CN106066748B - Sensor electrode path fault diagnosis - Google Patents
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Abstract
A processing system for a capacitive sensing input device includes a sensing module, a first internal diagnostic mechanism, and a determination module. The sensing module is configured to couple with a first sensor electrode path of the plurality of sensor electrode paths and is configured to drive the first sensor electrode path with a first signal. The first internal diagnostic mechanism is configured to couple with the second sensor electrode path and obtain a test signal output when the sensing module drives the first sensor electrode path with a first signal. The first internal diagnostic mechanism includes a selectable current source configured to be coupled with the second sensor electrode path and enabled during the obtaining of the test signal output. The determination module is configured to determine whether the first and second sensor electrode paths are ohmically coupled together based on the test signal output.
Description
Cross reference to related applications
This application claims priority and benefit from co-pending U.S. provisional patent application No. 62/151,958, entitled "CAPACITIVE SENSOR CHANNEL OPEN AND SHORT TEST," filed by Jorge sachedo and John m. Weinerth on 23/4 2015, having attorney docket No. SYNA-140181US01, and assigned to the assignee of the present application, the disclosure of which is incorporated herein by reference in its entirety.
This application is also a partial continuation of co-pending U.S. patent application No. 14/180,266, entitled "INIPUT DEVICETRANSMITTER PATH ERROR DIAGNOSIS" filed by Wen Fang on 13/2 2014 and claiming priority and benefit thereof, having attorney docket number syn a-20100211-a1.con, and assigned to the assignee of the present application, the disclosure of which is incorporated herein by reference in its entirety.
Application 14/180,266 is a continuation of and claims the benefit of co-pending U.S. patent application No. 13/012,943 entitled "INPUT DEVICETRANSMITTER PATH ERROR DIAGNOSIS" filed by Wen Fang on 25/1 2011, having attorney docket No. SYNA-20100211-a1 and assigned to the assignee of the present application.
Background
Input devices including proximity sensor devices (also commonly referred to as touch pads or touch sensor devices) are widely used in a variety of electronic systems. Proximity sensor devices typically include a sensing region, often differentiated by a surface, in which the proximity sensor device determines the presence, location, and/or motion of one or more input objects. The proximity sensor device may be used to provide an interface for an electronic system. For example, proximity sensor devices are often used as input devices in larger computing systems (such as opaque touch pads integrated or peripheral to a notebook or desktop computer). Proximity sensor devices are also often used in smaller computing systems, such as touch screens integrated in cellular phones.
Disclosure of Invention
In some processing system embodiments, a processing system for a capacitive sensing input device includes a sensing module, a first internal diagnostic mechanism, and a determination module. The sensing module is configured to couple with a first sensor electrode path of the plurality of sensor electrode paths and is configured to drive the first sensor electrode path with a first signal. The first internal diagnostic mechanism is configured to couple with the second sensor electrode path and obtain a test signal output when the sensing module drives the first sensor electrode path with the first signal. The first internal diagnostic mechanism includes a selectable current source configured to be coupled with the second sensor electrode path, and the selectable current source is enabled during the obtaining of the test signal output. The determination module is configured to determine whether the first and second sensor electrode paths are ohmically coupled together based on the test signal output. In some embodiments, the processing system is included in a capacitive sensing input device.
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The drawings referred to in the description of the drawings should not be understood as being drawn to scale unless specifically indicated. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various embodiments of the invention and, together with the description, serve to explain the principles discussed below, wherein like reference numerals refer to like elements.
Fig. 1A is a block diagram of an example input device, in accordance with an embodiment.
FIG. 1B illustrates a portion of an example sensor electrode pattern that can be used to generate all or part of a sensing region of an input device, in accordance with an embodiment.
Fig. 1C illustrates an example of a sensor electrode path in the form of a transmitter path, in accordance with various embodiments.
Fig. 1D illustrates an example of a sensor electrode path in the form of a receiver path, in accordance with various embodiments.
Fig. 2A and 2B illustrate major components of a transmitter path in two example input devices, in accordance with an embodiment.
FIG. 3 illustrates an example processing system that can be used with an input device in accordance with various embodiments.
Fig. 4 illustrates an example of a first type of internal diagnostic mechanism coupled with a transmitter circuit, in accordance with various embodiments.
Fig. 5A, 5B, and 5C illustrate flow diagrams of example methods of input device transmitter path error diagnosis, in accordance with various embodiments.
Fig. 6A illustrates an example of a second type of internal diagnostic mechanism coupled with a sensor electrode path, in accordance with various embodiments.
Fig. 6B illustrates a second type of internal diagnostic mechanism coupled with a sensor electrode path and the use of a grounded conductive plate, in accordance with various embodiments.
7A, 7B, 7C, 7D, 7E, and 7F illustrate flow diagrams of example methods of sensor electrode path error diagnosis, in accordance with various embodiments.
Detailed Description
The following description of the embodiments is provided by way of example only and not by way of limitation. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding background or brief summary or the following detailed description.
Overview of the discussion
Various embodiments are described herein that provide input devices and methods that facilitate improved usability by facilitating methods, processing systems, input devices, and circuits that can more easily test the continuity of various conductive paths, such as transmitter paths and receiver paths (collectively, sensor electrode paths). In various embodiments described herein, the input device may be a capacitive sensing device.
The discussion is divided into three sections. In section 1, the discussion begins with a description of an example input device with which various embodiments described herein may be implemented or implemented; following is a description of an example processing system, components of which are subsequently described. The processing system may be used with an input device, such as a capacitive sensing device, or with some other device/system. In section 2, an example of a first type of internal diagnostic mechanism is described. The operation of the first type of processing system and its components, including internal diagnostic mechanisms, is further described in connection with the description of the example method of the input device communicating error diagnostics. In section 3, an example of a second type of internal diagnostic mechanism is described. The operation of the processing system and its components, of a second type including internal diagnostic mechanisms, is further described in connection with the description of the example method of electrode path fault diagnosis.
Part 1: example input device and example processing system
Example input device
FIG. 1A is a block diagram of an example input device 100, in accordance with embodiments of the present invention. The input device 100 may be configured to provide input to the electronic device 150. The input device 100 may be configured to provide input to an electronic system (not shown). As used in this document, the term "electronic system" (or "electronic device") broadly refers to any system capable of electronically processing information. Some non-limiting examples of electronic systems include personal computers of all sizes and shapes, such as desktop computers, laptop computers, netbook computers, tablets, web browsers, electronic book readers, and Personal Digital Assistants (PDAs). Additional example electronic systems include composite input devices, such as a physical keyboard including input device 100 and a separate joystick or key switch. Further example electronic systems include peripheral devices such as data input devices (including remote controls and mice), and data output devices (including display screens and printers). Other examples include remote terminals, kiosks, and video game machines (e.g., video game consoles, portable gaming devices, and the like). Other examples include communication devices (including cellular telephones, such as smart phones), and media devices (including recorders, editors, and players such as televisions, set-top boxes, music players, digital photo frames, and digital cameras). In addition, the electronic system may be a master or a slave of the input device.
The input device 100 can be implemented as a physical component of the electronic system or can be physically separate from the electronic system. Suitably, the input device 100 is capable of communicating with components of an electronic system using any one or more of the following: buses, networks, and other wired or wireless interconnections. Examples include, but are not limited to: inter integrated circuit (I)2C) Serial Peripheral Interface (SPI), personal system 2 (PS/2), Universal Serial Bus (USB), Bluetooth
Radio frequency RF and infrared data association (IrDA).
In fig. 1A, the input device 100 is shown as a proximity sensor device (also commonly referred to as a "touch pad" or "touch sensor device") configured to sense input provided by one or more input objects 140 in a sensing region 120. Some example input objects include fingers and a stylus, as shown in FIG. 1A.
The sensing region 120 encompasses any space above, around, in, and/or near the input device 100 in which the input device 100 is capable of detecting user input (e.g., user input provided by one or more input objects 140). The size, shape, and location of a particular sensing region may vary widely from embodiment to embodiment. In some embodiments, the sensing region 120 extends into space in one or more directions from the surface of the input device 100 until signal-to-noise ratios prevent sufficiently accurate object detection. The distance that the sensing region 120 extends in a particular direction, in various embodiments, may be on the order of less than a millimeter, millimeters, centimeters, or more, and may vary significantly depending on the type of sensing technology used and the desired accuracy. Accordingly, some embodiments sense input, including being non-contact with any surface of input device 100, being in contact with an input surface (e.g., a touch surface) of input device 100, being in contact with an input surface of input device 100 coupled with an amount of applied force or pressure, and/or combinations thereof. In various embodiments, the input surface may be provided by a surface of a housing in which the sensor electrodes are located, by a panel applied over the sensor electrodes or any housing, etc. In some embodiments, the sensing region 120 has a rectangular shape when projected onto an input surface of the input device 100.
The input device 100 may utilize any combination of sensor components and sensing technologies to detect user input in the sensing region 120. The input device 100 includes one or more sensing elements for detecting user input. As a few non-limiting examples, input device 100 may use capacitive, inverted dielectric, resistive, inductive, magnetic, acoustic, ultrasonic, and/or optical technologies.
Some implementations are configured to provide images across a one-dimensional, two-dimensional, three-dimensional, or higher dimensional space. Some implementations are configured to provide projections of input along a particular axis or plane.
