Patent ID: 12242699

DETAILED DESCRIPTION

FIG.1is a schematic block diagram of an embodiment of a data communication system10that includes a plurality of computing devices12, a wireless computing device14, one or more servers16, one or more databases18, one or more networks24, one or more wireless access points22, and a plurality of identifying devices38. Embodiments of computing devices12and14are similar in construct and/or functionality with a difference being that computing devices12couple to the network(s)24via a wired network card and the wireless communication devices14coupled to the network(s) via a radio frequency wireless connection. In an embodiment, a computing device can have both a wired network card and a wireless network card such that it is both a computing device12and a wireless computing device14. In addition, any or all of the computing devices, wireless computing device, access point, or server16can include circuitry that allows data to be exchanged with other computing devices via capacitive-coupling.

For example, computing device12-1includes a drive-sense circuit (DSC)28that can be used to capacitively couple an information signal generated by another DSC28included in identifying device38. The information signal is generated by passing one or more signals having one or more frequencies through an electrode illustrated as capacitor C1. The information signal is coupled to an electrode illustrated as capacitor C2, via a capacitive path illustrated as capacitor C3, when the identifying device or a human in physical contact with the identifying device, comes within physical proximity of computing device12-1. When the information signal is capacitively coupled to C2via C3the signal causes a change in the current flowing through C2. The changes in current flowing through C2cause changes in an impedance associated with C2, and those changes are processed to extract data from the information signal.

In another example, computing device12-2includes a low voltage drive circuit (LVDC)26, which can be used to capacitively couple an information signal generated by computing device12-2using another LVDC26. The capacitive coupling mechanism is the same as described with respect to computing device12-1. In this example, however, the information signal can be exchanged either from computing device12-2to computing device12-3, or from computing device12-3to computing device12-2.

In yet another example, wireless computing device14includes touch-sensitive panel32. An information signal, for example an identification code, is generated by an identifying device38including a DSC28, and is capacitively coupled via C3to the touch-sensitive panel32included in wireless computing device14. The capacitive coupling mechanism is the same as in the previous examples.

In a further embodiment, server16includes an LVDC26. An information signal, for example an access code, is generated by an identifying device38including a DSC28, and is capacitively coupled via C3to the LVDC26included in server16. The capacitive coupling mechanism is the same as already described, and as explained further with respect to subsequent figures.

A computing device12and/or14may be a portable computing device and/or a fixed computing device. A portable computing device may be a social networking device, a gaming device, a cell phone, a smart phone, a digital assistant, a digital music player, a digital video player, a laptop computer, a handheld computer, a tablet, a video game controller, and/or any other portable device that includes a computing core. A fixed computing device may be a computer (PC), a computer server, a cable set-top box, a satellite receiver, a television set, a printer, a fax machine, home entertainment equipment, a video game console, and/or any type of home or office computing equipment.

A server16is a special type of computing device that is optimized for processing large amounts of data requests in parallel. A server16includes similar components to that of the computing devices12and/or14with more robust processing modules, more main memory, and/or more hard drive memory (e.g., solid state, hard drives, etc.). Further, a server16is typically accessed remotely; as such it does not generally include user input devices and/or user output devices. However, in some embodiments, server16can include a touch-sensitive panel that allows capacitive coupling of an identifier or other information, for example an identification or access code used to control access to the server. In addition, an embodiment of a server is a standalone separate computing device and/or may be a cloud computing device.

A database18is a special type of computing device that is optimized for large scale data storage and retrieval. A database18includes similar components to that of the computing devices12and/or14with more hard drive memory (e.g., solid state, hard drives, etc.) and potentially with more processing modules and/or main memory. Further, a database18is typically accessed remotely; as such it does not generally include user input devices and/or user output devices. In addition, an embodiment of a database18is a standalone separate computing device and/or may be a cloud computing device.

The network(s)24includes one or more local area networks (LAN) and/or one or more wide area networks (WAN), which may be a public network and/or a private network. A LAN may be a wireless-LAN (e.g., Wi-Fi access point, Bluetooth, ZigBee, etc.) and/or a wired LAN (e.g., Firewire, Ethernet, etc.). A WAN may be a wired and/or wireless WAN. For example, a LAN is a personal home or business's wireless network, and a WAN is the Internet, cellular telephone infrastructure, and/or satellite communication infrastructure.

FIG.2is a schematic block diagram of another embodiment of a data communication system10that includes the computing devices12, the server16, and the database18coupled to each other via electrodes85, which are illustrated as capacitors. In practice, however, the electrodes85act as plates of an air-dielectric capacitor. Each device12-x,16, and18includes one or more LVDCs26that work in conjunction with the electrodes85for communicating data capacitively.

An LVDC26functions to convert transmit digital data212(FIG.20) from its host device into an information signal that is capacitively coupled to another host device a path including C3. As an example, a host device is a computing device, a server, or a database. As another example, a host device is an interface included in one the computing device, the server, or the database. In various embodiments discussed herein, host device that transmits an information signal representing an identifier, or identification code, is referred to as an identifying device. A host device that receives an information signal can be a stand-alone touch-sensitive panel with or without display capabilities, or a device that includes or is communicatively coupled to a touch-sensitive panel.

The LVDC26of one host device functions to generate the information signal, which represents the transmit digital data212(FIG.20) to have an oscillating component at one or more frequencies. The LVDC26of another host device functions to convert variations in a sensed electric field caused by receipt of the information signal, into received digital data that is provided to its host. An LVDC26is capable of communicating data with one or more other LVDCs using a plurality of frequencies. Each frequency, or combination of frequencies, supports a conveyance of data.

FIG.3is a block diagram illustrating a touch-sensitive panel32including multiple drive-sense circuits28capacitively coupled to an identifying device38via electric fields E-field134and E-field236. To receive a capacitively-coupled information signal from identifying device38, touch-sensitive panel32generates E-field134by applying sense signals to column electrodes85cand/or row electrodes85r. When E-field134is generated by sense signals, it is referred to as a sense electric field, a sensing field, or some variation thereof. In this example, the row electrodes85rand column electrodes85cfunction, individually or in combination, as a first plate of an air-gap capacitor.

Identifying device38generates E-field236by applying transmit data to electrode85. In this example, electrode85functions as the opposite plate of the air-gap capacitor. When E-field236is generated by transmit data, it is referred to herein as an information signal. The information signal (E-Field236) causes changes in the sense electric field (E-Field134). These changes produce variations in self-capacitances associated with row electrodes85rand/or column electrodes85c. Variations in the self-capacitances of a particular row or column electrodes can be detected as changes in impedance measured by a drive sense circuit coupled to that particular row or column electrode.

A drive-sense circuit28includes an op-amp33coupled to receive a reference signal at its inverting input, a dependent current source39having an output coupled to the non-inverting input of op-amp33, a feedback circuit37coupling the output of op-amp33to an input of the dependent current source39, and an analog-to-digital converter (ADC)35coupled to the output of op-amp33. Note that although a non-inverting embodiment is illustrated, inverting embodiments can also be used.

Because the voltages at the inverting and non-inverting inputs to the op-amp are equal, the reference signal will be placed on the row or column electrode coupled to the non-inverting input of the op-amp. The electrode will have a capacitance, and present a load that draws a given amount of current, which is supplied by the dependent current source39. Any changes to the self-capacitance of the electrode coupled to the op-amp will cause a change in the amount of current provided to the electrode by dependent current source39. Changes in the current provided by dependent current source39will cause corresponding changes in the outputs of the op-amp. Changes in the output of the op-amp are converted to sensed values31by the analog to digital converter35.

FIG.4is a schematic block diagram of an embodiment of a computing device14. The computing device14includes a touch-sensitive panel32-1, a core control module40, one or more processing modules42, one or more main memories44, cache memory46, a video graphics processing module48, a display50, an Input-Output (I/O) peripheral control module52, one or more input interface modules56, one or more output interface modules58, one or more network interface modules60, and one or more memory interface modules62. A processing module42is described in greater detail at the end of the detailed description section and, in an alternative embodiment, has a direct connection to the main memory44. In an alternate embodiment, the core control module40and the I/O and/or peripheral control module52are one module, such as a chipset, a quick path interconnect (QPI), and/or an ultra-path interconnect (UPI).

The touch-sensitive panel32-1includes a touch screen display80, a plurality of sensors30, a plurality of drive-sense circuits (DSC), one or more switch networks401and403, a switch controller405, and a touch screen processing module82. In general, the sensors (e.g., electrodes, capacitor sensing cells, capacitor sensors, etc.) detect a proximal touch of the screen, sense a capacitively-coupled information signal, or some combination of the two. Switch controller405selects particular sensors (row and column electrodes) to be coupled to particular drive-sense circuits (DSCs) to adjust a touch resolution and/or a sense resolution of all or part of the touch screen display80. Switch controller405can receive information from any or all of the processing modules, and use that information as a basis for selecting sensors/DSC coupling arrangements. Switch controller405then transmits control signals to the switch network(s)401and403causing the switch networks to selectively couple the selected sensors to the selected drive sense circuits. For example, when one or more fingers touches the screen, or when an information signal is received, capacitances of sensors proximal to the touch(es) are affected (e.g., impedance changes). The drive-sense circuits (DSC) coupled to the affected sensors detect the change and provide a representation of the change to the touch screen processing module82, which may be a separate processing module or integrated into the processing module42. By changing the coupling of sensors to DSCs, a touch resolution or sensing resolution of the touch screen display can be changed. By using different coupling arrangements in different areas of the touch screen display, multiple different resolutions can be realized concurrently in those different areas.

