be apparent to those skilled in the art who benefit from this disclosure that embodiments of the disclosure can be practiced without these specific details. In some instances, to avoid obscuring the description, well-known structures and apparatuses are shown in block diagram form rather than in detail.

[0090] Certain parts of the specific implementation are presented according to algorithms and symbolic representations of operations on data bits within computer memory. These algorithmic descriptions and representations are means used by those skilled in the art of data processing to most effectively communicate the essence of their work to others skilled in the art. Here, an algorithm is generally considered to be a self-consistent sequence of steps leading to a desired result. These steps are those requiring physical manipulation of physical quantities. Typically, although not essential, these quantities take the form of electrical or magnetic signals that can be stored, transmitted, combined, compared, and otherwise manipulated. It has been shown that these signals are sometimes referred to as bits, values, elements, symbols, characters, terms, numbers, etc., primarily due to their widespread use.

[0091] 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, as is apparent from the above discussion, it can be understood that throughout the specification, discussions using terms such as “determine,” “detect,” “compare,” “reset,” “add,” and “calculate” refer to the actions and processing of a computing system or similar electronic computing device, which manipulates data represented as physical (e.g., electronic) quantities in the registers and memories of the computing system and converts these data into other data similarly represented as physical quantities in the memory or registers of the computing system or other such information storage, transmission, or display devices.

[0092] The terms “example” or “exemplary” as used herein are intended to serve as examples, instances, or illustrations. Any aspect or design described herein as an “example” or “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects or other designs. Rather, the use of the terms “example” or “exemplary” is intended to present the concept in a concrete manner. As used herein, the term “or” is intended to mean inclusive “or” rather than exclusive “or.” That is, unless otherwise specified or clear from the context, “X comprises A or B” is intended to mean any natural inclusive arrangement. That is, if X comprises A, X comprises B, or X comprises both A and B, then “X comprises A or B” is satisfied in any of the foregoing cases. Furthermore, unless otherwise specified or clearly defined from the context for the singular form, the articles “a” and “an” as used herein and in the appended claims should generally be construed as meaning “one or more.” Moreover, unless so described, the use of the terms “implementation” or “an implementation” or “a mode of implementation” throughout the document is not intended to mean the same implementation or mode of implementation.

[0093] 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 may include general-purpose computers that can be selectively activated or reconfigured by a computer program stored in a computer. Such computer programs may be stored in non-transitory computer-readable storage media, 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 considered as including a single medium or multiple media (e.g., a centralized or distributed database and / or associated caches and servers) storing one or more sets of instructions. The term "computer-readable medium" should also be considered as including any medium capable of storing, encoding, or carrying a set of instructions that are executed by a machine and cause the machine to perform any one or more of the methods of this embodiment. The term "computer-readable storage medium" should therefore be considered as including, but not limited to, solid-state memory, optical media, magnetic media, and any medium capable of storing a set of instructions for execution by a machine and causing the machine to perform any one or more of the methods of this embodiment.

[0094] The algorithms and displays 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 build more specialized devices to perform the required method steps. The desired structures of various such systems will become apparent from the description below. Furthermore, this implementation is described without reference to any particular programming language. It should be understood that various programming languages ​​can be used to implement the teachings of the implementations described herein.

[0095] The foregoing description sets forth numerous specific details, such as examples of specific systems, components, methods, etc., to provide a good understanding of several embodiments of this disclosure. However, it will be apparent to those skilled in the art that at least some embodiments of this disclosure can be practiced without these specific details. In other instances, well-known components or methods have not been described in detail, or have been presented in a simple block diagram format, in order to avoid unnecessarily obscuring embodiments of the invention. Therefore, the specific details set forth above are merely exemplary. Specific implementations may differ from these exemplary details and are still considered to be within the scope of this embodiment.

[0096] It should be understood that the above description is intended to be illustrative and not restrictive. Many other embodiments will become apparent to those skilled in the art after reading and understanding the above description. Therefore, the scope of this embodiment should be determined by referring to the appended claims and the full scope of their authorized equivalents.

Claims

1. An apparatus comprising: One or more receiving channels, each receiving channel being configured to scan a corresponding sensor group among multiple sensors; Multiple multiplexers, each multiplexer being configured to selectively couple a corresponding sensor among the multiple sensors to a corresponding receiving channel or reference voltage; One or more offset voltage sources, each of the one or more offset voltage sources being coupled to a corresponding receiving channel; as well as Processing apparatus, the processing apparatus being configured to: Detection of one or more short circuits among the plurality of sensors is based on DC current sensing, wherein the detection includes detecting the one or more short circuits based on scanned DC leakage current from each of the plurality of sensors; as well as One or more open circuits among the plurality of sensors are detected based on AC current sensing of each of the one or more receiving channels.

2. The device according to claim 1, wherein, In order to detect the one or more short circuits, the processing device is configured to: Iteratively connect each unscanned sensor in each sensor group to its corresponding receiving channel to scan each sensor in parallel, while each other sensor in the plurality of sensors is connected to a reference voltage, until each of the plurality of sensors has been scanned; and Each sensor group is scanned sequentially, wherein, in order to scan the sensor group, the processing device is configured to: Each sensor in the sensor group is connected to its corresponding receiving channel to scan each sensor in the sensor group in parallel.

3. The device according to claim 2, wherein, The reference voltage is a compensation signal applied to the plurality of sensors to minimize the capacitance seen by each receiving channel.