In some capacitive implementations of the input device 100, a voltage or current is applied to create an electric field. Nearby input objects cause changes in the electric field and produce detectable changes in the capacitive coupling, which can be detected as changes in voltage, current, etc.
Some capacitive implementations utilize a regular or irregular pattern of arrays or other capacitive sensing elements to create an electric field. In some capacitive implementations, the individual sensing elements may be ohmically shorted together to form larger sensor electrodes. Some capacitive implementations utilize resistive patches, which may be resistive uniform.
Some capacitive implementations utilize a "self-capacitance" (or "absolute capacitance") sensing method based on changes in the capacitive coupling between the sensor electrodes and the input object. In various embodiments, an input object near the sensor electrode alters the electric field near the sensor electrode, thereby changing the changed capacitive coupling. In one implementation, an absolute capacitance sensing method operates by modulating a sensor electrode relative to a reference voltage (e.g., systematically ground), and by detecting capacitive coupling between the sensor electrode and an input object.
Some capacitive implementations utilize a "mutual capacitance" (or "transcapacitive") sensing method based on changes in the capacitive coupling between sensor electrodes. In various embodiments, an input object near the sensor electrodes alters the electric field between the sensor electrodes, thereby changing the changed capacitive coupling. In one implementation, a transcapacitive sensing method operates by detecting capacitive coupling between one or more transmitter sensor electrodes (also "transmitter electrodes" or "transmitters") and one or more receiver sensor electrodes (also "receiver electrodes" or "receivers"). The transmitter sensor electrode may be modulated relative to a reference voltage (e.g., system ground) to transmit a transmitter signal. The receiver sensor electrodes may remain substantially stable with respect to a reference voltage to facilitate receipt of a resulting signal, including a response corresponding to the transmitter signal. The sensor electrodes may be dedicated transmitters or receivers, or may be configured to both transmit and receive.
In FIG. 1A, processing system 110 is shown as a component of input device 100. The processing system 110 is configured to operate the hardware of the input device 100 to detect input in the sensing region 120. The processing system 110 includes part or all of one or more Integrated Circuits (ICs) and/or other circuit components. (e.g., a processing system for a mutual capacitance sensor device may include a transmitter circuit configured to transmit signals with transmitter sensor electrodes, and/or a receiver circuit configured to receive signals with receiver sensor electrodes). In some embodiments, the processing system 110 also includes electronically readable instructions, such as firmware code, software code, or the like. In some embodiments, the components making up the processing system 110 are located together, such as near the sensing elements of the input device 100. In other embodiments, the components of processing system 110 are physically independent, with one or more components proximate to the sensing element of input device 100 and one or more components elsewhere. For example, the input device 100 may be a peripheral coupled to a desktop computer, and the processing system 110 may include software configured to run on a central processing unit of the desktop computer and one or more ICs (perhaps with associated firmware) separate from the central processing unit. As another example, the input device 100 may be physically integrated in a phone, and the processing system 110 may include circuitry and firmware as part of the main processor of the phone. In some embodiments, the processing system 110 is dedicated to implementing the input device 100. In other embodiments, the processing system 110 also performs other functions, such as operating a display screen, actuating a haptic actuator, and so forth.
The processing system 110 may be implemented as a set of modules that handle different functions of the processing system 110. Each module may include circuitry, firmware, software, or a combination thereof, as part of the processing system 110. In various embodiments, different combinations of modules may be used. Example modules include a hardware operation module for operating hardware such as sensor electrodes and a display screen, a data processing module for processing data such as sensor signals and position information, and a reporting module for reporting information. Additional example modules include a sensor operation module configured to operate a sensing element to detect an input; a recognition module configured to recognize a gesture, such as a mode change gesture; and a mode change module for changing the operation mode.
In some embodiments, the processing system 110 responds to user input (or lack thereof) in the sensing region 120 directly by causing one or more actions. Example actions include changing operating modes, and GUI actions such as cursor movement, selection, menu navigation, and other functions. In some embodiments, the processing system 110 provides information about the input (or lack thereof) to some portion of the electronic system (e.g., to a central processing system of the electronic system that is separate from the processing system 110, if such a separate central processing system exists). In some embodiments, some portion of the electronic system processes information received from the processing system 110 to take action on user input, such as facilitating a full range of actions, including mode change actions and GUI actions.
For example, in some embodiments, the processing system 110 operates the sensing elements of the input device 100 to generate electrical signals indicative of an input (or lack thereof) in the sensing region 120. The processing system 110 may perform any suitable amount of processing on the electrical signals in generating the information provided to the electronic system. For example, the processing system 110 may digitize analog electrical signals obtained from the sensor electrodes. As another example, the processing system 110 may perform filtering or other signal conditioning. As yet another example, the processing system 110 may subtract or otherwise account for the baseline such that the information reflects the difference between the electrical signal and the baseline. As further examples, the processing system 110 may determine location information, recognize input as a command, recognize handwriting, and so forth.
"position information" as used herein broadly encompasses absolute position, relative position, velocity, acceleration, and other types of spatial information. Exemplary "zero-dimensional" positional information includes near/far or contact/non-contact information. Exemplary "one-dimensional" position information includes position along an axis. Exemplary "two-dimensional" positional information includes motion in a plane. Exemplary "three-dimensional" positional information includes instantaneous or average velocity in space. Further examples include other representations of spatial information. Historical data regarding one or more types of location information may also be determined and/or stored, including, for example, historical data that tracks location, motion, or instantaneous speed over time.
In some embodiments, the input device 100 is implemented with additional input components operated by the processing system 110 or by some other processing system. These additional input components may provide redundant functionality for input in the sensing region 120, or some other functionality. FIG. 1A shows buttons 130 near the sensing region 120 that can be used to facilitate selection of items using the input device 100. Other types of additional input components include sliders, balls, wheels, switches, and the like. Conversely, in some embodiments, the input device 100 may be implemented without other input components.
In some embodiments, the input device 100 includes a touch screen interface and the sensing region 120 overlaps at least a portion of an active area of the display screen. For example, input device 100 may include substantially transparent sensor electrodes overlying the display screen and provide a touch screen interface for an associated electronic system. The display screen may be any type of dynamic display capable of displaying a visual interface to a user and may include any type of Light Emitting Diode (LED), organic LED (oled), Cathode Ray Tube (CRT), Liquid Crystal Display (LCD), plasma, electro-luminescence (EL), or other display technology. The input device 100 and the display screen may share physical elements. For example, some embodiments may use some of the same electrical components for display and sensing. As another example, the display screen may be partially or entirely operated by the processing system 110.
It should be understood that while embodiments of the present invention are described in the context of fully functioning devices, the mechanisms of the present invention are capable of being distributed as a program product (e.g., software) in a variety of forms. For example, the mechanisms of the present invention can be implemented and distributed as a software program on an information bearing medium readable by an electronic processor (e.g., a non-transitory computer readable and/or recordable/writable information bearing medium readable by the processing system 110). In addition, embodiments of the present invention apply equally regardless of the particular type of media used to carry out the distribution. Examples of non-transitory, electronically readable media include various optical disks, memory sticks, memory cards, memory modules, and so forth. The electronically readable medium may be based on flash, optical, magnetic, holographic, or any other storage technology.
Fig. 1B illustrates portions of an example sensor electrode pattern that may be arranged to generate all or part of a sensing region of an input device, in accordance with an embodiment. For clarity of illustration and description, a simple rectangular pattern is shown, however it will be appreciated that other patterns may be used. The sensing pattern is comprised of a plurality of receiver electrodes 170 (170-1, 170-2, 170-3, … 170-n) and a plurality of transmitter electrodes 160 (160-1, 160-2, 160-3, … 160-n) overlying one another and disposed over a substrate 180. In this example, the touch sensing pixels are centered at the location where the transmitter and receiver electrodes cross. It will be appreciated that some form of insulating material is typically disposed between the transmitter electrode 160 and the receiver electrode 170. In one embodiment, transmitter electrodes 160 (160-1, 160-2, 160-3, … 160-n) and receiver electrodes 170 (170-1, 170-2, 170-3, … 170-n) may be disposed on similar layers, wherein the transmitter electrodes include a plurality of jumpers disposed on the second layer. In various embodiments, touch sensing includes sensing input objects located anywhere in the sensing region 120 and may include: no contact with any surface of input device 100, contact with an input surface of input device 100 (e.g., a touch surface), contact with an input surface of input device 100 that couples a certain amount of force or pressure, and/or combinations thereof.
Fig. 1C illustrates an example of a sensor path 190 in the form of an emitter path 190A, in accordance with various embodiments. FIG. 1C shows processing system 110 coupled to trace 195-1 via connection/pin 191-1 and trace 195-1 coupled to transmitter electrode 160-1 via connection/pin 191-2. Herein, at most, the transmitter electrode together with all electrical paths is considered a transmitter path, wherein the electrical paths couple the transmitter electrode with the transmitter circuitry in the processor. However, in some embodiments, the transmitter path may be shortened and/or include fewer components, such as when there is a transmitter path error or when the input device is only partially assembled. Thus, as shown in FIG. 1C, transmitter path 190A may include a transmitter electrode (e.g., 160-1), connections/pins 191-1 and 191-2, and trace 195-1. In one embodiment, the transmitter path includes connection/pin 191-1 and trace 195-1. In another embodiment, the transmitter path includes connection/pin 191-1, trace 195-1, and connection/pin 191-2. In a further embodiment, the transmitter path includes connection/pin-1, trace 195-1, connection/pin-2, and transmitter electrode 160-1. In other embodiments, the transmitter path may include other traces and connections. For example, in one embodiment, connection/pin-2 may couple trace 195-1 with another trace, where the trace is then coupled with transmitter electrode 160-1 via another connection. In such embodiments, the transmitter path 190A may include one or more of any traces, connections, and transmitter electrodes. Connection/pin-1 and connection/pin-2 include a hot bar connection, a zero insertion force connection, a pad, and a sensor channel. In other embodiments, connections 191-1 and 191-2 comprise any device capable of coupling trace 195-1 with processing system 110 or transmitter electrode 160-1.
