HK1191463A - Automatic gain control for an nfc reader demodulator - Google Patents

Abstract

The invention discloses an automatic gain control for an NFC reader demodulator. An apparatus and method is disclosed to provide improved NFC communications. A first NFC device antenna transmits information to a second NFC device by driving an antenna module with a current to generate a magnetic field. The magnetic field is modulated and the information is transmitted according to a first set of operating parameters. A second NFC device harvests power from the magnetic field and communicates information to the first NFC device by modulating the magnetic field according to a second set of operating parameters, which is received by the first NFC device. The first NFC device recovers a signal metric from the modulated magnetic field. The first NFC device uses the signal metric to provide feedback regarding the second set of operating parameters. Various systems are presented to utilize the signal metric feedback and provide efficient and reliable communications between the first and second NFC devices.

Description

Automatic gain control for NFC reader demodulator

Cross reference to related patent

This application claims priority to U.S. non-provisional application No. 13/532,087 filed on 25/6/2012, the contents of which are incorporated herein by reference.

Technical Field

The present invention relates to Near Field Communication (NFC), and more particularly to adaptively controlling one or more operating parameters of an NFC device.

Background

Near Field Communication (NFC) devices are being integrated into mobile devices, such as smartphones, to facilitate their use in conducting daily transactions. For example, rather than carrying a large number of credit cards, credit information provided by the credit cards may be loaded into and stored in the NFC device for use as needed. The NFC device is simply tapped to the credit card terminal to relay credit information to the credit card terminal to complete the transaction. As another example, a ticketing writing system, such as used in bus and train terminals, may simply write fare information onto an NFC device, rather than providing a paper ticket to a passenger. The passenger simply taps the NFC device to the reader to ride the bus or train without using a paper ticket.

NFC devices are operable such that a first NFC device, commonly referred to as a "reader," communicates using power from a dedicated power source (e.g., a battery), and a second NFC device, commonly referred to as a "tag," communicates without the need for a dedicated power source. The tag obtains or derives power from the reader's communications.

The power level of modulated data used for communication between NFC devices is liable to fluctuate. Such fluctuations may be based on various conditions, such as operating environment fluctuations or fluctuations in the distance between the tag and the reader. If the fluctuation of the modulated data is significant, communication between NFC devices may be inefficient or infeasible.

Disclosure of Invention

(1) A Near Field Communication (NFC) device comprising:

an antenna module configured to transmit data according to a first gain parameter;

a detection module configured to receive data from a second near field communication device using the first gain parameter and to provide a gain adjustment signal based on the first gain parameter; and

a controller module configured to adjust the first gain parameter based on the gain adjustment signal.

(2) The near field communication device of (1), wherein the detection module comprises:

a peak detector circuit configured to provide a peak signal indicative of a peak power level of the received data;

a comparator configured to provide a difference signal based on a difference between the peak signal and a reference signal; and

a latch circuit configured to provide the gain adjustment signal based on the difference signal.

(3) The near field communication device of (2), wherein the controller is further configured to provide a gating signal indicating that no transmit or receive state is present.

(4) The near field communication device of (3), wherein the peak signal or the gain adjustment signal is provided in response to the gating signal.

(5) The near field communication device of (1), wherein the controller is further configured to provide a gating signal indicating that no transmit or receive state is present.

(6) The near field communication device of (1), wherein the gain parameter comprises:

an antenna drive current, the controller further configured to adjust the antenna drive current in response to the gain adjustment signal.

(7) The near field communication device of (1), wherein the gain parameter comprises a gain/attenuation block setting, the near field communication device further comprising:

a demodulator coupled to a gain/attenuation block, the controller further configured to adjust the gain/attenuation block setting in response to the gain adjustment signal.

(8) The near field communication device of (1), wherein the near field communication device is coupled to an electronic device, the electronic device and the near field communication device together being configured to perform NFC communication.

(9) The near field communication device of (1), wherein the controller is further configured to provide a reference signal based on an operational threshold for NFC communications.

(10) A Near Field Communication (NFC) device comprising:

a controller configured to generate a strobe signal indicating a state in which data is not transmitted or received;

a detector module configured to detect a communication signal and provide a signal metric in response to the strobe signal; and

an adjustment module configured to adjust an operating parameter of the near field communication device based on the signal metric.

(11) The near field communication device of (10), wherein the signal metric comprises a filter adjustment signal, the near field communication device further comprising:

a modulator coupled to the first filter; and

a demodulator coupled to the second filter,

and wherein the adjustment module is further configured to adjust a filter setting of the first filter or the second filter in response to the filter adjustment signal.