The touch screen processing module82processes the representative signals from the drive-sense circuits (DSC) to determine the location of the touch(es). This information is inputted to the processing module42for processing as an input. For example, a touch represents a selection of a button on screen, a scroll function, a zoom in-out function, etc. The touch screen processing module82also operates to at least partially process information signals capacitively coupled to the touch screen display with sensors80from a remote device, e.g., identifying device. Further processing of the information signal may be performed by the I/O interface54or other components of the computing device14.

Each of the main memories44includes one or more Random Access Memory (RAM) integrated circuits, or chips. For example, a main memory44includes four DDR4 (4thgeneration of double data rate) RAM chips, each running at a rate of 2,400 MHz. In general, the main memory44stores data and operational instructions most relevant for the processing module42. For example, the core control module40coordinates the transfer of data and/or operational instructions from the main memory44and the memory64-66. The data and/or operational instructions retrieved from memory64-66are the data and/or operational instructions requested by the processing module or will the instructions most likely be needed by the processing module. When the processing module is done with the data and/or operational instructions in main memory, the core control module40coordinates sending updated data to the memory64-66for storage.

The memory64-66includes one or more hard drives, one or more solid state memory chips, and/or one or more other large capacity storage devices that, in comparison to cache memory and main memory devices, is/are relatively inexpensive with respect to cost per amount of data stored. The memory64-66is coupled to the core control module40via the I/O and/or peripheral control module52and via one or more memory interface modules62. In an embodiment, the I/O and/or peripheral control module52includes one or more Peripheral Component Interface (PCI) buses to which peripheral components connect to the core control module40. A memory interface module62includes a software driver and a hardware connector for coupling a memory device to the I/O and/or peripheral control module52. For example, a memory interface62is in accordance with a Serial Advanced Technology Attachment (SATA) port.

The core control module40coordinates data communications between the processing module(s)42and the network(s)26via the I/O and/or peripheral control module52, the network interface module(s)60, and a network card68or70. A network card68or70includes a wireless communication unit or a wired communication unit. A wireless communication unit includes a wireless local area network (WLAN) communication device, a cellular communication device, a Bluetooth device, and/or a ZigBee communication device. A wired communication unit includes a Gigabit LAN connection, a Firewire connection, and/or a proprietary computer wired connection. A network interface module60includes a software driver and a hardware connector for coupling the network card to the I/O and/or peripheral control module52. For example, the network interface module60is in accordance with one or more versions of IEEE 802.11, cellular telephone protocols, 10/100/1000 Gigabit LAN protocols, etc.

The core control module40coordinates data communications between the processing module(s)42and input device(s)72via the input interface module(s)56and the I/O and/or peripheral control module52. An input device72includes a keypad, a keyboard, control switches, a touchpad, a microphone, a camera, etc. An input interface module56includes a software driver and a hardware connector for coupling an input device to the I/O and/or peripheral control module52. In an embodiment, an input interface module56is in accordance with one or more Universal Serial Bus (USB) protocols.

The core control module40coordinates data communications between the processing module(s)42and output device(s)74via the output interface module(s)58and the I/O and/or peripheral control module52. An output device74includes a speaker, etc. An output interface module58includes a software driver and a hardware connector for coupling an output device to the I/O and/or peripheral control module52. In an embodiment, an output interface module56is in accordance with one or more audio codec protocols.

The processing module42communicates directly with a video graphics processing module48to display data on the display50. The display50includes an LED (light emitting diode) display, an LCD (liquid crystal display), and/or other type of display technology. The display has a resolution, an aspect ratio, and other features that affect the quality of the display. The video graphics processing module48receives data from the processing module42, processes the data to produce rendered data in accordance with the characteristics of the display, and provides the rendered data to the display50.

In various embodiments, touch screen processing module82can receive touch-related image information, rate of motion information, content meta-data and/or other video content-related information from the video graphics processing module48.

FIG.5is a schematic block diagram of an embodiment of a drive sense circuit28that includes a first conversion circuit110and a second conversion circuit112. The first conversion circuit110converts a sensor signal116into a sensed signal120. The second conversion circuit112generates the drive signal component114from the sensed signal112. As an example, the first conversion circuit110functions to keep the sensor signal116substantially constant (e.g., substantially matching a reference signal) by creating the sensed signal120to correspond to changes in a receive signal component118of the sensor signal. The second conversion circuit112functions to generate a drive signal component114of the sensor signal based on the sensed signal120to substantially compensate for changes in the receive signal component118such that the sensor signal116remains substantially constant.

In an example, the drive signal116is provided to the electrode85as a regulated current signal. The regulated current (I) signal in combination with the impedance (Z) of the electrode creates an electrode voltage (V), where V=I*Z. As the impedance (Z) of electrode changes, the regulated current (I) signal is adjusted to keep the electrode voltage (V) substantially unchanged. To regulate the current signal, the first conversion circuit110adjusts the sensed signal120based on the receive signal component118, which is indicative of the impedance of the electrode and change thereof. The second conversion circuit112adjusts the regulated current based on the changes to the sensed signal120.

As another example, the drive signal116is provided to the electrode85as a regulated voltage signal. The regulated voltage (V) signal in combination with the impedance (Z) of the electrode creates an electrode current (I), where I=V/Z. As the impedance (Z) of electrode changes, the regulated voltage (V) signal is adjusted to keep the electrode current (I) substantially unchanged. To regulate the voltage signal, the first conversion circuit110adjusts the sensed signal120based on the receive signal component118, which is indicative of the impedance of the electrode and change thereof. The second conversion circuit112adjusts the regulated voltage based on the changes to the sensed signal120.

FIG.6is a schematic block diagram of another embodiment of a drive sense circuit28that includes a first conversion circuit110and a second conversion circuit112. The first conversion circuit110includes a comparator (comp) and an analog to digital converter35. The second conversion circuit112includes a digital to analog converter132, a signal source circuit133, and a driver.

In an example of operation, the comparator compares the sensor signal116to an analog reference signal122to produce an analog comparison signal124. The analog reference signal122includes a DC component and an oscillating component. As such, the sensor signal116will have a substantially matching DC component and oscillating component. An example of an analog reference signal122will be described in greater detail with reference toFIG.15.

The analog to digital converter35converts the analog comparison signal124into the sensed signal120. The analog to digital converter (ADC)35may be implemented in a variety of ways. For example, the (ADC)35is one of: a flash ADC, a successive approximation ADC, a ramp-compare ADC, a Wilkinson ADC, an integrating ADC, a delta encoded ADC, and/or a sigma-delta ADC. The digital to analog converter (DAC)214may be a sigma-delta DAC, a pulse width modulator DAC, a binary weighted DAC, a successive approximation DAC, and/or a thermometer-coded DAC.

The digital to analog converter (DAC)132converts the sensed signal120into an analog feedback signal126. The signal source circuit133(e.g., a dependent current source, a linear regulator, a DC-DC power supply, etc.) generates a regulated source signal135(e.g., a regulated current signal or a regulated voltage signal) based on the analog feedback signal126. The driver increases power of the regulated source signal135to produce the drive signal component114.

FIG.7is a schematic block diagram of an example of a first drive sense circuit28-1coupled to a column electrode85-cand a second drive sense circuit28-2coupled to a row electrode85-rwith an identifying device38proximal to the electrodes. In this example, when it is said that the identifying device is “proximal” to the electrodes, the identifying device38is close enough to capacitively couple an information signal from the identifying device38to the electrodes. In the illustrated example, the identifying device can be, for example, a pen. Each of the drive sense circuits include a comparator, an analog to digital converter (ADC)35, a digital to analog converter (DAC)132, a signal source circuit133, and a driver. The functionality of this embodiment of a drive sense circuit was described with reference toFIG.6. The identifying device is operable to transmit a signal at one or more frequencies. In the illustrated embodiment, the identifying device is a pen transmitting an information signal at a frequency of f4, which affects the self and mutual capacitances of the electrodes85. The identifying device is not limited to transmitting the information signal at a single frequency, and can instead encode an identifier using multiple frequencies, patterns of frequencies, amplitudes, timing, or some combination thereof.

In this example, a first reference signal122-1is provided to the first drive sense circuit28-1. The first reference signal includes a DC component and/or an oscillating component at frequency f1. The first oscillating component at f1is used to sense impedance of the self-capacitance of the column electrode85c. The first drive sense circuit28-1generates a first sensed signal120-1that includes three frequency dependent components. The first frequency component at f1corresponds to the impedance of the self-capacitance at f1, which equals 1/(2πf1Cp1). The second frequency component at f2corresponds to the impedance of the mutual-capacitance at f2, which equals 1/(2πf2Cm_0). The third frequency component at f4corresponds to the signal transmitted by the identifying device.