FIG. 1D illustrates an example of a second type of sensor path 190 in the form of a receiver path 190B, in accordance with various embodiments. FIG. 1D shows processing system 110 coupled with trace 195-2 via connection/pin-3 and trace 195-2 coupled with receiver electrode 170-1 via connection/pin-4. Herein, at most, a receiver electrode along with all electrical paths is considered a receiver path, where the electrical paths couple the receiver electrode with receiver circuitry in a processor. However, in some embodiments, the receiver path may be shortened and/or include fewer components, such as when there is a receiver path error or when the input device is only partially assembled. Thus, as shown in FIG. 1D, receiver path 190A may include a receiver electrode (e.g., 170-1), connections 191-3 and 191-4, and trace 195-2. In one embodiment, the receiver path includes connection/pin 191-3 and trace 195-2. In another embodiment, the receiver path includes connection/pin-3, trace 195-2, and connection/pin-4. In a further embodiment, the receiver path includes connection/pin-3, trace 195-2, connection/pin-4, and receiver electrode 170-1. In other embodiments, the receiver path may include other traces and connections. For example, in one embodiment, connection/pin-4 may couple trace 195-2 with another trace, where the trace is then coupled with receiver electrode 170-1 via another connection. In such embodiments, receiver path 190A may include one or more of any traces, connections, and receiver electrodes. Connection/pin-3 and connection/pin-4 include a hot bar connection, a zero insertion force connection, a pad, and a sensor channel. In other embodiments, connections 191-3 and 191-4 comprise any device capable of coupling trace 195-2 with processing system 110 or receiver electrode 170-1.
In other embodiments, multiple transmitter electrodes 160 and multiple receiver electrodes 170 are coupled with the processing system 110 by multiple traces, where each transmitter electrode and receiver electrode is coupled with the processing system 110 by a different trace. Further, in some embodiments, the plurality of transmitter electrodes 160 is coupled with the first plurality of traces, wherein the plurality of transmitter electrodes 160 and the first plurality of traces are disposed over the substrate 180. A connection device comprising a second plurality of traces couples the processing system 110 with a transmitter electrode of the plurality of transmitter electrodes 160 by coupling a trace of the first plurality of traces with a corresponding trace of the second plurality of traces. Each of the second plurality of traces is then coupled to a different connection in the processing system 110. In such an example, the transmitter path may include at least one of: the transmitter electrodes, corresponding traces in the first plurality of traces, corresponding traces in the second plurality of traces, any connections between corresponding traces, any connections between the transmitter electrodes and corresponding traces, and connections between corresponding traces in the second plurality of traces and transmitter circuitry of the processing system 110.
Fig. 2A and 2B illustrate major components of a transmitter path in two example input devices, in accordance with an embodiment. Input device 100A is shown in FIG. 2A, while input device 100B is shown in FIG. 2B. Both of these input devices 100A and 100B are shown overlaid on a display, however the embodiments described herein may be used with input devices that are not implemented in conjunction with a display. In various embodiments, the input devices 100A and 100B may share elements with a display. For example, the transmitter electrode 160 may be common to both the input device (100A or 100B) and the display, with the transmitter electrode 160 configured for both capacitive sensing and display updating. In one embodiment, the common voltage electrode (Vcom electrode) of the display is segmented to form the transmitter electrode 160. In other embodiments, the elements of input devices 100A and 100B may be disposed within a display, such as on a polarizer, color filter, or other substrate of the display. In one embodiment, the transmitter electrode 160 and the receiver electrode 170 may be arranged on the same layer of the substrate or on different layers of the substrate: the substrate overlies the display.
The input device 100A includes a clear transcapacitive touch screen 210 configured with a sensor electrode pattern of transmitter electrodes 160 and receiver electrodes 170 (see, e.g., fig. 1B for one example of such a sensor electrode pattern). In many embodiments, the sensor electrodes are composed of a transparent material and/or are accessible only at one end. As shown, the touch screen 210 is disposed on a glass frame of a Thin Film Transistor (TFT) glass 220 of the display. The processing system 110 is disposed on a Flexible Printed Circuit (FPC) board 230A. FPC 230A includes a connector 235 for connecting to other electronic devices (e.g., electronic device 150), a connector 237 for coupling components of a display, and a first portion (e.g., a socket) of a Zero Insertion Force (ZIF) connection 241 for removably coupling FPC 240A. The FPC 240A includes a second portion of the ZIF connection 241 (e.g., pins configured to fit into a ZIF socket), and a connector 245 that couples with the transmitter electrode 160 and the receiver electrode 170 of the touchscreen 210. Between the second portion of the ZIF 241 and the connector 245, the FPC 240A includes traces that couple the transmitter circuitry of the processing system 110 and the transmitter electrodes 160, and traces that couple the receiver circuitry of the processing system 110 and the receiver electrodes 170. In fig. 2A, the components making up the transmitter path may include any one or more of the following: transmitter circuitry of the processing system 110A, ZIF connections 241, traces on the flexible printed circuit 240A, connectors 245, and transmitter electrodes (e.g., 160-1) on the touch screen 210. It will be appreciated that a short or open circuit may occur anywhere in this transmitter path, and the embodiments described herein may be used to diagnose the occurrence of a short or open circuit and, in some cases, the components in the transmitter path in which the short or open circuit is located.
The input device 100B includes a clear transcapacitive touch screen 210 configured with a sensor electrode pattern of transmitter electrodes 160 and receiver electrodes 170 (see, e.g., fig. 1B for one example of such a sensor electrode pattern). In many embodiments, the sensor electrodes are composed of a transparent material and/or are accessible only at one end. As shown, the touch screen 210 is disposed on a glass frame of a Thin Film Transistor (TFT) glass 220 of the display. The processing system 110 is disposed on a Flexible Printed Circuit (FPC) board 230B. FPC 230B includes connectors 235 for connecting to other electronic devices (e.g., electronic device 150), connectors 237 for coupling components of a display, and pads (not visible) on which solder hotbar connections are made for coupling FPC 240B. The FPC 240B includes a hot bar connector 243, and a connector 245, which are coupled with the transmitter electrode 160 and the receiver electrode 170 of the touch screen 210. Between the thermal wand connector 243 and the connector 245, the FPC 240B includes traces that couple the transmitter circuitry of the processing system 110 and the transmitter electrodes 160, and traces that couple the receiver circuitry of the processing system 110 and the receiver electrodes 170. In fig. 2B, the components making up the transmitter path may include any one or more of the following: transmitter circuitry of processing system 110A, a hot bar connector 243, traces on flexible printed circuit 240B, a connector 245, and transmitter electrodes (e.g., 160-1) on touch screen 210. It will be appreciated that a short or open circuit may occur anywhere in this transmitter path, and the embodiments described herein may be used to diagnose the occurrence of a short or open circuit and, in some cases, the components in the transmitter path in which the short or open circuit is located.
Example processing System
Fig. 3 illustrates an example processing system 110A that can be used with an input device (e.g., input device 100), in accordance with various embodiments. Processing system 110A may be implemented using one or more ASICs, one or more ICs, one or more controllers, or some combination thereof. In one embodiment, the processing system 110A is communicatively coupled with a plurality of transmitter and a plurality of receiver electrodes that implement the sensing region 120 of the input device 100. In one embodiment of the input device 100, the processing system 110A includes a sensing module 301 (including a transmitter circuit 305 and a receiver circuit 315), a demodulation circuit 325, a calculation circuit 335, an internal diagnostic mechanism 345, and a determination module 355. In some embodiments, the processing system 110A and the input device 100 of which the processing system is a part may be disposed in or communicatively coupled with an electronic device (such as a display device, computer, or other electronic device) 150.
In various embodiments, sensor module 301 includes circuitry (e.g., transmitter circuitry 305 and receiver circuitry 315) and operates to interact with sensor electrodes of a sensor electrode pattern, which (sensor electrode pattern) is used to generate sensing region 120. This includes operating the first plurality of sensor electrodes to be silent, driven by the transmitter signal, for transcapacitive sensing, and/or for absolute capacitive sensing. This also includes operating the second plurality of sensor electrodes to be silent, driven by the transmitter signal, for transcapacitive sensing, and/or for absolute capacitive sensing.
The sensor module 301 is configured to obtain a transcapacitive resulting signal by transmitting with a first one of a plurality of sensor electrodes of the input device and receiving with a second one of the plurality of sensor electrodes. In absolute capacitive sensing, the sensor electrodes are both driven and used to receive the resulting signal caused by the signal driven onto the sensor electrodes.