(12) A near field communication device according to (10), wherein the signal metric is provided based on a comparison with an operating parameter threshold.

(13) The near field communication device of (10), comprising:

an antenna module configured to transmit a communication signal through the antenna driver output.

(14) The near field communication device of (13), wherein the detector module is further configured to determine an impedance of the antenna module.

(15) The near field communication device of (14), wherein the signal metric is selected from the group consisting of:

an antenna module impedance level;

an antenna module power level;

an antenna module voltage level; and

antenna module current level.

(16) A method for controlling communications in a Near Field Communication (NFC) device, the method comprising:

transmitting, by the first near field communication device, a first signal via a magnetic field based on the first gain parameter;

receiving, by the first near field communication device, a second signal via a magnetic field from a second near field communication device using the second gain parameter;

measuring, by the first near field communication device, a signal metric to provide a parameter adjustment signal; and

adjusting, by the first near field communication device, the first gain parameter based on the parameter adjustment signal.

(17) The method of (16), wherein the adjusting step further comprises:

gating-adjusting the first gain parameter corresponding to the magnetic field in an unmodulated state.

(18) The method of (16), the near field communication device comprising an adjustable antenna driver, and wherein the transmitting step comprises:

transmitting, by the adjustable antenna driver, the first signal, and wherein the adjusting step comprises:

adjusting, by the first near field communication device, a voltage or a current of the adjustable antenna driver.

(19) The method of (16), further comprising:

a reference signal is generated and a reference signal is generated,

wherein the adjusting step comprises:

adjusting the first gain parameter based on the reference signal.

(20) The method of (16), further comprising the steps of:

storing the first gain parameter as recorded data in a memory,

wherein the adjusting step comprises:

adjusting the first gain parameter based on the recorded data.

Drawings

Fig. 1 illustrates a block diagram of NFC device operation according to an exemplary embodiment of the present invention;

fig. 2 illustrates a block diagram of an NFC reader device capable of optimizing communications according to an exemplary embodiment of the present invention;

fig. 3 illustrates a block diagram of a detection module that may be used in an NFC device according to an exemplary embodiment of the present invention;

fig. 4 illustrates a block diagram of an NFC controller module and modulator that may be used in an NFC device according to an exemplary embodiment of the invention;

fig. 5A illustrates a block diagram of one configuration of an antenna driver and an antenna module that may be used in an NFC device according to an exemplary embodiment of the present invention;

fig. 5B illustrates a block diagram of a second configuration of an antenna driver and an antenna module that may be used in an NFC device according to an exemplary embodiment of the invention;

fig. 6 illustrates a timing diagram of the timing of communications that may be used by an NFC device according to an exemplary embodiment of the invention;

the present invention will now be described with reference to the accompanying drawings. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the reference number.

Detailed Description

The following detailed description refers to the accompanying drawings that illustrate exemplary embodiments consistent with this invention. References in the detailed description to "one exemplary embodiment," "an example exemplary embodiment," etc., indicate that the exemplary embodiment described may include a particular feature, structure, or characteristic, but every exemplary embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same exemplary embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an exemplary embodiment, it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other exemplary embodiments whether or not explicitly described.

The exemplary embodiments described herein are for purposes of illustration and not limitation. Other exemplary embodiments are possible, and modifications may be made to the exemplary embodiments within the spirit and scope of the invention. Therefore, the detailed description is not intended to limit the invention. Rather, the scope of the invention is to be defined only by the following claims and their equivalents.

Embodiments of the invention may be implemented in hardware, firmware, software, or any combination thereof. Embodiments of the invention may also be implemented as instructions stored on a machine-readable medium, which may be read and executed by one or more processors. A machine-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computing device). For example, a machine-readable medium may include read-only memory (ROM), random-access memory (RAM), magnetic disk storage media, optical storage media, flash-memory devices, electrical, optical, acoustical or other form of propagated signals (e.g., carrier waves, infrared signals, digital signals, etc.), and others. Further, firmware, software, routines, instructions may be described herein as performing certain actions. However, it should be understood that such descriptions are merely for convenience and that such actions in fact result from computing devices, processors, controllers, or other devices executing the firmware, software, routines, instructions, etc.

The following detailed description of exemplary embodiments will so fully reveal the general nature of the invention that others can, by applying knowledge within the skill of the art, readily modify and/or adapt for various applications such exemplary embodiments, without undue experimentation, without departing from the spirit and scope of the present invention. Therefore, such adaptations and modifications are intended to be within the meaning and range of equivalents of the exemplary embodiments, based on the teaching and guidance presented herein. It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by the skilled artisan in light of the teachings herein.

