An electronic device for contactless communication and a control method

Abstract

The embodiment of the specification discloses an electronic device and a control method for non-contact communication. In the scheme, the electronic device comprises an antenna, a communication chip and a load adjustment circuit; wherein the antenna is connected with the load adjustment circuit, and the load adjustment circuit is connected with the communication chip; the load adjustment circuit comprises a first state and a second state; the load impedance of the electronic device in the first state is different from the load impedance of the electronic device in the second state; if the electronic device acquires a low-power card detection (LPCD) signal sent by a card reader device, the communication chip is used for controlling the load adjustment circuit to switch from the first state to the second state, so that the card reader device switches to a normal card detection mode.

Description

[0001] This application is a divisional application of "An electronic device and control method for contactless communication (Application date: March 19, 2025, Application No.: 202510325295.8)". Technical Field

[0002] This application relates to the field of contactless communication technology, and more particularly to an electronic device and control method for contactless communication. Background Technology

[0003] Near Field Communication (NFC) is a short-range, high-frequency wireless communication technology that allows electronic devices to exchange data when they are close to each other. NFC technology evolved from contactless Radio Frequency Identification (RFID) and enables fast and convenient data transmission over distances of just a few centimeters. Typical applications include mobile payments, access control, smart posters, product authentication, and interconnectivity between Internet of Things (IoT) devices.

[0004] In practical applications, smartphones and other mobile terminal devices can act as NFC card readers to communicate with NFC slave devices such as NFC cards, NFC tags, and NFC devices with radio frequency circuits. To save power, NFC card readers can operate in a low-power mode, allowing them to detect nearby NFC cards in Low Power Card Detection (LPCD) mode. However, in LPCD mode, the reader's sensitivity to slave devices decreases, significantly reducing the success rate of detecting slave devices and impacting the user experience.

[0005] Therefore, improving the success rate of card detection is a technical problem that urgently needs to be solved. Summary of the Invention

[0006] This specification provides an electronic device and control method for contactless communication to solve the problem of low card detection success rate in existing card reader devices.

[0007] To solve the above-mentioned technical problems, the embodiments in this specification are implemented as follows.

[0008] This specification provides an electronic device for contactless communication, comprising an antenna, a communication chip, and a load adjustment circuit. The antenna is connected to the load adjustment circuit, and the load adjustment circuit is connected to the communication chip. The load adjustment circuit includes a first state and a second state. The load impedance of the electronic device in the first state differs from that in the second state. If the electronic device receives a low-power card detection (LPCD) signal from a card reader device, the communication chip controls the load adjustment circuit to switch from the first state to the second state, so that the card reader device switches to normal card detection mode.

[0009] This specification provides an NFC tag, which includes the aforementioned electronic components.

[0010] This specification provides a contactless communication control method applied to the aforementioned electronic device, comprising: acquiring a detection signal emitted by a card reader device; if the detection signal is a low-power card detection LPCD signal, generating a first control signal; based on the first control signal, the electronic device switching from a first state to a second state so that the card reader device switches to a normal card detection mode; the load impedance of the electronic device in the first state is different from the load impedance of the electronic device in the second state.

[0011] At least one embodiment of this specification can achieve the following beneficial effects:

[0012] The electronic device provided in the embodiments of this specification may include a load adjustment circuit capable of adjusting the load impedance. After detecting a signal emitted by a card reader device in LPCD mode, the load adjustment circuit can switch from the first state to the second state. The load impedance of the electronic device in the first state is different from that in the second state. By changing the load impedance of the electronic device, the amplitude or phase of the signal emitted by the card reader device can be significantly changed after encountering the electronic device, which can facilitate the card reader device to enter the normal card detection mode from LPCD mode, thereby increasing the identification probability of contactless communication and the probability of successful card detection by the card reader device. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments or prior art of this specification, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of the structure of an electronic device for contactless communication provided in the embodiments of this specification;

[0015] Figure 2 This is a schematic diagram of an electronic device provided in the embodiments of this specification;

[0016] Figure 3 This is a schematic diagram of an electronic device provided in the embodiments of this specification;

[0017] Figure 4 This is a schematic diagram of an electronic device provided in the embodiments of this specification;

[0018] Figure 5 This is a schematic diagram of an electronic device provided in the embodiments of this specification;

[0019] Figure 6 This is a schematic diagram of an electronic device provided in the embodiments of this specification;

[0020] Figure 7 This is a flowchart illustrating a contactless communication control method provided in the embodiments of this specification. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of one or more embodiments of this specification clearer, the technical solutions of one or more embodiments of this specification will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this specification, and not all of them. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of one or more embodiments of this specification.

[0022] Many specific details are set forth in the following description to provide a full understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of this application; therefore, this application is not limited to the specific embodiments disclosed below.

[0023] The terminology used in one or more embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the scope of one or more embodiments of this application. The singular forms “a,” “the,” and “the” used in one or more embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” used in one or more embodiments of this application refers to and includes any or all possible combinations of one or more associated listed items. It should be understood that although the terms first, second, etc., may be used to describe various information in one or more embodiments of this application, such information should not be limited to these terms. These terms are used only to distinguish information of the same type from one another. For example, first may also be referred to as second without departing from the scope of one or more embodiments of this application, and similarly, second may also be referred to as first. Depending on the context, the word “if” as used herein can be interpreted as “when,” “in response to a determination,” or “when…”.

[0024] First, the terms and concepts involved in one or more embodiments of this application will be explained.

[0025] Contactless communication refers to technologies that transmit information without direct physical contact. It uses electromagnetic waves or other wireless signals to transmit and communicate data, avoiding the safety hazards associated with physical contact. The core principle of contactless communication is to use radio waves or other electromagnetic waves to transmit information. The electromagnetic signal generated by the sender is received and decoded by the receiver, thus completing the data transmission. Common contactless communication technologies include Near Field Communication (NFC), Radio Frequency Identification (RFID), and wireless charging.

[0026] RFID (Radio Frequency Identification): Its principle is to achieve target identification through non-contact data communication between the reader and the tag. There are different frequency types, such as low frequency, high frequency, and ultra-high frequency.

[0027] NFC (Near Field Communication) is a short-range wireless communication technology that enables near-field communication between two devices, allowing for data transmission, writing, and reading. It typically operates at a high frequency of 13.56MHz. NFC is based on RFID (Radio Frequency Identification) technology and can be considered a subset of RFID, or a special form of RFID.

[0028] NFC technology mainly includes three communication modes: Reader / Writer Mode, Card Emulation Mode, and Peer-to-Peer Mode.