The transmitter circuit 305 operates to transmit a transmitter signal on one or more of the sensor electrodes 160, 170. The signals conveyed on the sensor electrodes each propagate through a sensor electrode path (e.g., 190A, 190B) to the respective sensor electrode. In some embodiments, the transmitter electrode or the receiver electrode is part of a sensor electrode path. Various embodiments of sensor electrode paths have been described previously in connection with fig. 1C, 1D, 2A and 2B. Transmitter circuitry 305 may transmit a transmitter signal (waveform) on one or more of the plurality of sensor electrodes 160 or 170 over a given time interval. Transmitter circuit 305 may also be used to couple one or more of the plurality of sensor electrodes (160 and/or 170 and corresponding sensor electrode paths) to a high impedance, ground, or constant voltage when it is not transmitting waveforms on such sensor electrodes. The transmitter signal may be a square wave, a trapezoidal wave, or some other waveform.
Transcapacitive sensing occurs when transmission is completed with a first sensor electrode and reception of the resulting signal is completed with a second, different sensor electrode. Absolute capacitive sensing occurs when transmission is done with one sensor electrode and reception of the resulting signal is done with the same sensor electrode.
Demodulation circuit 325 operates to demodulate the received resulting signals obtained from one or more sensor electrodes. In one embodiment, the resulting signal is or may be affected by user input. For example, the received resulting signal may be affected in amplitude, phase, or frequency by user input, such as placing an input object 140 into the sensing region 120.
The calculation circuit 335 operates to calculate/determine a measure of absolute capacitance and/or a measure of variation across capacitive coupling between the transmitter electrode and the receiver electrode. The computation circuitry 335 then uses these metrics to determine positional information of the input object (if any) relative to the sensing region 120. In one embodiment, the measure of variation is determined based on the demodulated output, which is obtained by demodulation circuit 325.
The internal diagnostic mechanism 345 includes one or more internal diagnostic mechanisms (e.g., 345-a in fig. 4 and 345-B in fig. 6A and 6B). For example, in one embodiment, each of the transmitter circuits 305 (e.g., 305-1 in fig. 4) may be configured with its own diagnostic mechanism in the manner described in fig. 4. In other embodiments, as shown in fig. 6A and 6B, one or more internal diagnostic mechanisms may be selectively coupled with one or more sensor electrode paths 190 (e.g., transmitter path 190-a and/or receiver path 190-B). The internal diagnostic mechanism 345A is used by the processing system 110A to monitor the transmitter path and establish an optional weak leakage path coupled with the transmitter path. For example, the selectable leakage path may be selected to discharge charge that has been driven onto the transmitter path. The output of the internal diagnostic mechanism 345-a coupled to a particular transmitter path may be monitored to measure any charge or signal on the transmitter path to which it is coupled. Internal diagnostic mechanism 345-B is coupled with one or more sensor electrode paths 190 and is used to diagnose errors in sensor electrode paths 190, such as open or short circuits to other sensor electrode paths 190. Depending on the mode of use, the output of the internal diagnostic mechanism 345-B may indicate to the processing system 110A whether the sensor electrode path 190 under test is open or short; and in some embodiments, the nature of the short circuit may be further characterized. In one embodiment, the internal diagnostic mechanism 345-A is disposed on the same silicon die as part of the same integrated circuit as the transmitter circuit 305, thereby eliminating the need for an external test tool. In one embodiment, the internal diagnostic mechanism 345-B is disposed on the same silicon die as part of the same integrated circuit as the processing system 110A, thereby eliminating the need for an external test tool. The function of the internal diagnostic mechanism 345 will be described in detail in conjunction with the discussion of fig. 4 and fig. 6A and 6B.
The determination module 355 receives the output from the one or more internal diagnostic mechanisms 345 and uses the output to determine whether there is an interruption (open circuit) or ohmic coupling (i.e., some degree of short circuit) in one or more of the sensor electrode paths of the input device and, in some cases, where there is an open circuit in a particular sensor electrode path. Determining the presence of an open or short circuit can prevent a defective input device from exiting a production cycle as it is either being processed or repaired. Further, determining components located in sensor electrode paths where an open circuit exists can facilitate decisions regarding repair or treatment. For example, if an open circuit is determined to be in a portion of the sensor electrode path within the touch screen or touch pad, the touch screen/touch pad is often disposed of because of the difficulty of repair, while other components within the sensor electrode path may be secured and reused. Similarly, if it is determined that the open circuit is elsewhere within the input device (not within the touch screen/touch pad), the touch screen/touch pad can be saved while one or more other components are replaced, re-soldered, re-seated, or re-engaged. Additionally, if an open circuit condition can be characterized as occurring only at or above a certain voltage level, the market may be able to be characterized as acceptable for use in certain applications or for certain users, but unacceptable for other situations with more severe operating conditions. Such characterization allows some components that could otherwise be handled, failed, or sent for repair to be used.
Part 2: input device transmitter path error diagnosis
Example internal diagnostic mechanism
Fig. 4 shows an example of a first type of internal diagnostic mechanism 345-a1 coupled with transmitter circuit 305-1, in accordance with an embodiment. In one embodiment, the internal diagnostic mechanism 345-A1 is disposed on the same silicon die as the transmitter circuit 305-1, thereby eliminating the need for an external test tool. In various embodiments, this is a minimal addition to an entire ASIC or other integrated circuit, as only a few components are required to implement the internal diagnostic mechanism 345-a 1.
IN one embodiment, transmitter circuit 305-1 is a tri-state digital driver that transmits an Input (IN) signal and provides this signal at an output (TX OUT) and onto transmitter path 190A (only a portion of which is shown) IN response to being enabled with an enable signal (EN). In one embodiment, transmitter circuit 305-1 is operable to drive the output (TX OUT) as well as transmitter path 190A based on a selectable drive level or strength of the strength input received at STR. In one embodiment, transmitter circuit 305-1 is operable to drive the output (TX OUT) and transmitter path 190A at a selectable speed or slew rate. Additionally, in the absence of the enable signal on EN, the output of TX OUT enters a tri-state mode, which maintains transmitter path 190A at a high impedance. It should be appreciated that the input device may have one or more transmitter circuits such as transmitter circuit 305-1. For example, in one embodiment, there may be one or more transmitter circuits such as 305-1 coupled to each transmitter electrode (e.g., transmitter electrode 160-1) in the input device. Connector 410 is an electrically conductive connector of an ASIC, controller, or other integrated circuit in which transmitter circuit 305-1 is disposed.
The internal diagnostic mechanism 345-A1 includes a buffer output OUT _1 coupled to the output TXOUT of the transmitter circuit 305-1. As shown, buffering is provided by two series connected inverters INV1 and INV 2. It should be appreciated that other mechanisms may provide suitable buffering. In one embodiment, OUT _1 is provided to the determination module 355. As shown, in one embodiment, it may include multiple outputs (OUT _1, OUT _2, OUT _3, … OUT _ n) from each of multiple internal diagnostic mechanisms 345 that are multiplexed together by multiplexer 440 into a single output line OUT that can be selected by determination module 355 by providing a select signal SEL _ B to multiplexer 440.
Internal diagnostic mechanism 345-a1 also includes an optional leakage path 430 that can be selected with diagnostic signal DIAG _1, diagnostic signal DIAG _1 including an input select signal on optional diagnostic node 431 of optional leakage path 430. Optional drain path 430 couples transmitter path 190A to ground through transistor T1. As shown, the gate of the transistor T1 is coupled to the enable input EN of the transmitter circuit 305-1 through the inverter INV 1. In one embodiment, optional leakage path 430 is only effective when both selection mechanisms are enabled. In various embodiments, the first selection mechanism T1 is enabled when EN is low (not enabled). When DIAG _1 is enabled (high), the second selection mechanism, optional diagnostic node 431, is enabled. The optional leakage path 430 may be formed in a variety of ways, such as with an optional current source or with an optional weak pull-down transistor arranged in series between the transistor T1 and ground.
The optional leakage path 430 is a weak leakage path, where the term "weak" means that the path is weak enough that a fully charged nominal (un-shorted or open) transmitter path 190A can be sampled multiple times before discharging. In one embodiment, being discharged may be represented by a logic zero. The relative weakness is chosen such that the desired granularity is provided by the number of nominal case (no short or open circuit) samples that should be available. For example, in one embodiment, optional leakage path 430 may be designed to provide 10 nominal samples (very coarse granularity) separated by 10 nanosecond intervals before fully discharging fully charged transmitter path 190A. In embodiments where it is only desirable to determine whether there is an open circuit in the transmitter path 190A, ten samples may provide sufficient granularity. In another embodiment, optional leakage path 430 may be designed to provide 100 nominal samples (finer granularity than ten samples) separated by 10 nanosecond intervals before fully discharging fully charged transmitter path 190A. In embodiments where it is desirable to determine whether an open circuit exists in the transmitter path 190A, and further estimate where in the transmitter path the open circuit is located, one hundred samples may provide sufficient granularity. The sample shows that when the leakage path is enabled, the output OUT _1 is gated and measured. The gating and measuring of the output is repeated at known, defined intervals (e.g., every 10 nanoseconds) until the gated output of the transmitter path 190A is measured to have been fully discharged. In one embodiment, a full discharge is represented by a logic zero. Each gating and measurement constitutes a sample. In this manner, both the time taken to reach full discharge (discharge rate) and the number of samples can be measured by the determination module 355.
