KR20210079250A - Low power mode display device with an integrated sensing device - Google Patents

Abstract

According to the present disclosure, provided is an input device including a reference voltage modulator modulating reference voltage rails when performing capacitive sensing in general. According to one embodiment, the reference voltage rails are coupled with DC power providing electric power to operate a panel including a touch sensing area and an integrated display screen. Before the performance of capacitive sensing, the input device separates the DC power from the reference voltage rails, and can use the rails, for example, can use the reference voltage rails to modulate VDD and VGND. The input device can include a receiver which simultaneously captures result signals from a plurality of display electrodes and/or sensor electrodes when modulating the reference voltage rails. Thereafter, the result signals can be processed to determine whether an input object interacts with the input device.

Description

LOW POWER MODE DISPLAY DEVICE WITH AN INTEGRATED SENSING DEVICE

Embodiments of the present invention relate generally to electronic devices, and more particularly, to modulating reference voltages to perform capacitive sensing.

Input devices, including proximity sensor devices (also commonly referred to as touchpads or touch sensor devices) are widely used in various electronic systems. A proximity sensor device generally includes a sensing region, often bounded by a surface, from which the proximity sensor device determines the presence, location and/or motion of one or more input objects. Proximity sensor devices may be used to provide interfaces to an electronic system. For example, proximity sensor devices are often used as input devices for large computing systems (such as opaque touchpads integrated into or accompanying notebook or desktop computers). Proximity sensor devices are also often used in small computing systems (such as touch screens integrated in cellular phones).

One embodiment described herein includes an input device that includes a plurality of sensor electrodes and a processing system. The processing system includes: a sensor module configured to operate a plurality of sensor electrodes for capacitive sensing; a reference voltage modulator configured to modulate reference voltage rails of the processing system; and a receiver configured to simultaneously acquire resultant signals from the sensor electrodes to detect an input object while modulating the reference voltage rails.

Another embodiment described herein includes a processing system comprising a sensor module configured to drive a plurality of sensor electrodes for capacitive sensing and a reference voltage modulator configured to modulate reference voltage rails of the processing system, wherein the voltage rail Before modulating the voltages, the processing system is configured to electrically short the reference voltage rails from the at least one DC power supply. The processing system also includes a receiver configured to acquire the resulting signals using the sensor electrodes to detect an input object while modulating the voltage rails.

Another embodiment described herein includes an input device comprising a plurality of sensor electrodes, each sensor electrode comprising at least one common electrode of a display device, wherein the sensor electrodes are disposed on a common plane in a matrix arrangement. are placed The input device includes a sensor module configured to operate a plurality of sensor electrodes for capacitive sensing; a reference voltage modulator configured to modulate reference voltage rails of the processing system; and a processing system comprising a receiver configured to acquire result signals using the sensor electrodes to detect an input object while modulating the voltage rails.

Another embodiment described herein includes driving a capacitive sensing signal on a plurality of sensor electrodes at an input device; and electrically shorting the reference voltage rails from the at least one DC power supply. After electrically shorting the reference voltage rails, the method includes modulating the reference voltage rails. The method includes capturing resultant signals using sensor electrodes to detect an input object while modulating voltage rails.

In order that the above-mentioned features of the present invention may be understood in detail, a more detailed description of the present disclosure, briefly summarized above, may be made with reference to embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the appended drawings illustrate only certain typical embodiments of the present disclosure, and thus should not be regarded as limiting of their scope, as the present disclosure may admit to other equally effective embodiments. do.
1 is a block diagram of an exemplary system including an input device, in accordance with embodiments of the present invention;
2 is an input device modulating reference voltage rails for performing capacitive sensing, in accordance with one embodiment described herein.
3 is an input device that modulates reference voltage rails for performing capacitive sensing, in accordance with one embodiment described herein.
4 is an input device modulating reference voltage rails for performing capacitive sensing, in accordance with one embodiment described herein.
5 is a circuit diagram of a reference voltage modulator, in accordance with one embodiment described herein.
6 is a flow diagram of waking up an input device from a low power state using modulated reference voltage rails, in accordance with one embodiment described herein.
7 illustrates an example electrode arrangement for performing capacitive sensing, in accordance with one embodiment described herein.
8 is an input device for detecting a noise signal or communication signal from an active input object, according to an embodiment described herein.
9 is a circuit diagram of a receiver for acquiring resultant signals to identify a noise or communication signal, according to an embodiment described herein.
10 is a flow diagram for identifying noise or communication signals using capacitive sensing, in accordance with one embodiment described herein.
11 illustrates various capacitances between an input device and an environment, according to an embodiment described herein.
12 is an input device modulating reference voltage rails for performing capacitive sensing, in accordance with one embodiment described herein.
13 is a flow chart for mitigating the effects of a low ground mass condition, according to one embodiment described herein.
14 illustrates various capacitances between an input device and an environment, according to an embodiment described herein.
15 is a chart showing results of mitigating the effects of a low ground mass condition, in accordance with one embodiment described herein.

To facilitate understanding, like reference numerals have been used, where possible, to designate like elements common to the drawings. It is intended that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation. The drawings referenced herein are not to be construed as drawn to scale unless specifically stated. In addition, the drawings are often simplified and details or components are omitted for clarity of presentation and description. The drawings and description are provided to explain the principles described below, wherein like designations refer to like elements.

The following detailed description is merely exemplary in nature and is not intended to limit the disclosure or its applications and uses. Moreover, there is no intention to be bound by any expressed or implied theory set forth in the preceding technical field, background, brief summary or the following detailed description.

Various embodiments of the present invention provide an input device comprising a reference voltage modulator that modulates reference voltage rails when performing capacitive sensing. In one embodiment, the reference voltage rails are coupled to a DC power source that provides power for operating a panel including a display screen integrated with a touch sensitive area. Before performing capacitive sensing, the input device may disconnect the DC power source from the reference voltage rails and use the reference voltage rails to modulate the _{rails - eg, V DD} and V _{GND .} For example, a reference voltage modulator may change the voltages on the rails by the same increment. That is, if the high reference rail (eg, V _DD ) increases by 1V, the reference voltage modulator also increases the low reference rail (eg, V _GND ) by 1V. In this example, the voltage difference between the reference voltage rails remains constant as the rails are modulated. As used herein, separating the reference voltage rails may not require physically shorting the rails from the power source. Instead, the reference voltage rails may be inductively or capacitively coupled to the power source.

In one embodiment, the reference voltage rails are modulated (and capacitive sensing is performed) when the input device is in a low power state. In one example, the display/sensing panel (and backlight, if applicable) is turned off and draws no power. Nevertheless, by modulating the reference voltage rails, the sensor electrodes in the display and display/sensing panel can be used to perform capacitive sensing. In other words, by modulating the reference voltage rails, an input object (eg, a finger) that is capacitively coupled to sensor electrodes in the display and panel can be detected by measuring the change in capacitance. Once the input object is detected, the input device wakes up and switches from the low power state to the active state.

In one embodiment, when performing capacitive sensing by modulating reference voltage rails, the display and sensor electrodes are treated as one capacitive pixel or electrode. As such, by measuring the resulting signals from the measurement display and sensor electrodes, the input device determines whether the input object is closest to the panel but not the specific location on the panel the input object is touching or hovering over. does not Instead, once in the active state, the input device may perform a more granular type of capacitive sensing technique that identifies a specific location of the input object in the sensing area. When performing capacitive sensing in the active state, the input device may drive DC voltages onto the reference voltage rails - that is, the rails are not modulated or the rails sense the current or charge required to do so. modified without

Referring now to the drawings, FIG. 1 is a block diagram of an exemplary input device 100 in accordance with embodiments of the present invention. The input device 100 may be configured to provide input to an electronic system (not shown). As used herein, the term “electronic system” (or “electronic device”) broadly refers to any system capable of electronically processing information. Some non-limiting examples of electronic systems are personal computers of all sizes and types, such as desktop computers, laptop computers, netbook computers, tablets, web browsers, e-book readers, and personal digital assistants. terminals (PDAs). Additional example electronic systems include composite input devices, such as input device 100 and physical keyboards that include separate joysticks or key switches. Additional exemplary electronic systems include peripherals, 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 appliances (eg, video game consoles, portable gaming devices, and the like). Other examples include communication devices (including cellular phones such as smartphones), and (recorders, editors, and players, such as televisions, set-top boxes, music players, digital picture frames, and media devices (including digital cameras). Furthermore, the electronic system may be a host or a slave to an input device.

The input device 100 may be implemented as a physical part of an electronic system, or may be physically separate from the electronic system. When appropriate, input device 100 may communicate with parts of an electronic system using any one or more of the following: buses, networks, and other wired or wireless interconnects. Examples include I ² C, SPI, PS/2, Universal Serial Bus (USB), Bluetooth, RF, and IRDA.

1 , an input device 100 is a proximity sensor device (also sometimes referred to as a “touchpad” or “touch sensor device”) configured to sense input provided by one or more input objects 140 in a sensing area 120 . referred to as ). Exemplary input objects include fingers and styluses, as shown in FIG. 1 .

Sensing area 120 may be over, around, inside and/or around input device 100 from which input device 100 may detect user input (eg, user input provided by one or more input objects 140 ). It encompasses any space nearby. The sizes, shapes, and locations of particular sensing regions may vary significantly from embodiment to embodiment. In some embodiments, sensing area 120 extends spatially from the surface of input device 100 in one or more directions until signal-to-noise ratios interfere with sufficiently accurate object detection. The distance this sensing area 120 extends in a particular direction, in various embodiments, may be approximately less than millimeters, millimeters, centimeters or more, and may vary significantly depending on the type of sensing technology used and the desired accuracy. It may change. Accordingly, some embodiments provide for contact with any surfaces of the input device 100 , contact with an input surface (eg, a touch surface) of the input device 100 , an applied force or pressure, and/or these Sense input that includes no contact with the input surface of the input device 100 coupled with some amount of a combination of . In various embodiments, the input surfaces may be provided by surfaces of the casings on which the sensor electrodes reside, by face sheets provided over the sensor electrodes or any casings, etc. In some embodiments, sensing area 120 has a rectangular shape when projected onto an input surface of input device 100 .

The input device 100 may detect user input in the sensing area 120 using any combination of sensor components and sensing techniques. Input device 100 includes one or more sense elements for detecting user input. As various non-limiting examples, input device 100 may use capacitive, elastic, resistive, inductive, magnetic, acoustic, ultrasonic, and/or optical techniques.

Some implementations are configured to provide images that span 1, 2, 3, or higher dimensional spaces. Some implementations are configured to provide projections of the input along specific axes or planes.

In some resistive implementations of input device 100 , the flexible and conductive first layer is separated from the conductive second layer by one or more spacer elements. During operation, one or more voltage gradients are created across the layers. Depressing the flexible first layer may deflect the flexible first layer sufficiently to create electrical contact between the layers, resulting in voltage outputs reflecting the point(s) of contact between the layers. These voltage outputs may be used to determine position information.

In some inductive implementations of input device 100 , one or more sense elements capture loop currents induced by a resonant coil or pair of coils. Some combination of magnitude, phase, and frequency of the currents may then be used to determine position information.

In some capacitive implementations of input device 100 , a voltage or current is provided to generate an electric field. Adjacent input objects cause changes in the electric field, resulting in detectable changes in capacitive coupling that may be detected as changes in voltage, current, or the like.

Some capacitive implementations generate electric fields using arrays of capacitive sensing elements or other regular or irregular patterns. In some capacitive implementations, separate sensing elements are resistively shorted together to form larger sensor electrodes. Some capacitive implementations utilize resistance sheets that may be uniformly resistive.

Some capacitive implementations use “self-capacitance” (or “absolute capacitance”) sensing methods based on changes in capacitive coupling between sensor electrodes and an input object. In various embodiments, an input object proximate to the sensor electrodes changes the electric field proximate to the sensor electrodes, thereby changing the measured capacitive coupling. In one implementation, the absolute capacitive sensing method operates by modulating the sensor electrodes relative to a reference voltage (eg, system ground) and detecting capacitive coupling between the sensor electrodes and input objects.

Some capacitive implementations use “mutual capacitance” (or “transcapacitance”) sensing methods based on changes in capacitive coupling between sensor electrodes. In various embodiments, an input object proximate to the sensor electrodes changes the electric field between the sensor electrodes, thereby changing the measured capacitive coupling. In one implementation, the transcapacitance sensing method comprises one or more transmitter sensor electrodes (also “transmitter electrodes” or “transmitters”) and one or more receiver sensor electrodes (also “receiver electrodes” or “receivers”). ) by detecting the capacitive coupling between The transmitter sensor electrodes may be modulated relative to a reference voltage (eg, system ground) to transmit transmitter signals. The receiver sensor electrodes may be held substantially constant relative to the reference voltage to facilitate reception of the resulting signals. The resulting signal may include influence(s) corresponding to one or more transmitter signals, and/or one or more sources of interference in the environment (eg, other electromagnetic signals). The sensor electrodes may be dedicated transmitters or receivers, or may be configured to do both transmit and receive.