[0029] Reader / Writer Mode is a common operating mode, similar to barcode or QR code scanning. In this mode, NFC devices can read or write information to NFC tags or devices containing NFC tags. For example, in payment scenarios, a mobile phone can be in Reader / Writer Mode to obtain payment information from the payment device for payment. A device in this mode can be called a card reader device.

[0030] In Card Emulation Mode, an NFC device can emulate a smart card, allowing it to be used as a payment card, access card, or other type of card. The device can interact with existing contactless infrastructure, such as POS machines or access control systems. For example, a mobile phone can be used as a bank card for payments in stores; as an access card in offices or residences; or as a transit card for public transportation. Devices in this mode can be referred to as slave devices.

[0031] In Peer-to-Peer Mode, two NFC-enabled devices can exchange data. Both devices must be active and capable of sending and receiving data. It is primarily used for file transfer, social networking, and interactive games. Examples include quickly pairing Bluetooth or Wi-Fi connections via NFC to transfer files or photos; exchanging business cards, contact information, or social media links by tapping two phones; and swapping characters or sharing items in multiplayer games.

[0032] An NFC tag is a tiny electronic chip with a built-in antenna that enables short-range communication with NFC-enabled devices, such as smartphones, via radio waves. These tags are typically very thin and can be embedded in various items, such as posters, business cards, product packaging, and devices.

[0033] LPCD (Low Power Card Detection) mode: also known as low-power card detection mode or low-power card search mode. LPCD is a technology used in radio frequency (RF) for efficient detection of nearby contactless smart cards or tags, primarily to reduce the power consumption of card readers while waiting for a smart card or tag to approach. In LPCD mode, a card reader periodically sends low-power pulses. When the card reader detects a change in signal amplitude on the antenna that exceeds a preset threshold, it can determine that a card is approaching and initiate further interaction. Specifically, when a card enters the RF field, its presence causes changes in signal amplitude and phase. LPCD mode utilizes a software-based card detection mechanism and an LPCD algorithm to detect these changes, determining if a card is approaching and triggering further communication. LPCD mode is particularly important in portable devices such as mobile phones, its main advantage being its low power consumption. Mobile phones typically require long standby times, and frequent activation of functions such as NFC (Near Field Communication) can significantly drain the battery. LPCD mode allows the phone to continuously detect near-field communication signals in the background while maintaining a low power consumption level. Once a card is detected, the phone can quickly switch from a low-power state to a full-featured state to perform transactions or data exchanges.

[0034] Standard Card Detection Mode: Also known as normal card detection mode or normal card search mode. To improve the speed and success rate of contactless communication, the card reader device can typically operate in full-function mode during communication, i.e., standard card detection mode. In practical applications, in both LPCD mode and standard card detection mode, the card reader device (e.g., mobile terminal devices such as mobile phones) emits signals at a preset frequency. For example, in NFC near-field communication scenarios, the card reader device can emit a 13.56MHz sine wave in both LPCD mode and standard card detection mode. The difference lies in the transmission time and amplitude of the sine wave between LPCD mode and standard card detection mode. For example, in LPCD mode, the pulse width is typically in the microsecond range, while in standard card detection mode, the pulse width is typically in the tens of milliseconds range.

[0035] Currently, mobile devices such as smartphones are increasingly used as active devices for contactless communication such as NFC (Near Field Communication). However, mobile devices are typically battery-powered, and to control power consumption, they often incorporate low-power designs, such as setting LPCD (Low-Power Delivery) mode. For example, when a phone screen is off, the card reader function is usually disabled, and most phones automatically enter LPCD mode after the screen is on for a period of time. When a mobile device in LPCD mode approaches an NFC target device, such as an NFC tag or NFC slave device, it can switch to standard card detection mode. In practical applications, the mobile device will only be woken up from LPCD mode and enter standard card detection mode when the intensity change of its emitted radio frequency signal is greater than or equal to a preset threshold, as sensed by the NFC target device it is approaching. However, in LPCD mode, the signal strength emitted by the mobile device is weaker, and the amplitude of the emitted radio frequency signal is lower than that in standard card detection mode. Therefore, the amplitude change caused by the NFC target device on the other end of the signal will also be reduced accordingly. This makes it impossible for the mobile device to determine whether there is an NFC target device nearby by the change in the amplitude of the signal. Consequently, the mobile device cannot switch to standard card detection mode, which significantly reduces the success rate of the mobile device sensing the NFC target device. This, in turn, affects the success rate of near-field communication and the user experience.

[0036] The technical solutions provided in the various embodiments of this specification are described in detail below with reference to the accompanying drawings.

[0037] Figure 1 This is a schematic diagram of the structure of an electronic device for contactless communication provided in the embodiments of this specification. Figure 1 As shown, the electronic device may include an antenna 102, a communication chip 104, and a load adjustment circuit 106. The antenna 102 is connected to the load adjustment circuit 106, and the load adjustment circuit 106 is connected to the communication chip 104. This electronic device can function as a slave or passive device in contactless communication, or a component of either a slave or passive device can communicate with a card reader device. Specifically, the electronic device can be a contactless tag, such as an NFC tag, or it can function as a component of a slave or passive device in contactless communication. For example, contactless communication may include NFC near-field communication, and the electronic device can be part of an NFC device with NFC tag functionality.

[0038] Antenna 102 may include a metal coil, specifically a conventional NFC antenna or other antenna used to receive radio frequency signals, and can be used to receive signals from a card reader device. The specific shape or size of the antenna may be the same as or similar to the shape or size of the antenna coil of the card reader device, so as to achieve better coupling with the card reader device. Antenna 102 may be a pure coil or an antenna containing some electronic components, such as a coil and a capacitor connected in parallel with the coil, etc., without specific limitations.

[0039] The communication chip 104 can be a conventional NFC tag chip, capable of absorbing energy through the radio frequency field provided by the card reader device to complete communication and related tasks. For example, the communication chip can be an Ntag series IC chip, such as Ntag213, Ntag215, Ntag216, etc.; or a Mifare series IC chip, such as Mifare1 S50, Mifare1 S70, and Mifare Ultralight, etc.; or an I-CODE series IC chip, such as I-CODE2, etc.; or an FM series IC chip, such as FM11RF08, etc.; or an ST25 series IC chip, such as ST25DV-I2C, ST25TV, ST25TN, ST25TA, and ST25TB, etc. The specific model of the communication chip is not limited here. The communication chip may include components such as control circuitry and memory.

[0040] The communication chip 104 can directly or indirectly control the state of the load adjustment circuit 106. Specifically, it can control the parameter information of the components in the load adjustment circuit, or it can be expressed as controlling the parameter information of the load impedance in the load adjustment circuit.