Although the description of the present invention will be described in terms of NFC, one of ordinary skill in the relevant art will recognize that the present invention may be applied to other communications using the near field and/or the far field without departing from the spirit and scope of the present invention. For example, while the present invention is described using NFC-enabled communication devices, one of ordinary skill in the relevant art will recognize that the functionality of these NFC-enabled communication devices may be applied to other communication devices using the near field and/or the far field without departing from the spirit and scope of the present invention.

Exemplary Near Field Communication (NFC) operating Environment

Fig. 1 shows a block diagram of an NFC environment according to an exemplary embodiment of the present invention. The NFC environment 100 provides for wireless communication of information, such as one or more commands and/or data, between a first NFC device 102 and a second NFC device 104 in sufficient proximity to each other. As will be apparent to one of ordinary skill in the relevant art(s) without departing from the spirit and scope of the present invention, the first NFC device 102 and/or the second NFC device 104 may be implemented as stand-alone or discrete devices, or may be incorporated into or coupled to another electronic device or host device (such as a mobile phone, portable computing device), another computing device (such as a personal computer, notebook, or desktop computer), a computer peripheral (such as a printer, portable audio and/or video player, payment system), a ticket writing system (such as a parking ticketing system, bus ticketing system, train ticketing system, or admission ticketing system), or in a ticket reading system, toy, game, poster, packaging, advertising material, product inventory checking system, and/or any other suitable electronic device.

The first NFC device 102 and/or the second NFC device 104 interact with each other to exchange information in a peer-to-peer (P2P) communication mode or a reader/writer (R/W) communication mode. In the P2P communication mode, the first NFC device 102 and the second NFC device 104 may be configured to operate according to an active communication mode and/or a passive communication mode. The first NFC device 102 modulates its corresponding information onto a first carrier wave in accordance with the first operating parameter P1 (referred to as modulated information communication) and generates a first magnetic field by applying the modulated information communication to a first antenna to provide the first information communication 152. In the active communication mode, the first NFC device 102 stops generating the first magnetic field after transferring its respective information to the second NFC device 104. Alternatively, in the passive communication mode, the first NFC device 102 continues to apply the first carrier wave without its corresponding information (referred to as unmodulated information communication) in accordance with the first operating parameter P1, thereby continuing to provide the first information communication 152 when information has been transferred to the second NFC device 104.

The first NFC device 102 is sufficiently proximate to the second NFC device 104 such that the first information communication 152 is inductively coupled to the second antenna of the second NFC device 104. The second NFC device 104 demodulates the first information communication 152 to recover the information according to the second operating parameter P2. The second NFC device 104 may respond to this information by: the second information communication 154 is provided in the active communication mode by modulating its corresponding information onto a second carrier wave in accordance with the second operating parameter P2 and generating a second magnetic field by applying the modulated information communication to a second antenna. Alternatively, the second NFC device 104 may respond to the information by: the second antenna is modulated with its corresponding information to modulate the first carrier, thereby providing second information communication 154 in a passive communication mode.

In the R/W communication mode, the first NFC device 102 is configured to operate in an initiator or reader mode of operation and the second NFC device 104 is configured to operate in a recipient or tag mode of operation. However, this example is not limiting, and persons skilled in the relevant art will recognize that the first NFC device 102 may be configured to operate in tag mode and the second NFC device 104 may be configured to operate in reader mode in accordance with the teachings herein without departing from the spirit and scope of the present invention. The first NFC device 102 modulates its respective information onto a first carrier according to the first operating parameter P1 and generates a first magnetic field by applying the modulated information communication to a first antenna to provide a first information communication 152. Once the information has been transferred to the second NFC device 104, the first NFC device 102 continues to apply the first carrier without its corresponding information in accordance with the first operating parameters P1 to continue to provide the first information communication 152. The first NFC device 102 is sufficiently proximate to the second NFC device 104 such that the first information communication 152 is inductively coupled to the second antenna of the second NFC device 104.

The second NFC device 104 obtains or derives power from the first information communication 152 to recover, process, and/or respond to the information. Further, the second NFC device 104 may respond to this information by: the second antenna is modulated with its corresponding information in accordance with the second operating parameter P2 to thereby modulate the first carrier wave to provide the second information communication 154.