In one embodiment, the signal DIAG _1 is provided by the determination module 355 or some other portion of the processing system 110A. In one embodiment, the signal DIAG _1 may be provided to multiple internal diagnostic mechanisms simultaneously. In one other embodiment, the diagnostic input is provided to a demultiplexer and routed as a specific diagnostic signal to any one of a plurality of internal diagnostic mechanisms. This is accomplished by splitting the DIAG signal to the selected internal diagnostic mechanism in response to the select signal. In various embodiments, such signal splitting allows only a few signal lines to be utilized in order for processing system 110A to direct the input select signal onto the corresponding selectable leakage paths of a large number of internal diagnostic mechanisms.
Detecting interrupts
The determination module 355 may determine whether there is an interruption along the transmitter path based on a measure of its rate of discharge during a time period that occurs after the transmitter path has been charged by the transmitter circuit 305. This is because the discharge rate is longer for larger capacitances and shorter for smaller capacitances, and because the amount of capacitive loading is directly related to the transmitter path length. For example, transmitter circuit 305-1 fully charges transmitter path 190A for a first time period and is disabled for a second time period. In one embodiment, during the first time period, an enable signal is sent to the internal diagnostic mechanism 345-A1. During the second time period, the rate of discharge of transmitter path 190A is measured using internal diagnostic mechanism 345-A1 and determination module 355. By comparing the discharge rate of the transmitter path 190A to a predetermined discharge rate threshold or range of values for the transmitter path 190A, the determination module 355 may determine whether there is an open circuit for the transmitter path 190A because when there is an open circuit in the transmitter path, the discharge rate may be shorter than the nominal discharge rate threshold, and the closer the open circuit is to the transmitter circuit 305, it is progressively shorter relative to the nominal discharge rate threshold. As the open circuit is closer to transmitter circuit 305-1, the discharge rate will become shorter because the open circuit will result in a shorter than normal transmitter path, and thus its capacitive loading (in response being driven) will be progressively less than that of nominal transmitter path 190A.
In some embodiments, the predetermined discharge rate threshold (or range of values) to which the measured discharge rate is compared may be determined from empirical data measured on similar, nominal (no short or open circuit) transmitter paths, or may be modeling data for similar, nominal transmitter paths. Likewise, additional predetermined thresholds/ranges, which are associated with the location of an open circuit in a particular component or the location on the transmitter path, may similarly be determined from empirical or modeled data. Such predetermined thresholds or ranges may be established once in a manufacturing scenario, and utilized when testing many components (e.g., hundreds, thousands, or millions) in a production line.
Detecting ohmic coupling
The determination module 355 may also use an internal diagnostic mechanism 345-a1 and/or a similar internal diagnostic mechanism 345 coupled with other transmitter paths other than the transmitter path 190A to determine whether a short circuit exists between the transmitter paths or between the transmitter path and a reference voltage of the input device.
In one embodiment, similar to the case where the interrupt test is complete (as described above) and the case where the capacitive load is higher than, rather than lower than expected (e.g., the discharge rate is longer than expected based on modeled or empirical data for the nominal transmitter path), the determination module 355 may determine whether the portion of the tested transmitter path is ohmically coupled (e.g., shorted to some extent) to the receiver electrode path 190-B of the input device. In one embodiment, the circuitry includes receiver electrodes, such as receiver electrode 170-1, and/or any elements coupled with receiver circuitry of processing system 110A, such as traces and corresponding connections. This determination may be made because a longer path may be created with this short, which may withstand a higher than nominal capacitive load, indicated by a longer than nominal discharge rate.
In one embodiment, when a first transmitter path 190A is driven by the transmitter circuit 305 while the other transmitter paths are held at a high impedance by the transmitter circuit 305, the determination module 355 may measure an output of a second internal diagnostic mechanism, which is coupled to the second transmitter path, to determine whether any of the driven signals escape to the second transmitter path. If there is a bleed, the determination module 355 may determine that the first transmitter path is ohmically coupled (e.g., shorted) to the second transmitter path in some manner. A similar metric may be obtained from the output of the diagnostic mechanism of the third or other transmitter paths to determine if any of these other transmitter paths are shorted to the first transmitter path. In a further embodiment, the output of a first internal diagnostic mechanism (e.g., 345-a1 in fig. 4) coupled with a first transmitter path (e.g., transmitter path 190A) may be sampled to determine if a short exists in the first transmitter path. The process includes driving a first transmitter path to a high value with a transmitter circuit of the path (e.g., transmitter circuit 305-1) during a period of time. The determination module 355 determines that the transmitter path is shorted to ground or other transmitter path if the output of the first internal diagnostic mechanism measures some value less than the driven value while the driving is occurring.
In another embodiment, to determine whether a first transmitter path 190A is ohmically coupled (e.g., shorted to some extent) to an adjacent (second) transmitter path, the second transmitter path may be driven by transmitter circuit 305 with an opposite signal relative to the signal driven onto the first transmitter path. The determination module 355 determines that the first and second transmitter paths are ohmically coupled (shorted) if a zero value is detected at the output OUT _1 of the first internal diagnostic mechanism 345-A1 or the output of a second internal diagnostic mechanism coupled to the second transmitter path (e.g., OUT _ 2). The technique may be similarly implemented between the first transmitter path 190A and a third transmitter path, where the third transmitter path is driven with a signal opposite to the signal driven onto the first transmitter path and a zero output value is measured at the output OUT _1 of the first internal diagnostic mechanism 345-a1 or the output of a third internal diagnostic mechanism coupled to the third transmitter path (e.g., OUT _ 3). For example, the transmitter path 190A may be a transmitter path in the middle, with a second transmitter path adjacent to it on one side and a third transmitter path adjacent to it on the other side. In other embodiments, the technique for detecting a short between the first transmitter path 190A and the second transmitter path may be cycled between the first transmitter path 190A and each additional transmitter path in the input device. Similar tests may be performed between each possible pair of two transmitter paths in the input device.
In yet another embodiment, to determine whether the first transmitter path 190A is ohmically coupled (e.g., somewhat shorted) to the reference potential, a transmitter signal is transmitted by the transmitter circuit 305-1 onto the transmitter path 190A. While transmitting the transmitter signal, the other transmitter path remains at a high impedance and the determination module 355 selects or enables the output of the first internal diagnostic mechanism 345-A1 so that it can measure the resulting signal at output OUT _ 1. From this sampled result signal at the output of the internal diagnostic mechanism 345-a1, the determination module 355 determines whether the first transmitter path is ohmically coupled to the reference potential of the input device (e.g., ground or some internal voltage therein). For example, in one embodiment, if the measured resultant signal is low (e.g., a logic zero), it may be determined that the transmitter path is ohmically coupled to ground, and if the measured resultant signal is higher than expected (e.g., a logic one), it may be determined that the transmitter path is ohmically coupled to a reference voltage higher than ground potential. In another embodiment, if the measured resulting signal is lower than expected, it may be determined that the transmitter path is ohmically coupled to ground, and if the measured resulting signal is higher than expected, it may be determined that the transmitter path is ohmically coupled to a reference voltage higher than ground potential.
Example method of input device transmitter path error diagnosis
Fig. 5A, 5B, and 5C illustrate a flow diagram of an example method of input device transmitter path error diagnosis, in accordance with an embodiment. For illustrative purposes, in describing the flow diagram 500, reference will be made to the components of the processing system 110A of FIG. 3 and the components of the transmitter circuit 305-1 and the internal diagnostic circuit 345-A1 of FIG. 4. In some embodiments, not all of the steps described in flowchart 500 may be implemented. In some embodiments, other steps than those described may be implemented. In some embodiments, the steps described in flowchart 500 may be performed in an order different than illustrated and/or described.
At 510 of flow diagram 500, in one embodiment, the method transmits with a first transmitter path of a plurality of transmitter paths in an input device for a first time period. It will be appreciated that the transmitter paths are each configured for capacitive sensing, and thus each transmitter path includes a transmitter electrode, such as transmitter electrode 160-1 in fig. 1B. Referring to fig. 4, in one embodiment, if transmitter path 190A is considered the first transmitter path, this includes a transmitter circuit 305-1 that passes through TX OUT onto transmitter path 190A.
At 520 of flow diagram 500, in one embodiment, an optional leakage path of an internal diagnostic mechanism in the processing system is enabled for a second time period. The second time period is independent of and follows the first time period. With further reference to FIG. 4, in one embodiment, EN is disabled for a second time period, thereby activating emitter T1 for the second time period. During a second time period, processing system 110A then provides an enable to node 431 in the form of DIAG _1 to enable optional leakage path 430.
At 530 of flow diagram 500, in one embodiment, it may be determined whether there is an interruption (i.e., an open circuit) in the first transmitter path. For example, the determination module 355 makes such a determination based on the measured rate of discharge of the first transmitter path. The discharge rate is obtained over a second time period by inputting an optional leakage path of an internal diagnostic mechanism (e.g., 345-a 1) of the processing system in the device.
At 540 of flow diagram 500, in one embodiment, the method further includes transmitting the first transmitter signal with the first transmitter path for a third time period. The third time period may be the same as the first time period or may be later than the second time period. The transmitter signal may be a signal, such as a square wave, trapezoidal wave, or other waveform, that is transmitted by a transmitter circuit (e.g., transmitter circuit 305-1) in transmitter circuit 305 in a first transmitter path (e.g., transmitter path 190).