[0041] The load adjustment circuit may include a first state and a second state, wherein the load impedance of the electronic device in the first state is different from that in the second state. If the electronic device receives a low-power card detection (LPCD) signal sent by the card reader device, the communication chip controls the load adjustment circuit to switch from the first state to the second state, so that the card reader device switches to normal card detection mode.

[0042] In practical applications, electronic devices communicate with card reader devices via contactless communication such as NFC. The card reader device, as the active device, provides the energy required for communication. The electronic device can be considered equivalent to the load of the card reader device; when the load impedance characteristics of the electronic device change, the feedback signal acquired by the corresponding card reader device will also change. The electronic devices in the embodiments of this specification can be used in NFC tags for NFC communication, or in tags for other contactless communication. As long as the card reader device corresponding to the contactless communication tag has the need to switch from LPCD mode to normal card detection mode, the contactless communication tag can include the electronic devices provided in this specification.

[0043] The electronic device provided in the embodiments of this specification may include a load adjustment circuit capable of adjusting the load impedance. After detecting a signal emitted by a card reader device in LPCD mode, the load adjustment circuit can switch from the first state to the second state. The load impedance of the electronic device in the first state is different from that in the second state. By changing the load impedance of the electronic device, the amplitude or phase of the signal emitted by the card reader device can be significantly changed after encountering the electronic device, which can facilitate the card reader device to enter the normal card detection mode from LPCD mode, thereby increasing the identification probability of contactless communication and the probability of successful card detection by the card reader device.

[0044] In practical applications, card reader devices transmit radio frequency (RF) signals. When the antenna in the electronic device senses the RF signal, it affects the RF signal emitted by the card reader. The card reader device can detect changes in the signal, such as changes in amplitude, phase, and other parameters. Existing NFC tags have a fixed degree of influence on the various signals emitted by the card reader device. For example, if the card reader device emits multiple signals in LPCD mode, the difference sensed by the card reader for these signals remains constant. This leads to fatigue-related actions in the card reader device, preventing it from switching to normal card detection mode. The electronic device provided in the embodiments of this specification can change the state of the load impedance during the card reader device's card detection process, allowing the card reader device to reflect different changes and facilitating the switching to normal card detection mode.

[0045] As one implementation, the load impedance of a circuit can be adjusted by adjusting the circuit's resonant point. In the embodiments of this specification, the load adjustment circuit can be a tuning circuit, also called a resonant circuit or an LC circuit, which is a circuit including an inductor (L) and / or a capacitor (C). In this specification, the load adjustment circuit 106 is connected to the antenna 102, which can constitute a circuit capable of adjusting the resonant frequency. The load adjustment circuit 106 can include a first state and a second state. The inductance or capacitance values ​​of the load adjustment circuit in the first state are different from those in the second state, resulting in different resonant points of the load adjustment circuit in the two states, which can also manifest as different load impedances.

[0046] In one implementation, in the first state, the resonant point of the electronic device can conform to a preset resonant point. For example, in the first state, the resonant frequency of the electronic device can be equal to the preset resonant frequency or have a small difference from the preset resonant frequency. In the second state, the resonant point of the electronic device can deviate from the preset resonant point. For example, in the second state, the resonant frequency of the electronic device can be greater than or less than the preset resonant frequency of the preset resonant point.

[0047] In another implementation, the resonant point of the electronic device in the first state may deviate from the preset resonant point, while in the second state the resonant point of the electronic device may conform to the preset resonant point.

[0048] A resonant point can represent the point at which a resonant circuit exhibits maximum response or minimum impedance at a specific frequency. In the embodiments of this specification, the resonant point of the electronic device can represent the resonant point of a resonant circuit including a load adjustment circuit. A preset resonant point can be the resonant point of the card reader device corresponding to its operating carrier frequency band; the preset resonant point can also be represented by a resonant frequency. The operating frequency of the card reader device can be its resonant frequency so that it can be recognized by slave devices.

[0049] For example, the operating carrier frequency band of commonly used NFC communication card reader devices is around 13.56MHz, or it can operate within the range of 13.56±0.7MHz. The preset resonant point can be the point of maximum response or minimum impedance exhibited in this operating carrier frequency band, and the preset resonant frequency can be 13.56MHz, or a frequency within the range of 13.56±0.7MHz.

[0050] In this embodiment, the communication chip 104 can be used to control the load adjustment circuit 106 to be in a first state or a second state. Specifically, if the electronic device receives a low-power card detection (LPCD) signal sent by the card reader device, the communication chip can control the load adjustment circuit to switch from the first state to the second state. By adjusting the resonant point, the communication chip can facilitate the card reader device to exit the low-power card detection (LPCD) mode so that the card reader device can switch to the normal card detection mode.

[0051] The low-power card detection LPCD signal can be a signal emitted by the card reader device in the low-power card detection LPCD mode.

[0052] The card reader device can be a mobile phone, smartwatch, computer, POS machine, or other active device capable of contactless communication, such as an NFC card reader device. The electronic devices provided in the embodiments of this specification can be slave devices or components of contactless communication. For example, the electronic devices provided in the embodiments of this specification can be part of an active or passive NFC tag or NFC card, or they can be part of an electronic device serving as an NFC slave device.

[0053] Taking NFC (Near Field Communication) as an example, the card reader device can actively emit electromagnetic signals, such as a 13.56MHz signal in LPCD mode. The antenna included in the electronic components provided in this specification can sense the electromagnetic signals emitted by the card reader device. The electronic components in this specification can sense the presence of a card reader device through the antenna. If the electronic components detect a signal from a low-power card detection LPCD mode card reader device, they can switch the load adjustment circuit, causing the card reader device to switch from LPCD mode to normal card detection mode.

[0054] In one implementation, the electronic device can be in a first state when it is not in operation, or when no card reader device is nearby and no radio frequency signal emitted by the card reader device is detected. The resonant point of the electronic device can conform to a preset resonant point, such as a resonant frequency of 13.56MHz. If a card reader device approaches, and the electronic device or its antenna senses the low-power card detection (LPCD) signal sent by the card reader device, the communication chip can control the electronic device to switch from the first state to a second state. In the second state, the resonant point of the electronic device can deviate from the preset resonant point, such as a resonant frequency of 11MHz, 12MHz, or 15MHz, while the card reader device operates at a frequency of 13.56MHz. By adjusting the resonant point, the amplitude or phase change of the feedback signal obtained by the card reader device under the influence of the electronic device can be increased, promoting the card reader device to activate the normal card detection mode. In practical applications, if the card reader device switches from LPCD mode to normal card detection mode and transmits signals in normal card detection mode, after the electronic device receives the signal sent by the card reader device in normal card detection mode, it can adjust the resonant point of the electronic device to the resonant point that matches the card reader's working mode. For example, it can restore from the second state to the first state to ensure communication efficiency and also to prepare for the next wake-up of the card reader device in LPCD mode.