Continuing with this example, a second reference signal122-2is provided to the second drive sense circuit28-2. The second analog reference signal includes a DC component and/or two oscillating components: the first at frequency f1and the second at frequency f2. The first oscillating component at f1is used to sense impedance of the shielded self-capacitance of the row electrode85-rand the second oscillating component at f2is used to sense the unshielded self-capacitance of the row electrode85-r. The second drive sense circuit28-2generates a second sensed signal120-2that includes three frequency dependent components. The first frequency component at f1corresponds to the impedance of the shielded self-capacitance at f3, which equals 1/(2πf1Cp2). The second frequency component at f2corresponds to the impedance of the unshielded self-capacitance at f2, which equals 1/(2πf2Cp2). The third frequency component at f4corresponds to an information signal transmitted by the identifying device.

As a further example, the identifying device transmits a sinusoidal signal having a frequency of f4. When the identifying device is near the surface of the touch screen, electromagnetic properties of the signal increase the voltage on (or current in) the electrodes proximal to the touch of the identifying device, or a person in contact with the identifying device. Since impedance is equal to voltage/current and as a specific example, when the voltage increases for a constant current, the impedance increases. As another specific example, when the current increases for a constant voltage, the impedance increases. The increase in impedance is detectable and is used as an indication of a touch.

FIG.8is a schematic block diagram illustrating an example of an information signal, which is generated by an identifying device, being sensed by a few drive sense circuits and being processed by a portion of the touch screen processing module of a touch screen display that is similar toFIG.7, with the difference being a touch of either the identifying device, or the touch of a person in contact with the identifying device. In this example, the self-capacitance and/or mutual capacitance of the electrodes is affected by the information signal transmitted by the identifying device38, as well as by a touch.

The effected self-capacitance of the column electrode85cis processed by the first bandpass filter160and the frequency interpreter164to produce a self-capacitance value168-1a. The effected mutual capacitance of the column electrode85cand row electrode85ris processed by the second bandpass filter162and the frequency interpreter166to produce a mutual-capacitance value170-1a.

The effected shielded self-capacitance of the row electrode85ris processed by the third bandpass filter160-1and the frequency interpreter164-1to produce a shielded self-capacitance value168-2a. The effected unshielded self-capacitance of the row electrode85ris processed by the fourth bandpass filter162-1and the frequency interpreter166-1to produce an unshielded self-capacitance value170-2a. As illustrated byFIGS.7and8, a touch screen, or other touch-sensitive panel, can be used to perform its normal touch-sensing function, while concurrently sensing a capacitively coupled information signal.

FIG.9is a diagram illustrating an identifying device implemented as a wearable ring. The wearable ring includes a housing170-1in the shape of ring, transmit electrode85t, and grounding electrodes85gseparated from the transmit electrode85tby dielectric172. The circuitry illustrated and discussed with reference toFIG.12is also included within the housing. The circuitry can be embedded in the dielectric172, with appropriate connections to grounding and transmit electrodes.

In an example of operation, the ring is worn on a user's finger, so that the grounding electrodes85gcontact the user's body. Signals having one or more frequencies are applied to the transmit electrode to generate an information signal. The electric field will vary in accordance with the signals applied to the transmit electrode. The grounding electrodes provide a capacitive grounding path for the signals. The signals cause the transmit electrode to generate an electric field encoding an information signal, which can be sensed by a touch-sensitive panel in proximity to the user. The exact distances required for capacitively coupling the information signal to a touch-sensitive panel can vary based on the strength of the electric field generated by the transmit electrode, a number and size of row and column electrodes employed by the touch-sensitive panel being used to sense the information signal, a manner in which the row and column electrodes of the touch-sensitive device are coupled to drive sense circuits, a strength and frequency of reference signals used by the touch-sensitive device, environmental conditions such as humidity, and the like. Note that because the user forms part of the capacitive signal path, the user's touch can, in some embodiments, be used as the means for capacitively coupling the information signal to a touch-sensitive panel.

In some embodiments, a battery can be included in the housing, and used to supply the identifying device with power. In other embodiments the identifying device includes circuitry capable of harvesting harvest power from electrical fields generated by a proximate touch-sensitive panel by using the transmit electrode to receive a power signal from the touch-sensitive panel. Power harvesting is discussed further with respect toFIG.17.

FIG.10is a diagram illustrating an identifying device implemented as a pair of glasses. The illustrated identifying device includes a housing170-2in the shape of a pair of glasses, transmit electrode85t, and grounding electrodes85gseparated from the transmit electrodes85tby dielectric172. The glasses-shaped identifying device functions in a manner similar to the ring-shaped identifying device.

FIG.11is a diagram illustrating an identifying device implemented as a carriable/wearable device. The illustrated identifying device includes a housing170-3in the shape of a FOB, tag, or small keycard attachable to a keychain, necklace, bracelet or the like. The FOB-shaped identifying device functions similarly to the other identifying devices discussed inFIGS.9and10, with the exception of an optional actuating button176.

In some embodiments, the housing of the FOB-shaped identifying device can include an adhesive strip, snap, hook and loop fastener, or the like that permits mounting the identifying device on a package, clothing, or other object. The identifying device also includes transmit electrode85t, and a grounding electrode85gseparated from the transmit electrodes85tby dielectric172. The grounding electrode85gcan be implemented as a conductive material forming a portion of the housing. When the conductive portion of the housing contacts a user's body, the grounding electrode85gcompletes the capacitive ground path.

In at least one embodiment, the actuating button176can be used to apply or remove power from circuitry included in the identifying device. In other embodiments, the grounding electrode85gcan be formed as a planar sheet or pad of conductive material, positioned within the housing; pressing the actuating button176couples the user to the grounding electrode.

FIG.12is a schematic block diagram illustrating a communication system including an identifying device38capacitively coupled to a touch-sensitive panel32. Identifying device38includes a power supply unit92, an ID frequency generator95, a driver30, and a transmit electrode85t. Touch sensitive panel32includes row electrodes85r, column electrodes85c, drive sense circuits28, a processing module93that further includes an access control module98and a frequency generation module91, memory94, and a communications module96configured to communicate to a communications network via a wired connection, via a radio-frequency wireless connection, or the like.

In an example of operation, identifying device38uses the ID frequency generator95to generate a modulated signal having one or more selected carrier frequencies, which are modulated to carry the identifier. Examples of operations, modulation types, and carrier frequencies that are used to produce the information signal are discussed further with refence toFIGS.15,16A,16B,18and19. The information signal carrying the identifier are supplied to the ID driver circuit30, which increases the power of those signals, and then applies the information signal to the transmit electrode85t, which is transmitted by creating an electric field corresponding to the signals making up the identifier. The frequency band of the information signal is in a frequency band that will be efficiently capacitively coupled from the identifying device38to the touch-sensitive panel32. The frequency band used has to be high enough to be efficiently transmitted via capacitively coupling and low enough not to be in an RF band.

The touch-sensitive panel32receives the information signal via capacitive coupling between the transmit electrode85tand the row and column electrodes, via a path including C3. The capacitive coupling path that includes C3is formed when the identifying device, or a human in contact with the identifying device is physically proximate to the touch sensitive panel32. The drive sense circuits28sense changes in impedance caused by changes in the self-capacitance of the row and/or column electrodes caused by presence of the information signal. The drive sense circuits output sensed signals, which include the information signal, to processing module93. Processing module93uses the access control module98to combine the sensed signals and recognize, recover, recreate, or otherwise extract the identifier included in the information signal transmitted by the identifying device38. Processing module93can store the identifier in memory94, communicate the identifier to an external device via communications module96, or use the identifier in conjunction with local processing functions.

The frequency generation module91determines and controls generation of frequencies to be used by the drive sense circuits for: sensing reference signals, providing power signals to be used by the identifying device38for power harvesting, and transmitting capacitively coupled data back to the identifying device38. For example, the identifying device can include a second touch-sensitive panel similar to touch-sensitive panel32, that supports two-way capacitive communications. Further, the processing module93functions to detect touches on the touch-sensitive panel32. Thus, as will be further described with reference toFIGS.29-31, a touch of the touch-sensitive panel32may convey information based upon one or more touch locations while the identifier is communicated from the identifying device38to the touch-sensitive panel32. This combination of information or conveyance of the identifier alone may be very useful for various applications, including package delivery, the identification of a user to unlock operation of a device serviced by the touch-sensitive panel32, e.g., cell phone, tablet computer, or other computing device, to identify a user for access to secure equipment or a secure location, e.g., in an industrial location, office location, home, etc.

FIG.13is a block diagram of an access control module98included in a touch-sensitive panel. Access control module98includes an ID generation module170for recognizing an identifier carried by the information signal transmitted by the identifying device, a security authorization module177for using an identifier recognized by ID generation module170to control access to various functions, and an event storage module178for storing information related to extraction and recognition of identifiers, and security access authorizations or denials associated with the extracted identifiers.

The ID generation module170includes a pattern module130and a comparison module174. The extracted data from one or more drive sense circuits is used by pattern module130and comparison module174to identify patterns representing identifiers.

An identifier can be represented by one or more frequencies or patterns of frequencies included in the information signal transmitted by the identifying device. The identifier can also be represented by one or more amplitudes or patterns of amplitudes of the one or more frequencies. In further embodiments, the identifier can also be represented by a timing or spatial pattern of those one or more frequencies. Any combination of frequency, frequency order, amplitude, amplitude order, spatial arrangements, or the like can be used consistent with the teachings set forth herein.