4. The device according to claim 1, wherein, In order to detect the one or more short circuits, the processing device is configured to: The following process is performed iteratively until each of the plurality of sensors has been scanned: Each unscanned sensor in each sensor group is connected to its corresponding receiving channel to scan the individual sensor in each sensor group in parallel, while each other sensor in the plurality of sensors is masked. as well as The presence of any short circuits is determined by half-cycle data generated by each receiving channel while scanning individual sensors in each sensor group in parallel.

5. The device according to claim 1, wherein, The detection of one or more short circuits based on DC leakage current occurs as part of a touch scan.

6. The device of claim 1, further comprising a shielding generator configured to apply a compensation signal to the plurality of sensors to minimize the baseline capacitance of each receiving channel and detect the one or more open circuits, wherein, The processing device is configured to: Restore the baseline capacitance of each receive channel; Scan each of the plurality of sensors via the one or more receiving channels; as well as The one or more open circuits are detected by comparing the analog-to-digital converter readings from each receiving channel with data from the normal operating range.

7. A system comprising: The touch panel includes multiple sensors; as well as A touchscreen controller, operatively coupled to the touch panel, includes: one or more receiving channels, each configured to scan a corresponding sensor group among a plurality of sensors; and one or more offset voltage sources, each of the one or more offset voltage sources coupled to a corresponding receiving channel, wherein the touchscreen controller is configured to: A compensation signal is applied to one or more gate lines and data lines of the touch panel to minimize the baseline capacitance of each receive channel; Detecting one or more short circuits among the plurality of sensors based on DC current sensing, wherein the detection includes detecting the one or more short circuits based on scanned DC leakage currents from each of the plurality of sensors; and One or more open circuits among the plurality of sensors are detected based on AC current sensing of each of the one or more receiving channels.

8. The system according to claim 7, wherein, In order to detect the one or more open circuits based on alternating current sensing, the touchscreen controller is configured to: Restore the baseline capacitance of each receive channel; Scan each of the plurality of sensors via the one or more receiving channels; as well as The one or more open circuits are detected by comparing the analog-to-digital converter readings from each receiving channel with data from the normal operating range.

9. The system according to claim 8, wherein, To restore the baseline capacitance of each receive channel, the touchscreen controller is configured to: Modify one or more of the amplitude and phase of the compensation signal so that the waveform of the compensation signal is different from the waveform generated by each receiving channel; or The compensation signal is maintained for the gate line, and one or more of the amplitude and phase of the compensation signal are modified for the data line.

10. The system according to claim 7, wherein, In a truly embedded configuration, the touchscreen controller is operatively coupled to the touch panel.

11. The system according to claim 7, wherein, In order to detect the one or more short circuits, the touchscreen controller is configured to: Iteratively connect each unscanned sensor in each sensor group to its corresponding receiving channel to scan each sensor in parallel, while each other sensor in the plurality of sensors is connected to a reference voltage, until each of the plurality of sensors has been scanned; and Each sensor group is scanned sequentially, wherein, in order to scan the sensor group, the touchscreen controller is used to: Each sensor in the sensor group is connected to its corresponding receiving channel to scan each sensor in the sensor group in parallel.

12. The system according to claim 11, wherein, The reference voltage is the compensation signal.

13. The system according to claim 7, wherein, In order to detect the one or more short circuits, the touchscreen controller is configured to: The following operation is performed iteratively until each of the plurality of sensors has been scanned: The first sensor in each sensor group is connected to the corresponding receiving channel to scan the first sensor in each sensor group in parallel, while each of the other sensors in the plurality of sensors is shielded. as well as The presence of any short circuits is determined by half-cycle data generated by each receiving channel while the first sensor in each sensor group is scanned in parallel.

14. A method comprising: One or more DC offset voltage sources are activated, each of which is operatively coupled to one or more receiving channels, and each of the one or more receiving channels is configured to scan a corresponding sensor group among a plurality of sensors. Iteratively connect the individual unscanned sensors in each sensor group to the corresponding receiving channel to scan the individual sensors in each sensor group in parallel, while each other sensor in the plurality of sensors is masked, until each sensor in the plurality of sensors has been scanned; as well as The presence of any short circuits among the plurality of sensors is determined by using half-cycle data generated by each receiving channel while simultaneously scanning the first sensor in each sensor group in parallel. The half-cycle data generated by the receiving channel while scanning the sensor includes even-numbered samples with a first value generated at even-numbered half-cycles and odd-numbered samples with a second value generated at odd-numbered half-cycles. The short circuit of the sensor is determined based on the DC leakage current of the sensor, and the DC leakage current of the sensor includes the difference between the even-numbered and odd-numbered samples of the half-cycle data of the sensor.

15. The method according to claim 14, wherein, Each of the plurality of sensors is coupled to a corresponding multiplexer among the plurality of multiplexers, and each multiplexer is configured to selectively couple a corresponding sensor among the plurality of sensors to a corresponding receiving channel or reference voltage.

16. The method according to claim 15, wherein, The reference voltage is a compensation signal applied to the plurality of sensors to minimize the baseline capacitance of each receiving channel.

17. The method of claim 16, further comprising: Restore the baseline capacitance of each receive channel; Scan each of the plurality of sensors; as well as One or more open circuits are detected by comparing the analog-to-digital converter readings from each receiving channel with data from the normal operating range.

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