[0055] In another implementation, the resonant point of the electronic device in the first state can deviate from a preset resonant point. If a card reader device approaches, the electronic device or its antenna senses the low-power card detection (LPCD) signal sent by the card reader device. The communication chip can then control the electronic device to switch from the first state to the second state, where the resonant point of the electronic device can conform to the preset resonant point. By adjusting the resonant point, the amplitude or phase change of the feedback signal obtained by the card reader device under the influence of the electronic device can be increased, promoting the card reader device to activate the normal card detection mode. In practical applications, if the card reader device switches from LPCD mode to normal card detection mode and transmits a signal in normal card detection mode, after the electronic device receives the signal sent by the card reader device in normal card detection mode, or after communication with the card reader device ends, the resonant point of the electronic device can be adjusted to deviate from the resonant point of the card reader's operation, such as returning from the second state to the first state, to prepare for the next activation of the card reader device in LPCD mode.

[0056] The electronic device provided in the embodiments of this specification can adjust the load adjustment circuit after detecting the signal emitted by the card reader device in LPCD mode. This causes a significant change in the amplitude or phase of the signal emitted by the card reader device after it encounters the electronic device. This can facilitate the card reader device to enter the normal card detection mode from LPCD mode, thereby increasing the identification probability of contactless communication and the probability of successful card detection by the card reader device.

[0057] Some related technologies employ ALM (Always Listen Mode) tag chips powered by an additional power supply to improve the success rate of card detection for mobile terminals. In ALM mode, the tag chip can continuously listen to signals from the reader with extremely low power consumption and respond quickly when a valid signal is received. Other related technologies use a separate active signal wake-up circuit to prompt the mobile terminal to exit LPCD mode. It is evident that the methods employed in these related technologies are complex and costly, making them unsuitable for practical implementation.

[0058] The electronic devices provided in the embodiments of this specification have simple structures, do not require overly complex circuits or additional power supplies, are low in cost, and are more conducive to implementation in practical applications.

[0059] Taking the NFC frequency of 13.56MHz as an example, its resonant frequency is Its impedance value: Where wL is the inductive impedance value. The capacitive reactance is: ; the frequency angle is:

[0060] Through relevant theoretical calculation formulas, we can find that both the impedance and phase (frequency angle) that cause amplitude changes are related to the values ​​of inductance and capacitance.

[0061] The electronic devices provided in the embodiments of this specification can influence the signals emitted by the card reader device by changing the capacitance or inductance values, enabling the card reader device to smoothly switch from LPCD mode to normal card detection mode. From the perspective of the card reader device, the electronic devices provided in this specification can serve as the load for the card reader device, and this specification can facilitate the smooth switch of the card reader device from LPCD mode to normal card detection mode by adjusting the load parameters.

[0062] In one implementation, the load adjustment circuit may include an LC resonant circuit capable of changing circuit parameters. Optionally, the load adjustment circuit may include at least a first capacitor and a first adjustable inductor. The first capacitor is connected in parallel with the antenna; the first adjustable inductor is connected in series with the antenna; and the adjustable terminal of the first adjustable inductor is connected to the communication chip, so that the communication chip can adjust the inductance value of the inductor according to the signal acquired by the antenna.

[0063] Specifically, in the first state, the inductance value of the first adjustable inductor is a first inductance value, and in the second state, the inductance value of the first adjustable inductor is a second inductance value. In this embodiment, the resonant frequency of the electronic device can be adjusted by adjusting the inductance value of the load adjustment circuit. Wherein, if the resonant frequency of the electronic device in the second state is less than the resonant frequency of the electronic device in the first state, then the first inductance value is less than the second inductance value. If the resonant frequency of the electronic device in the second state is greater than the resonant frequency of the electronic device in the first state, then the first inductance value is greater than the second inductance value.

[0064] In one implementation, if the electronic device receives a low-power card detection (LPCD) signal sent by the card reader, the load adjustment circuit needs to switch from the first state to the second state. Assuming that the resonant frequency of the electronic device in the first state is the operating resonant frequency of the card reader, and the resonant frequency of the electronic device in the second state is less than the operating resonant frequency of the card reader; or, if the resonant frequency of the electronic device in the first state is greater than the operating resonant frequency of the card reader, and the resonant frequency of the electronic device in the second state is equal to the operating resonant frequency of the card reader, this can be expressed as the resonant frequency of the electronic device in the second state being less than the resonant frequency of the electronic device in the first state. In this case, the resonant frequency of the electronic device can be lowered, and the load adjustment circuit switches from the first state to the second state. Specifically, this can be achieved by increasing the inductance value of the first adjustable inductor. In this case, the second inductance value can be greater than the first inductance value, i.e., the first inductance value can be less than the second inductance value.

[0065] In another implementation, if the electronic device receives a low-power card detection (LPCD) signal sent by the card reader, the load adjustment circuit needs to switch from the first state to the second state. Assuming that the resonant frequency of the electronic device is equal to the operating resonant frequency of the card reader in the first state, and greater than the operating resonant frequency of the card reader in the second state; or, if the resonant frequency of the electronic device is less than the operating resonant frequency of the card reader in the first state, and equal to the operating resonant frequency of the card reader in the second state, this can be expressed as the resonant frequency of the electronic device in the second state being greater than that in the first state. This can be achieved by reducing the inductance value of the first adjustable inductor. In this case, the second inductance value can be less than the first inductance value, i.e., the first inductance value is greater than the second inductance value.

[0066] Figure 2 This is a schematic diagram of an electronic device provided in an embodiment of this specification. Figure 2 As shown, the load adjustment circuit 106 may include a first capacitor C1 and a first adjustable inductor L1. The first capacitor C1 is connected in parallel with the antenna 102, and the first adjustable inductor L1 is connected in series with the first capacitor C1, or it can be represented as the first adjustable inductor L1 being connected in series with the antenna 102.

[0067] Specifically, one end A of antenna 102 can be connected to one end b of the first adjustable inductor L1, and the other end a of the first adjustable inductor L1 can be connected to one input terminal IN1 of communication chip 104. The other input terminal IN2 of communication chip 104 can be connected to the other end B of antenna 102. The adjustable terminal c of the first adjustable inductor L1 can be connected to the signal control terminal GPO of communication chip 104. Communication chip 104 can output analog or digital control signals to control the inductance value of the first adjustable inductor L1. One end d of the first capacitor C1 can be connected to the other end a of the first adjustable inductor L1, and the other end e of the first capacitor C1 can be connected to the other end B of antenna 102.