In a specific example, an identifier may be defined as a pattern of four frequencies, with the first and third frequencies having an amplitude representing logic 1's and the second and fourth frequencies having amplitudes representing logic 0's during a first period of time, followed immediately in time by those same four frequencies, but with the second and fourth frequencies having amplitudes representing logic 1's and the first and third frequencies having amplitudes representing logic 0's.

As another example, an identifier can be defined as a specific sequence of 8 frequency groups G1-G8made up of 4 different frequencies, f1-f4; G1includes f1and f2, the G2includes f2and f3; G3includes f3and f4, G4includes f1and f3, G5includes another instance of f1and f2, G6includes f3and f4, G7includes f2and f4, while G8includes a third instance of f1and f2.

Pattern module130receives extracted data from one or more row and column electrodes, and attempts to reconstruct and identify a pattern of the original information signal, so that the identifier can be recognized. The pattern module130operates to recognize the pattern by temporarily storing the extracted data in registers, or in a cache memory, in the order in which it is received. The comparison module174can be used to compare the temporarily stored data to data stored in lookup tables that correlate particular patterns to known identifiers. This comparison can be performed in near-real time, each time a piece of extracted data received, until a matching identifier is found in the lookup table. In other implementations, a “begin” tag and/or an “end” tag can be encoded in the information signal, and the pattern module stores and tests extracted data received between the begin and end tags. In some implementations, different drive sense circuits respond to different frequency components of an information signal. In some such cases, the pattern module can receive multiple items of extracted data at once, and can determine which drive sense circuit transmitted the data based on the data line on which the extracted data is received. When extracted data is received by row or column electrodes in different portions of the touch-sensitive display, the spatial location of the electrodes can be taken into account when attempting to identify a spatial pattern that forms part of the identifier extracted from the information signal.

Security authorization module177validates/approves access requests171received from an external device via communications module96, or provided internally to main processing module93. The access requests can include requests for full or partial access to local functionality of a touch-sensitive panel in which access control module98is located, for example a request for access to communications module96, access to a software application, access to locally stored files, or the like. In other embodiments, an access request can specify access to functionality associated with a different device, for which the touch-sensitive panel32provides primary or secondary authentication services.

For example, a security system may receive a request for authorization to enter a room in the form of an alphanumeric PIN entered into a keypad. Upon validation of the PIN, the keypad sends an access request to a mobile device carried by a user associated with the PIN. The mobile device associated with the user includes a touch screen configured in accordance with the teachings set forth herein. The user's mobile device prompts the user to place an identifying device proximate to the touch screen. In response to the prompt, the user places an identifying device, e.g. a FOB, in proximity to the touch screen. The FOB transmits an identifier included in a capacitively-coupled information signal, which is sensed by the touch screen of the user's device. The access module verifies the identifier, and responds to the security system that a valid identifier has been received. The security system can then act on that response to allow the user to enter the room.

Security authorization module177can determine whether a valid identifier has been received by querying event storage178. In one example, ID generation module170stores an event record in event storage178in response to identifying a valid identifier. The event record can include a time, a pointer to the identifier, and other pertinent information. Similarly, ID generation module170stores an event record if pattern module130recognizes an identifier, but comparison module174or security authorization module177determines that the identifier is invalid because it is included in a revocation list.

FIG.14is a schematic diagram of switch networks coupling signals having different frequencies to different electrodes for use in providing power and/or sensing capacitively-coupled information signals. In embodiments such as those discussed with reference toFIG.4, a touch-sensitive device includes one or more switch networks for selectively coupling electrodes to drive sense circuits to adjust sensitivity, resolution, and the like. Selectively coupling drive-sense circuits to particular frequencies can be performed in conjunction with selectively coupling drive-sense circuits to particular electrodes, so that different sense or transmit frequencies can be distributed to different portions of a touch-sensitive display, or to different combinations of row and column electrodes.

Frequency generation module91generates signals having frequencies for use in power coupling, data transmission, and/or sensing. The signals are selectively coupled to particular drive-sense circuits using switch network401-1. The drive-sense circuits are selectively coupled to particular electrodes85via switch network401. In the illustrated embodiment, switch network401also selectively couples power signals generated by frequency generation module91to particular electrodes85via driver30, effectively bypassing one or more drive sense circuits. Driver30can be used in some embodiments to increase the strength of power signals provided for power harvesting by identifying devices. The power harvesting signals may have the same frequency as one or more of the sensing or data signals generated by frequency generation module91, but in at least one embodiment, the power signals have a different frequency than sensing or data signals. The frequency of the power harvesting signals, fPowercan be selected to provide more transmitted power, to provide frequency separation between sense and power signals, or the like.

In the illustrated example, electrodes in a first physical area of a touch-sensitive panel are used to provide power that can be harvested by an identifying device, while other frequencies are used in another portion of the touch-sensitive panel is used to sense a capacitively-coupled information signal. In this example, three electrodes are coupled together, forming a relatively larger electrode pad in one portion of the touch-sensitive panel for use in power transmission. A first sensing/transmission signal having a frequency f2is coupled through a single drive-sense circuit to two electrodes85, forming an electrode sensing pad from electrodes in a portion of the touch-sensitive panel different from the portion used for power transmission. A second sensing/transmission signal having a frequency f4is coupled through a drive-sense circuit to a single electrode in yet another portion of the touch-sensitive panel. By controlling how many electrodes are coupled to particular drive-sense circuits and to particular frequencies, various embodiments provide flexibility in establishing sensing sensitivity sensing, transmission power, and the like.

FIG.15is a schematic block diagram of an identification frequency generator95included in an identifying device. The identifier is represented at a programmed ID value189(identifier) and includes 40 bits, which supports 210 unique identifiers. With the example ofFIG.15, four bits of the identifier189are carried by four carrier frequencies f1, f2, f9and f10. Multiplexor188is controlled to select four bits of the identifier (programmed ID value189) at a time to be modulated with corresponding carrier frequencies via amplitude modulators185-1,185-2,185-3and185-4. Thus, to convey a 40 bit identifier, 10 unique time segments are required. Thus, the embodiment ofFIG.15illustrates a combination of time-division and frequency-division multiplexing to convey the identifier from a first device to a second device.

FIGS.16A and16Bare diagrams illustrating the modulation of carrier signals to carry identification codes in accordance with embodiments of the present disclosure.FIG.16Aillustrates an embodiment in which 10 carriers (of unique frequencies) are employed in a time divided fashion to carry a 40 bit identifier. Thus, with the usage of 10 carriers, four time intervals are required to transmit the 40 bit identifier from an identifying device to the touch-sensitive panel of another device.FIG.16Billustrates an embodiment in which 40 carries (of unique frequencies) are employed to carry a 40 bit identifier. Thus, with the usage of 40 carriers, the 40 bit identifier is transmitted in a single time interval from an identifying device to the touch-sensitive panel of another device.

Note that with the embodiments described herein, the information signal may include other components in a time divided fashion, such other components including a preamble, a synchronization component, a header, and a CRC check component, for example. In such case, the identifier would be considered the payload. The header may indicate a format of the payload, e.g., frequency modulated, time modulated, frequency/time modulated, bit length, encoding format, etc. The header may be transmitted on a single carrier frequency that is continuously scanned by the touch-sensitive panel and that is modulated in a particular format. With the header information received, the receiving device configures itself to receive the payload, which includes the identifier.

FIG.17is a diagram illustrating an identifying device harvesting power from electric fields generated by a touch-sensitive panel. Transmit electrodes85t(FIGS.9-11) can be used as RX electrodes85RXfor power harvesting, while grounding electrodes85g(FIGS.9-11) can be used for common electrodes85Com. In other implementations, different electrodes can be used for sensing and power harvesting. As illustrated byFIG.17, a power signal received at the identifying device by the power supply unit92will create a voltage between RX electrode85RXand common electrode85Com. Common electrode85Comis shown being coupled to a half-wave rectifier, which produces a half-wave rectified voltage that can be filtered and regulated by power supply unit92to provide power for the identifying device. A power supply unit92includes components that capture energy coupled to the various enabled electrodes, stores the energy, and provides the energy to power other components of the identifying device that does not have independent power, e.g., a battery.

FIG.18is a schematic block diagram of examples of digital data formats in accordance with embodiments of the present disclosure. As known, digital data is a string of binary values. A binary value is either a logic “1” or a logic “0”. One binary value corresponds to a bit of the digital data. How the bits are organized into data words establishes the meaning for the data words. For example, American Standard Code for Information Interchange (ASCII) defines characters using 8-bits of data. For example, a capital “A” is represented as the binary value of 0100 0001 and a lower case “a” is represented as the binary value of 0110 0001.

A binary value can be expressed in a variety of forms. In a first example format, a logic “1” is expressed as a positive rail voltage for the duration of a 1-bit clock interval and logic “0” is expressed as a negative rail voltage for the duration of the 1-bit clock interval; or vice versa. The positive rail voltage refers to a positive supply voltage (e.g., Vdd) that is provided to a digital circuit (e.g., a circuit that processes and/or communicates digital data as binary values), the negative rail voltage refers to a negative supply voltage or ground (e.g., Vss) that is provided to the digital circuit, and the common mode voltage (e.g., Vcm) is half way between Vdd and Vss. The 1-bit clock interval corresponds to the inverse of a 1-bit data rate.