In FIG. 1 , processing system 110 is shown as part of an input device 100 . The processing system 110 is configured to operate hardware of the input device 100 to detect an input in the sensing area 120 . The processing system 110 includes portions or all of one or more integrated circuits (ICs) and/or other circuit components. For example, a processing system for a mutual capacitance sensor device may include a transmitter circuit configured to transmit signals by the transmitter sensor electrodes, and/or a receiver circuit configured to receive signals by the receiver sensor electrodes). In some embodiments, processing system 110 also includes electronic-readable instructions, such as firmware code, software code, and/or the like. In some embodiments, the components making up the processing system 110 are located together, eg, in the vicinity of the sense element(s) of the input device 100 . In other embodiments, the components of the processing system 110 are physically separate from one or more components proximate to the sensing element(s) of the input device 100 , and one or more components elsewhere. For example, input device 100 may be a peripheral coupled to a desktop computer, and processing system 110 includes a central processing unit of the desktop computer and one or more separate (possibly with associated firmware) from the central processing unit. It may include software configured to execute ICs. As another example, the input device 100 may be physically integrated into a phone, and the processing system 110 may include circuits and firmware that are part of the phone's main processor. In some embodiments, the processing system 110 is dedicated to implementing the input device 100 . In other embodiments, processing system 110 also performs other functions, such as operating display screens, driving haptic actuators, and the like.

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 that is part of the processing system 110 , firmware, software, or a combination thereof. In various embodiments, different combinations of modules may be used. Exemplary modules include hardware operation modules that operate hardware such as sensor electrodes and display screens, data processing modules that process data such as sensor signals and position information, and reporting modules that report information. Additional exemplary modules include sensor operation modules configured to operate the sense element(s) to detect input, identification modules configured to identify gestures such as mode change gestures, and mode change modules to change modes of operation. include

In some embodiments, processing system 110 directly responds to user input (or lack of user input) in sensing area 120 by causing one or more actions. Exemplary actions include changing operating modes, as well as GUI actions such as cursor movement, selection, menu navigation, and other functions. In some embodiments, processing system 110 is an input (or, if there is such a separate central processing system) to some portion of an electronic system (eg, to a central processing system of an electronic system separate from processing system 110 ). , the lack of input). In some embodiments, some portion of the electronic system receives the received from the processing system 110 to take an action according to user input, eg, to facilitate a full range of actions, including mode change actions and GUI actions. process information.

For example, in some embodiments, the processing system 110 generates electrical signals representative of an input (or lack of input) in the sense region 120 , the sense element(s) of the input device 100 . operates Processing system 110 may perform any suitable amount of processing on the electrical signals when generating information provided to the electronic system. For example, processing system 110 may digitize analog electrical signals obtained from sensor electrodes. As another example, processing system 110 may perform filtering or other signal conditioning. Also, as another example, processing system 110 may subtract or otherwise utilize a baseline such that the information reflects a difference between the electrical signals and the baseline. As yet further examples, processing system 110 may determine location information, recognize inputs as instructions, recognize handwriting, and the like.

“Location information,” as used herein, broadly encompasses absolute position, relative position, velocity, acceleration, and other types of spatial information. Exemplary “zero-dimensional” location information includes near/far or contact/non-contact information. Exemplary “one-dimensional” location information includes locations along an axis. Exemplary “two-dimensional” position information includes motions in a plane. Exemplary “three-dimensional” positional information includes instantaneous or average velocities in space. Additional examples include other representations of spatial information. For example, historical data relating to one or more types of location information may also be determined and/or stored, including historical data that tracks location, motion, or instantaneous velocity over time.

In some embodiments, the input device 100 is implemented with additional input components that are operated by the processing system 110 or by some other processing system. These additional input components may provide extra functionality for input into sensing area 120 , or some other functionality. 1 shows buttons 130 proximate to sensing area 120 that may be used to facilitate selection of items using input device 100 . Other types of additional input components include sliders, balls, wheels, switches, and the like. Conversely, in some embodiments, input device 100 may be implemented without any other input components.

In some embodiments, input device 100 includes a touch screen interface, and sensing area 120 overlaps at least a portion of an active area of a display screen. For example, input device 100 may include substantially transparent sensor electrodes that overlay a display screen and may provide a touch screen interface to an associated electronic system. The display screen may be any kind of dynamic display capable of displaying a visual interface to the user, including any kind of light emitting diode (LED), organic LED (OLED), cathode ray tube (CRT), liquid crystal display (LCD), plasma, electroluminescence (EL), or other display technologies. The input device 100 and the display screen may share physical elements. For example, some embodiments may use some of the same electrical components to display and sense. As another example, the display screen may be operated in part or in whole by the processing system 110 .

Although many embodiments of the invention are described in the context of a fully functional device, it should be understood that the mechanisms of the invention may be distributed in various forms as a program product (eg, software). For example, the mechanisms of the present invention may be implemented on information bearing media readable by electronic processors (eg, non-transitory computer-readable and/or rewritable/writable information carrying media readable by processing system 110 ). ) may be implemented and distributed as a software program on Moreover, embodiments of the present invention apply equally regardless of the particular type of medium used to effect the distribution. Examples of non-transitory electronically readable media include various disks, memory sticks, memory cards, memory modules, and the like. Electronically readable media may be based on flash, optical, magnetic, hologram, or any other storage technology.

2 is an input device 200 modulating reference voltage rails for performing capacitive sensing, in accordance with one embodiment described herein. The input device 200 includes a power source 202 , a host 204 , a processing system 110 , a backlight 232 , and a display/sense panel 234 . _{In one embodiment, the power supply 202 connects at least two reference voltages, V DD} and V _GND , that provide power to the processing system 110 , the backlight 232 , and the display/sense panel 234 . It is a DC power source that outputs. The power source 202 may be a battery or a power converter plugged to an external power source (eg, an AC or DC electrical grid). As used herein, the low reference voltage (ie, V _GND ) is also referred to as chassis ground 208 to indicate that it is the reference voltage for the input device 200 . In contrast, other power domains in input device 200 may include local ground references (eg, local ground 216 ), which may be the same voltage as chassis ground 208 or a different voltage. For example, as described below, in some time periods, local ground 216 may be the same voltage as chassis ground 208 , but at other time periods it is modulated by being induced with different voltages.

In one embodiment, the host 204 is the host 204 of the input device 200 that performs any number of functions, such as making calls, transmitting data wirelessly, executing an operating system or applications, etc. It represents a general system. Host 204 includes a display source 206 that provides updated data frames to processing system 110 . For example, the display source 206 may be a graphics processing unit (GPU) that transmits pixel or frame data to the processing system 110 to update a display on the display/sensing panel 234 . To provide updated display data, the display source 206 is coupled to the processing system 110 via a high-speed link 244 that may transmit data at a rate greater than or equal to 1 Gbit per second at the full frame rate. ring is For example, display source 206 may communicate display data over high-speed link 244 using ^{DisplayPort™ (eg, eDP) or MIPI® display interfaces.} This interface may include a single pair (eg, differential) or multi-wire physical connections - eg, 3-wire signaling, multiple links by shared clock, embedded clock, 3-level signaling, etc.) .

The processing system 110 includes switches 210 , 212 , a timing controller 220 , and a power management controller 230 . Switches 210 , 212 selectively couple reference voltage rails 211A, 211B to power supply 202 . Using the control signal 218 , the timing controller 220 can electrically connect and short the reference voltage rails 211 to the power supply 202 by opening and closing the switches 210 , 212 . Although shown as a resistive connection, in other embodiments, the reference voltage rails 211 may be capacitively or inductively coupled to the power supply 202 . In any case, the switches 210 , 212 may be used to short the reference voltage rails 211 from the power supply 202 while the modulating signal 228 may be used to modulate the voltage rails.

When switches 210 , 212 are closed, power supply 202 charges bypass capacitor 214 . When switches 210 , 212 are open, the charge stored on bypass capacitor 214 is transferred to various components in power input device 200 (eg, power management controller 230 , backlight 232 , or It can be used to power the reference voltage rails 211 which are then used to power the panel 234 . In one embodiment, timing controller 220 operates switches 210 , 212 using control signal 218 to maintain a substantially constant, average voltage across capacitor 214 and rails 211 . It can also be opened and closed periodically. Alternatively, a separate control element (eg, a flyback inductor) may control the voltage across capacitor 214 , while timing controller 220 uses signal 228 to control reference voltage rails 211 . ) is modulated.

The timing controller 220 includes a sensor module 222 , a display module 224 , and a reference voltage modulator 226 . The sensor module 222 is coupled to a display/sensing panel 234 , and more specifically, to sensor electrodes 242 in the panel 234 , either directly or via a modulating signal 228 . . Using the sensor electrodes 242 , the sensor module 222 performs capacitive sensing in the sensing area 120 shown in FIG. 1 , which may include sensor electrodes 242 . As described above, sensor module 222 may use self-capacitance, mutual capacitance, or a combination of both, to identify a particular location in sensing area 120 to which an input object is touching or hovering over. have.

Display module 224 includes display circuitry 236 (eg, source drivers and gate select logic) and display electrodes 240 (eg, source electrodes, gate electrodes) to update the display in panel 234 . , common electrodes). For example, based on display data received from the display source 206 , the display module 224 iterates through rows of the display using the gate electrodes and uses the source electrodes at the selected row. Update each of the display pixels. As such, the display module 224 can receive updated display frames from the host 204 and update (or refresh) individual pixels in the display/sensing panel 234 accordingly.

The reference voltage modulator 226 outputs a modulating signal 228 that modulates the reference voltage rails 211 . In one embodiment, the reference voltage modulator 226 only modulates the voltage rails 211 when the rails 211 are shorted from the power supply 202 (ie, when the switches 210 , 212 are open). do. Doing so causes the modulating signal 228 to modulate the reference voltage rails 211 with respect to the power supply 202 outputs - ie, V _DD and V _GND. If the power supply 202 is not electrically shorted when the reference voltage rails 211 are modulated, then V _DD and V _GND are another configuration in the input device 200 depending on the power supplied by the power supply 202 . The elements may be shorted by the modulating signal 228 which may cause them to behave unpredictably or improperly. For example, host 204 (or other components in input device 200 , not shown) may also use power source 202 to power its components. The host 204 may be designed to operate with unmodulated power sources, so that unless the modulated signal 228 is electrically isolated from the power source 202 , the signal 228 will negatively affect the host 204 . may affect

In one embodiment, the modulating signal 228 modulates the reference voltage rails by increasing or decreasing the voltages on these rails in a separately quantified or periodic manner. In one example, modulating signal 228 causes the same or similar voltage change on both voltage rails 211A and 211B such that the voltage difference between rails 211 remains substantially constant. For example, if V _DD is 4V and V _GND is 0V, the modulating signal is applied to both rails such that voltage rail 211A varies between 5V and 3V but voltage rail 211B varies between -1V and 1V. You can also add a 1V voltage swing to the phase. Nevertheless, the voltage difference (ie, 4V) between the rails 211 remains the same. Moreover, the modulated signal 228 may be a periodic signal (eg, a sinusoidal or square wave), or a non-periodic signal for which modulation is not performed using a repetitive signal. In one embodiment, the capacitive sensing measurement is demodulated in a manner that matches the modulating waveform of the modulating signal 228 .

By modulating the reference voltage rails 211 with respect to chassis ground, from the perspective of the processing system 110, it appears as if the outside world and input objects coupled to the chassis have the voltage signals being modulated. That is, for a powered system in processing system 110 , its voltage is stable and not coupled to any input object closest to panel 234 and modulated reference voltage rails 211 . The rest of the world, including the other components in the input device 200 that is not, appears to be modulating. One advantage of modulating the reference voltage rails 211 is that all components coupled to the rails 211 are modulated by the modulating signal 228 . Thus, a separate modulated signal need not be driven on the display electrodes 240 , the display circuitry 236 , or the power management controller 230 to protect these electrodes from interfering with capacitive sensing. In other words, the voltage difference between the electrodes used to perform capacitive sensing and the various components in the display panel 234 does not change. Thus, although the electrodes and components in panel 234 are capacitively coupled, this coupling capacitance affects the resulting signal generated on the electrodes. Moreover, standard components may be used - ie, the display circuit 236 and power management controller 230 do not need to be modified to perform guarding.

A power management controller 230 (eg, one or more power management integrated circuits (PMICs)) feeds the display circuitry 236 and the backlight 232 in the display/sensing panel 234 via panel power sources 231 . Several voltages are provided for The power management controller 230 may include a plurality of different power sources that supply various voltages (eg, TFT gate voltages V _GH , VHL , source voltages, VCOM, etc.). To generate the various voltages, the power supplies use inductive boost circuits or capacitive charge pumps to convert the DC voltage provided by the reference voltage rails 211 by circuitry in the backlight 232 or panel 234 . They may be switched power supplies, which change to the desired DC voltage. Power supplies may also include buck circuits that efficiently feed low voltage digital circuits, such as gigabit serial links.

In one embodiment, the reference voltage modulator 226 may modulate the voltage rails 211 when the input device 200 is in a low-power state. In a mobile device, such as a smartphone with an LCD display, most of the power consumed by the display system is consumed by the backlight 232 , the display module 224 , and the display circuitry 236 . In one example, backlight 232, when on, draws 1-3 W, while display module 224 and display circuitry 236 draws 0.5-1 W. In contrast, the sensor module 222 may draw 50-150 mW when performing capacitive sensing. Accordingly, power consumption can be greatly reduced if both the backlight 232 and the display module 224 are deactivated when in a low power state. In one embodiment, the backlight 232 and display module 224 are not powered while the reference voltage rails 211 are being modulated.

However, when the sensor and display modules 222 , 224 are located on the same integrated circuit, the display control signals 233 are used to deactivate the display module 224 and the sensor module 222 and the sensor control signal It may still be impossible to perform capacitive sensing using s 235 . In this example, the input device is a capacitive input device performed by sensor module 222 to determine when to wake up from a low-power state (ie, to determine when a user's finger approaches panel 234 ). Relying on sensing, the display module 224 must also be active, meaning that the input device 200 does not benefit from the power savings of disabling the display module 224 . In contrast, the input device 200 shown in FIG. 2 can perform capacitive sensing without powering the disconnected sensor module 222 when it is in a low power state, and thus the sensor module 222 and the display It can benefit from the power savings that can disable both module 224 . Accordingly, in the low-power state, the sensor module 222 , the display module 224 , the power management controller 230 , the backlight 232 , and the display sensing circuit 236 may be deactivated, respectively.