[0068] In this embodiment, the load adjustment circuit includes a series-connected adjustable inductor and a parallel-connected capacitor, which, together with the inductance L0 of the antenna coil body, form a resonant circuit. The adjustable inductor can be an inductor whose inductance value can be adjusted or changed, and can also be called a variable inductor.

[0069] In one implementation, when the adjustable inductor is idle, such as when the antenna does not sense a signal sent by the card reader, there is no card reader nearby sending near-field communication signals, or contactless data transmission is completed with the card reader, the load adjustment circuit can be in the first state. In this case, the resonant point of the resonant circuit including the first capacitor and the first adjustable inductor in the electronic device can deviate from the preset resonant point, such as deviating by 13.56MHz, resulting in a higher impedance. Relative to the card reader, the load is large, and the signal sensed back by the card reader changes significantly. When a field approaches, the antenna senses the radio frequency (RF) signal transmitted by the card reader device, converts the RF signal into electrical energy, and supplies it to the communication chip. The communication chip can determine that there is a card reader device nearby transmitting a low-power card detection signal, and can send a control signal to the first adjustable inductor, causing the inductance value of the first adjustable inductor to increase or decrease. The load adjustment circuit can switch from a first state to a second state. In this case, the resonant point of the resonant circuit including the first capacitor C1 and the first adjustable inductor L1 in the electronic device will meet the preset resonant point, such as exactly 13.56MHz. The impedance is low, the load is smaller relative to the card reader device, and the change in the signal sensed by the card reader device is smaller, but the change in the signal becomes larger relative to continuous signal changes. This can effectively solve the problem that the card reader device does not trigger the normal card detection function due to continuously receiving the same change value. Therefore, the method of this embodiment can cause the signal change sensed by the card reader device to meet the requirements, and the card reader device can start the normal card detection mode.

[0070] Similarly, as another implementation, in the idle state, the load adjustment circuit is in the first state. In the first state, the resonant point of the electronic device can be the same as the preset resonant point, with low impedance and low return loss. Relative to the card reader device, the load is small, and the change in the signal sensed by the card reader device is small. When a field approaches, the antenna senses the radio frequency signal sent by the card reader device. After the communication chip determines that the radio frequency signal is a low-power card detection LPCD signal, it can adjust the load adjustment circuit from the first state to the second state. In the second state, the load adjustment circuit can deviate from the preset resonant point, with high impedance and high return loss. Relative to the card reader device, the load is large, and the change in the signal sensed by the card reader device is larger, which can trigger the normal card detection mode of the card reader device.

[0071] In the embodiments described in this specification, the resonant point of the electronic device can also be adjusted by adjusting the capacitance value of the electronic device, thereby promoting the card reader device to enter normal card detection mode. As one implementation, the load adjustment circuit may include an adjustable capacitor, forming an adjustable LC resonant circuit with the antenna. Optionally, the load adjustment circuit may include at least a first adjustable capacitor. The first adjustable capacitor is connected in parallel with the antenna; the adjustable terminal of the first adjustable capacitor is connected to the communication chip, so that the communication chip can adjust the capacitance value according to the signal acquired by the antenna.

[0072] Specifically, in the first state, the first adjustable capacitor has a first capacitance value, and in the second state, the first adjustable capacitor has a second capacitance value. In this embodiment, the resonant frequency of the electronic device can be adjusted by adjusting the inductance value of the load adjustment circuit. Wherein, if the resonant frequency of the electronic device in the second state is less than the resonant frequency of the electronic device in the first state, then the first capacitance value is less than the second capacitance value; if the resonant frequency of the electronic device in the second state is greater than the resonant frequency of the electronic device in the first state, then the first capacitance value is greater than the second capacitance value.

[0073] As one implementation method, it is assumed that the resonant point of the electronic device in the first state is equal to the preset resonant point, and the resonant point of the electronic device in the second state is lower than the preset resonant point, which can also be expressed as the resonant frequency of the electronic device being lower than the preset resonant frequency; or, the resonant point of the electronic device in the first state is greater than the preset resonant point, and the resonant point of the electronic device in the second state is equal to the preset resonant point. If the electronic device obtains the low-power card detection LPCD signal sent by the card reader device, the load adjustment circuit needs to switch from the first state to the second state, which can be achieved by increasing the capacitance value of the first adjustable inductor, that is, the first capacitance value can be less than the second capacitance value.

[0074] As another implementation, assuming that the resonant point of the electronic device in the first state is equal to the preset resonant point, and the resonant point of the electronic device in the second state is higher than the preset resonant point, it can also be expressed as the resonant frequency of the electronic device being higher than the preset resonant frequency; or, the resonant point of the electronic device in the first state is less than the preset resonant point, and the resonant point of the electronic device in the second state is equal to the preset resonant point. If the electronic device obtains the low-power card detection LPCD signal sent by the card reader device, the load adjustment circuit needs to switch from the first state to the second state, which can be achieved by reducing the capacitance value of the first adjustable capacitor, that is, the first inductance value can be greater than the second inductance value.

[0075] Figure 3 This is a schematic diagram of an electronic device provided in an embodiment of this specification. Figure 3As shown, the load adjustment circuit 106 may include a first adjustable capacitor C2. The first adjustable capacitor C2 is connected in parallel with the antenna 102 to form a resonant circuit. Specifically, one end f of the first adjustable capacitor C2 can be connected to one end A of the antenna 102, and the other end g of the first adjustable capacitor C2 can be connected to the other end B of the antenna 102. The adjustable end h of the first adjustable capacitor C2 can be connected to the signal control terminal GP0 of the communication chip. The communication chip 104 can output analog or digital control signals to control the capacitance value of the first adjustable capacitor C2. In practical applications, one end f and the other end g of the first adjustable capacitor C2 can be the fixed ends of the adjustable capacitor, such as a fixed pin; the adjustable end h of the first adjustable capacitor C2 can be the movable end of the adjustable capacitor, such as a fixed pin.

[0076] Antenna 102 can also be connected to communication chip 104. Specifically, one end A of antenna 102 can be connected to one input terminal IN1 of communication chip 104, and the other end B of antenna 102 can be connected to another input terminal IN2 of communication chip 104, so that communication chip 104 can detect the signal sensed by antenna 102.

[0077] In this embodiment, the load adjustment circuit includes a first adjustable capacitor C2 connected in parallel. This first adjustable capacitor C2 and the inductance L0 of the antenna coil body can form a resonant circuit. The adjustable capacitor can be a capacitor whose capacitance value can be adjusted or changed, and can also be called a variable capacitor.