At 550 of flow diagram 500, while transmitting the first transmitter signal at step 540, in one embodiment, the method also determines whether the first transmitter path is ohmically coupled to a second transmitter path of the plurality of transmitter paths. For example, in one embodiment, the determination module 355 makes such a determination based on a first resulting signal measured at an output of a second internal diagnostic mechanism coupled to the second transmitter path. The second result signal is obtained through an output of the second internal diagnostic mechanism while the first transmitter signal is transmitted in the first transmitter path. It will be appreciated that the second internal diagnostic mechanism, in one embodiment, is circuitry identical to that of the first internal diagnostic mechanism 345-a1 except that it is coupled to the second transmitter path. OUT _2, as shown in FIG. 4, is an example of an output from such a second internal diagnostic mechanism.
At 560 of flow chart 500, in one embodiment, the method further includes determining whether the first transmitter path is ohmically coupled to a third transmitter path of the plurality of transmitter paths. Similar to step 550, in one embodiment, the determination module 355 makes such a determination based on a second result signal received at an output of a third internal diagnostic mechanism coupled to the third transmitter path. The second result signal is obtained through an output of the third internal diagnostic mechanism while the first transmitter signal is transmitted in the first transmitter path. It will be appreciated that the third internal diagnostic mechanism, in one embodiment, is circuitry identical to that of the first internal diagnostic mechanism 345-a1, except that it is coupled with the third transmitter path. OUT _3, as shown in FIG. 4, is an example of an output from such a third internal diagnostic mechanism. The second transmitter signal may be the same or different from the first transmitter signal and may be a square wave, a trapezoidal wave, or some other waveform.
At 570 of flow diagram 500, in one embodiment, the method described in 510 through 530 further includes determining whether the first transmitter path is ohmically coupled to the receiver path of the capacitive sensing device. The determination module 355, in one embodiment, makes this determination based on a comparison of a metric of capacitive loading of the first transmitter path to a predetermined capacitive loading threshold. The predetermined capacitive loading threshold may be obtained from empirical or modeled data, but for a nominal (neither short nor open) version of the first transmitter path. The capacitive loading threshold may be expressed as a discharge rate or as a time required to discharge the first transmitter path through an optional leakage path of an internal diagnostic mechanism. The determination module 355 determines that the first transmitter path is shorted to the receiver path if the actual measured capacitive load is greater than the predetermined threshold by a predetermined margin (e.g., 10% or more, as one non-limiting example).
At 580 of flow diagram 500, in one embodiment, the method described in 510 through 530 further includes determining whether there is an interruption based on a comparison of a measure of capacitance of the first transmitter path to a predetermined transmitter path capacitance threshold. A measure of capacitance is obtained by the selectable leakage path. For example, it is enabled and the output is repeatedly strobed (sampled) at regular intervals to indirectly determine a measure of capacitance by measuring the rate of discharge (until the time taken for the transmitter path to fully discharge or reach a logical zero).
Part 3: sensor electrode path fault diagnosis
Example internal diagnostic mechanism
FIG. 6A illustrates an example of a second type of internal diagnostic mechanism 345-B1 coupled with sensor electrode path 190-2, in accordance with an embodiment. In one embodiment, the internal diagnostic mechanism 345-B1 is disposed on the same silicon die as the processing system 110A, thus eliminating the need for an external test tool with test circuitry. In various embodiments, this is a minimal addition to an entire ASIC or other integrated circuit, as only a few components are required to implement the internal diagnostic mechanism 345-B1. As shown in fig. 6A, a built-in self test (BIST) input BIST ON is provided to enable amplifiers 620 and 630, which are coupled to the gates of transistors 640 and 650, respectively. Processing system 110A provides BIST ON in the form of one or more signal bits. In embodiments using a single bit, it may be buffered by logic 610 as an enable signal and coupled to both amplifiers 620 and 630. In embodiments where more than one complex bit is used for BIST ON, logic 610 may decode the input to provide different levels of enable signals to one or more of amplifiers 620 and 630, thereby controlling how much one or both of transistors 640 and 650 are turned ON. In one embodiment, amplifier 620 has a low voltage rail coupled to ground and a high voltage rail coupled to VDDTX. In some embodiments, VDDTX may be equal to the highest voltage typically transferred by processing system 110A onto the transmitter electrode during capacitive sensing. In one embodiment, amplifier 630 has a low voltage rail coupled to ground and a high voltage rail coupled to VDDH. In some embodiments, VDDH may be equal to the highest voltage for processing system 110A. As shown, the source of transistor 640 is coupled to VDDTX and the drain of transistor 640 is coupled to the source of transistor 650. The drain of transistor 650 is coupled to the input of schmitt trigger 660 and one side of switch 670. The other side of switch 670 is coupled with sensor electrode path 190 (e.g., 190-2 as shown). The output of the Schmitt trigger 660, BIST OUT, is the output of the internal diagnostic mechanism 345-B1 and is provided to the processing system 110A (which, in some embodiments, is coupled to the determination module 355, for example) for use. It is to be appreciated that when enabled, transistor pair 640 and 650 can act as a current source and/or pull-up coupling connected sensor electrode path 190 (e.g., 190-2, when switch 670 is closed) to a selected voltage level supplied by VDDTX.
FIG. 6A also shows that sensing module 301 can be coupled to sensor electrode path 190-1 of multiple sensor electrode paths 190. Sensing module 301 (e.g., transmitter circuit 305) can be selectively coupled with any sensor electrode path 190 and used to drive signals onto the sensor electrode path 190 coupled thereto. In addition, one or more other internal diagnostic mechanisms 345-B may be selectively coupled or decoupled from sensor electrode path 190. For example, internal diagnostic mechanism 345-B2 may be selectively coupled or decoupled from sensor electrode path 190-3, and internal diagnostic mechanism 345-Bn may be selectively coupled or decoupled from sensor electrode path 190-m.
Fig. 6B illustrates a second type of internal diagnostic mechanism 345-B1 coupled with sensor electrode path 190-2 and the use of a ground conductive plate 680, in accordance with various embodiments. In FIG. 6B, internal diagnostic mechanism 345-B0 is illustrated as coupled to sensor electrode path 190-1. A ground conductive plate 680 is coupled to each of the sensor electrode paths 190. As will be described further below, during open circuit testing, the ground conductive plate 680 may be electrically coupled externally across one or more sensor electrode paths 190 to facilitate testing for an open circuit condition.
The circuits shown in fig. 6A and 6B may be used to test one or more sensor electrode paths 190 of a capacitive sensor or capacitive input device for open and/or short circuits. As shown in fig. 1C and 1D, sensor electrode path 190 may include: pins/connections on the processing system; a pin/connection on a processing system and a routing trace coupled to the pin/connection; pins/connections on a processing system, routing traces coupled to the pins/connections on the processing system, and couplings (e.g., pins or other connections) for coupling the traces to the sensor electrodes; and/or pins/connections on a processing system, routing traces coupled to pins/connections on the processing system, couplings (e.g., pins or other connections) for coupling traces to sensor electrodes, and sensor electrodes.
Detecting ohmic coupling (short circuit)
In some embodiments, an internal diagnostic mechanism 345-B may be used to implement the short circuit test. For example, referring to fig. 6A, a short circuit test may be completed to determine if one or more sensor electrode paths 190 are shorted together. In one embodiment, to determine whether one or more sensor electrode paths 190 are shorted together, a separate internal diagnostic mechanism 345-B is selectively coupled to each untested sensor electrode path. The pull-up (shown in fig. 6A as transistors 640 and 650) is enabled for each sensor electrode path not being tested. A resistance value is set for each sensor electrode path. The resistance value is optional depending ON the voltage value set by the BIST pull-up through the BIST ON signal for the particular internal diagnostic mechanism 345B. By testing at different voltage levels, the selectable resistance ranges allow shorts to be measured at different resistance values. For example, there may be no short circuit at low voltages, there may still be no short circuit at medium voltages, but there may be a short circuit at high voltages (low, medium and high relative to the system level voltage). In some embodiments, the resistance being measured may be increased and/or tested at various resistance levels for advanced failure analysis purposes. That is, shorts at higher resistance levels may not be of interest to some applications and/or customers. Thus, if the resistance level at which the short occurs can be characterized, some components that would not otherwise pass testing performed at only one resistance level (e.g., a high resistance level) can pass at other resistance levels and be deemed acceptable for use. The Schmitt trigger gates 660 on all sensor electrode paths 190 not tested are enabled and the sensing module 301 is configured to drive a low voltage signal onto the sensor electrode path 190 to be tested (e.g., 190-1). In some embodiments, the low voltage signal may be any signal with a voltage value that is lower than the highest voltage value available to drive onto the sensor electrode path. That is, the highest voltage value may be a high voltage value of the transmitter signal applied to the sensor electrode when driven for capacitive sensing. If any sensor electrode path 190 (e.g., 190-2 to 190-m) is shorted to the sensor electrode path 190 (e.g., 190-1) to be tested, the output BIST OUT of that shorted sensor electrode path 190 will produce a '1'. In some embodiments, a short may be defined as a resistive (i.e., ohmic) coupling between 0 and about 50000 ohms. However, in some embodiments, the resistive coupling may be higher than 50000 ohms. A short circuit may occur at any point along the sensor electrode path 190. For a good connection without a short circuit, the output BISTOUT will produce a '0'. Different lanes can be tested by changing which lanes have BIST pull-ups enabled and which are driven to low signals.