To perform capacitive sensing in a low-power state when the sensor module 222 is deactivated, in one embodiment, the reference voltage modulator 226 causes the display to modulate at least one of the voltage rails 211 . and circuitry for capturing signals - ie, result signals - from the sensor electrodes 240 , 242 . To do this, the reference voltage modulator 266 includes a separate receiver (not shown in FIG. 2 ) that measures the resulting signals. In addition, the reference voltage modulator 266 may have a filter (analog or digital) and other circuitry, such as an analog-to-digital converter (ADC) for sampling the resulting signals. Based on measuring changes in the coupling capacitance 246 between the input object 140 and the display/sensing panel 234 , the input device 200 determines that of the input object proximate to or in contact with the panel 234 . Proximity can be detected. In one embodiment, the resulting signals are simultaneously acquired from both the display electrodes 240 and the sensor electrodes 242 . Display and sensor electrodes 240 , 242 may be coupled to reference voltage rails 211 by panel 234 . For example, display and sensor electrodes 240 , 242 provide power for display updating (eg, gate line voltage, Vcom voltage, source voltage) and power for capacitive sensing (eg, individual sensor electrodes 242 ). ) to a power management controller 230 that provides voltages for powering receivers coupled to . In turn, the power management controller 230 receives its power via the reference voltage rails 211 . Thus, the display and sensor electrodes 240 , 242 (as well as other components in panel 234 ) have a common electrical node with reference voltage modulator 226 (ie, modulating signal 228 is a voltage rail the same electrical node that couples to 211B). Thus, when modulating the reference voltages 211 , it modulates the power supplies in the power management controller 230 , which in turn modulates the various components in the panel 234 - such as the display and sensor electrodes 240 242) - making the input device 200 measurable of user inputs.

Since a reference voltage modulator 226 is also coupled to this common node, the modulator 226 will simultaneously capture the resulting signals from the display and sensor electrodes 240 , 242 when modulating the reference voltage rails 211 . may be In other words, the reference voltage modulator 226 acquires the combined result signals from all coupled electrodes in parallel, rather than individually capturing the result signals at different time periods from the various electrodes in the panel 234 . Needs to be. By simultaneously capturing the resulting signals, panel 234 may be considered as a single large capacitive pixel or electrode. As the input object approaches any portion or location in the panel 234 , the display and sensor electrodes 240 , 242 at that portion increase in capacitance (eg, self-capacitance) caused by the proximity of the input object. Resulting signals are generated indicative of a change in . Thus, in one embodiment, by evaluating the resulting signals captured by the reference voltage modulator 226 , the input device 200 can determine whether the input object is closest to the panel 234 . However, because the panel is one capacitive electrode (instead of a plurality of separate capacitive electrodes or pixels), the device 200 identifies a particular portion or location in the panel 234 where the input object is located. You may not be able to

In one embodiment, instead of using both the display and sensor electrodes 240 , 242 to perform capacitive sensing when modulating the reference voltage rails 211 , the reference voltage modulator 226 only uses the display electrodes 240 . ) or just the resulting signals from the sensor electrodes 242 . As long as the electrodes coupled to the reference voltage modulator cover substantially the entire area of the panel 234 , the input device 200 can detect the input object regardless of the particular location of the object in the panel 234 . .

Once an input object is detected, the input device 200 may switch from a low power state to an active state in which modulated signals are received during a display update time. For example, the input device 200 may activate the sensor module 222 to perform a different capacitive sensing technique. Unlike capacitive sensing, which is performed using reference voltage modulator 226 , this capacitive sensing technique may logically partition the sensing area of panel 234 into a plurality of capacitive pixels. By determining which capacitive pixel (or pixels) has an associated capacitance that is changed by the input object, the input device can determine a particular location or area of the panel 234 that the input object is touching or hovering over. can As noted above, the sensor module 222 may use self-capacitance sensing, mutual capacitive sensing, or some combination thereof to identify the location of the input object in the sensing area.

In one embodiment, the reference voltage rails 211 are always (eg, inductively or capacitively) isolated from the power supply 202 , thus selectively shorting the power supply 202 before being modulated as described above. need to be Instead, processing system 110 and display/sensing panel 234 are separate, separate power sources (eg, inductively coupled to power) coupled to reference voltage rails 211 that only feed these components. separate batteries or charged capacitors). As such, the reference voltage modulator 226 ensures that modulating the voltage rails 211 does not adversely affect other components in the input device 200 where level translation or isolation in communication interfaces is important, for example. Without the need to guarantee, these voltage rails 211 can be modulated for capacitive sensing.

Components in processing system 110 may be arranged in many different configurations on one or more integrated circuits (chips). In one embodiment, the sensor module 222 , the display module 224 , and the reference voltage modulator 226 may be disposed on the same integrated circuit. In one embodiment, the sensor module 222 may be disposed on a different integrated circuit than the reference voltage modulator 226 . In another embodiment, the sensor module 222 , the display module 224 , and the reference voltage modulator 226 may be disposed on three separate integrated circuits. In another embodiment, the sensor module 222 and the reference voltage modulator 226 are disposed on the same integrated circuit, but the display module 224 is disposed on a separate integrated circuit. Moreover, in one embodiment, the display module is disposed on one integrated circuit, but the sensor module 222 and at least a portion of the display circuit 236 (eg, source driver, mux, or TFT gate driver) are disposed on a second integrated circuit. disposed on the circuit, and the reference voltage modulator 226 is disposed on the third integrated circuit.

In one embodiment, the processing system 110 includes an integrated circuit including a power management controller 230 , a timing controller 220 , and a high-speed link 244 for coupling to a host 204 . The integrated circuit may also include receivers and sources drivers for performing display updating and capacitive sensing. Moreover, instead of being located on different substrates, the integrated circuit may be disposed on the same substrate supporting the display/sensing panel 234 . The common substrate may include traces that couple the integrated circuit to the display and sensor electrodes 240 , 242 .

Moreover, in some displays (eg, LED or OLED), a backlight may not be required. Nevertheless, the reference voltage rail modulation techniques described above may be used to perform capacitive sensing.

3 is an input device 300 modulating reference voltage rails for performing capacitive sensing, in accordance with one embodiment described herein. The input device 300 includes a voltage regulator 315 for controlling and maintaining _{rail voltages V DD} and V _GND provided by a power source (not shown). In an embodiment, the voltage regulator 315 may be replaced with a battery and/or the power controller 230 may separate the modulated power domain 310 from the unmodulated power domain 305 . Similar to input device 200 , device 300 includes a timing controller 220 that outputs control signals 330A, 330B that control switches 210 , 212 (ie, transistors). . As above, before modulating the reference voltage rails 211 (V _{DD _MOD} and V GND_MOD ), the timing controller 220 opens the switches 210 , 212 to _{connect the reference voltage rails 211 to the reference voltage.} Electrically short from V _DD and V _{GND .}

When the reference voltage rails 211 are _{electrically isolated from the reference voltages V DD} and V _GND , the input device 300 operates in two separate power domains - an unmodulated power domain 305 and a modulated power domain. It has a power domain 310 . The unmodulated power domain 305 includes components to the left of the dashed line 301 , while the modulated power domain 310 includes components to the right of the dashed line 301 . Components in unmodulated power domain 305 operate using unmodulated, DC reference voltages V _DD and V _GND , while components in modulated power domain 310 operate on reference voltage rails ( _{211) and operates} using the modulated reference voltages V _DD _MOD and V _{GND _ MOD.} As above, the reference voltage rails 211 are modulated by a modulating signal 228 generated by a reference voltage modulator 226 . For example, the modulated signal 228 may be driven to a voltage less than _{V DD} /2, which may be the input voltage to the receiver 325 . In one embodiment, the reference voltage modulator may be located in the power management controller 230 or the source driver instead of on the timing controller 220 as shown.

As shown, the timing controller 220 includes a high-speed data interface 320 (eg, an eDP or MIPI standard interface) in the unmodulated power domain 305 . As such, at least one of the modules in the timing controller 220 is in the unmodulated power domain 305 , while at least one of the modules is in the modulated power domain 310 . Although not shown, the sensor module and display module may also be in the modulated power domain 310 . Moreover, although the reference voltage modulator 226 is shown in the modulated power domain 310 , the modulator 226 will also generate a modulating signal 228 to chassis ground in the unmodulated power domain 305 . may be considered to be in the unmodulated power domain 305 . The communication module may further provide modulation signals 228 and power domain separation controls 330 .

By placing the high-speed data interface 320 in the unmodulated power domain 305 , the timing controller 220 can communicate directly to the host 204 . That is, since the data interface 320 and the host 204 are both in the unmodulated power domain 305 , they may transmit data signals directly. In contrast, if the interface 320 was in the modulated power domain 310 and used its modulated reference voltages to operate, the interface 320 could be removed from the host 204 without substantial increase in cost, power, and design time. It may not be possible to detect and identify the received data signals. Although not shown, the timing controller 220 may include level shifters that allow the high-speed data interface 320 to communicate with other modules within the timing controller 220 . For example, when receiving update display data from the host 204 , the high-speed data interface 320 may use level shifters when transmitting the display data to a display module in the modulated power domain 310 .

In another embodiment, the entire timing controller 220 may be in the modulated power domain 310 . To communicate with the host 204 , a separate communication module may be communicatively coupled between the host 204 and the controller 220 . For example, the communication module may be located on an integrated circuit separate from the timing controller 220 . The communication module may transmit data signals to the timing controller 220 in the modulated power domain 310 and data signals received from the timing controller 220 may be transmitted to the host 204 in the unmodulated power domain 305 . It may include one or more level shifters that allow it to be.

The reference voltage modulator 226 includes a receiver 325 that captures the resulting signals from the display and sensor electrodes at the panel 234 when modulating the reference voltage rails 211 . The receiver 325 may modulate the rails 211 using the same electrical connection used by the modulating signal 228 to also capture the resulting signals. That is, the reference voltage modulator 226 may use the same port to transmit the modulation signal 228 and acquire the resulting signals from the display and sensor electrodes at the display/sense panel 234 . Alternatively, the reference voltage modulator 226 may use the display/sense panel 234 only to receive signals, while the modulated signal 228 may be used by another component (eg, a source driver or power management controller 230 ). )) is supplied to the reference electrode.

At the input device 300 , the power management controller 230 includes a number of power sources 335 that output a number of different DC voltages to the panel 234 via links 340 . To generate the various voltages, the power supplies 335 use inductive boost circuits or capacitive charge pumps to apply the voltages provided by the reference voltage rails 211 (ie, V _{DD _MOD} and V _{GND _MOD ).} ) to the voltages required by the components in panel 234 - eg, V _GH , V _GL , VCOM, etc. In one embodiment, when the reference voltage modulator 226 modulates the reference voltage rails 211 , the power management controller 230 may deactivate the power supplies 335 (eg, the input device is low-power state). However, when the input device 300 performs display updating or capacitive sensing when the voltage rails 211 are not being modulated, the power supplies 335 are active to provide DC power to the panel 234 . may be

4 is an input device 400 modulating reference voltage rails for performing capacitive sensing, in accordance with one embodiment described herein. In contrast to the input device 300 in FIG. 3 , the input device 400 includes a reference voltage modulator 410 that does not capture the resulting signals when modulating at least one of the voltage rails 211 . As shown, the reference voltage modulator 410 includes a transmitter 415 for generating a modulated signal 228 and is disposed in the power management controller 230 . However, the receiver 325 is not located in the modulator 410 . Instead, the receiver 325 is located external to the modulator 410 in the timing controller 220 (but may also be located elsewhere in the processing system 110 , such as on a separate integrated circuit). ). Thus, in this embodiment, the electrical path used to acquire the resulting signals is different from the electrical path used to drive the modulated signal 228 . Also, as shown herein, when capacitive signals are provided, for example, by capacitor 405 , a direct resistive connection between receiver 325 and modulated rail 211 is not required. Accordingly, FIGS. 3 and 4 illustrate that the resulting signals may be captured via one of the voltage rails 211 . In one embodiment, the receiver 325 is in the lowest impedance path for the modulating signal 228 to couple to electrodes in the display/sense panel 234 . In one embodiment, the transmitter 415 also drives the modulated signal 228 on the reference voltage rails 211 using a connection of the power management controller to the reference voltage rails 211 .

As shown, capacitor 405 is located in the electrical path coupling receiver 325 to voltage rail 211A, although capacitor 405 is optional. The receiver 325 determines when the input object is closest to the display/sensing panel 234 , the charge ( Alternatively, voltage) may be measured.

5 is a circuit diagram of the reference voltage modulator 226 shown in FIG. 3 , in accordance with one embodiment described herein. Modulator 226 includes an integrator 500 that outputs a modulated signal 228 . Moreover, since integrator 500 functions as a receiver, the modulator also captures the resulting signals from the display and sensor electrodes at the output of integrator 500 . One input of the amplifier in integrator 500 is coupled to a signal generator 515 that outputs a modulated signal that integrator 500 then uses to drive modulated signal 228 via feedback from the sensor output. For example, an integration function may be performed by capacitor 525 , eg, in a low pass filter, such that offset drift is compensated for, eg, by a reset switch or optional resistor 520 .