The first operating parameter P1 and the second operating parameter P2 represent a variety of configurable parameters that may be used by the first NFC device 102 and the second NFC device 104, respectively, to transmit, process, and receive information. For example, the first operating parameter P1 and/or the second operating parameter P2 may represent a gain to be used by their respective NFC devices, a modulation/demodulation scheme to be used by their respective NFC devices, a data rate to be used by their respective NFC devices, an encoding/decoding scheme to be used by their respective NFC devices, and/or any combination thereof. Generally, the first NFC device 102 and/or the second NFC device 104 may dynamically configure the first operating parameter P1 and the second operating parameter P2 to provide efficient communication between these NFC devices. In some cases, the first NFC device 102 may dynamically configure the second operating parameters P2 of the second NFC device 104, and the second NFC device 104 may dynamically configure the first operating parameters P1 of the first NFC device 102.

Exemplary NFC device

Fig. 2 illustrates a block diagram of an NFC reader device capable of optimizing communications according to an exemplary embodiment of the present invention. As shown in fig. 2, the NFC reader 200 may represent an exemplary embodiment of the first NFC device 102 and/or the second NFC device 104. The power supply and associated power coupling for the first NFC reader 200 are not shown in fig. 2. It should be noted that although a separate circuit block is illustrated in fig. 2, the circuit block is not necessarily implemented as hardware separate from the NFC controller module 202. Any, some, or all of the functions represented by the circuit blocks shown in fig. 2 may be implemented as part of a single controller. NFC controller module 202 may facilitate communication between another NFC device and/or control operation of various communication components of NFC reader 200. The NFC controller module 202 sends information to be transmitted to another NFC device as digital transmission data 201. The NFC controller module 202 also receives information from another NFC device via digital receive data 209.

The NFC controller module 202 may also provide a general control signal 207 to configure and/or control one or more configurable parameters of one or more circuit components. The one or more configurable parameters may represent, for example, a gain of NFC reader 200, a modulation/demodulation scheme to be used by NFC reader 200, an encoding/decoding scheme to be used by NFC reader 200, and/or any combination thereof. Other examples of these configurable parameters may include adjusting filter response, impedance matching, antenna gain, one or more antenna selections, driving antenna current, driving antenna voltage, gain/attenuation block settings, or selecting a particular communication protocol and/or modulation type. Any, some, or all of the operating parameters may be controlled, which may be integrated as part of the modulator 204, demodulator 208, antenna driver 212, and/or antenna module 210. Generally, the NFC controller module 202 may configure one or more configurable parameters via the generic control signal 207 such that the signal metric 205 is less than or equal to a maximum threshold, greater than or equal to a minimum threshold, and/or between the maximum threshold and the minimum threshold. Further, the NFC controller module 202 may optionally provide a gating signal 203 to be used by the detection module 206 to selectively provide signal metrics 205 at certain times. Finally, the NFC controller module 202 may provide one or more reference signals 215 that may be used to provide voltage and/or current threshold signals to be utilized by other circuitry of the NFC reader 200.

The detection module 206 monitors the recovery signal 211, which includes the modulation information received from the other NFC device. The detection module 206 measures and/or monitors the recovered signal 211 to generate a signal metric 205, such as a median voltage and/or current level, an average voltage and/or current level, an instantaneous voltage and/or current level, a root mean square voltage and/or current level, a median power, an average power, an instantaneous power, a root mean square power, a maximum voltage and/or current level, a minimum voltage and/or current level, and/or any other suitable signal metric that provides a signal metric 205 that will be apparent to one skilled in the relevant art without departing from the spirit and scope of the present invention. Depending on the type of signal metric 205 to be measured and/or monitored for a particular application, the recovered signal 211 may be provided at the antenna driver 212 and/or the antenna module 210, as shown in dashed lines in fig. 2.

Modulator 204 modulates digital transmit data 201 and converts it to the analog domain as modulated analog transmit data 213. The demodulator 208 demodulates the restored signal 211 and converts it into digital reception data 209 to be processed by the NFC controller module 202. The modulator 204 and/or the demodulator 208 may be characterized as having various configurable parameters that are configurable and/or controllable in response to the universal control signal 207.

The antenna driver 212 and the antenna module 210 cooperate to transmit a first information communication 252 and receive a second information communication 254. To transmit data, the antenna driver 212 applies the modulated analog transmit data 213 to generate an antenna drive signal 217. The antenna drive signal 217 is then fed to the antenna module 210, where the antenna module 210 transmits the first information communication 252 to another NFC device. In particular, the antenna module 210 applies the antenna drive signal 217 to its inductive coupling element to generate a magnetic field representative of the modulated analog transmit data 213, thereby providing the first information communication 152.