[0078] In this embodiment, the resonant frequency of the electronic components can be adjusted by changing the capacitance value, thus promoting the card reader to enter normal card detection mode. As one implementation, in the idle state, the load adjustment circuit can be in a first state where the resonant point deviates from the preset resonant point. The inductance of the first adjustable capacitor is C20, and the resonant point of the resonant circuit, including the first adjustable capacitor C2 and the antenna coil, can deviate from the preset resonant point. For example, a deviation of 13.56MHz results in a higher impedance. With a larger load relative to the card reader, the signal received by the card reader changes more significantly. When an electric field approaches, the communication chip determines that a card reader device is nearby transmitting a low-power card detection signal. It can then send a control signal to the first adjustable capacitor C2, adjusting its inductance value via the adjustable terminal. In this state, the capacitance of the first adjustable capacitor is C21, which can form a resonant circuit with the antenna coil. The resonant point of this circuit matches a preset resonant point, such as 13.56MHz. The impedance is low, resulting in a smaller load relative to the card reader device. The signal changes sensed by the card reader device are smaller, but the changes are larger compared to continuous signal changes. This effectively solves the problem of the card reader device not triggering normal card detection due to continuously receiving the same change value. Therefore, the method of this embodiment can ensure that the signal changes sensed by the card reader device meet the requirements, allowing the card reader device to start normal card detection mode.

[0079] Similarly, as one implementation method, in the idle state, the load adjustment circuit can be in a first state where the resonant point matches the preset resonant point. When the LPCD signal is detected, the first adjustable capacitor can be adjusted to make the load adjustment circuit move to a second state where the resonant point deviates from the preset resonant point, thereby changing the resonant frequency of the electronic device. This can also be represented as changing the load parameters, which can promote the card reader device to enter the normal card detection mode. For the specific principle, please refer to the aforementioned embodiments, which will not be repeated here.

[0080] In the embodiments of this specification, a controllable switch can also be used to make the fixed capacitor function as an adjustable capacitor, thereby adjusting the resonant point of the electronic device and promoting the card reader to start the normal card detection mode. Optionally, the load adjustment circuit described in the embodiments of this specification may include a second capacitor, a third capacitor, and a first controllable switch. The second capacitor may be connected in parallel with the antenna; the third capacitor may be connected in series with the first controllable switch and then in parallel with the antenna; the first controllable switch may be connected to the communication chip so that the communication chip can control the state of the first controllable switch.

[0081] Specifically, if the resonant frequency of the electronic device in the second state is less than the resonant frequency of the electronic device in the first state, then the first controllable switch can be in the open state in the first state and in the closed state in the second state, so that the capacitance value of the electronic device in the first state can be less than the capacitance value of the electronic device in the second state. If the resonant frequency of the electronic device in the second state is greater than the resonant frequency of the electronic device in the first state, then the first controllable switch is in the closed state in the first state and in the open state in the second state, so that the capacitance value of the electronic device in the first state can be greater than the capacitance value of the electronic device in the second state.

[0082] Figure 4 This is a schematic diagram of an electronic device provided in an embodiment of this specification. Figure 4 As shown, the load adjustment circuit 106 may include a second capacitor C4, a third capacitor C3, and a first controllable switch K1. One end p of the second capacitor C4 can be connected to one end A of the antenna 102, and the other end q of the second capacitor C4 can be connected to the other end B of the antenna 102. One end n of the third capacitor C3 can be connected to one end A of the antenna 102, and the other end m of the third capacitor C3 can be connected to one end s1 of the first controllable switch K1. The other end t1 of the first controllable switch K1 can be connected to the other end B of the antenna 102. The control terminal r1 of the first controllable switch K1 can be connected to the signal control terminal GPO of the communication chip 104, so that the communication chip 104 can control the switching state of the first controllable switch K1 to adjust the resonant point of the load adjustment circuit.

[0083] In practical applications, the first controllable switch K1 can be a switch whose switching state can be controlled by analog or digital signals. For example, it can be a switch controlled by pulse signals, voltage signals, current signals, etc. Specifically, the first controllable switch can be an electronic unit including a thyristor, or it can be an integrated electronic component, such as the TS5A3166 single-pole single-throw analog switch. The specific type and model of the first controllable switch K1 are not limited here, as long as it can achieve the function of adjusting the capacitance value.

[0084] The antenna 102 can also be connected to the communication chip 104. Specifically, one end A of the antenna 102 can be connected to one input terminal IN1 of the communication chip 104, and the other end B of the antenna 102 can be connected to another input terminal IN2 of the communication chip 104, so that the communication chip 104 can detect the signal sensed by the antenna 102 and execute the corresponding process.

[0085] In this embodiment, the available capacitor value in the load adjustment circuit is adjusted by the first controllable switch. The specific working principle can be found in the foregoing embodiments, and will not be repeated here.

[0086] In practical applications, the load impedance of electronic devices can also be expressed as the quality factor (Q) of the electronic devices. The Q value represents the ratio of energy storage to energy loss in a resonant circuit. Similar to the principles of the embodiments described above, in the embodiments of this specification, the Q value can also be adjusted by adjusting the resistance value of the electronic devices, thereby adjusting the load impedance and facilitating the switching of the card reader device from low-power LPCD mode to normal card detection mode.

[0087] Optionally, in the embodiments of this specification, the load impedance of the electronic device in the first state is different from that in the second state, specifically including: the resistance value of the electronic device in the first state is different from that in the second state.

[0088] Adjusting the resistance value of electronic components can also change the load impedance, effectively preventing the card reader from failing to activate the normal card detection mode due to fatigue or other reasons.

[0089] In one implementation, the load adjustment circuit includes a fourth capacitor, a first resistor, and a second controllable switch; the fourth capacitor is connected in parallel with the antenna; the first resistor and the second controllable switch are connected in series and then in parallel with the antenna; the second controllable switch is connected to the communication chip. In the first state, the second controllable switch is in a closed state, and in the second state, the second controllable switch is in an open state; or, in the first state, the second controllable switch is in an open state, and in the second state, the second controllable switch is in a closed state.

[0090] Figure 5 This is a schematic diagram of an electronic device provided in an embodiment of this specification. Figure 5 As shown, the load adjustment circuit 106 includes a fourth capacitor C5, a first resistor R1, and a second controllable switch K2. One end w1 of the fourth capacitor C5 can be connected to one end A of the antenna 102, and the other end w2 of the fourth capacitor C5 can be connected to the other end B of the antenna. The fourth capacitor C5 is connected in parallel with the antenna 102. One end v of the first resistor R1 can be connected to one end s2 of the second controllable switch K2, and the other end u of the first resistor R1 can be connected to one end A of the antenna 102. The other end t2 of the second controllable switch K2 can be connected to the other end B of the antenna. The first resistor R1 and the second controllable switch K2 are connected in series and then connected in parallel with the antenna 102. The controllable terminal r2 of the second controllable switch K2 can be connected to the signal control terminal GPO of the communication chip 104, so that the communication chip 104 adjusts the resistance value of the electronic device by controlling the state of the second controllable switch, thereby adjusting the load impedance of the electronic device.