Having generally described the function of reference voltage modulator 226 , integrator 500 is the charge that the amplifier must provide through capacitor 525 in order to modulate display and sensor electrodes in the display panel by modulating the reference voltage rails. Measure the amount of (using the resulting signals). Although not shown, the receiver 325 may be coupled to a filter and sampling circuit - eg, an ADC - to process the resulting signals. Moreover, FIG. 5 only illustrates one example of a suitable structure for a reference voltage modulator 226 and a receiver. Generally speaking, modulator 226 may be any kind of transmitter circuit that drives modulated signal 228 and any kind of analog circuit that receives a measurement of capacitance or a change in capacitance within a circuit. Alternatively, as shown in FIG. 4 , the receiver 325 may be separated from the reference voltage modulator. For example, the reference voltage modulator may include only a modulator that drives the modulated signal 228 , while the receiver may be located elsewhere in the processing system (eg, on a separate integrated circuit, power management controller, etc.). .

6 is a flow diagram illustrating a method 600 of waking up an input device from a low power state using modulated reference voltage rails, in accordance with one embodiment described herein. At block 605 , the timing controller electrically isolates the reference voltage rails from the power source by selectively shorting the rails or by using an indirect coupling method such as inductive coupling. For example, the power source may be a battery that provides DC voltage outputs (eg, V _DD and V _{GND ) to power various components in the input device.} Since the function of some components may be negatively affected by modulating the outputs of the power source, the timing controller electrically isolates the reference voltage rails from the battery. Alternatively, when performing capacitive sensing that does not modulate the reference voltage rails or update the display of the input device, the timing controller may allow the reference voltage rails to be electrically connected to a power source. During these time periods, the power source may drive unmodulated, DC voltages directly on the voltage rails. In some embodiments, power may be provided consistently even while the voltage rails are modulated, floated, or held at a constant voltage relative to chassis ground (eg, voltage rails are is inductively coupled to).

At block 610 , the input device configures the input device in a low-power state. In one embodiment, the input device may determine to enter a low-power state after identifying a period of inactivity if the user has failed to interact with the input device. For example, if the user does not use a function of the input device within a predefined period of time (eg, does not touch the sensing area, make a call, tap a button, etc.), the input device It can also switch to a power state. In another example, the user may instruct the input device to enter a low-power state by making a predefined gesture in the sensing area or activating a particular button.

In the low-power state, the input device saves power by disabling one or more components of the input device (eg, power supplies, PMICs, backlight, etc.). As shown in FIG. 2 , since the reference voltage modulator 226 captures the resulting signals for performing capacitive sensing, the sensor module 222 and the corresponding capacitive sensing circuit in the display/sensing panel 234 ( ) may be disabled. Similarly, if the low-power state does not require displaying an image, the display module 224 and the display circuitry 236 can be deactivated. Moreover, the input device can effectively deactivate components in the display/sensing panel 234 by deactivating the power management controller 230 that stops supplying power to the panel 234 . Also, deactivating the power management controller 230 may turn off the backlight 232 . In one embodiment, the low-power state indicates that at least all powered components in the sensor module 222 , the display module 224 , the power management controller 230 , and the display/sensing panel 234 are inactive. it means. However, in other embodiments, some of these components may remain powered in a low-power state.

At block 615 , the reference voltage modulator modulates the reference voltage rails with respect to the chassis ground of the input device. At block 620 , while modulating the voltage rails, the receiver simultaneously acquires the resulting signals from the display and sensor electrodes at the panel. To do this, the receiver may be coupled to a common electrical node - eg a supply voltage - to the display and sensor electrodes in the panel. Using the resulting signals, the receiver (or other component in the input device) determines a capacitance or change in capacitance corresponding to the display and sensor electrodes. By comparing this capacitance measurement to one or more thresholds, the input device can detect when the input object is proximate to the panel.

Although the receiver may be integrated into a reference voltage modulator that generates a signal for modulating the reference voltage rails, the receiver may be located somewhere on the processing system that allows it to be coupled to a display electrode and/or a sensor electrode in the panel. For example, the receiver may be located together on a separate integrated circuit or at a different location in the timing controller than the reference voltage modulator. Moreover, the receiver may be located on the power management controller. In one embodiment, regardless of its location, the receiver is coupled to one (or both) of the reference voltage rails being modulated.

At block 625 , the input device determines whether the input object is proximate to the display/sensing panel by evaluating the resulting signals captured at block 620 . If the input object is not proximate to the input device (eg, not touching the panel or hovering over the panel), the method 600 proceeds to 620 where the receiver again acquires the resulting signals while the voltage rails are modulated. For example, when in a low-power state, the input device may modulate the reference voltage rails at intervals to capture the resulting signal until an input object is detected. The duty cycle of these low power cycles is low - eg greater than 10 ms - but fast enough to track changes in the environment - eg faster than 100 seconds.

If an input object is detected at block 625 , the method 600 proceeds to block 630 , where the input device switches to an active state. In one embodiment, upon switching from the low-power state to the active state, at least one component that has been deactivated or powered down to the low-power state is activated. For example, the input device may activate a sensor module and capacitive sensing circuitry on the panel to perform capacitive sensing, thereby determining a particular location of the input object on the panel. Alternatively or additionally, the input device may activate the display module and display circuitry (and backlight) such that an image is displayed. In some low power modes, modulation of the reference voltage is not required when interference is being detected or when detecting the presence of an active pen. For example, when performing interference or active pen detection, duty cycles may be slow (eg, less than 100 ms).

In one embodiment, when in the active state, some of the components in the input device may still be inactive. For example, at block 630 , the input device may determine the location of the input object in the panel by activating only the components necessary to perform capacitive sensing. Display components (eg, backlight or display module) may still be deactivated. For example, when in the active state, the input device may use the sensor module to ensure that the input object detected at block 625 was not a false positive prior to activating the display components. In another example, the reference voltage modulator can detect when the input object approaches (eg, hovers over) the display, which then causes the input device to switch to an active state at block 630 . However, prior to activating the display components, the input device may use the sensor module to determine whether the user has performed a predefined wake-up gesture using the input object. Thus, although not shown in method 600, the active state draws more power than the low-power state, but draws less power than the fully active state, for example, in which both display updating and capacitive sensing are performed. may be in an intermediate power state.

7 illustrates an exemplary electrode arrangement for performing capacitive sensing, in accordance with one embodiment described herein. 7 illustrates a portion of an example sensor electrode pattern that includes sensor electrodes 710 configured to sense in a sensing area associated with the pattern, in accordance with some embodiments. For clarity of illustration and description, FIG. 7 shows a pattern of simple rectangles, and various components are not shown. Also, as illustrated, the sensor electrodes 710 include a first plurality of sensor electrodes 720 , and a second plurality of sensor electrodes 730 .

In one embodiment, the sensor electrodes 710 may be arranged on different sides of the same substrate. For example, each of the first and second plurality of sensor electrode(s) 720 , 730 may be disposed on one of the surfaces of the substrate. In other embodiments, the sensor electrodes 710 may be arranged on different substrates. For example, each of the first and second plurality of sensor electrode(s) 720 , 730 may be disposed on surfaces of separate substrates that may be attached together. In another embodiment, the sensor electrodes 710 are all located on the same side or surface of a common substrate. In one example, the first plurality of sensor electrodes include jumpers in regions where the first plurality of sensor electrodes intersect the second plurality of sensor electrodes, wherein the jumpers are insulated from the second plurality of sensor electrodes.

The first plurality of sensor electrodes 720 may extend in a first direction, and the second plurality of sensor electrodes 730 may extend in a second direction. The second direction may be similar to or different from the first direction. For example, the second direction may be parallel to, perpendicular to, or diagonal to the first direction. Also, the sensor electrodes 710 may each have the same size or shape, or different sizes and shapes. In an embodiment, the first plurality of sensor electrodes may be larger (larger surface area) than the second plurality of sensor electrodes. In other embodiments, the first plurality and second plurality of sensor electrodes may have a similar size and/or shape. Accordingly, the size and/or shape of one or more of the sensor electrodes 710 may be different from the size and/or shape of another one or more of the sensor electrodes 710 . Nevertheless, each of the sensor electrodes 710 may be formed in any desired shape on their respective substrates.

In other embodiments, one or more of the sensor electrodes 710 are disposed on the same side or surface of a common substrate and are separated from each other in the sensing area. The sensor electrodes 720 may be arranged in a matrix array, where each sensor electrode may be referred to as a matrix sensor electrode. Each sensor electrode of the sensor electrodes 710 in the matrix array may be of substantially similar size and/or shape. In an embodiment, one or more of the sensor electrodes of the matrix array of sensor electrodes 710 may vary in at least one of size and shape. Each sensor electrode of the matrix array may correspond to a pixel of the capacitive image. Also, two or more sensor electrodes of the matrix array may correspond to a pixel of the capacitive image. In various embodiments, each sensor electrode of the matrix array may be coupled to a separate capacitive routing trace of the plurality of capacitive routing traces. In various embodiments, the sensor electrodes 710 include one or more grid electrodes disposed between at least two sensor electrodes of the sensor electrodes 710 . The grid electrode and the at least one sensor electrode may be disposed on a common side of the substrate, on different sides of the common substrate, and/or on different substrates. In one or more embodiments, the sensor electrodes 710 grid electrode(s) may encompass the full voltage electrode of the display device. Although the sensor electrodes 710 are electrically isolated on the substrate, the electrodes may be coupled together outside of the sensing area - eg at the connection area. In one embodiment, the floating electrode may be disposed between the grid electrode and the sensor electrodes. In one particular embodiment, the floating electrode, the grid electrode, and the sensor electrode comprise all of the common electrode of the display device.

The processing system 110 shown in FIG. 1 uses modulated signals (ie, absolute capacitive sensing signals) of the sensor electrodes 710 to determine changes in the absolute capacitance of the sensor electrodes 710 . It may be configured to drive one or more sensor electrodes. In some embodiments, the processing system 110 is configured to drive a transmitter signal onto a first sensor electrode of the sensor electrodes 710 to receive the resulting signal with a second sensor electrode of the sensor electrodes 710 . The transmitter signal(s) and the absolute capacitive sensing signal(s) may be similar in at least one of shape, amplitude, frequency and phase. The processing system 110 may be configured to drive the grid electrode with a shielding signal to drive the grid electrode as a shielding and/or protective electrode. Further, the processing system 110 may configure the grid electrode with a transmitter signal such that capacitive coupling between the grid electrode and one or more sensor electrodes can be determined, or with an absolute capacitive sensing signal such that the absolute capacitance of the grid electrode can be determined It may be configured to drive.

As used herein, a shielding signal refers to a signal having either a constant voltage or a variable voltage signal (protection signal). The guard signal may be substantially similar to a signal in which at least one of amplitude and phase modulates the sensor electrode. Further, in various embodiments, the guard signal may have an amplitude that is greater than or less than the amplitude of the signal modulating the sensor electrode. In some embodiments, the guard signal may have a different phase than the signal modulating the sensor electrode. Electrically floating the electrode can be interpreted as a type of protection by floating, in cases where the second electrode receives the desired protecting waveform through capacitive coupling from the adjacent driven sensor electrode of the input device 100 . have.

As described above, in any of the sensor electrode arrangements described above, the sensor electrodes 710 can be formed on a substrate that is external or internal to the display device. For example, the sensor electrodes 710 may be disposed on an outer surface of a lens in the input device 100 . In other embodiments, the sensor electrodes 710 are disposed between the color filter glass of the display device and the lens of the input device. In other embodiments, at least a portion of the sensor electrodes and/or grid electrode(s) may be disposed such that they are between the thin film transistor substrate (TFT substrate) and the color filter glass of the display device 160 . In one embodiment, the first plurality of sensor electrodes are disposed between the TFT substrate and the color filter glass of the display device 160 , and the second plurality of sensor electrodes are disposed between the color filter glass and the lens of the input device 100 . do. In yet other embodiments, all of the sensor electrodes 710 are disposed between the TFT substrate and the color filter glass of the display device, wherein the sensor electrodes are disposed on the same substrate or on different substrates as described above. it might be

In any of the sensor electrode arrangements described above, the sensor electrodes 710 can be used for transcapacitance sensing or absolute capacitive sensing by dividing the sensor electrodes 710 into a transmitter electrode and a receiver electrode, or It may be operated by input device 100 for some mixture of both. Further, one or more of the sensor electrodes 710 or display electrodes (eg, source, gate, or reference (Vcom) electrodes) may be used to perform shielding.

Regions of localized capacitive coupling between the first plurality of sensor electrodes 720 and the second plurality of sensor electrodes 730 form capacitive pixels. The capacitive coupling between the first plurality of sensor electrodes 720 and the second plurality of sensor electrodes 730 is performed between the first plurality of sensor electrodes 720 and the second plurality of sensor electrodes 730 and It varies according to the proximity and motion of the input objects in the associated sensing area. Further, regions of localized capacitance between the first plurality of sensor electrodes 720 and the input object and/or the second plurality of sensor electrodes 730 and the input object also form capacitive pixels. As such, the absolute capacitance of the first plurality of sensor electrodes 720 and/or the second plurality of sensor electrodes is a sensing associated with the first plurality of sensor electrodes 720 and the second plurality of sensor electrodes 730 . It changes according to the proximity and motion of the input objects in the area.

In some embodiments, the sensor pattern is “scanned” to determine these capacitive couplings. That is, in one embodiment, the first plurality of sensor electrodes 720 are driven, for example, by the sensor module 222 in FIG. 2 to transmit transmitter signals. Transmitters may be operated such that one transmitter electrode transmits at a time or multiple transmitter electrodes transmit simultaneously. When multiple transmitter electrodes transmit simultaneously, these multiple transmitter electrodes may transmit the same transmitter signal and effectively create a larger transmitter electrode, or these multiple transmitter electrodes may transmit different transmitter signals. For example, multiple transmitter electrodes may transmit different transmitter signals according to one or more coding schemes enabling their combined effects on result signals of a second plurality of sensors.