In a second example format, a logic “1” is expressed as a non-return to zero waveform that, for the first half of the 1-bit interval, is at the positive rail voltage (Vdd) and for the second half of the 1-bit interval is at the negative rail voltage (Vss). A logic “0” is expressed as a non-return to zero waveform that, for the first half of the 1-bit interval, is at the negative rail voltage (Vss) and for the second half of the 1-bit interval is at the positive rail voltage (Vdd). Alternatively, a logic “0” is expressed as a non-return to zero waveform that, for the first half of the 1-bit interval, is at the positive rail voltage (Vdd) and for the second half of the 1-bit interval is at the negative rail voltage (Vss). A logic “1” is expressed as a non-return to zero waveform that, for the first half of the 1-bit interval, is at the negative rail voltage (Vss) and for the second half of the 1-bit interval is at the positive rail voltage (Vdd).

In a third example format, a logic “1” is expressed as a return to zero waveform that, for the first half of the 1-bit interval, is at the positive rail voltage (Vdd) and for the second half of the 1-bit interval is at the common mode voltage (Vcm). A logic “0” is expressed as a return to zero waveform that, for the first half of the 1-bit interval, is at the negative rail voltage (Vss) and for the second half of the 1-bit interval is at the common mode voltage (Vcm). Alternatively, a logic “0” is expressed as a return to zero waveform that, for the first half of the 1-bit interval, is at the positive rail voltage (Vdd) and for the second half of the 1-bit interval is at the common mode voltage (Vcm). A logic “1” is expressed as a return to zero waveform that, for the first half of the 1-bit interval, is at the negative rail voltage (Vss) and for the second half of the 1-bit interval is at the common mode voltage (Vcm).

With any of the digital data formats, a logic value needs to be within 10% of a respective rail voltage to be considered in a steady data binary condition. For example, for format 1, a logic 1 is not assured until the voltage is at least 90% of the positive rail voltage (Vdd). As another example, for format 1, a logic 0 is not assured until the voltage is at most 10% of the negative rail voltage (Vss).

FIG.19is a functional diagram of an embodiment of an LVDC26in accordance with embodiments of the present disclosure. In a data transmission mode, the LVDC26functions to convert transmit (TX) digital data190into an analog transmit signal196in the form of an electric field that is sensed by a sense electric field generated by another device. In one example, where LVDC26is included in an identifying device, the transmit digital data212is referred to as an information signal that carries an identifier associated with the identifying device. In this example, the information signal is applied to an electrode to generate an electric field—the analog transmit signal196is capacitively coupled to an external device (not illustrated), and the external device senses the information signal and extracts the identifier encoded into the analog transmit signal196.

In an example of a receive, or sensing mode, the transmit digital data212is a sinusoidal signal have a sensing frequency. In at least one embodiment, the sensing frequency is used as a reference frequency for a drive-sense circuit included in the LVDC, and allows the LDVC to identify changes in electrode impedance. The sinusoidal signal is applied to an electrode to generate analog TX signal196, which is used as a sense electric field having a frequency corresponding to the sensing frequency, e.g. the reference frequency of the drive-sense circuit. Variations in the sense electric field caused by an analog receive (RX) signal are sensed to recover receive digital data206. Note that an information signal, from the perspective of a sensing device, is referred to as an analog RX signal. The same signal, from the perspective of a transmitting device, is referred to as an analog TX signal.

In at least one embodiment, LDVC26is included in a touch-sensitive panel that includes multiple LDVCs. One or more of the LDVCs is configured to sense particular frequencies by applying reference signals with different frequencies to different drive-sense circuits included in the LDVCs. In some such embodiments, the information signal includes an identification code, and is made up of multiple different frequency components. Different LDVCs can be used to concurrently sense different frequency components of the identifying signal, or different frequency components can be sensed sequentially, by sequentially applying reference signals of different frequencies to one or more LDVCs over time.

The analog RX signal198is converted to receive (RX) digital data206by one or more LDVCs26. For implementations in which different frequency components of the information signal carry different portions of an identification code or other data to be recovered, received digital data from multiple LDVCs can be combined to extract the identification code from the information signal. In some embodiments, the presence of certain frequencies, or certain combinations of frequencies, may define the identification code carried by the information signal. In other embodiments, a spatial pattern, timing, or particular combination of frequencies, amplitudes, timing, and spatial patterns sensed by one or more LDVCs can be used to define the identification code.

Referring to transmit functionality, LVDC26receives the transmit digital data212from its host device and transmits the analog TX signal196to another LVDC capacitively coupled to LDVC26. The analog TX signal includes a DC component192and an oscillating component194. The oscillating component194includes data encoded into one or more channels of a frequency band. As an example, the transmit digital data is encoded into one channel, as such the oscillating component includes one frequency: the one corresponding to the channel. As another example, the transmit digital data is divided into x number of data streams. The LVDC encodes the x number of data streams on to x number of channels. Thus, the oscillating component194includes x number of frequencies corresponding to the x number of channels.

Referring to receive functionality, the LVDC26receives the analog RX signal198from another LVDC (e.g., the one it sent its analog TX signal to and/or another capacitively coupled LVDC. The analog RX signal198includes a DC component193and a receive oscillating component195. The receive oscillating component195includes data encoded into one or more channels of a frequency band by the other LVDC and has a very low magnitude. The LVDC converts the analog RX signal198into the receive digital data206, which it provides to its host device. Examples of a host device include an identifying device that may or may not include a touch-sensitive panel, a touchpad including a touch-sensitive panel, a laptop, a tablet, a smart phone, a display including a touch-sensitive panel, or any of the computing devices, wireless computing devices, servers, base stations, or wireless access points, illustrated inFIG.1.

FIG.20is a schematic block diagram of an embodiment of a Low Voltage Drive Circuit (LVDC)26included in a host device204, and coupled to an electrode configured to capacitively couple host device204to another device. In implementations where host device204includes touch-sensitive panel, such as a touch-screen, the electrode is one of multiple row and column electrodes included in the touch screen. In implementations where LVDC is included in a transmit device, such as a FOB, ring, or other similar device, that lacks a touch-sensitive panel, the electrode may be one of a limited number of transmit electrodes, for example a single transmit electrode.

The host device204includes a processing module93and memory94(e.g., volatile memory and/or non-volatile memory). The memory94can store all or part of an LVDC driver216application in some implementations. Processing module93can be a general purpose processor, providing functionality similar to that provided by a mobile phone or laptop computer, or a specialty processor with limited capabilities. For example, where host device204is an identifying device that operates using harvested power, Processing module93may perform a limited number of hardcoded functions, memory94may include a pre-programmed identifier, LVDC26may include logic circuitry and fixed signal generation circuitry configured to provide transmission of a limited number of different identification codes, e.g.1or2.

The LVDC26includes a drive sense circuit28, a receive analog to digital converter (ADC) circuit35, and a transmit digital to analog converter (DAC) circuit210. In embodiments without sensing/receiving capability, receive analog digital circuitry108may be omitted.

In an example of operation, the processing module104of the host device204accesses the LVDC driver216to set up the LVDC26for operation. For example, the LVDC driver216includes operational instructions and parameters that enable the host device204to effectively use the LVDC for data communications. For example, the parameters include two or more of: one or more communication scheme parameters; one or more data conveyance scheme parameters; one or more receive parameters; and one or more transmit parameters. A communication scheme parameter is one of: independent communication (e.g., push data to other device without prompting from other device); dependent communication (e.g., push or pull data to or from other device with coordination between the devices); one to one communication; half duplex communication; and full duplex communication.

A data conveyance scheme parameter is one of: a data rate per line; a number of bits per data rate interval; data coding scheme per line and per number of bits per data rate interval; direct data communication; modulated data communication; power level of signaling; and voltage/current level for a data coding scheme.

A receive parameter includes one of: a digital data format for the received digital data; a packet format for the received digital data; analog to digital conversion scheme in accordance with parameter(s) of the communication scheme and of the data conveyance scheme of transmitted data by other LVDCs; and digital filtering parameters (e.g., bandwidth, slew rate, center frequency, digital filter coefficients, number of taps of digital filtering, stages of digital filtering, etc.).

A transmit parameter includes one of: a digital data format for the transmit digital data; transmission frequencies; frequency patterns; timing patterns; a packet format for the transmit digital data (if data packets are used); and digital to analog conversion in accordance with parameter(s) of the communication scheme and of the data conveyance scheme.

Once the LVDC26is set up for a particular data communication, the transmit DAC circuit210receives the transmit digital data190from its host device204in one of the formats ofFIG.18, or another format, and at a data rate of the host device (typically in the KHz range). If necessary, the transmit DAC circuit210converts the format of the transmit digital data190in accordance with one or more transmit parameters232. In addition, the transmit DAC circuit210can synchronize the transmit digital data to produce a digital input of n-bits per time interval, where “n” is an integer greater than or equal to one.

The transmit DAC circuit210converts the digital input into analog outbound data234via a range limited digital to analog converter (DAC) and a DC reference source. The drive sense circuit28converts the analog outbound data234into the analog transmit signal196and drives it on to the electrode for capacitive coupling.