To receive data, the antenna driver 212 may be configured to provide a recovered signal 211 proportional to the antenna drive signal 217. During receive operations, the analog transmit data 213, and thus the antenna drive signal 217, is maintained in a substantially constant and unmodulated state. The antenna module receives the second information communication 254 from another NFC device that modulates the load of the antenna module 210 seen by the antenna driver 212 due to fluctuations at the other NFC device that sent the second information communication 254. Modulation of recovered signal 211 provides received data that is demodulated by demodulator 208. The antenna module 210 and/or the antenna driver 212 may be characterized as having various configurable parameters that are configurable and/or controlled in response to the universal control signal 207.

Exemplary detection Module

Fig. 3 illustrates a block diagram of a detection module that may be used in an NFC device according to an exemplary embodiment of the present invention. The detection module 300 measures and/or monitors a signal metric of a recovery signal (e.g., recovery signal 211) to be used by a controller module (e.g., controller module 202) to configure and/or control one or more configurable parameters of an NFC device (e.g., first NFC device 102, second NFC device 104, and/or NFC reader 200). The detection module 300 includes a peak detector circuit 320, a comparator 322, and a latch circuit 324. Detection module 300 may represent an exemplary implementation of detection module 206.

Detection module 300 receives recovered signal 211 and generates signal metric 205 proportional to the power level of recovered signal 211. Peak detector circuit 320 generates a peak signal 321 that tracks the maximum or peak power level of recovered signal 211. The peak detector circuit 320 is not limited to analog designs and may include various mixed signal components operating in the analog and/or digital domains. The operation and/or configuration of the peak detector circuit 320 may be enabled, disabled, and/or modified by the gating signal 203. Peak detector circuit 320 may be implemented in any suitable manner apparent to those skilled in the relevant art to detect the peak power level of recovered signal 211 without departing from the spirit and scope of the invention.

The comparator 322 compares the peak signal 321 with the reference signal 215. Comparator 322 outputs a difference signal 323 that is proportional to the difference between peak signal 321 and reference signal 215. The reference signal 215 is not limited to a predetermined value or a constant value, but may be dynamically changed by the NFC controller module 202 for a particular application and/or operating environment. The comparator 322 may be configured such that the difference signal 323 indicates the sign and/or magnitude of the difference between the peak signal 321 and the reference signal 215. In other words, by monitoring the change in peak signal 321 compared to reference signal 215, difference signal 323 can indicate whether the peak power of restored signal 211 is too high or too low.

The latch circuit 324 provides the signal metric 205 to the NFC controller module 202 based on the difference signal 323. The generation of the signal metric 205 using the difference signal 323 is accomplished by the gating signal 203. In this manner, latch circuit 324 acts as a "clutch" to change the state of signal metric 205 only when needed, even if the power levels associated with difference signal 323, peak signal 321, and/or restore signal 211 continuously fluctuate.

Exemplary NFC controller Module

Fig. 4 illustrates a block diagram of an NFC controller module and modulator that may be used in an NFC device according to an exemplary embodiment of the invention. In response to signal metric 205 of the recovery signal (e.g., recovery signal 211), NFC controller module and modulator 400 configures and/or controls one or more configurable parameters of the NFC device (e.g., first NFC device 102, second NFC device 104, and/or NFC reader 200). The NFC controller module and modulator 400 includes a Direct Digital Synthesizer (DDS) 402, an operation controller module 404, and an adjustment module 406. NFC controller module and modulator 400 may represent an exemplary implementation of NFC controller module 202 and modulator 204.

The DDS 402 receives a clock signal 401 for clock signal generation and frequency synthesis for the NFC device. The oscillator circuit for the clock signal 401 and the associated connections providing the clock signal 401 are not shown in fig. 4. The DDS 402 may also generate a strobe signal 203 to control the timing of the signal metrics 205. The strobe signal 203 may be generated as part of a DDS timing signal that indicates a time period during which the NFC device is not transmitting or receiving data. For example, the DDS 402 may also generate the strobe signal 203 in response to a controller DDS signal 407 generated by the operational controller module 404.