In one embodiment, the Schmitt trigger 660 is configured to output a logic low signal and a logic high signal based on the tested resistance of the electrode path as well as the supply voltage of the Schmitt trigger 660 and the current provided by the current source. By varying the supply voltage and/or the current supplied, the resistance tested can be varied. For example, to increase the value of the resistance tested, the supply voltage may be increased and/or the supplied current may be decreased. Further, to reduce the resistance tested, the supply voltage may be reduced and/or the current supplied may be increased. This is because the resistance tested is based on the trigger voltage divided by the current supplied, where the trigger voltage of the schmitt trigger 600 is a fraction of the supply voltage.
Detecting interruption (open circuit)
In some embodiments, an internal diagnostic mechanism 345-B may be used to implement the open circuit test. For example, referring to fig. 6B, an open circuit test may be completed to determine if an open circuit exists in one or more sensor electrode paths 190. The circuit shown in fig. 6B includes a pull-up circuit (e.g., transistors 640 and 650) that couples the selectively coupleable sensor electrode path 190 to a voltage signal and a schmitt trigger gate 660. During open circuit testing, the pull-up is enabled with BIST ON, and the voltage value is set to define the resistance value to be tested. Further, biston ON the schmitt trigger gate is enabled. A ground conductive plate 680 is coupled to each of the sensor electrode paths to be tested; which may be one sensor electrode path or a plurality of sensor electrode paths. During an open circuit test, a BIST OUT value of '1' represents to processing system 110A that an open circuit is present somewhere in the corresponding sensor electrode path 190, and a value of '0' represents to processing system 110A that no open circuit is present in the corresponding sensor electrode path 190.
Example method of sensor electrode path error diagnosis
7A, 7B, 7C, 7D, 7E, and 7F illustrate flow diagrams of example methods of sensor electrode path error diagnosis, in accordance with various embodiments. For purposes of illustration, during the description of flowchart 700, reference will be made to components in fig. 1A, 1B, 1C, 2A, 2B, and 3, as well as to the circuitry in fig. 6A and/or 6B. In some embodiments, not all of the steps described in flowchart 700 may be implemented. In some embodiments, other steps than those described may be implemented. In some embodiments, the steps described in flowchart 700 may be performed in an order different than illustrated and/or described.
Referring now to FIG. 7A, at 710 of flow diagram 700, in one embodiment, a capacitive sensing input device processing system drives a first sensor electrode path with a first signal. Referring to fig. 6A, in some embodiments, it includes a sensing module 301 of processing system 110A that drives sensor electrode path 190 (e.g., 190-1 as illustrated) with a first signal. Referring to fig. 1C and 1D, in some embodiments, first sensor electrode path 190-1 includes one or more of: pins of processing system 110A, sensor electrodes (e.g., 160 or 170), and coupling traces 195 between the sensor electrodes and the pins.
At 720 of flow diagram 700, in one embodiment, a first internal diagnostic mechanism coupled with a second sensor electrode path is used to obtain a test signal output while driving the first sensor electrode path with a first signal. The first internal diagnostic mechanism includes a selectable current source coupled to the second sensor electrode path and enabled during the obtaining of the test signal output. The first internal diagnostic mechanism is arranged as part of a capacitive sensing input device processing system. Referring to FIG. 6A, in some embodiments, it may include an internal diagnostic mechanism 345-B1 coupled with sensor electrode path 190-2. With further reference to fig. 6A, transistors 640 and 650 include selectable current sources that can be selected and adjusted based ON the BIST ON signal and logic 610 that routes enable/control signals to amplifiers 620 and 630. Transistors 640 and 650 are enabled during testing or acquisition of the BIST OUT signal from the internal diagnostic mechanism 345-B1. Referring to fig. 1C and 1D, second sensor electrode path 190-2, in some embodiments, includes one or more of: pins of processing system 110A, sensor electrodes (e.g., 160 or 170), and coupling traces 195 between the sensor electrodes and the pins.
At 730 of flow diagram 700, in one embodiment, the capacitive sensing input device processing system determines whether the first and second sensor electrode paths are ohmically coupled together based on the test signal output. In one embodiment, it includes processing system 110A or a component therein, such as determination module 355, that receives the BISTOUT signal from internal diagnostic mechanism 345-B1 and determines that ohmic coupling exists between sensor electrode path 190-1 and sensor electrode path 190-2 if BIST OUT is '1'; and in the case where BIST OUT is '0' (determining) there is no ohmic coupling between sensor electrode path 190-1 and sensor electrode path 190-2.
Referring now to FIG. 7B, at 740 of flowchart 700, in one embodiment, the method as described in 710-730 further includes a second internal diagnostic mechanism coupled with the third sensor electrode path to obtain a second test signal output when the first sensor electrode path is driven with the first signal. The second internal diagnostic mechanism includes a second selectable current source coupled to the third sensor electrode path and enabled during the obtaining of the second test signal output. The second internal diagnostic mechanism is arranged as part of a capacitive sensing input device processing system. Referring to FIG. 6A, in some embodiments, it may include an internal diagnostic mechanism 345-B2 coupled with sensor electrode path 190-3. With further reference to fig. 6A, the transistors equivalent to 640 and 650 within internal diagnostic mechanism 345-B2 include selectable current sources that can be selected and adjusted based on the BISTON signal and logic equivalent to logic 610 that routes the enable/control signals to amplifiers equivalent to 620 and 630. The transistors equivalent to 640 and 650 are enabled during the test and acquisition of the BIST OUT signal from the internal diagnostic mechanism 345-B2. Referring to fig. 1C and 1D, third sensor electrode path 190-3, in some embodiments, includes one or more of: pins of processing system 110A, sensor electrodes (e.g., 160 or 170), and coupling traces 195 between the sensor electrodes and the pins.
At 745 of flowchart 700, in one embodiment, the method as described in 740 further comprises determining, by the capacitive sensing input device processing system, based on the second test signal output, whether the first and third sensor electrodes are ohmically coupled together. In one embodiment, it includes processing system 110A or a component therein, such as a determination module 355, that receives the BIST OUT signal from internal diagnostic mechanism 345-B2 and determines that ohmic coupling exists between sensor electrode path 190-1 and sensor electrode path 190-3 if the BIST OUT is a '1'; and in the case where BIST OUT is '0' (determining) there is no ohmic coupling between sensor electrode path 190-1 and sensor electrode path 190-3.
Referring now to FIG. 7C, at 750 of flowchart 700, in one embodiment, the method as described in 710 through 730 further includes a third internal diagnostic mechanism coupled with the fourth sensor electrode path to obtain a third test signal output when the first sensor electrode path is driven with the first signal. The third internal diagnostic mechanism includes a third selectable current source coupled to the fourth sensor electrode path and enabled during acquisition of the third test signal output. The third internal diagnostic mechanism is arranged as part of a capacitive sensing input device processing system. Referring to FIG. 6A, in some embodiments, it may include an internal diagnostic mechanism 345-Bn coupled with the sensor electrode path 190-m. With further reference to fig. 6A, the transistors equivalent to 640 and 650 within the internal diagnostic mechanism 345-Bn include selectable current sources that can be selected and adjusted based on the BISTON signal and logic equivalent to logic 610 that routes the enable/control signals to amplifiers equivalent to 620 and 630. The transistors equivalent to 640 and 650 are enabled during the test and acquisition of the BIST OUT signal from the internal diagnostic mechanism 345-Bn. Referring to FIGS. 1C and 1D, fourth sensor electrode path 190-m, in some embodiments, includes one or more of: pins of processing system 110A, sensor electrodes (e.g., 160 or 170), and coupling traces 195 between the sensor electrodes and the pins.
At 755 of flowchart 700, in one embodiment, the method as described in 750 further comprises the capacitive sensing input device processing system determining whether the first and fourth sensor electrodes are ohmically coupled together based on the third test signal output. In one embodiment, it includes processing system 110A or a component therein, such as a determination module 355, that receives the BIST OUT signal from the internal diagnostic mechanism 345-Bn and determines that there is ohmic coupling between sensor electrode path 190-1 and sensor electrode path 190-m if the BIST OUT is '1'; and in the case where BIST OUT is '0' (determining) that there is no ohmic coupling between sensor electrode path 190-1 and sensor electrode path 190-m.
Referring now to fig. 7D, at 760 of flowchart 700, in one embodiment, the method as described in 710 through 730 further includes applying a schmitt trigger within the first internal diagnostic mechanism to provide the output signal. Referring to fig. 6A, the schmitt trigger gate 660 provides BIST OUT for use by the processing system 110A.
Referring now to FIG. 7E, at 770 of flowchart 700, in one embodiment, the method as described in 710 through 730 further comprises selecting a current level supplied by the current source when enabled from a plurality of different positive levels such that error detection is achieved at a selected one of the plurality of different levels of ohmic coupling. Referring to fig. 6A, the schmitt trigger gate BIST ON may be two or more bits of information that may be decoded by logic 610 and used to control how much voltage is applied by amplifiers 620 and 630 ON the gates of transistors 640 and 650, thereby providing multiple selectable positive levels of current (above zero) supplied by transistors 640 and 650 through switch 670 to the coupled sensor electrode path.