The drive sense circuit28receives the analog RX signal198and converts it into analog inbound data224. The receive ADC circuit108converts the analog inbound data224into received digital data206. The receive ADC circuit108filters the received digital data206in accordance with one or more receive parameters226to produce the filtered data. The receive ADC circuit108formats and packetizes the filtered data (as needed) in accordance with one or more receive parameters226to produce the received digital data206. The receive ADC circuit108provides the received digital data206to Processing module93.

FIG.21is a schematic block diagram of an embodiment of a drive sense circuit28of a Low Voltage Drive Circuit (LVDC)26coupled an electrode. The drive sense circuit28includes a change detection circuit250, a regulation circuit252, and a power source circuit254.

The change detection circuit250, the regulation circuit252, and the power source circuit254operate in concert to keep the inputs of the change detection circuit250to substantially match (e.g., voltage to substantially match, current to substantially match, impedance to substantially match). The inputs to the change detection circuit250include the analog outbound data234and signals applied to the electrode (e.g., the analog RX signal198and the analog TX signal196).

When there is no analog RX signal, the only signal applied to the electrode is the analog TX signal196. The analog TX signal196, is created by adjusting the operation of the change detection circuit250, the regulation circuit252, and the power source circuit254to match the analog outbound data234. Since the transmit the analog TX signal196tracks the analog outbound data234within the drive sense circuit28, when there is no analog RX signal158, the analog circuit250224is a DC value.

When an analog RX signal198is being received, the change detection circuit250, the regulation circuit252, and the power source circuit254continue to operate in concert to keep the inputs of the change detection circuit250to substantially match. With the presence of the analog RX signal198, the output of the change detection circuit250will vary based on the analog RX signal198, which produces the analog inbound data224. The regulation circuit252converts the analog inbound data224into a regulation signal260. The power source circuit254adjusts the generation of its output (e.g., a regulated voltage or a regulated current) based on the regulation signal260to keep the inputs of the change detection circuit250substantially matching.

According to another embodiment, and referring to at least ofFIGS.12,15and16, among other Figures, an identifying device includes a power supply unit, at least one electrode, an identification frequency generator, and an identification driver circuit The identification frequency generator couples to the power supply unit and is configured to produce a modulated signal having at least one modulated carrier frequency component that carries a programmed ID corresponding to the device. The identification driver circuit couples to the power supply unit, to the identification frequency generator, and to the at least one electrode, the identification driver circuitry configured to convert the modulated signal to a transmit signal and to couple the transmit signal to the at least one electrode for capacitively coupling of the transmit signal to a touch-sensitive panel.

This embodiment includes multiple optional aspects. With one aspect, the at least one electrode is configured to capacitively couple to the touch-sensitive panel via a human body. With another aspect, the at least one electrode is configured to couple to at least one external conductor. With still another aspect, the power supply unit is configured to collect energy that is capacitively coupled to the at least one electrode. With this aspect, the energy that is capacitively coupled to the at least one electrode is in a first frequency band and the at least one frequency component is in a second frequency band that differs from the first frequency band.

With another aspect, the modulated signal includes a single carrier frequency component that is modulated over time to carry all bits of the programmed ID. With still another aspect, the modulated signal comprises a plurality of carrier frequency components, each of which is modulated to carry a single bit of the programmed ID. With yet another aspect, the modulated signal comprises a plurality of carrier frequency components, each of which is modulated over time to carry multiple bits of the programmed ID. With any of these embodiments, the device includes a substrate onto which the power supply unit, the at least one electrode, the identification frequency generator, and the identification driver circuitry are formed/mounted. Further, with any of these aspects, the device includes a housing in which the power supply unit, the at least one electrode, the identification frequency generator, and the identification driver circuitry are mounted.

According to another embodiment, further referring to previously described Figures, a device includes at least one electrode to at least one electrode configured to capacitively couple to a touch-sensitive panel, a power supply unit, an identification frequency generator, and an identification driver circuit. The power supply unit is configured to collect energy that is capacitively coupled to the at least one electrode from the touch-sensitive panel. The identification frequency generator couples to the power supply unit and is configured to produce a modulated signal having at least one modulated carrier frequency component that carries a programmed ID corresponding to the device. The identification driver circuit couples to the power supply unit, to the identification frequency generator, and to the at least one electrode, and is configured to convert the modulated signal to a transmit signal and to couple the transmit signal to the at least one electrode for capacitively coupling of the transmit signal to a touch-sensitive panel.

This embodiment includes a number of optional aspects. With one aspect, the at least one electrode is configured to capacitively couple to the touch-sensitive panel via a human body. With another aspect, the at least one electrode is configured to couple to at least one external conductor. With a further aspect, the energy that is capacitively coupled to the at least one electrode is in a first frequency band and the at least one frequency component is in a second frequency band that differs from the first frequency band.

With still another aspect, the modulated signal comprises a single carrier frequency component that is modulated over time to carry all bits of the programmed ID. Further, with another aspect, the modulated signal includes a plurality of carrier frequency components, each of which is modulated to carry a single bit of the programmed ID. With still another aspect, the modulated signal includes a plurality of carrier frequency components, each of which is modulated over time to carry multiple bits of the programmed ID. Other described aspects may also be included with either of these described embodiments.

FIG.22is a schematic block diagram of another embodiment of a drive sense circuit28of an LVDC26coupled to one or more electrodes. The drive sense circuit28includes the change detection circuit250, the regulation circuit252, the power source circuit254, and a data input circuit255. The change detection circuit250, the regulation circuit252, and the power source circuit254function as discussed with reference toFIG.21to keep the inputs of the change detection circuit250substantially matching. In this embodiment, however, the inputs to the change detection circuit250are the signals applied to the electrode (e.g., the analog TX signal196and the analog RX signal198) and an analog reference signal122(e.g., a sinusoidal reference signal at a sensing frequency, a DC voltage reference signal or DC current reference signal). The analog outbound data234is inputted to the data input circuit255.

The data input circuit255creates the analog TX signal196from the analog outbound data234and drives it on to the electrode. In an example, the data input circuit255causes an electric field generated by the electrode to vary based on the analog inbound data224, thereby producing the analog TX signal196.

Since the analog TX signal196is being created outside of the feedback loop of the change detection circuit250, the regulation circuit252, and the power source circuit254, the analog inbound data224will include a component corresponding to the analog RX signal198and another component corresponding to the analog TX signal196.

FIG.23is a flowchart illustrating a method used by a touch-sensitive panel to identify a device based on a capacitively coupled information signal. As illustrated by block301, the touch sensitive panel generates electric fields by applying reference signals at one or more desired frequencies to one or more drive-sense circuits. The drive-sense circuits couple the reference signals to electrodes, which generated sensing fields corresponding to reference signals.

As illustrated by block303, the touch-sensitive panel receives a capacitively coupled information signal from an identifying device. The information signal can include one or more separate signals, each including one or more frequency components. The frequency components may be amplitude modulated.

As illustrated by blocks305and307, data is extracted from the information signal. As shown by block305, drive-sense circuits detect changes in electrode impedances caused by interactions of the information signal and the electric fields. As illustrated by block307, an analog to digital converter, which may or may not be included in the drive-sense circuit, converts the detected impedance changes into digital data.

As illustrated by block309, a processing module included in the touch-sensitive panel identifies the identifying device, e.g. the device that transmitted the information signal, based on the data extracted from the information signal. The identifying device can be identified using lookup tables or other data structures that link particular identifiers to particular devices, users, or the like. For example, data extracted from the information signal can be analyzed to identify patterns that correspond to particular identifiers, and then those particular identifiers can be linked to particular devices or users.

FIG.24is a flowchart illustrating a method of generating a power coupling signal by a touch-sensitive panel. As illustrated by block311, one or more electrode pads for power transmission are formed. The electrode pads can be formed by coupling multiple row and/or column electrodes to a single drive-sense circuit using one or more switch networks, by coupling multiple electrodes together and to an output of a frequency generation circuit, or the like. Row and column electrodes in different parts of a touch-sensitive display may be used to provide exclusively power coupling signals, exclusively sensing signals, or exclusively transmit signals. Alternatively power-coupling signals can be interleaved or otherwise mixed with sensing and/or transmit signals across multiple areas of the touch-sensitive display.

As illustrated by block313, frequency signals to be applied to particular electrodes or electrode pads are selected, and the information provided to a switch controller. The switch controller causes one or more switch networks to couple signals having selected frequencies to selected row and/or column electrodes.

As illustrated by blocks315and317, if one of the selected frequencies is a power-coupling signal, a power-coupling reference or drive signal at a power-coupling frequency is provided to selected row and/or column electrodes individually, or to electrode pads formed using multiple row and/or column electrodes. As illustrated by blocks315and319, if no power-coupling signal will be used, sensing reference/drive signals are provided to selected electrodes at the frequencies selected at block313.

The decision at block315can be made based on capability data included in the information signal, by cross-referencing an identifier extracted from an information signal with information included in a device capabilities lookup table, or the like. For example, an identification code extracted from an information signal generated by a particular identifying device may be used to look up stored information indicating the capabilities of that particular identifying device. Those capabilities can include information indicating whether the identifying device includes power-harvesting capabilities.

In some embodiments, the decision about whether to generate a power-coupling signal can be based on a type of identifying device. The type of identifying device can be determined, in some cases, based on the identifier itself (is it an older identifier or a newer identifier), based on frequency components or patterns included in the information signal, or the like. In yet other embodiments, the decision to generate a power-coupling system may depend on capabilities of the touch-sensitive panel.