[0091] The antenna 102 can also be connected to the communication chip 104. Specifically, one end A of the antenna 102 can be connected to one input terminal IN1 of the communication chip 104, and the other end B of the antenna 102 can be connected to another input terminal IN2 of the communication chip 104, so that the communication chip 104 can detect the signal sensed by the antenna 102 and execute the corresponding process.

[0092] In practical applications, the state of the second controllable switch can be set according to actual needs. For example, in the first state, the second controllable switch can be in the closed state, and in the second state, the second controllable switch can be in the open state; or, in the first state, the second controllable switch can be in the open state, and in the second state, the second controllable switch can be in the closed state.

[0093] Assuming the electronic device is in an idle state (state 1) and the second controllable switch is closed, upon detecting an LPCD signal from the card reader, the second controllable switch can switch to the open state. This changes the resistance, Q value, and load impedance of the electronic device, prompting the card reader to transition from LPCD mode to normal card detection mode. To ensure efficient information transmission, the electronic device can be restored to the first state after the card reader enters normal card detection mode, such as by reclosing the second controllable switch. Similarly, if the second controllable switch is open in the first state, detecting an LPCD signal from the card reader can also close the second controllable switch, prompting the card reader to enter normal card detection mode.

[0094] In practical applications, when the electronic device is idle, its Q value can be within a preset range. This preset range represents the Q value of the electronic device after the card reader starts normal card detection mode or during the process of obtaining tag information through polling. Alternatively, when the electronic device is idle, its Q value can deviate from the preset range, such as being too large or too small. Specific parameters can be set according to actual needs and are not limited here.

[0095] In another implementation, the load adjustment circuit includes a first adjustable resistor and a fifth capacitor; the fifth capacitor is connected in parallel with the antenna; the first adjustable resistor is connected in series with the antenna; and the adjustable terminal of the first adjustable resistor is connected to the communication chip. In the first state, the resistance value of the first adjustable resistor is a first resistance value, and in the second state, the resistance value of the first adjustable resistor is a second resistance value.

[0096] Figure 6 This is a schematic diagram of an electronic device provided in an embodiment of this specification. Figure 6As shown, the load adjustment circuit 106 may include a first adjustable resistor R2 and a fifth capacitor C6. One end y1 of the fifth capacitor C6 is connected to one end A of the antenna 102, and the other end y2 of the fifth capacitor C6 is connected to the other end B of the antenna 102. The fifth capacitor C6 is connected in parallel with the antenna 102. One end x2 of the first adjustable resistor R2 is connected to one end A of the antenna 102, and the other end x1 can be connected to one input terminal IN1 of the communication chip 104. The adjustable end of the first adjustable resistor R2 can be connected to the signal control terminal GPO of the communication chip 104. The other end B of the antenna 102 can be connected to another input terminal IN2 of the communication chip 104, so that the communication chip 104 can detect the signal sensed by the antenna 102 and execute the corresponding process.

[0097] In the first state, the resistance value of the first adjustable resistor R2 is the first resistance value, and in the second state, the resistance value of the first adjustable resistor is the second resistance value. The first resistance value and the second resistance value are different.

[0098] In practical applications, the first and second resistance values ​​can be set according to actual needs. (As mentioned above...) Figure 5 The circuit shown is similar in principle and uses... Figure 6 The electronic components shown can also facilitate the card reader to initiate normal card detection mode. Further details are omitted here.

[0099] It is understandable that the above embodiments mainly describe the circuit parts that play a major role. In practical applications, necessary electronic components can be added to the circuits shown in the above embodiments, or the connection order of components can be adjusted, etc., according to actual needs. For example, for... Figures 2 to 6 The circuit shown can also incorporate electronic components such as resistors and inductors in series, or capacitors in parallel. Furthermore, the above... Figures 2 to 6 The schematic diagrams provided in this manual are only for the purpose of making the electronic devices provided clearer. In actual applications, other forms of circuits can also be used to adjust the load impedance. The specific form of the circuit is not limited here.

[0100] To improve the stability of electronic devices, the communication chip in the embodiments of this specification may optionally be a chip with energy recovery and energy output functions. The power output terminal of the communication chip can be connected to the power input terminal of the load adjustment circuit to provide power for the state transition of the load adjustment circuit.

[0101] As mentioned above, the first adjustable capacitor, first adjustable inductor, first adjustable resistor, first controllable switch, or second controllable switch can be components with a power input terminal. The communication chip can provide the necessary power for adjustment, specifically short-term power, such as providing instantaneous power to the circuit for starting the component. In one implementation, the power output terminal of the communication chip can be connected to the power input terminal of the first and / or second controllable switches to provide power to them.

[0102] In practical applications, a communication chip with energy recovery and energy output functions, along with the aforementioned antenna and load adjustment circuit, can be used to form a passive NFC tag, or the main circuit part of a passive NFC tag.

[0103] In practical applications, an external power supply can also be used to power the electronic device or the load regulation circuit within the electronic device. Optionally, the electronic device may include a power input terminal for connecting to an external power source so that the power source provides electrical energy to the electronic device.

[0104] In one implementation, the power input terminal of the electronic device can represent the power input terminal of the load adjustment circuit and / or the communication chip, and the external power supply can provide operating power to the load adjustment circuit and / or the communication chip.

[0105] The power source for electronic devices can be located outside the device itself, such as a battery or power module. There is no specific limitation on the type of power source; the parameters can be set according to the actual circuit requirements.

[0106] As another implementation, the power supply device may also include a power element, such as a battery. The power element can be connected to a load regulation circuit and / or a communication chip to provide power to the electronic device. The power element can be fixed or integrated with the communication chip, load regulation circuit, etc., on the same circuit board, or it can be placed separately; this is not limited here.

[0107] In practical applications, the load adjustment circuit can be a circuit controlled by digital signal levels. To facilitate the control of the load adjustment circuit, the communication chip in this embodiment can have the function of outputting digital signal levels. The load adjustment circuit is connected to the communication chip, which specifically includes: the digital signal level output pin of the communication chip is connected to the digital signal input terminal of the load adjustment circuit via the communication chip.

[0108] The digital signal level output pin of the communication chip can represent the signal control terminal of the communication chip. This pin can be connected to the adjustable terminal of the load adjustment circuit used to control the capacitor or inductor. For example, it can be connected to at least one of the adjustable terminal of the first adjustable inductor, the adjustable terminal of the first adjustable capacitor, and the control terminal of the controllable switch.