The operation controller module 404 sends information 403 (such as data and/or one or more commands) to the DDS 402 for modulation by the DDS onto a carrier wave as digital transmit data 201. The operation controller module 404 receives the digital receive data 209 and provides a reference signal 215. Although reference signal 215 is shown as a single line in fig. 4, it should be noted that any number of reference signals may be present as part of an NFC device for a variety of different purposes. The reference signal 215 may be an analog and/or digital signal value, any of which may be changed or held at a constant value for a particular application and/or environmental condition. The operational controller module 404 may communicate with the adjustment module 406 using a controller adjustment signal 405. By communicating with the adjustment module 406, the operational controller module 404 may also define the universal control signal 207 based on the type of adjustment to be made to other circuit components.

The operation controller module 404 may be configured to record (log) various communication parameters, such as the bit error rate of the digital received data 209, the signal metrics 205, and/or the generic control signal 207. The operation controller module 404 may store the recorded data in, for example, a non-volatile memory and access the recorded data at initialization or after a power reset. By comparing the recorded values and associating with the stored parameters, the operation controller module 404 may utilize the universal control signal 207 to configure the NFC device for most efficient communication according to the recorded data history.

In response to the signal metric 205, the adjustment module 406 provides a general control signal 207. The adjustment module 406 may configure the one or more configurable parameters via the general control signal 207 such that the signal metric 205 is less than or equal to a maximum threshold, greater than or equal to a minimum threshold, and/or between the maximum threshold and the minimum threshold. For example, if the signal metric 205 is too low or too high, the adjustment module 406 may configure the general control signal 207 to adjust a drive current that drives an antenna of the NFC device.

First exemplary antenna driver and antenna module

Fig. 5A illustrates a block diagram of one configuration of an antenna driver and an antenna module that may be used in an NFC device according to an exemplary embodiment of the invention. The antenna driver and antenna module 500 generates a recovered signal by monitoring, sampling, and/or measuring voltage fluctuations, current fluctuations, and/or power fluctuations in the output of the antenna driver 502. The universal control signal 207 may be utilized to control and/or configure various operating parameters of the antenna driver and antenna module 500. Antenna driver and antenna module 500 includes an antenna driver 502, a resonant interface 504, and a coupling element 506. The antenna driver and antenna module 500 may represent an exemplary implementation of the antenna driver 212 and antenna module 210. More specifically, antenna driver 502 may represent an exemplary embodiment of antenna driver 212, and resonant interface 504 and coupling element 506 may together represent an exemplary embodiment of antenna module 210.

Although the signals shown in fig. 5A are described throughout as differential signals, the present invention is not limited thereto. Any of the signals shown in fig. 5A may be used in a single drive or differential drive mode of operation using any suitable manner of transmitting and/or receiving a communicating magnetic field, as would be apparent to one skilled in the relevant art without departing from the spirit and scope of the invention.

Although fig. 5A illustrates a single antenna driver 502, resonant interface 504, and coupling element 506, it should be noted that the invention is not so limited. For example, multiple antenna drivers 502, resonant interfaces 504, and/or coupling elements 506 may be implemented to support modifications for various applications, including increasing communication distances, operating frequencies, and/or communication protocols.

Although the recovered signal 211 is shown as a single wire, the recovered signal 211 may be a single-ended or differential drive signal as long as compatibility is maintained between all signals 501, 503, and 211 operating within the antenna module 500. The restore signal 211 may be generated using any suitable means that should be apparent to one skilled in the relevant art without departing from the spirit and scope of the invention.

The antenna driver 502 transmits the modulated analog transmit data 213 by driving the resonant interface 504 with differential signals 501.1 and 501.2. The power levels of the differential signals 501.1 and 501.2 and the strength of the generated magnetic field are proportional to the current output by the antenna driver 502. The current and/or voltage output by the antenna driver 502 may be adjusted by the universal control signal 207.

For example, antenna driver 502 may operate as a configurable current mirror. In such a configuration, an indication of the output current driven by differential signals 501.1 and 501.2 is provided by restore signal 211. In such a configuration, antenna driver 502 may act as a voltage driver, thereby inducing a current through resonant interface 504 and coupling element 506 and correspondingly generating a magnetic field.

Thus, the antenna driver 502 may sense the differential signals 501.1 and 501.2 for information provided by another NFC device to provide the recovered signal 211. For example, another NFC device (e.g., second NFC device 104) inductively receives the generated magnetic field with its corresponding coupling element to derive power and process and/or provide a response to the information. Once this other NFC device gets sufficient power, it may send a second information communication 154 through load modulation of its respective coupling element. For example, load modulation may be achieved by shunting the current induced at the second coupling element. The load modulation by the other NFC device appears as a modulation of the generated magnetic field. Because recovery signal 211 is proportional to the generated magnetic field, as the magnetic field is modulated, recovery signal 211 is also modulated. By adjusting the magnetic field strength with the universal control signal 207, control of the power level of the recovered signal 211 may thus be obtained, thereby ensuring an appropriate power level for demodulation and efficient communication.