The receiver sensor electrodes may be operated singly or in multiples to capture the resulting signals. The resulting signals may be used to determine measurements of capacitive couplings in the capacitive pixels. The receive electrodes may also be scaled (eg, by a multiplexer) with a reduced number of capacitive measurement inputs to receive signals.

In other embodiments, scanning the sensor pattern comprises driving one or more sensor electrodes of the first and/or second plurality of sensor electrodes with absolute sense signals while receiving resultant signals with the one or more sensor electrodes. do. The sensor electrodes may be driven and received such that one second electrode is driven and received at a time, or a plurality of sensor electrodes are driven and received at the same time. The resulting signals may be used to determine measurements of capacitive couplings at the capacitive pixels or along each sensor electrode.

The set of measurements from the capacitive pixels form a “capacitive frame”. The capacitive frame may include a “capacitive image” representing capacitive couplings in pixels and/or a “capacitive profile” representing capacitive couplings along each sensor electrode. Multiple capacitive frames may be captured over multiple time periods used to derive information regarding input to the sensing region, and differences therebetween. For example, successive capacitive frames captured over successive time periods may be used to track the motion(s) of one or more input objects entering, leaving, and within the sensing region.

The background capacitance of the sensor device is a capacitive frame that is not associated with any input object in the sensing area. Background capacitance varies with environment and operating conditions, and may be estimated in several ways. For example, some embodiments take “baseline frames” when no input object is determined to be in the sensing region and use those baseline frames as estimates of their background capacitances.

Capacitive frames can be adjusted to the background capacitance of the sensor device for more efficient processing. Some embodiments achieve this by “baselining” the measurements of capacitive couplings in the capacitive pixels to generate “baselined capacitive frames”. That is, some embodiments compare measurements forming the capacitance frames to appropriate “baseline values” of “baseline frames” and determine changes from that baseline image. These baseline images may also be used in the low power modes described above for profile sensing or in active modulated active pens.

Interference and active pen detection

8 is an input device 800 for detecting a noise (ie, interference) signal or communication signal from an active input object, in accordance with one embodiment described herein. Input device 800 has a structure similar to input device 300 in FIG. 3 , and in fact, individual input devices may be capable of performing the reference voltage modulation described in FIG. 3 as well as interference and active input object detection. . However, in other embodiments, the input device may be configured to perform only one of these functions. In one embodiment, the active object is actively modulated with respect to chassis ground, with a known or configurable frequency, duty cycle, timed encoding, or the like.

The timing controller 805 in the input device 800 includes a central receiver 810 coupled to a low reference voltage rail 211B. Similar to receiver 325 in FIG. 3 , central receiver 810 is coupled with the display and sensor electrodes in display/sensing panel 234 via power sources in power management controller 230 . In one embodiment, the voltage rails 211 may also be coupled directly to the panel 234 , but indirectly to other components in the panel 234 through power sources in the controller 230 . As such, the central receiver 810 may be directly coupled to some components in the display/sensing panel 234 . In either case, all electrodes (and possibly other components in panel 234 ) are coupled to a common electrical node with central receiver 810 , so panel 234 functions as a single capacitive pixel. can do.

However, the central receiver 810 need not be coupled to both the display and sensor electrodes in the panel 234 but may instead be coupled only to the display electrodes or only to the sensor electrodes. However, by limiting the number of electrodes coupled (eg, to a single source driver) with the central receiver 810 , the size of the sensing area in the panel 234 (or the sensitivity of the capacitive pixels), even across the panel It may be reduced so that a small portion of the panel is measured even though the electrodes are scanned across.

Unlike the embodiment shown in FIG. 3 , the input device 800 modulates the reference voltage rails 211 to detect an interference or communication signal from an active input object (eg, a stylus or pen with a wireless transmitter). I never do that. Instead, the rails 211 may maintain unmodulated, DC voltages with respect to chassis ground. However, similar to FIG. 3 , the timing controller 805 may electrically short the voltage rails 211 from the _{power source voltages V DD} and V _{GND before detecting an interference or communication signal.} Using signals 330A, 330B, timing controller 805 shorts voltage rails 211 from the power source voltages by opening switches 210 and 212 . Alternatively, the reference voltage rails 211 may be inductively coupled to power source voltages, in which case the rails 211 are always isolated from these voltages.

When a noise source or active input object is in proximity to the electrodes on the panel 234 , the interference signal generated by the noise source or the digital communication signal generated by the input object is the resultant signal that is then captured by the central receiver 810 . sensor electrodes in panel 234 and on the display. By processing the resulting signals, the input device 800 can identify and compensate for the interfering signal. Some non-limiting examples of actions that input device 800 may take to compensate for interfering signals are switching different sensing frequencies, limiting the number of input objects to be reported, proximity detection or glove detection and stopping using some features like, increasing the number of frames averaged before detecting the touch location, ignoring any new input objects detected when interference occurs, sensor indicating that the input object has left the sensing area preventing the module from reporting, or changing the capacitive frame rate.

If the resulting signals are caused by an active input object, the input device 800 can decode the digital signal and perform a corresponding action. When the active input object transmits a communication signal using a wireless transmitter, the display and sensor electrodes on panel 234 serve as antennas for receiving the signal. Thus, neither the noise source nor the active input object need be in contact with the panel 234 to generate the resulting signals on the electrodes in the panel 234 - for example, the input object may be hovering over the panel 234. have.

Moreover, the display/sensing panel 234 includes a number of local receivers 815 , each of which may be coupled to a respective sensor electrode in the panel 234 . When performing capacitive sensing, local receivers 815 measure the resulting signals from individual sensor electrodes that can be used to identify a particular location on the panel 234 that is in contact with or hovering over the input object. . In one embodiment, local receivers 815 may perform a function similar to receiver 810 - ie, both receivers 810, 815 measure capacitance. In one embodiment, instead of using the central receiver 810 to detect an interfering signal or communication signal from an active input object, the input device combines all resultant signals received by local receivers 815 on panel 234 . can do. However, detecting interfering signals and communication signals may require more power, or more complex or expensive circuitry than the circuitry required to perform capacitive sensing using only the receiver 810 . As such, if the local receivers 815 have been used to detect interference or communication signals, they may be more expensive than the local receivers 815 used to perform capacitive sensing using only the modulated signal. Thus, instead of having multiple expensive receivers 815 , the input device 800 may use only one central receiver 810 that can be used to detect interference and communication signals. The central receiver 810 may have a larger dynamic range, a faster ADC, and/or more noise immunity than the local receivers 815 such that the local receivers 815 are more expensive to manufacture than the central receiver 810 . there may be Thus, in one embodiment, instead of having tens or hundreds, or expensive, local receivers 815 capable of discriminating interference and communication signals from an active input object, the input device 800 has only one - that is, a central receiver ( 810). Because local receivers 815 may not be used to detect interference or communication signals, they may be more expensive than would otherwise be possible.

In one embodiment, interference or communication signals may be measured while the display is being updated. That is, the timing controller may include a display module that is actively updating pixels in the display/sensing panel 234 while the central receiver 810 is capturing signals as described above. Although the power management controller 230 and panel 234 are _{selectively shorted (or disconnected) from the power source voltages V DD} and V _GND , the charge stored in the bypass capacitor 214 is transferred to the voltage rails 211 . can be used to power the display to enable display updates. When the charge across the capacitor 214 drops to a threshold, the timing controller 805 connects the voltage rails 211 and the capacitor back to the power source voltages V _DD and V _GND or otherwise reduces the power source voltages to the rail. may be coupled (eg, inductively coupled) to s 211 . Moreover, the central receiver 810 may stop measuring interference or communication signals when the _{voltage rails 211 are ohmically coupled to the power source voltages V DD} and V _{GND .} However, the capacitor 214 (eg, 15-150 microfarads) takes enough time for the central receiver 810 to be able to discern an interfering signal generated by noise or a communication signal provided by an active pen or stylus. During this time, it may store enough charge to power power management controller 230 and panel 234 .

9 is a circuit diagram of a central receiver 810 for acquiring resulting signals to identify a noise or communication signal, in accordance with an embodiment described herein. The central receiver 810 includes an integrator 900 for acquiring the resulting signals from the display and sensor electrodes, similar to the integrator 500 . The integrator 900 may be implemented as a low pass filter with a feedback capacitor 915 and an optional resistor 920 when the feedback signal is measured and controls the reference voltage on one of the rails 211 . As shown, one input of the amplifier in integrator 900 is _{coupled to V GND} (eg, chassis ground or V _DD /2). In one embodiment, the central receiver 810 is the lowest impedance path between the noise source or active pen and chassis ground. As such, the interfering signals generated by the noise source or the resulting signals caused by the communication signal generated by the input object flow through the central receiver 810 and rather than through other components in the input device. , is thus measured by the central receiver 810 . In other words, by selectively shorting or isolating the voltage rails from the power source, the central receiver 810 becomes the lowest impedance path between the noise source and active input object and chassis ground, and thus, the noise source and active input object. The resulting signals generated by <RTI ID=0.0>F</RTI> mainly flow through the central receiver 810 and integrator 900 where the signals can be measured.

Integrator 900 is, however, only one type of circuit suitable for performing the functions of central receiver 810 . Generally speaking, the central receiver 810 may be any analog circuit that measures capacitance. For example, central receiver 810 may include circuitry that measures the accumulated charge or voltage across capacitor 925 , or circuitry that measures capacitance using current flowing through central receiver 810 . .

10 is a flow diagram illustrating a method 1000 for identifying a noise or communication signal using capacitive sensing, in accordance with one embodiment described herein. At block 1005 , the input device disconnects the reference voltage rail from the power source. For example, switches may selectively short the reference voltage rails from the power source or the rails may be permanently disconnected from the power source by inductive coupling. In one embodiment, a capacitor (eg, bypass capacitor 214 shown in FIG. 8 ) is a component in the input device that is powered by reference voltage rails that may be shorted when capacitive sensing signals are received. may be connected between the rails to provide temporary power to the For example, display updating and capacitive sensing may be performed while voltage rails are disconnected from the power supply.

At block 1010 , the central receiver is coupled to chassis ground (through its power sources) and to one or more display electrodes and/or sensor electrodes at the display/sensing panel. Moreover, the central receiver may provide a low impedance path between the electrodes and ground. Thus, when a noise source is capacitively coupled to the electrodes in the panel or when a communication signal from an active input device is received on the electrodes, a current loop is formed that flows through the central receiver.

At block 1015 , the central receiver simultaneously acquires the resulting signals from the display and sensor electrodes. For example, the display electrodes, the sensor electrodes, and the central receiver may be coupled to a common electrical node such that a combination of resultant signals generated on the display and sensor electrodes flows through the receiver and arrives at chassis ground.

In an embodiment, the central receiver may capture the resulting signals when in the low-power state cited above in FIG. 6 when the display and sensor modules are deactivated. During the first time period, the input device may acquire the resulting signals while the reference voltage rails are not modulated to identify an interfering signal or communication signal. During a second period of time, the input device may capture the resulting signals while the reference voltage rails are modulated as described in FIG. 6 . Moreover, if an interfering signal is detected during the first time period, the input device may change the modulated signal used to modulate the voltage rails during the second time period to avoid harmful interference from the noise source. However, as noted above, the method 1000 may also be performed alone or in parallel with updating the display when the input device is in an active or high-power state.

At block 1020 , the input device identifies at least one of an interfering signal and a communication signal from the active input device based on the acquired resulting signals. Once an interfering signal is identified, the input device may compensate for that signal by, for example, switching a modulating signal that is outside the range of the interfering signal when performing capacitive sensing. When a communication signal is received, the input device may process the signal to determine information regarding the active input object. For example, the communication signal may be a current gradient of an input object relative to a display/sensing panel, a particular color or marking to be displayed at a location where the input object contacts the panel, or another object attempting to pair with the input object or input device ( For example, an ID for Bluetooth connection) may be identified. In another example, the communication signal is for switching to a low-power state, waking up from a low-power state, opening a particular application, using an input object to change the shape of markings made on the display, etc. Indicates to the input device that a button on the input object that may correspond to a particular function in the same input device has been pressed by the user.

In an embodiment, when a communication signal is received, the input device may increment the number of detection frames used to detect the input object relative to the number of capacitive frames. Alternatively or additionally, the input device performs a coarse search (sensing using groups of sensor electrodes), and once the position of the input object is detected during the coarse search, then a finer search (local receiver) By performing sensing on each sensor electrode using the s individually), it is also possible to search for the location of the input object in the sensing area.

Mitigate the Effects of Low Ground Mass

11 illustrates various capacitances between an input device and its environment, according to an embodiment described herein. As shown, the system 1100 includes an input device 1105 , an input object 1110 , and a ground 1115 , capacitively coupled. The input device 1105 includes a sensing area 1120 on the display/sensing panel described above for performing capacitive sensing. In one embodiment, by measuring the change in capacitance between the sensing area 1120 and the input object 1110 ( _CT ), the input device 1105 indicates that the input object 1110 is in contact with the sensing area 1120 and or whether to hover over it. In some examples, the input device 1105 may determine a particular location in the sensing area 1120 with which the input object 1110 is interacting.