FIG.25is a flowchart illustrating use of transmission patterns to extract an identification code from a capacitively coupled information signal. As illustrated by block321, electric fields are generated by applying drive signals to row and column electrodes included in a touch-sensitive panel. As illustrated by block323, an information signal capacitively coupled to the touch sensitive panel is sensed, e.g. by detecting changes in electrode impedance. As shown by block325, the impedance changes are converted to received data by drive-sense circuits.

As illustrated by block327, one or more transmission patterns associated with the sensed information signal are identified. For example, the information signal may include certain frequency, spatial, amplitude, and/or timing patterns. For example, an identifier to be extracted from an information signal may be represented by a pattern of repeating frequencies, by a pattern of varying amplitudes associated with certain frequencies, by a length of time a given pattern repeats before being varied, by varying a number of frequencies used to create the information signal, or the like. Data extracted from the information signal having a single frequency can include digital data modulated onto that single frequency to cause corresponding variations in an electric field that is capacitively coupled to a touch-sensitive panel.

As illustrated by block329, the identified pattern can be recognized as an identifier or identification code by comparing the identified pattern to a list of known identifiers or identification codes. In some embodiments, the identified pattern can be used to positively identify the device transmitting the information signal based on characteristics of the identifier, such as a number of frequency components, a range of frequencies used, a type of pattern used, or the like.

FIG.26is a flowchart illustrating a method of capacitively communicating between an identifying device and a touch-sensitive panel. As illustrated by block331, an identifying device can begin generating an information signal by generating an identification code that includes one or more frequencies, one or more frequency or other patterns, or the like. Generating the identification code includes, generating the signals used to construct the identification code. Assume, for example, that an identification code requires transmission of two signals having a first frequency and a second frequency, and each of those signals is required to encode the same 4-bit digital word. The identifying device will generate a first signal, having a first frequency, and amplitude modulate the first signal to include the 4-bit digital word. The signal strength of the first signal will be regulated, as illustrated by block333, and the first regulated signal will be applied to a transmit electrode to generate a corresponding electrical field, as shown by block335. As illustrated by block337, the electric field corresponding to the first signal will be capacitively coupled to an external device, such as a touch-sensitive panel. The first signal may be transmitted for a predefined period of time, to ensure that the first signal can be recognized.

The identifying device will then generate a second signal, having a second frequency, and amplitude modulate the second signal to include the 4-bit digital word. The signal strength of the second signal will be regulated, and the second regulated signal will be applied to a transmit electrode to generate a corresponding electrical field. The electric field corresponding to the second signal will be capacitively coupled to an external device, such as a touch-sensitive panel. The second signal may be transmitted for a predefined period of time, to ensure that the second signal can be recognized. Upon receipt of the second signal, the touch-sensitive panel will recognize the pattern by matching it to a known identifier pattern.

In some embodiments, the first and second signal can be mixed, and applied to the transmit electrode concurrently. It will be appreciated that described set of signals concurrently may define a different identification code than the identification code defined by sequential transmission of those same signals.

FIG.27is a flowchart illustrating a method of controlling access based on an identifier extracted from a capacitively-coupled information signal. As illustrated by block339, electric fields are generated by applying drive signals to row and column electrodes included in a touch-sensitive panel of computing device. As illustrated by block341, an information signal, which encodes an identifier, is capacitively coupled to the touch-sensitive panel. The information signal is sensed using changes in electrode impedances caused by the information signal. As illustrated by block343, the impedance changes are converted to received data. The identifier is extracted/recovered from the information signal based on the received data, as illustrated by block345.

As illustrated by block347, access to one or more functions of a computing device are controlled based on the extracted identifier. Access to functions can include access to a network interface card included in the touch-sensitive panel, access to an application already executing on the touch-sensitive panel, access to functionality that allows launching a program or application, access to a mail, social media, or other communication platform accessible via the touch-sensitive panel. Functionality being controlled can include unlocking a door, turning on a light, starting or stopping a vehicle, booting or shutting down a computing device, dialing a phone number, activating an appliance, transmitting a stored file or password associated with the extracted identifier, automatically deleting a pre-designated file or set of files, access an encrypted hard drive, or the like.

Controlling access can include transmitting the extracted identifier to an external service, and allowing or denying access to a function based on a response from that service. Controlling access can also include receiving a request for access, and granting that request based on the extracted identifier. Controlling access can further include determining a time difference between receiving a request for access and receiving the information signal. Controlling access can also include automatically executing a function, without requiring any additional user action, in response to determining that the extracted identifier is valid. Controlling access can also include providing access to a financial account, automatically populating one or more fields in a computerized form.

FIG.28is a flowchart illustrating another method of controlling access to requested functionality based on an identifier extracted from a capacitively-coupled information signal. As illustrated by block349, an identifier is generated based on data extracted from a capacitively-coupled information signal. As illustrated by block351, the identifier is provided to a security authorization module. As shown by block353an event record associated with receipt of the identifier is stored.

As illustrated by block355, a request for access to device functionality is received. The request can be an internal request generated by a process running on the touch-sensitive display, or an external request receive via a communications interface included in the touch-sensitive display. As illustrated by block357, a check is made to determine whether the identifier allows access to the requested functionality. For example, if access to particular file is requested, a list indicating identifiers that are allowed access to the function. In other embodiments the security authorization module can transmit the identifier to an external service, such as an active directory service, that makes the access determination and informs the security authorization module of its decision.

As illustrated by block359, if the identifier does not provide authorization to access the requested functionality, the security authorization module denies the access, and generates (or updates) an event record including information about the access request, the identifier, and the denial of access, as illustrated by block361. In some embodiments denying access can include denying access to all or part of a process, file, application, device, or the like.

As illustrated by block363, if the identifier is sufficient to provide authorization to access the requested functionality, the security authorization module grants the access, and generates (or updates) an event record including information about the access request, the identifier, and the access grant, as illustrated by block365. Granting access can include transmitting an authorization message to an application or process associated with the requested functionality. In some embodiments granting access can include granting full access, or only partial access.

FIG.29is a diagram illustrating a hand of a user on which an identifying device in the form of a ring is located and another finger of the hand contacting a touch-sensitive panel in accordance with embodiments of the present disclosure. The identifying device404is worn on the hand402of a user and couples the identifier to a touch-sensitive panel400in accordance with the structure(s) and operation(s) previously described herein. With this illustration, the information signal produced by the identifying device404is capacitively coupled via the hand402of the user to the touch-sensitive panel400. In various operations, the information signal may be coupled to the touch-sensitive panel400without an actual touch by hand402on touch-sensitive panel400. In such case, sufficient capacitive coupling exists between the hand402and the touch-sensitive panel400without a touch to support transmission of the information signal from the identifying device404, through the hand402, to the touch-sensitive panel400.

In one use case, the identifier is used to authenticate a user for access to equipment, to restricted access spaces, and/or for other authentication purposes. In another use case, the identifier is simply used to provide evidence of the user proximate the touch-sensitive panel400. In a package delivery example, the touch-sensitive panel400may be located proximate a door of a dwelling and the identifier provides proof that the user was present at a particular time, and perhaps for a particular purpose. As will be described further with reference toFIGS.30and31, the user's presence may be used for package delivery or other delivery proof. Because the identifier is employed to identify a particular individual, which may work for a particular service company, e.g., package delivery company, receipt of the identifier by the touch-sensitive panel400, touching of the user's hand402to the touch-sensitive panel and relaying of the identifier evidences the user's presence at a particular time.

FIG.30is a diagram illustrating a package delivery system in accordance with embodiments of the present disclosure. With this embodiment, a delivery person454delivers package456to location, e.g., home, office, warehouse, etc. The location includes touch-sensitive panel450that receives information regarding the delivery person454and/or package456. Structure452, which may be a door mat, electrode structure, or another structure may also be present to couple information signals. An identifying device458or458is worn by the user454and conveys an identifier to the touch-sensitive panel450. The structure and operation of the equivalent circuitry and devices for supporting communication of information signals illustrated inFIG.30is consistent with that previously described herein.

The package456may also include an identifying device466that is operable to convey a corresponding identifier to the touch-sensitive panel450via the body of the delivery person454. As an example of operation, the package456has a unique identifier, which is conveyed to the touch-sensitive panel450. The touch-sensitive panel450is coupled to a communication infrastructure and conveys received information, which may be further used to confirm delivery of the package456. Conveying information via the structure452may be performed similarly/consistently with conveying information via touch-sensitive panel450. The identifying device466may couple to electrodes462and/or464, which increases capacitive coupling between the identifying device466and the touch-sensitive panel for energy collection and information signal communication purposes.

FIG.31is a diagram illustrating a package delivery system in accordance with embodiments of the present disclosure. The structure and operations illustrated inFIG.31is similar/same to that ofFIG.30. However, withFIG.31, the delivery person454holds the package near touch-sensitive panel450and information is conveyed directly from identifying device466.

FIG.32is a diagram illustrating a package identification system in accordance with embodiments of the present disclosure. With the system ofFIG.32, packages458,460, and462are carried by conveyer belt as they pass touch-sensitive panel450. Each of the packages includes an identifying device that capacitively couples to the touch-sensitive panel450and transmits respective information signals to identify the package. The structures and operations previously described herein support communications of this system.