The resonant interface 504 may include various impedance matching networks and/or transformer coupling elements to properly match the impedance of the antenna driver 502 and the impedance of the coupling element 506. The resonant interface 504 provides the appropriate connections and circuitry to accommodate the differential signals 501.1 and 501.2 to provide the differential antenna signals 503.1 and 503.2 for transmitting the first information communication 152. In some cases (e.g., where multiple coupling elements 506 are used), the resonant interface 504 may also include a switching network. The antenna switching network may switch between several antennas or a group of antennas to accommodate various physical locations of another NFC device to support diversity antenna switching to increase or decrease antenna gain or to support various communication frequencies and/or protocols. The resonant interface 504 may be configured to receive the universal control signal 207 and to implement this additional functionality in response to one or more signal metrics 205, as shown in dashed lines in fig. 5A. This additional functionality can be controlled and adjusted alone or in conjunction with the adjustment of the antenna driver 502 to provide greater communication efficiency and reliability.

The coupling element 506 includes one or more antennas designed to generate magnetic fields for transmitting and receiving the first information communication 152 and the second information communication 154, respectively. In general, coupling element 506 includes one or more capacitors, inductors, resistors, magnetic coil antennas, or any combination thereof configured and arranged to form a tuning element. These capacitors, inductors, resistors may be configured and arranged to form a series resonant circuit, a parallel tuned circuit, or any combination thereof. The coupling element 506 may be a single antenna or several antennas capable of operating at the same or different resonant frequencies. The coupling element 506 may be configured to receive the general control signal 207 and to implement additional functionality in response to one or more signal metrics 205, as shown in dashed lines in fig. 5A. For example, the switching network functionality described for the resonant interface 504 may be included as part of the coupling element 506. The coupling element 506 may also have one or more tuning circuits for tuning the antenna element to a particular resonant frequency or resonant frequency band for a particular application. This accessory functionality may be provided alone or in conjunction with the current regulation of antenna driver 502 and/or the functionality of resonant interface 504 to provide greater communication efficiency and reliability.

For example, the resonant interface 504 and/or the coupling element 506 may be an integrated part of the NFC device (the first NFC device 102 and/or the NFC reader 200), e.g., implemented as part of a single Integrated Circuit (IC), a semiconductor wafer, a chip, and/or integrated as part of a Printed Circuit Board (PCB) design. The resonant interface 504 and/or the coupling element 506 may also be external devices, off-chip, or separate from other NFC components. Signal metrics of antenna driver 502 (e.g., voltage, current, and/or impedance of antenna driver 502) may be tuned to match the impedance represented by off-chip resonant interface 504 and/or coupling element 506. Antenna driver 502 may be tuned by generic control signal 207 in accordance with appropriate signal metrics 205 provided by recovered signal 211.

Second exemplary antenna driver and antenna Module

Fig. 5B illustrates a block diagram of a second configuration of an antenna driver and an antenna module that may be used in an NFC device according to an exemplary embodiment of the invention. The antenna driver and antenna module 520 operates in a substantially similar manner to the antenna module 500, and therefore, only the differences between the antenna driver and antenna module 500 and the antenna driver and antenna module 520 are discussed in detail. Resonant interface 522 may be designed with appropriate circuitry to provide restored signals 211 at one or more points in either a differential or single-ended mode of operation. A restored signal 211 configured in this manner may provide additional and/or alternative signal metrics, such as the RMS power level of the magnetic field, the impedance of the resonant interface 522, and/or the impedance of the coupling element 506.

Although fig. 5A-5B are illustrated as separate embodiments for providing one or more signal metrics 205 via recovered signal 211, the invention is not so limited. It should be understood by those skilled in the art that the recovered signal 211 may be monitored at the antenna driver 502 and/or the resonant interface 504 without departing from the spirit and scope of the present invention.

Exemplary NFC communications timing

Fig. 6 illustrates a timing diagram of the timing of communications that may be used by an NFC device according to an exemplary embodiment of the invention. The timing diagram 600 illustrates data packet transfer over time 607 between a first NFC device configured to operate in a reader mode of operation (e.g., the first NFC device 102 and/or the NFC reader 200) and a second NFC device configured to operate in a tag mode of operation (such as the second NFC device 104).