When performing capacitive sensing, however, the resulting signals measured by the input device 1105 may also be affected by other capacitances in the system 1100 other than _CT. For example, the input object 1110 may be capacitively coupled to the chassis of the input device 1105 indicated by _{C BC .} Further, both the input object 1110 and the chassis of the input device 1105 are generally capacitively coupled to ground 1115 , as _{both are represented by C IG} and C _{BG , respectively.} The capacitances C _BC , C _BG , and C _IG are referred to herein as ground states 1125 . In general, the input device 1105 is unable to control the capacitances in ground states 1125 that change as the environment of the device 1105 changes. _{For example, the capacitance C BC} between the input object 1110 and the chassis changes depending on whether the user is holding the input device 1105 or the device 1105 is lying on a table. Moreover, when the user is standing on Earth or in an aircraft, the capacitance C _IG between the input object 1110 and ground 1115 changes. The input device 1105 may not have any mechanism to measure the position of the input device 1105 and the input object 1110 in its environment, so that the capacitances in ground states 1125 measure _{C T .} may not be able to accurately determine whether it affects the ability of the input device 1105 to

_{Since the capacitance C T} between the sensing area 1120 and the input object 1110 is generally the smallest capacitance shown in FIG. 11 , it is the limiting impedance, so it is the amount of the signal received at the input object 1105 . dominate the However, since the capacitances in ground states 1125 decrease as the position of the input device 1105 or input object 1110 in the environment changes, these capacitances are the input device 1105 monitoring _{CT accurately.} ) may reduce the ability of For example, to the combined capacitance of C _T in series with the ground state of the 1125 have the same value (e.g., 1-10 pF) and C _T, the signal received from the input device due to the C _T is split in half For example, if the input device 1105 is positioned above the user's lap, the capacitance C _BG may be approximately 50 pF, and thus may have little effect on signals measured by the input device 1105 . However, if the input device 1105 is placed on a table in contact with the ground 1115 , the capacitance C _BG may be approximately 5 pF. Since the capacitances C _T and C _BG are now equal _{, the effect on the resulting signals captured by the input device 1105 due to C T} (ie, the capacitance that the input device 1105 is trying to monitor) is is roughly halved. Arrangements in which the capacitance at ground conditions 1125 significantly affects the resulting signals measured by the input device 1105 are referred to herein as low ground mass (LGM) conditions.

If an LGM state is present, the input device 1105 may compare the resulting signals to thresholds used to detect a touch or hover event assuming that the capacitances of the ground states 1125 are large, in which case: The input device 1105 may fail to detect a low capacitive change in a touch/hover event. To accurately detect touch/hover events during LGM state, input device 1105 can adjust thresholds lower independently of LGM or based on host control mode (eg, battery is charging); However, as noted above, it may be difficult or impossible to detect arrangements of input device 1105 , input object 1110 , and ground 115 that result in an LGM condition. Instead, embodiments herein measure the resulting signals at the central receiver representing the overall capacitance of the environment (including those at ground states 1125 ) by modulating the reference voltage rails as described above. This total capacitance is correlated to measurements made at local receivers connected to individual sensor electrodes in sensing area 1120 . In one embodiment, the resulting signals acquired by the local receivers are normalized using the resulting signals acquired by the central receiver, thereby reducing the effect of the capacitances at ground states 1125 on the local capacitance measurements. offset (or mitigate). In another embodiment, the thresholds are adjusted to utilize the estimated LGM based on a central receiver measurement combined with local receiver measurements.

12 is an input device 1200 modulating reference voltage rails for performing capacitive sensing, in accordance with one embodiment described herein. Similar to the input devices shown in FIGS. 3 and 4 , the input device 1200 modulates the reference voltage rails 211 to perform capacitive sensing using a reference voltage modulator 226 . In one embodiment, timing controller 220 opens switches 210 , 212 such _{that reference voltage rails 211 are shorted from supply voltages V DD} and V _{GND .} As mentioned above, shorting the power supplies voltages adversely affects other components in the input device 1200 (not shown _{) where the modulation signal 228 also depends on V DD} and V _{GND for power.} It can also prevent impact.

Reference voltage modulator 226 includes a central receiver 1205 that captures the resulting signals generated by modulating reference voltage rails 211 . That is, while the modulating signal 228 is active, the central receiver 1205 measures the resulting signals from the display electrode and/or sensor electrodes 240 , 242 at the panel 234 . In general, since the central receiver 1205 is coupled to the reference voltage rails 211 , the receiver 1205 is a panel 234 that is electrically coupled (directly or indirectly) to the voltage rails 211 . The resulting signals may be captured from any components in . Referring to FIG. 11 , in one embodiment, the resulting signals measured by the central receiver 1205 include capacitance C _T as well as capacitances at ground states 1125 - ie, C _BC , C _IG , and C . Affected by _BG. Moreover, although the central receiver 1205 is shown coupled to a reference voltage rail 211B, in other embodiments, the receiver 1205 may be coupled to an upper voltage rail 211A or other power supplies 335 . may be Moreover, the central receiver 1205 need not be located on the controller 220 , but may be located on the same integrated circuit as the power management controller 230 or on a separate integrated circuit.

Input device 1200 also includes local receivers 1210 located in display/sensing panel 234 . In one embodiment, each of the local receivers 1210 is coupled to only one of the sensor electrodes to measure a local capacitance value corresponding to the panel 234 . That is, in contrast to the result signals captured by the central receiver 1205 which are affected by the total capacitance of the display/sense panel 234 , the result signals measured by the local receivers 1210 are the sub of the panel 234 . - Affected by the local capacitance value for the part. The shape and size of the sub-portion of the panel 234 may directly depend on the shape and size of the sensor electrode 242 coupled to the local receiver 1210 . In one embodiment, the local receiver 1210 may be coupled to multiple sensor electrodes 242 . In any case, the local receivers 1210, similar to the central receiver 1205, measure the capacitance value for only the portion of the sensing area defined by panel 234, rather than measuring the total capacitance value for panel 234. do.

Although the input device 1200 may measure the resultant signals at the central receiver 1205 in a different (non-overlapping) time period than when the input device 1200 measures the resultant signals at the local receivers 1210 , one embodiment In , the central and local receivers 1205 , 1210 measure the resulting signals in parallel (eg, measure both on the same local receiver 1205 and on the central receiver 1210 simultaneously). In other words, when modulating the reference voltage rails 211 using the modulating signal 228 , both the central receiver 1205 and the local receivers 1210 can capture the resulting signals. The result signals measured by the central receiver 1205 include the result signals generated by all the sensor electrodes 242 (as well as other components in the panel 234 , such as the display electrodes 240 ). while the resulting signals captured by each of the local receiver 1210 are generated on only one, or a subset of, the sensor electrodes 242 and/or their thresholds. It may also be assumed that user inputs and LGM states change slowly for these measurements. As such, measurements made even at overlapping times may be combined to estimate LGM states.

Although the resulting signals measured by the central and local receivers 1205 , 1210 are different, the measured values are equally affected by the capacitances at ground states 1125 shown in FIG. 11 . That is, assuming that there are no changes in the arrangement of the input device 1105 with respect to the input object 1110 and ground 1115 when measuring the total capacitance and when measuring the local capacitances, the ground for these measurements is States 1125 are essentially the same. Based on this relationship, the input device 1200 in FIG. 12 normalizes the resulting signals received on the local receivers 1210 to mitigate or eliminate the effect of ground conditions on local capacitance measurements. The total capacitance indicated by the resulting signals received at the receiver 1205 is available.

13 is a flow chart for a method 1300 of mitigating the effects of an LGM condition, in accordance with one embodiment described herein. At block 1305 , the timing controller electrically connects the reference voltage rails from _{the DC power source (ie, supply voltages V DD} and V _GND ) to the DC power source (ie, supply voltages V DD and V GND ) by selectively shorting or using an indirect coupling technique such as inductive coupling. separated by Referring to FIG. 12 , the timing controller 220 uses the gate voltages to deactivate the switches 210 , 212 to short the reference voltage rails 211 from the DC power supply.

At block 1310 , the reference voltage modulator generates a signal that modulates at least one of the reference voltage rails. In one embodiment, the modulation is performed relative to _{chassis ground (eg, V GND ).} Thus, in terms of components in the input device that are not connected to the reference voltage rails, the components connected to the modulated reference voltage rail are modulating. However, from the perspective of the components connected to the reference voltage rail, it appears that the input object is modulating, as well as other components in the input device.

At block 1315 , the central receiver acquires the resulting signals from the plurality of sensor electrodes. Since the sensor electrodes may establish a sensing area for the display/sensing panel, by capturing the resulting signals from the sensor electrodes, the central receiver can derive a general capacitive measurement for the panel from the resulting signals, at block 1320 . can In an embodiment, the general capacitive measurement may be the current in the input device caused by the resulting signals. Alternatively, the general capacitive measurement may be a digital signal derived from the resulting signals using an ADC at the central receiver. In one embodiment, the general capacitive measurement is caused by the resulting signals generated on all sensor electrodes in the display/sensing panel and represents the total capacitance of the panel. Moreover, the central receiver may capture the resulting signals from the display electrodes and other circuitry in the panel, deriving a general capacitive measurement. 14 illustrates an example system in which a general capacitive measurement may be measured by a central receiver.

14 illustrates various capacitances between an input device 1105 and an environment 1405 , in accordance with one embodiment described herein. In one embodiment, the environment 1405 includes an enclosing area proximate to the input device 1105 . For example, the environment 1405 may include objects with which the input device 1105 is in contact, such as a table on which the device 1105 rests or a user's hand holding the device 1105 as well as the input object 1110 . may include objects that are capacitively coupled to the input device 1105 but may not contact the device 1105 , such as a finger or a stylus, such as In one embodiment, the environment 1405 may include a ground.

As shown in FIG. 14 , different components in the input device 1105 are capacitively coupled to objects in the environment 1405 . For example, the environment is capacitively coupled to the back plate chassis 1410 (eg, C ₁ ) and the display/sensing panel 234 (C _{2 ).} The value of these capacitances may vary depending on the location of the input device 1105 in the environment as well as conditions of the environment (eg, humidity). For example, _{the values of C 1} and C ₂ may change when the input device 1105 is seated on a table versus when being carried by a user. The capacitances C ₁ and C ₂ may define, at least in part, grounding conditions of the input device 1105 . _{As described above, if these capacitances have similar values to the capacitance C T} between the input object 1110 and the current conveyor 1420 , an LGM condition may occur.

_{The capacitance C 3} between the environment 1405 and the input object 1110 can also affect the ground states of the input device 1105 . The capacitance C ₃ may vary depending on the input objects location with respect to ground. For example, _{the value of C 3} may be smaller when the user (who is holding the input object 1110 ) is standing on an insulating surface instead of standing directly on the earth. Similar to capacitances C ₁ and C ₂ , the relative locations of input object 1110 and objects in environment 1405 change _{capacitance C 3} to negatively affect the ability of input device 1105 to measure _{C T .} It can lead to an LGM condition that can be crazy.

14 also includes _{a capacitance C HC} between the back plate chassis 1410 (which may be coupled to chassis ground) and an input object that may be part of a ground state for the input device 1105 . For example, if the input device 1105 is a laptop and the input object 1110 is a user, the capacitance C _HC may change depending on whether the input device 1105 is seated on the user's lap or on a table. _{Moreover, FIG. 14 includes a coupling capacitance C P} between the input object 1110 and the display/sensing panel 234 . In addition to being capacitively coupled to the current conveyor 1420 (and a corresponding sensor electrode coupled to the conveyor 1420 ), the input object 1110 includes display electrodes, other sensor electrodes, source drivers, gate line It may be coupled to other components in panel 234 , such as selection logic and the like. In one embodiment, the capacitance C _P represents the total capacitance between the input object 1110 and the various components in the panel 234 .

The central receiver 1205 is illustrated in this embodiment as an integrator that captures the resulting signals from the display electrode and/or sensor electrode (as well as other circuitry) in the display/sensing panel 234 . The acquired signals are affected by the various capacitances in FIG. 14 , and as a result, by processing the acquired signals when modulating the reference voltage rails, the central receiver provides the general capacitive sensing described in block 1320 of FIG. 13 . measurements can be derived. Although not shown, the central receiver 1205 may include a demodulator, filter, buffer, and/or ADC to process the acquired signals to derive a general capacitive sensing measurement. Note that current conveyor 1420 and central receiver integrator 1205 serve a similar purpose as integrator 500 and integrator 900 described above. Also, although 1205 is shown _{as a reset switch to incorporate a capacitance C FB} , it is the resistor 520 for continuous time sensing, just as integrators 500 , 900 may incorporate a reset switch for discrete time sensing. ) may incorporate a low-pass filter resistor such as It is also noted that the current conveyor 1420 may also be used to increase the effective dynamic range of the integrator 1205 by performing level shifting of the capacitive sense current to the voltage reference of the integrator 1205 . A similar current conveyor may also be included in integrators 500 , 900 to perform the same functions. Alternatively, if the dynamic range of the integrator 1205 is sufficient, the current conveyor 1420 may be unnecessary. Currents from the display/sense panel 234 and the input object (eg, via separate local receiver supplies) may be routed directly to the _{integrator 1205 , while its reference V REF is being modulated.}

_{The output voltage (V OUT} ) of the integrator 1205 when acquiring the resulting signals may be expressed as:

(1)

(One)

The capacitance CB represents the background capacitance, where C _T = C _F + C _B . The current from the display/sensing panel 234 to the back plate chassis 1410 via the power modulation supply (V _{MOD ) can be expressed as:}

(2)

(2)

13 , at block 1325 , the input device determines a local capacitive sensing measurement from each of the sensor electrodes. That is, instead of capturing result signals from multiple electrodes (eg, a group of sensor electrodes or both the display and sensor electrodes) similar to a central receiver, the input device uses each local receiver, The resulting signals may be captured. By processing the resulting signals, the local receivers can each determine a local capacitive sensing measurement representative of a localized capacitance value for the portion of the sensing region that includes the sensor electrode to which the local receiver is coupled. Thus, unlike normal capacitive sensing measurements derived by the central receiver, local capacitive sensing measurements may represent capacitance for a sub-portion of the sensing area in the display/sensing panel. However, notwithstanding this difference between the general capacitance measurement and the local capacitance measurement, both of these measurements may be equally affected by the ground conditions of the input device. That is, referring to FIG. 14 , the capacitances C ₁ , C ₂ , C ₃ , C _HC and C _P may have the same effect with respect to local and general capacitance measurements. Thus, if the values of the capacitances C ₁ , C ₂ , C ₃ , C _HC and C _P change, the local and general capacitance measurements change in a corresponding manner.