It is noted that terminologies as may be used herein such as bit stream, stream, signal sequence, etc. (or their equivalents) have been used interchangeably to describe digital information whose content corresponds to any of a number of desired types (e.g., data, video, speech, text, graphics, audio, etc. any of which may generally be referred to as ‘data’). A touch-sensitive pad referred to herein may also be referred to as a touch-sensitive panel and vice versa. These terms are used interchangeably herein to refer to a structure that senses touch and that may also be used to transmit and/or receive information signals as described herein.

As may be used herein, the terms “substantially” and “approximately” provide an industry-accepted tolerance for its corresponding term and/or relativity between items. For some industries, an industry-accepted tolerance is less than one percent and, for other industries, the industry-accepted tolerance is 10 percent or more. Other examples of industry-accepted tolerance range from less than one percent to fifty percent. Industry-accepted tolerances correspond to, but are not limited to, component values, integrated circuit process variations, temperature variations, rise and fall times, thermal noise, dimensions, signaling errors, dropped packets, temperatures, pressures, material compositions, and/or performance metrics. Within an industry, tolerance variances of accepted tolerances may be more or less than a percentage level (e.g., dimension tolerance of less than +/−1%). Some relativity between items may range from a difference of less than a percentage level to a few percent. Other relativity between items may range from a difference of a few percent to magnitude of differences.

As may also be used herein, the term(s) “configured to”, “operably coupled to”, “coupled to”, and/or “coupling” includes direct coupling between items and/or indirect coupling between items via an intervening item (e.g., an item includes, but is not limited to, a component, an element, a circuit, and/or a module) where, for an example of indirect coupling, the intervening item does not modify the information of a signal but may adjust its current level, voltage level, and/or power level. As may further be used herein, inferred coupling (i.e., where one element is coupled to another element by inference) includes direct and indirect coupling between two items in the same manner as “coupled to”.

As may even further be used herein, the term “configured to”, “operable to”, “coupled to”, or “operably coupled to” indicates that an item includes one or more of power connections, input(s), output(s), etc., to perform, when activated, one or more its corresponding functions and may further include inferred coupling to one or more other items. As may still further be used herein, the term “associated with”, includes direct and/or indirect coupling of separate items and/or one item being embedded within another item.

As may be used herein, the term “compares favorably”, indicates that a comparison between two or more items, signals, etc., provides a desired relationship. For example, when the desired relationship is that signal 1 has a greater magnitude than signal 2, a favorable comparison may be achieved when the magnitude of signal 1 is greater than that of signal 2 or when the magnitude of signal 2 is less than that of signal 1. As may be used herein, the term “compares unfavorably”, indicates that a comparison between two or more items, signals, etc., fails to provide the desired relationship.

As may be used herein, one or more claims may include, in a specific form of this generic form, the phrase “at least one of a, b, and c” or of this generic form “at least one of a, b, or c”, with more or less elements than “a”, “b”, and “c”. In either phrasing, the phrases are to be interpreted identically. In particular, “at least one of a, b, and c” is equivalent to “at least one of a, b, or c” and shall mean a, b, and/or c. As an example, it means: “a” only, “b” only, “c” only, “a” and “b”, “a” and “c”, “b” and “c”, and/or “a”, “b”, and “c”.

As may also be used herein, the terms “processing module”, “processing circuit”, “processor”, “processing circuitry”, and/or “processing unit” may be a single processing device or a plurality of processing devices. Such a processing device may be a microprocessor, micro-controller, digital signal processor, microcomputer, central processing unit, field programmable gate array, programmable logic device, state machine, logic circuitry, analog circuitry, digital circuitry, and/or any device that manipulates signals (analog and/or digital) based on hard coding of the circuitry and/or operational instructions. The processing module, module, processing circuit, processing circuitry, and/or processing unit may be, or further include memory and/or an integrated memory element, which may be a single memory device, a plurality of memory devices, and/or embedded circuitry of another processing module, module, processing circuit, processing circuitry, and/or processing unit. Such a memory device may be a read-only memory, random access memory, volatile memory, non-volatile memory, static memory, dynamic memory, flash memory, cache memory, and/or any device that stores digital information. Note that if the processing module, module, processing circuit, processing circuitry, and/or processing unit includes more than one processing device, the processing devices may be centrally located (e.g., directly coupled together via a wired and/or wireless bus structure) or may be distributedly located (e.g., cloud computing via indirect coupling via a local area network and/or a wide area network). Further note that if the processing module, module, processing circuit, processing circuitry and/or processing unit implements one or more of its functions via a state machine, analog circuitry, digital circuitry, and/or logic circuitry, the memory and/or memory element storing the corresponding operational instructions may be embedded within, or external to, the circuitry comprising the state machine, analog circuitry, digital circuitry, and/or logic circuitry. Still further note that, the memory element may store, and the processing module, module, processing circuit, processing circuitry and/or processing unit executes, hard coded and/or operational instructions corresponding to at least some of the steps and/or functions illustrated in one or more of the Figures. Such a memory device or memory element can be included in an article of manufacture.

One or more embodiments have been described above with the aid of method steps illustrating the performance of specified functions and relationships thereof. The boundaries and sequence of these functional building blocks and method steps have been arbitrarily defined herein for convenience of description. Alternate boundaries and sequences can be defined so long as the specified functions and relationships are appropriately performed. Any such alternate boundaries or sequences are thus within the scope and spirit of the claims. Further, the boundaries of these functional building blocks have been arbitrarily defined for convenience of description. Alternate boundaries could be defined as long as the certain significant functions are appropriately performed. Similarly, flow diagram blocks may also have been arbitrarily defined herein to illustrate certain significant functionality.

To the extent used, the flow diagram block boundaries and sequence could have been defined otherwise and still perform the certain significant functionality. Such alternate definitions of both functional building blocks and flow diagram blocks and sequences are thus within the scope and spirit of the claims. One of average skill in the art will also recognize that the functional building blocks, and other illustrative blocks, modules and components herein, can be implemented as illustrated or by discrete components, application specific integrated circuits, processors executing appropriate software and the like or any combination thereof.

In addition, a flow diagram may include a “start” and/or “continue” indication. The “start” and “continue” indications reflect that the steps presented can optionally be incorporated in or otherwise used in conjunction with one or more other routines. In addition, a flow diagram may include an “end” and/or “continue” indication. The “end” and/or “continue” indications reflect that the steps presented can end as described and shown or optionally be incorporated in or otherwise used in conjunction with one or more other routines. In this context, “start” indicates the beginning of the first step presented and may be preceded by other activities not specifically shown. Further, the “continue” indication reflects that the steps presented may be performed multiple times and/or may be succeeded by other activities not specifically shown. Further, while a flow diagram indicates a particular ordering of steps, other orderings are likewise possible provided that the principles of causality are maintained.

The one or more embodiments are used herein to illustrate one or more aspects, one or more features, one or more concepts, and/or one or more examples. A physical embodiment of an apparatus, an article of manufacture, a machine, and/or of a process may include one or more of the aspects, features, concepts, examples, etc. described with reference to one or more of the embodiments discussed herein. Further, from figure to figure, the embodiments may incorporate the same or similarly named functions, steps, modules, etc. that may use the same or different reference numbers and, as such, the functions, steps, modules, etc. may be the same or similar functions, steps, modules, etc. or different ones.

While the transistors in the above described figure(s) is/are shown as field effect transistors (FETs), as one of ordinary skill in the art will appreciate, the transistors may be implemented using any type of transistor structure including, but not limited to, bipolar, metal oxide semiconductor field effect transistors (MOSFET), N-well transistors, P-well transistors, enhancement mode, depletion mode, and zero voltage threshold (VT) transistors.

Unless specifically stated to the contra, signals to, from, and/or between elements in a figure of any of the figures presented herein may be analog or digital, continuous time or discrete time, and single-ended or differential. For instance, if a signal path is shown as a single-ended path, it also represents a differential signal path. Similarly, if a signal path is shown as a differential path, it also represents a single-ended signal path. While one or more particular architectures are described herein, other architectures can likewise be implemented that use one or more data buses not expressly shown, direct connectivity between elements, and/or indirect coupling between other elements as recognized by one of average skill in the art.

The term “module” is used in the description of one or more of the embodiments. A module implements one or more functions via a device such as a processor or other processing device or other hardware that may include or operate in association with a memory that stores operational instructions. A module may operate independently and/or in conjunction with software and/or firmware. As also used herein, a module may contain one or more sub-modules, each of which may be one or more modules.

As may further be used herein, a computer readable memory includes one or more memory elements. A memory element may be a separate memory device, multiple memory devices, or a set of memory locations within a memory device. Such a memory device may be a read-only memory, random access memory, volatile memory, non-volatile memory, static memory, dynamic memory, flash memory, cache memory, and/or any device that stores digital information. The memory device may be in a form a solid-state memory, a hard drive memory, cloud memory, thumb drive, server memory, computing device memory, and/or other physical medium for storing digital information.

While particular combinations of various functions and features of the one or more embodiments have been expressly described herein, other combinations of these features and functions are likewise possible. The present disclosure is not limited by the particular examples disclosed herein and expressly incorporates these other combinations.