As shown in fig. 6, the first NFC device optionally receives and/or processes one or more commands and/or information from the host device or a user of the first NFC device during an initialization timeframe 602. The initialization time frame 602 may also correspond to an initialization time period after the first NFC device is reset, restarted, turned on, or otherwise initialized before the first NFC device performs a communication function.

As further shown in fig. 6, the first NFC device transmits information (e.g., the first information communication 152) as a transmission data packet 603 within one or more transmission time frames 604. Thereafter, the first NFC device waits for a processing time frame 606 for the second NFC device to recover and/or process the transmission data packet 603. During this time, the first NFC device continues to apply its respective carrier without information to allow the second NFC device to obtain or obtain power for recovering and/or processing the transmission data packet 603. The first NFC device receives a response to the information as a receive data packet 605 within one or more receive time frames 608.

The first NFC device may dynamically configure various configurable parameters during the processing time frame 606. In some cases, the first NFC device may provide a gating signal (e.g., gating signal 203) to selectively configure various configurable parameters. The strobe signal may indicate that various configurable parameters are adjusted when at the first logic level and may indicate that various configurable parameters remain in their current state when at the second logic level. For example, the first NFC device may dynamically adjust its gain during processing time frame 606, as discussed above in fig. 3.

The processing time frame 606 represents the duration of communication between the first NFC device and the second NFC device, whereby no information is exchanged between these devices. In general, any changes due to various configurable parameters of the first NFC device during one or more of the transmission time frame 604 and/or the reception time frame 608 may be misinterpreted as information. Because the first NFC device does not transmit or receive information to or from the second NFC device during processing timeframe 606, this timeframe may be used by the first NFC device to adjust various configurable parameters.

Conclusion

It is to be understood that the detailed description section, and not the abstract section, is intended to be used to interpret the claims. The abstract may set forth one or more, but not all exemplary embodiments of the invention, and is thus not intended to limit the invention and the appended claims in any way.

The present invention has been described above with the aid of functional building blocks illustrating the implementation of specified functions and relationships thereof. The boundaries of these functional building blocks have been arbitrarily defined herein for the convenience of the description. Other boundaries may be defined so long as the specified functions and relationships thereof are appropriately performed.

It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

Claims (10)

1. A Near Field Communication (NFC) device comprising:

an antenna module configured to transmit data according to a first gain parameter;

a detection module configured to receive data from a second near field communication device using the first gain parameter and to provide a gain adjustment signal based on the first gain parameter; and

a controller module configured to adjust the first gain parameter based on the gain adjustment signal.

2. The near field communication device of claim 1, wherein the detection module comprises:

a peak detector circuit configured to provide a peak signal indicative of a peak power level of the received data;

a comparator configured to provide a difference signal based on a difference between the peak signal and a reference signal; and

a latch circuit configured to provide the gain adjustment signal based on the difference signal.

3. The near field communication device of claim 2, wherein the controller is further configured to provide a gating signal indicating that no transmit or receive state is present.

4. A near field communication device according to claim 3, wherein the peak signal or the gain adjustment signal is provided in response to the gating signal.

5. The near field communication device of claim 1, wherein the controller is further configured to provide a gating signal indicating that no transmit or receive state is present.

6. The near field communication device of claim 1, wherein the gain parameter comprises:

an antenna drive current, the controller further configured to adjust the antenna drive current in response to the gain adjustment signal.

7. Near field communication device according to claim 1, wherein the gain parameter comprises a gain/attenuation block setting, the near field communication device further comprising:

a demodulator coupled to a gain/attenuation block, the controller further configured to adjust the gain/attenuation block setting in response to the gain adjustment signal.

8. Near field communication device according to claim 1, wherein the near field communication device is coupled to an electronic device, the electronic device and the near field communication device together being configured to perform NFC communication.

9. A Near Field Communication (NFC) device comprising:

a controller configured to generate a strobe signal indicating a state in which data is not transmitted or received;

a detector module configured to detect a communication signal and provide a signal metric in response to the strobe signal; and

an adjustment module configured to adjust an operating parameter of the near field communication device based on the signal metric.

10. A method for controlling communications in a Near Field Communication (NFC) device, the method comprising:

transmitting, by the first near field communication device, a first signal via a magnetic field based on the first gain parameter;

receiving, by the first near field communication device, a second signal via a magnetic field from a second near field communication device using the second gain parameter;

measuring, by the first near field communication device, a signal metric to provide a parameter adjustment signal; and

adjusting, by the first near field communication device, the first gain parameter based on the parameter adjustment signal.