In an embodiment, local receivers may acquire result signals in parallel with a central receiver that acquires the result signals. In other words, both local and central receivers measure the resulting signals while the input device modulates the reference voltage rail. Moreover, local and central receivers may also process the resulting signals in parallel to derive local and general capacitive sensing measurements, although this is not a requirement. One advantage of simultaneously acquiring the resulting signals on local and general receivers is that the ground conditions are the same (eg, measured simultaneously). If the resulting signals were acquired at different times, the location of the input device in its environment may change, thereby changing ground conditions. As discussed below, if the ground conditions are the same when acquiring the resulting signals at both the normal and local receivers, by correlating the signals, the input device can remove the effect of ground conditions from the local capacitive measurements. However, even if the local and central receivers do not acquire the resulting signals in parallel, any slow varying (relative to the rate at which the capacitive measurements were taken) in ground conditions between when the local and central receivers measure the resulting signals. The change may be small, thus still allowing the input device to correlate the signals to mitigate or eliminate the effects of ground conditions.

Using the circuit diagram in FIG. 14 as an example, the current measured to detect a touch through _{CT at current conveyor 1420 may be represented as follows:}

(3)

(3)

_{The current I 1} in Equation 2 between the display/sensing panel 234 and the back plate chassis 1410 is strongly correlated with the current I _{2 in Equation 3 .} For example, each of these currents depends on the _{capacitances C HP} and C _{1 .} As the arrangement of the input device 1105 in the environment 1405 changes, the capacitances C _HP and C ₁ may result in an LGM state.

Returning to FIG. 13 , at block 1330 , the input device uses the resulting signals acquired by the central receiver to mitigate the effect of ground conditions on the resulting signals acquired by the local receivers. In one embodiment, the resulting signals measured by the central receiver (or a general capacitive measurement derived therefrom) are used to normalize the resulting signals captured by the local receiver (or a local capacitive measurement derived therefrom). do. For example, the current I ₂ in equation 3 (eg, a local capacitive sensing measurement) _{can be normalized by dividing by the current I 1} in equation 2 (eg, a general capacitive sensing measurement).

(4)

(4)

The normalized current shown in Equation 4 is more for the capacitances forming the ground states, compared to the dependencies in _{the currents I 1} and I ₂ , which result in a normalized current that is not strongly correlated to the _{capacitances C HC} and C _{1 .} It has a small dependency. In other words, _{changes in the values of the capacitances C HC} and C ₁ cause small changes (or no change) to the normalized current when compared to the changes in the non-normalized currents I ₁ and I _{2 .} may cause

15 is a chart 1500 illustrating results of mitigating the effects of an LGM condition, according to one embodiment described herein. Specifically, the upper plot 1505 illustrates the corrected local receiver signal normalized using the resulting signals captured by the central receiver, while the lower plot 1510 illustrates the uncorrected signal. As shown, the upper plot 1505 shows the capacitive coupling between the input object 1110 and the back plate chassis 1410 (ie, C _HC ) and the back plate chassis 1410 and environment than the lower plot 1510 . It is less sensitive to changes in the capacitive coupling between (1405) (ie, C _{1 ).} Accordingly, changes in the values of the ground state capacitances C _HC and C ₁ are greater for the normalized capacitive sense signals in plot 1505 than the unnormalized capacitive sense signals in plot 1510 . less impact

Another advantage of normalizing the local capacitive sensing measurement using the general capacitive sensing measurement is that the normalized signals do not depend on _{V MOD .} Thus, any noise coupled to the voltage used to modulate the reference voltage rails is canceled. Even further, normalizing local and general capacitive measurements may also mitigate noise introduced by objects that result in ground conditions. For example, referring to FIG. 14 , any noise introduced to the input device 1105 through the _{coupling capacitances C 1} , C ₂ , C ₃ , C _HC and C _{P is captured by the local and central receivers.} It may be canceled by correlating the resulting signals. Thus, any noise signal introduced by ground state capacitances coupling the input device to external objects can be eliminated.

A first group of example implementations may be described as follows:

In a first example, the input device comprises:

a plurality of sensor electrodes; and

A processing system, comprising:

a sensor module configured to operate a plurality of sensor electrodes for capacitive sensing;

a reference voltage modulator configured to modulate reference voltage rails of the processing system, and

and a receiver configured to simultaneously acquire resultant signals from the sensor electrodes to detect an input object while modulating the reference voltage rails.

In a second example of the input device of Example 1, each sensor electrode comprises at least one common electrode of a display device.

In a third example of the input device of Example 2, the plurality of sensor electrodes are disposed as a matrix of sensor electrodes on the same layer.

In a fourth example of the input device of Example 3, the at least one grid electrode is disposed between at least two of the sensor electrodes in the same layer.

In a fifth example of the input device of Example 2, the input device further includes a plurality of receiver electrodes, wherein the plurality of sensor electrodes include a plurality of transmitter electrodes.

In a sixth example of the input device of Example 1, the input device further comprises a display, wherein the sensor electrodes are external to the display.

In a seventh example of the input device of Example 1, the sensor module is disposed within an integrated circuit, wherein at least a portion of the reference voltage modulator is external to the integrated circuit.

In an eighth example of the input device of Example 1, the processing system further comprises a display module configured to update pixels in the display screen, wherein the display module is disposed in the first integrated circuit and wherein at least a portion of the sensor module is configured to disposed within the integrated circuit, wherein at least a portion of the reference voltage modulator is disposed outside the first and second integrated circuits.

In a ninth example of the input device of Example 1, the processing system further comprises a display module configured to update pixels in the display screen, wherein the display module is disposed in the first integrated circuit and includes at least one of the sensor module and the reference voltage modulator. A portion is disposed within the second integrated circuit.

In a tenth example of the input device of Example 1, the processing system further comprises a display module configured to update pixels in the display screen, wherein the display module is disposed within the integrated circuit and wherein at least a portion of the reference voltage modulator is external to the integrated circuit. is in

In an eleventh example of the input device of Example 1, the processing system comprises:

a display module configured to update pixels in the display screen, the display module configured as a timing controller and disposed within the first integrated circuit; and

further comprising a source driver configured to update pixels based on signals received from the display module, wherein the source driver and the sensor module are disposed in a second integrated circuit, wherein at least a portion of the reference voltage modulator comprises first and second disposed outside the integrated circuits.

In a twelfth example of the input device of Example 1, the reference voltage modulator and the receiver are disposed on the same integrated circuit, wherein the receiver is configured to modulate the reference voltage rails.

In a thirteenth example of the input device of Example 1, the reference voltage modulator includes a transmitter that generates a modulating signal for modulating the reference voltage rails.

In a fourteenth example of the input device of Example 1, the processing system further comprises a display module configured to update pixels in the display screen using the reference voltage rails, wherein when updating the pixels, the reference voltage rails are not modulated. maintained at non-DC voltages.

In a fifteenth example of the input device of Example 14, the input device comprises:

and a power management controller configured to provide a plurality of power rails using the reference voltage rails, wherein the power management controller is in a low-power state when the reference voltage modulates the reference voltage rails and the display module places the pixels in the low-power state. It is active when updating.

In a sixteenth example of the input device of Example 1, the input device further comprises a plurality of display electrodes, wherein the receiver receives from both the display electrodes and the sense electrodes for performing capacitive sensing while modulating the reference voltage rails. and to simultaneously acquire the resulting signals.

In a seventeenth example of the input device of Example 1, the input device further comprises a display panel comprising a display screen and a backlight, wherein the reference voltage modulator is configured to modulate the reference voltage rails when the backlight and the display panel are turned off. do.

In an eighteenth example of the input device of Example 1, prior to modulating the voltage rails, the processing system is configured to electrically short the reference voltage rails from the at least one DC power supply.

In a 19th example of the input device of Example 18, the input device comprises:

display source;

display panel; and

and a high-speed data interface disposed on the same integrated circuit as the reference voltage modulator, the data interface configured to communicate with the display source to receive display data for updating the display screen, the high-speed data interface being the reference voltage rail The portion of the unmodulated voltage domain that contains the power voltage rails that remain coupled to the DC supply when they are electrically shorted from the DC supply.

In a twentieth example, the processing system comprises:

a sensor module configured to drive a plurality of sensor electrodes for driving capacitive sensing;

a reference voltage modulator configured to modulate reference voltage rails of a processing system, wherein prior to modulating the voltage rails, the processing system is configured to electrically short the reference voltage rails from at least one DC power supply; and

and a receiver configured to acquire resultant signals using the sensor electrodes to detect an input object while modulating the voltage rails.

In a twenty-first example, the processing system of the twentieth example comprises:

and a display module configured to update pixels in the display screen using the reference voltage rails, wherein when updating the pixels, the reference voltage rails are maintained at unmodulated DC voltages.

In a twenty-second example, the processing system of the twenty-first example, a display module, is configured to couple to a plurality of display electrodes for updating pixels, wherein the receiver is a display electrode for performing capacitive sensing while modulating reference voltage rails. configured to simultaneously acquire result signals from both the poles and the sensing electrodes.

In a twenty-third example, the processing system of the twentieth example comprises:

A display module further comprising a display module configured to update pixels in the display screen, wherein the display module is disposed on the integrated circuit along at least a portion of the sensor module.

In a twenty-fourth example, the processing system of the twentieth example comprises:

A display module further comprising: a display module configured to update pixels in the display screen, wherein the display module is disposed in a first integrated circuit and at least a portion of the sensor module and the reference voltage modulator is disposed in a second integrated circuit.

In a twenty-fifth example, the processing system of the twentieth example comprises:

further comprising a display module configured to update pixels in the display screen, wherein the display module is disposed in a first integrated circuit and at least a portion of the sensor module is disposed in a second integrated circuit, wherein at least a portion of the reference voltage modulator comprises: It is disposed outside the first and second integrated circuits.

In a 26th example, the processing system of the twentieth example comprises:

Further comprising a display module configured to update pixels in the display screen, wherein the display module is disposed within the integrated circuit, and wherein at least a portion of the reference voltage modulator is external to the integrated circuit.

In a twenty-seventh example, the processing system of the twentieth example comprises:

a display module configured to update pixels in the display screen, the display module configured as a timing controller and disposed within the first integrated circuit; and

further comprising a source driver configured to update pixels based on signals received from the display module, wherein the source driver and the sensor module are disposed in a second integrated circuit, wherein at least a portion of the reference voltage modulator comprises first and second disposed outside the integrated circuits.

In a 28th example, the processing system of the twentieth example, before modulating the voltage rails, the processing system is configured to electrically short the reference voltage rails from the at least one DC power supply.

In a twenty-ninth example, the input device comprises: a plurality of sensor electrodes; and a processing system,

each sensor electrode comprising at least one common electrode of a display device, the sensor electrodes being disposed on a common plane in a matrix array,

The processing system is

a sensor module configured to operate a plurality of sensor electrodes for capacitive sensing;

a reference voltage modulator configured to modulate reference voltage rails of the processing system, and

and a receiver configured to acquire resultant signals using the sensor electrodes to detect an input object while modulating the voltage rails.

In a thirtieth example, in the input device of example 29, prior to modulating the voltage rails, the processing system is configured to electrically short the reference voltage rails from the at least one DC power supply, the processing system comprising:

and a display module configured to update pixels in the display screen using the reference voltage rails, wherein when updating the pixels, the reference voltage rails are maintained at unmodulated DC voltages.

In the 31st method, the method comprises:

driving a capacitive sensing signal on the plurality of sensor electrodes at the input device;

electrically shorting the reference voltage rails from the at least one DC power supply;

after electrically shorting the reference voltage rails, modulating the reference voltage rails; and

and capturing the resulting signals using the sensor electrodes to detect an input object while modulating the voltage rails.

A second group of example implementations may be described as follows:

In a first example, the input device comprises:

a plurality of display electrodes;

a plurality of sensor electrodes; and

A processing system comprising:

a reference voltage modulator configured to modulate the reference voltage rails for a first period of time, the processing system comprising:

update the display using the display electrodes and reference voltage rails of the processing system during a second time period that is non-overlapping with the first time period, and

configured to acquire resultant signals from the plurality of sensor electrodes during a first time period, wherein the reference voltage rails are maintained at unmodulated, constant voltages for the first time period.

In a second example, the input device of the first example includes capacitively coupled reference voltage rails.

In a third example, the input device of the first example comprises:

further comprising source drivers coupled to the plurality of sensor electrodes, wherein the source drivers are configured to drive a capacitive sense signal onto the sensor electrodes for capacitive sensing, wherein the capacitive sense signal is a modulated reference voltage derived from the rails.

In a fourth example of the input device of the third example, the source sensor electrodes are protected from at least one interfering signal when driven by a capacitive sensing signal derived from the modulated reference voltage rails.

In a fifth example, the input device of the third example comprises:

gate electrodes for updating the display; and

Further comprising source electrodes for updating the display, wherein when driving a capacitive sensing signal onto the sensor electrodes, the gates electrodes float and the source electrodes are protected.

In a sixth example, the input device of the first example comprises:

and a power management controller configured to receive the unmodulated reference voltage rails when updating the display and convert the reference voltage rails to power voltages for powering display circuitry in a display panel including the display.

In a seventh example of the input device of the sixth example, the power management controller is in a low-power state when the reference voltage modulator modulates the reference voltage rails and is in an active state when the display module updates pixels.