Referring now to fig. 7F, at 780 of flow diagram 700, in one embodiment, the method as described in 710 through 730 further comprises obtaining, by the first internal diagnostic mechanism, a second test output signal when the pull-up voltage is selectively coupled to the second sensor electrode path while the grounded conductive object (such as grounded conductive plate 680) is also coupled with the second sensor electrode path. Referring to FIG. 6B, in some embodiments, it may include diagnosing whether an open circuit condition exists in sensor electrode path 190-2 at a separate time using internal diagnostic mechanism 345-B1. For example, the circuit shown in fig. 6B includes a pull-up circuit (e.g., transistors 640 and 650) that couples the selectively coupled sensor electrode path 190 (e.g., sensor electrode path 190-2) to a voltage signal and onto the schmitt trigger gate 660.
At 785 of flowchart 700, in one embodiment, the method as described in 780 further comprises determining, by the capacitive sensing input device processing system, based on the value of the second test output signal, whether an open circuit exists in the second electrode path. During open circuit testing, the pull-up is enabled with BIST ON, and the voltage value is set based ON the BIST ON signal decoded by logic 610 and provided to amplifiers 620 and 630. The voltage level defines the resistance value of the test open circuit.
Generally, the higher the voltage level is selected, the lower the resistance value of the sensor electrode path at which an open circuit is tested. During open circuit testing, BIST OUT on the Schmitt trigger gate 660 is enabled by the selected voltage level. Ground conductive plate 680 is coupled to each of the sensor electrode paths to be measured, in this example, at least to sensor electrode path 190-2. During an open circuit test, when the determination module 355 receives the BIST OUT value of '1' from the Schmitt trigger 660, it determines that an open circuit exists somewhere in the sensor electrode path 190-2. During an open circuit test, when the determination module 355 receives the BIST OUT value of '0' from the Schmitt trigger 660, it determines that an open circuit is not present in the sensor electrode path 190-2. Schmitt trigger 660 is configured to output a logic low signal and a logic high signal based on the measured resistance of the electrode path as well as the supply voltage of the schmitt trigger and the current provided by the current source. By varying the supply voltage and/or the supplied current, the resistance tested can be varied.
Thus, the embodiments and examples set forth herein are presented to best explain various selected embodiments of the invention and its particular application and to thereby enable those skilled in the art to make and use the embodiments of the invention. Those skilled in the art, however, will recognize that the foregoing description and examples have been presented for the purpose of illustration and example only. The description as set forth is not intended to be exhaustive or to limit embodiments of the invention to the precise form disclosed.
Claims (15)
1. A processing system for a capacitive sensing input device, the processing system comprising:
a sensing module configured to couple with a first sensor electrode path of a plurality of sensor electrode paths, wherein the sensing module is configured to drive the first sensor electrode path with a first signal;
a first internal diagnostic mechanism configured to couple with a second sensor electrode path and configured to obtain a test signal output when the sensing module drives the first sensor electrode path with the first signal, wherein the first internal diagnostic mechanism comprises a selectable current source configured to couple with the second sensor electrode path, and wherein the selectable current source is enabled during the obtaining of the test signal output;
a determination module configured to determine whether the first and second sensor electrode paths are ohmically coupled together based on the test signal output;
the first internal diagnostic mechanism is further configured to obtain a second test signal output when a pull-up voltage is selectively coupled to the second sensor electrode path while a grounded conductive object is also coupled with the second sensor electrode path; and
the determination module is further configured to determine whether an open circuit exists in the second sensor electrode path based on a value of the second test signal output.
2. The processing system of claim 1, further comprising:
a second internal diagnostic mechanism configured to couple with a third sensor electrode path and configured to obtain a second test signal output when the sensing module drives the first sensor electrode path with the first signal, wherein the second internal diagnostic mechanism includes a second selectable current source configured to couple with the third sensor electrode path, and wherein the second selectable current source is enabled during the obtaining of the second test signal output; and
wherein the determination module is further configured to determine whether the first and third sensor electrode paths are ohmically coupled together based on the second test signal output.
3. The processing system of claim 2, further comprising:
a third internal diagnostic mechanism configured to couple with a fourth sensor electrode path and configured to obtain a third test signal output when the sensing module drives the first sensor electrode path with the first signal, wherein the third internal diagnostic mechanism includes a third selectable current source configured to couple with the fourth sensor electrode path, and wherein the third selectable current source is enabled during the obtaining of the third test signal output; and
wherein the determination module is further configured to determine whether the first and fourth sensor electrode paths are ohmically coupled together based on the third test signal output.
4. The processing system of claim 1, wherein the first internal diagnostic mechanism further comprises a schmitt trigger configured to provide an output signal from the first internal diagnostic mechanism.
5. The processing system of claim 1, wherein the selectable current source comprises a selectable variable current source, wherein a positive level of current when the selectable variable current source is enabled is also selectable such that a test can be performed to discern different levels of ohmic coupling.
6. The processing system of claim 1, wherein the first sensor electrode path comprises at least one of a pin of the processing system, a sensor electrode, and a trace coupled between the sensor electrode and the pin.
7. A capacitive sensing input device, comprising:
a sensor electrode pattern including a plurality of sensor electrodes; and
a processing system coupled with the plurality of sensor electrodes and configured to perform capacitive sensing with the plurality of sensor electrodes, the processing system further configured to:
driving a first sensor electrode path with a first signal, wherein the first sensor electrode path includes a first sensor electrode of the plurality of sensor electrodes;
obtaining a test signal output while driving the first sensor electrode path with the first signal using a first internal diagnostic mechanism coupled with a second sensor electrode path, wherein the first internal diagnostic mechanism includes a selectable variable current source, wherein a positive level of current is also selectable when the selectable variable current source is enabled such that a test can be completed to discern different levels of ohmic coupling, wherein the selectable variable current source is coupled with the second sensor electrode path, wherein the selectable variable current source is enabled during the obtaining of the test signal output, and wherein the second sensor electrode path includes a second sensor electrode of the plurality of sensor electrodes; and
determining whether the first and second sensor electrode paths are ohmically coupled together based on the test signal output.
8. The capacitive sensing input device of claim 7, further comprising a flex circuit configured to couple signals between said processing system and said plurality of sensor electrodes.
9. The capacitive sensing input device of claim 8, wherein the first sensor electrode path comprises at least one of a pin of the processing system, the first sensor electrode, and a trace disposed on the flex circuit and coupled between the first sensor electrode and the pin.
10. The capacitive sensing input device of claim 7, wherein said processing system is further configured to:
obtaining a second test signal output while driving the first sensor electrode path with the first signal using a second internal diagnostic mechanism, wherein the second internal diagnostic mechanism comprises a second selectable variable current source coupled with the third sensor electrode path, wherein the second selectable variable current source is enabled during the obtaining of the second test signal output, and wherein the third sensor electrode path comprises a third sensor electrode of the plurality of sensor electrodes; and
determining whether the first and third sensor electrode paths are ohmically coupled together based on the second test signal output.
11. The capacitive sensing input device of claim 10, wherein said processing system is further configured to:
obtaining a third test signal output while driving the first sensor electrode path with the first signal using a third internal diagnostic mechanism, wherein the third internal diagnostic mechanism includes a third selectable variable current source coupled with the fourth sensor electrode path, wherein the third selectable variable current source is enabled during the obtaining of the third test signal output, and wherein the fourth sensor electrode path includes a fourth sensor electrode of the plurality of sensor electrodes; and
determining whether the first and fourth sensor electrode paths are ohmically coupled together based on the third test signal output.
12. The capacitive sensing input device of claim 7, wherein said first internal diagnostic mechanism further comprises a Schmitt trigger configured to provide an output signal from said first internal diagnostic mechanism.
13. A method of sensor electrode path fault diagnosis, comprising:
driving a first sensor electrode path with a first signal using a capacitive sensing input device processing system;
obtaining a test signal output while driving the first sensor electrode path with the first signal using a first internal diagnostic mechanism coupled with a second sensor electrode path, wherein the first internal diagnostic mechanism includes a selectable current source coupled with the second sensor electrode path, wherein the selectable current source is enabled during the obtaining of the test signal output, and wherein the first internal diagnostic mechanism is arranged as part of the capacitive sensing input device processing system;
providing an output signal of the first internal diagnostic mechanism using a Schmitt trigger within the first internal diagnostic mechanism; and
determining, by the capacitive sensing input device processing system, based on the output signals, whether the first and second sensor electrode paths are ohmically coupled together.
14. The method of claim 13, further comprising:
obtaining a second test signal output while driving the first sensor electrode path with the first signal using a second internal diagnostic mechanism coupled with a third sensor electrode path, wherein the second internal diagnostic mechanism includes a second selectable current source coupled with the third sensor electrode path, wherein the second selectable current source is enabled during the obtaining of the second test signal output, and wherein the second internal diagnostic mechanism is arranged as part of the capacitive sensing input device processing system; and
determining, by the capacitive sensing input device processing system, based on the second test signal output, whether the first and third sensor electrode paths are ohmically coupled together.
15. The method of claim 13, further comprising:
obtaining, by the first internal diagnostic mechanism, a second test signal output when selectively coupling a pull-up voltage to the second sensor electrode path while a grounded conductive object is also coupled with the second sensor electrode path; and
determining, by the capacitive sensing input device processing system, whether an open circuit exists in the second sensor electrode path based on the value of the second test signal output.
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