In an eighth example of the input device of the fourth example, the receiver is configured to simultaneously acquire result signals from both the sensing electrodes and the display electrodes for performing capacitive sensing.

In a ninth example, the input device of the first example comprises:

Further comprising a backlight, wherein the reference voltage modulator is configured to modulate the reference voltage rails while the backlight and the display are turned off.

In a tenth example, the input device of the first example comprises:

display source;

display panel; and

and a high-speed data interface disposed on the same integrated circuit as the reference voltage modulator;

The data interface is configured to communicate with a display source to receive display data for updating a display, wherein the high speed data interface maintains a power voltage rail that remains unmodulated when the reference voltage rails are modulated by a reference voltage modulator. is the portion of the unmodulated voltage domain that contains

In an eleventh example, the processing system comprises:

a reference voltage modulator configured to modulate the reference voltage rails for a first period of time;

a receiver configured to acquire, during the first time period, result signals for the plurality of sensor electrodes; and

a display module configured to update the display using the plurality of display electrodes and the reference voltage rails during a second period of time that does not overlap the first period of time;

Here, the reference voltage rails are held at unmodulated, DC voltages for a second time period.

In a twelfth example of the eleventh example processing system, the reference voltage rails are capacitively coupled.

In a thirteenth example of the eleventh example processing system, the processing system comprises:

and a power management controller configured to receive the unmodulated reference voltage rails when updating the display and convert the reference voltage rails to power voltages for powering display circuitry in a display panel including the display.

In a fourteenth example of the processing system of the thirteenth example, the power management controller is in a low-power state when the reference voltage modulator modulates the reference voltage rails and is in an active state when the display module updates pixels.

In a fifteenth example of the eleventh example processing system, the receiver is configured to simultaneously acquire resultant signals from both the sensing electrodes and the display electrodes for performing capacitive sensing.

In a sixteenth example of the processing system of the eleventh example, the processing system is configured to modulate the reference voltage rails while the backlight and the display are turned off.

In a seventeenth example, the processing system of the eleventh example comprises:

and a high-speed data interface disposed on the same integrated circuit as the reference voltage modulator, the data interface configured to communicate with a display source to receive display data for updating the display, the high-speed data interface being a reference voltage rail The portion of the unmodulated voltage domain that contains the power voltage rails that remain unmodulated when they are modulated by a reference voltage modulator.

In an eighteenth example, the method comprises:

updating pixels in a display of an input device using reference voltage rails and a plurality of display electrodes for a first period of time, wherein the reference voltage rails are maintained at unmodulated DC voltages for a first period of time , the updating step;

modulating the reference voltage rails during a second time period that does not overlap the first time period; and

and acquiring resultant signals from the plurality of sensor electrodes based on modulating the reference voltage rails.

In a 19th example of the method of example 18, the input device is in a low power state for a second period of time, the method comprising:

After detecting the input object based on the resulting signals:

switching the input device from a low power state to an active state; and

and stopping modulating the reference voltage rails.

In the twentieth example, the method of the eighteenth example comprises:

The method further includes electrically shorting the DC power supply from the reference voltage rails prior to modulating the reference voltage rails.

In a twenty-first example of the method of example eighteen, acquiring the resulting signals comprises:

Simultaneously receiving respective result signals from the display electrodes and the sensor electrodes, wherein the respective result signals are used to perform capacitive sensing.

A third group of example implementations may be described as follows:

In a first example, the input device comprises:

a plurality of sensor electrodes; and

A processing system comprising:

a reference voltage modulator configured to modulate a reference voltage used to provide power to the plurality of power supplies;

a central receiver configured to simultaneously acquire first result signals from the plurality of sensor electrodes when the reference voltage is being modulated; and

a plurality of local receivers each coupled to at least one of the sensor electrodes, the local receivers being configured to acquire second resultant signals from the sensor electrodes;

The processing system is configured to use the first result signal to mitigate an effect of the grounding condition on the second result signal.

In a second example, the input device of the first example comprises:

The reference voltage further includes a controller configured to short the reference voltage from the DC power source while being modulated.

In a third example, the input device of the first example comprises:

A display/sensing panel comprising a plurality of sensor electrodes, a plurality of local receivers, and a plurality of display electrodes, wherein each of the sensor electrodes is coupled to only one of the local receivers.

In a fourth example of the input device of the first example, acquiring the second result signals on the local receivers occurs in parallel with acquiring the first result signals on the central receiver when the reference voltage is modulated.

In a fifth example of the input device of the first example, the central receiver is configured to acquire third result signals from the plurality of display electrodes while the reference voltage is being modulated, and wherein the processing system is configured to: and to mitigate the effect using the third resultant signals.

In a sixth example of the input device of the first example, the ground state includes (i) a first capacitive coupling between an input object interacting with the input device and ground, and (ii) a second capacitance between the input device and ground. at least one of the sexual couplings.

In a seventh example of the input device of the first example, the processing system comprises:

and a display module configured to update pixels in the display screen, wherein the display module and the local receivers are disposed within a common integrated circuit.

In an eighth example of the input device of the first example, the processing system comprises:

Further comprising a display module configured to update pixels in the display screen, wherein the display module is disposed in a first integrated circuit and at least a portion of the local receivers are disposed in a second integrated circuit.

In a ninth example of the input device of the first example, a plurality of sensor electrodes are disposed in a matrix array.

In a tenth example, the processing system comprises:

a reference voltage modulator configured to modulate a reference voltage used to provide power to the plurality of power supplies;

a central receiver configured to simultaneously acquire first result signals from the plurality of sensor electrodes when the reference voltage is being modulated; and

a plurality of local receivers configured to acquire second result signals from the plurality of sensor electrodes;

Here, the processing system is configured to mitigate an effect of the grounding state on the second result signals using the first result signals.

In an eleventh example, the processing system of the tenth example comprises:

and a controller configured to short the reference voltage from the DC power source while the reference voltage is being modulated.

In a twelfth example of the processing system of the tenth example,

A power management controller comprising power supplies, wherein the power supplies are configured to provide power to the display.

In a thirteenth example of the tenth example processing system, acquiring the second result signals on the local receivers occurs in parallel with acquiring the first result signals on the central receiver when the reference voltage is modulated.

In a fourteenth example of the tenth example processing system, the central receiver is configured to acquire third result signals from the plurality of display electrodes while the reference voltage is being modulated, wherein the processing system is a ground applied to the second result signals. and to mitigate the effect of the state using the third result signals.

In a fifteenth example of the processing system of the tenth example, the ground state is determined by: (i) a first capacitive coupling between ground and an input object interacting with a chassis comprising the processing system, and (ii) between the chassis and ground. at least one of the second capacitive couplings.

In a sixteenth example, the method comprises:

modulating a reference voltage used to provide power to a plurality of power supplies;

simultaneously acquiring first resultant signals from the plurality of sensor electrodes at a central receiver while modulating the reference voltage;

acquiring second resultant signals from the sensor electrodes at the plurality of local receivers; and

and mitigating the effect of the grounding state on the second result signal using the first result signal.

In the seventeenth example, the method of the sixteenth example comprises:

The method further includes electrically isolating the reference voltage from the DC power supply while the reference voltage is being modulated.

In an eighteenth example of the method of the sixteenth example, the first result signals are acquired at the central receiver in parallel with acquiring the second result signals at the plurality of local receivers.

In a 19th example of the method of Example 16,

simultaneously acquiring third result signals from the plurality of display electrodes at the central receiver while modulating the reference voltage; and

The method further includes mitigating an effect of the grounding state on the second result signal by using the third result signal.

Accordingly, the embodiments and examples disclosed herein have been presented in order to best explain the embodiments in accordance with the present technology and its particular application, and to enable those skilled in the art to make and use the present technology. However, it will be appreciated by those skilled in the art that the foregoing description and examples have been presented for purposes of illustration and example only. The description as disclosed is not intended to be exhaustive or to limit the disclosure to the precise form disclosed.

In light of the above description, the scope of the present disclosure is determined by the claims that follow.

Claims (22)

As an input device,
a plurality of sensor electrodes;
a plurality of display electrodes configured to be driven for display updating; and
processing system;
The processing system comprises:
a plurality of local receivers each coupled to respective sensor electrodes of the plurality of sensor electrodes, the plurality of local receivers configured to acquire first result signals from the plurality of sensor electrodes field; and
a central receiver comprising an integrator coupled to each sensor electrode of the plurality of sensor electrodes and to at least one display electrode of the plurality of display electrodes at a common electrical node, the integrator comprising: each of the plurality of sensor electrodes; the central receiver configured to simultaneously acquire second result signals from a sensor electrode and the at least one display electrode, the plurality of local receivers and the central receiver configured to measure the first and second result signals in parallel receiving set
An input device comprising: The method of claim 1,
and the processing system is configured to use the first result signals to determine a measure of a change in capacitive coupling between an input object and the plurality of sensor electrodes. The method of claim 1,
the processing system is configured to identify a communication signal transmitted by an active input object external to the input device based on the second result signals or to identify a measure of interference based on the second result signals; input device. As an input device,
a plurality of sensor electrodes;
a plurality of display electrodes configured to be driven for display updating; and
processing system;
The processing system comprises:
a plurality of local receivers each coupled to respective sensor electrodes of the plurality of sensor electrodes, the plurality of local receivers configured to acquire first result signals from the plurality of sensor electrodes field; and
a central receiver comprising an integrator coupled to each sensor electrode of the plurality of sensor electrodes and to at least one display electrode of the plurality of display electrodes at a common electrical node, the integrator comprising: each of the plurality of sensor electrodes; configured to simultaneously acquire second result signals from a sensor electrode and the at least one display electrode, the integrator comprising an amplifier having an input coupled to an unmodulated reference voltage when acquiring the second result signals; the central receiver
An input device comprising: 5. The method of claim 4,
and the processing system is configured to use the first result signals to determine a measure of a change in capacitive coupling between an input object and the plurality of sensor electrodes. 5. The method of claim 4,
the processing system is configured to identify a communication signal transmitted by an active input object external to the input device based on the second result signals or to identify a measure of interference based on the second result signals; input device. The method of claim 1,
wherein the central receiver is coupled to a constant reference voltage source and is unmodulated when acquiring the second result signals. 8. The method of claim 7,
wherein the integrator comprises an amplifier, wherein an input of the amplifier is coupled to the constant reference voltage source when acquiring the second result signals. The method of claim 1,
and switches configured to selectively disconnect a display from a power source when the integrator acquires the second result signals. 10. The method of claim 9,
further comprising a capacitive power storage element coupled to the power source via the switches;
when the switches are activated, the capacitive power storage element is charged by the power source. 11. The method of claim 10,
a display module configured to update the display using the charge stored in the capacitive power storage element, the display module updating the display at least in part in parallel with capturing the second result signals; input device. The method of claim 1,
The capturing of the second result signals from each sensor electrode of the plurality of sensor electrodes and the at least one display electrode comprises: from each sensor electrode of the plurality of sensor electrodes and each display electrode of the plurality of display electrodes. and receiving the second result signals. 5. The method of claim 4,
and switches configured to selectively disconnect a display from a power source when the integrator acquires the second result signals. 14. The method of claim 13,
further comprising a capacitive power storage element coupled to the power source via the switches;
when the switches are activated, the capacitive power storage element is charged by the power source. 15. The method of claim 14,
a display module configured to update the display using the charge stored in the capacitive power storage element, the display module updating the display at least in part in parallel with capturing the second result signals; input device. 5. The method of claim 4,
The capturing of the second result signals from each sensor electrode of the plurality of sensor electrodes and the at least one display electrode comprises: from each sensor electrode of the plurality of sensor electrodes and each display electrode of the plurality of display electrodes. and receiving the second result signals. A method for performing capacitive sensing with an input device, comprising:
acquiring, via a plurality of local receivers, first result signals from a plurality of sensor electrodes, each of the plurality of local receivers being coupled to a corresponding one of the plurality of sensor electrodes acquiring the resulting signals; and
simultaneously acquiring, via an integrator of a central receiver, second result signals from each sensor electrode of the plurality of sensor electrodes and from at least one display electrode of a plurality of display electrodes, the integrator at a common node the second result signal comprising an amplifier coupled to each of the sensor electrodes and the at least one display electrode, the amplifier having an input coupled to an unmodulated reference voltage when acquiring the second result signals A method for performing capacitive sensing with an input device, comprising the step of capturing them. 18. The method of claim 17,
determining a measure of a change in capacitive coupling between an input object and the plurality of sensor electrodes using the first result signals. 18. The method of claim 17,
identifying a communication signal transmitted by an active input object external to the input device based on the second result signals, or identifying a measure of interference based on the second result signals , a method for performing capacitive sensing with an input device. A capacitive sensing method using an input device, comprising:
acquiring, via the plurality of local receivers, first result signals from the plurality of sensor electrodes; and
simultaneously acquiring, via an integrator of a central receiver, second resultant signals from each sensor electrode of the plurality of sensor electrodes and from at least one display electrode of the plurality of display electrodes, the integrator comprising the plurality of sensor electrodes at a common electrical node coupled to each sensor electrode of the sensor electrodes and to the at least one display electrode, wherein the plurality of local receivers and the central receiver are configured to measure the first and second result signals in parallel A method of capacitive sensing using an input device, comprising the step of acquiring the resulting signals. 21. The method of claim 20,
and determining a measure of a change in capacitive coupling between an input object and the plurality of sensor electrodes using the first result signals. 22. The method of claim 21,
identifying a communication signal transmitted by an active input object external to the input device based on the second result signals, or identifying a measure of interference based on the second result signals , a capacitive sensing method using an input device.

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