[0109] In practical applications, electronic devices may also include power supply devices or use external power supply devices connected to communication chips, so that the communication chip can generate digital signal levels for controlling load adjustment circuits based on the electrical energy provided by the power supply element or external power supply device.

[0110] In practical applications, an external digital signal circuit can also be used to provide signals for controlling the load adjustment circuit. Optionally, the electronic device in the embodiments of this specification may further include a digital signal conversion unit; the load adjustment circuit is connected to the communication chip, specifically including: the input terminal of the digital signal conversion unit is connected to the antenna for acquiring the radio frequency signal acquired by the antenna; the output terminal of the digital signal conversion unit is connected to the load adjustment circuit for providing a digital signal level to the load adjustment circuit so that the load adjustment circuit switches from the first state to the second state.

[0111] A digital signal conversion unit can be a unit capable of processing a sinusoidal signal to generate a controllable digital signal level. Examples include envelope detector circuits and half-wave rectifier circuits. The specific circuit design of the digital signal conversion unit is not limited here.

[0112] In practical applications, the digital signal conversion unit can also be connected to the communication chip. When the communication chip determines that the radio frequency signal acquired by the antenna is an LPCD signal, the digital signal conversion unit can generate a digital signal level. Alternatively, the digital signal level generated by the digital signal conversion unit can be provided to the load adjustment circuit through the communication chip. The communication chip can provide the digital signal level to the load adjustment circuit according to actual needs. For example, when the communication chip determines that the radio frequency signal acquired by the antenna is an LPCD signal, the communication chip can provide the digital signal level generated by the digital signal conversion unit to the load adjustment circuit. Or, after communication with the card reader device is completed or the normal card detection function of the card reader device is successfully activated, the communication chip can stop providing the digital signal level to the load adjustment circuit so that the load adjustment circuit can return to its previous state.

[0113] It is understood that the circuits or electronic components provided in the above embodiments can be used independently or in combination. For example, the above... Figures 2 to 6The load adjustment circuits shown can be used individually or in combination; no specific limitation is made here. If multiple load adjustment circuits are used, the electronic components in different circuits can be shared, such as the first capacitor and the second capacitor mentioned above being the same capacitor. Of course, the electronic components in different load adjustment circuits can also be used independently; this is also not limited here.

[0114] In practical applications, the degree to which the resonant point of the electronic device deviates from the preset resonant point or the degree to which the Q value deviates from the preset range in the first or second state can be the same or different for the aforementioned load adjustment circuits. For an electronic device, if two or more of the above-mentioned load adjustment circuits are configured, upon receiving the LPCD signal from the card reader device, these multiple load adjustment circuits can be triggered simultaneously, or only one load adjustment circuit can be selected to operate, or multiple load adjustment circuits can be used in a decreasing manner. To achieve the first or second state, it can be implemented using one of the aforementioned load adjustment circuits or multiple load adjustment circuits, depending on actual needs; no limitation is made here.

[0115] In practical applications, the load adjustment circuit can also be configured to be adjustable in multiple levels. For example, the states representing deviation from the preset resonance point mentioned above can include multiple sub-states, and the differences between the different sub-states can be different degrees of deviation from the preset resonance point. Alternatively, it can be understood that the load adjustment circuit can include not only the first and second states mentioned above, but also a third state, and even a fourth state, etc. The degree of deviation from the preset resonance point in the third and / or fourth states differs from that in the second state. For example, in the third state, the degree of deviation of the electronic device from the preset resonance point can be greater than in the second state. In practical applications, assuming that switching the load adjustment circuit from the first state to the second state is needed to promote the card reader device to start the normal card detection mode, if the card reader device still does not start the normal card detection mode within a preset time after switching to the second state, the load adjustment circuit can be switched to the third state to further promote the card reader device to start the normal card detection mode. The specific settings of the load adjustment circuit are not limited here.

[0116] Based on the same idea, this specification also provides an NFC tag in the embodiments, which includes the electronic devices provided above.

[0117] An NFC tag can be broadly understood as the other party capable of NFC near-field communication with a card reader device; it can also be called the passive party in NFC communication, using the energy provided by the card reader device to send tag information to the card reader device. The communication process or principle between the NFC tag and the card reader device can be found in relevant technical introductions, and will not be elaborated upon here.

[0118] NFC tags can take various forms, such as cards, stickers, labels, keychains, pendants, wristbands, bracelets, badges, name tags, and flexible tags. Alternatively, NFC tags can be embedded within objects, such as toys, furniture, or devices, like electronic devices with NFC tags. NFC tags can be passive or active; there are no restrictions on their specific form.

[0119] It should be understood that the connection order of some components of the electronic device described in one or more embodiments of this specification may be interchanged according to actual needs, or some components may be omitted or deleted.

[0120] Based on the same idea, this specification also provides a control method based on the above-mentioned electronic devices in the embodiments. Figure 7 This is a flowchart illustrating a contactless communication control method provided in the embodiments of this specification. It can be applied to the aforementioned electronic devices. Specific details of the electronic devices can be found in the above embodiments and will not be repeated here. Figure 7 As shown, the control method may include:

[0121] Step 702: Obtain the detection signal sent by the card reader device.

[0122] In practical applications, card reader devices can actively emit detection signals to detect nearby passive communication devices. Card reader devices can be terminal devices such as mobile phones, computers, smartwatches, and POS machines.

[0123] The electronic devices provided in the embodiments of this specification can be NFC tags for NFC near-field communication scenarios, or electronic devices for other radio frequency communication scenarios, such as passive devices applied in RFID radio frequency identification scenarios, such as ETC identification. Specific practical scenarios can include various scenarios such as payment, transportation, access control, information promotion, and management.

[0124] The antenna of an electronic device can acquire the detection signal emitted by the card reader and send it to the communication chip or signal analysis component for signal analysis.

[0125] Step 704: If the detection signal is a low-power card detection LPCD signal, then generate the first control signal.

[0126] Communication chips in electronic devices can be chips with LPCD detection capabilities, used to detect whether the signal acquired by the antenna is a low-power card detection LPCD signal. Alternatively, they can determine whether the detected signal is a low-power card detection LPCD signal through time characteristic analysis, instruction parsing, etc. For example, an LPCD signal manifests as a brief and periodic radio frequency field pulse, such as sending an extremely short activation signal every 500ms, like a 25μs pulse signal. The radio frequency field of a normal signal persists until data exchange is completed. The communication chip can determine the duration of the field strength using an internal timer, thereby determining whether the detected signal is a low-power card detection LPCD signal. Alternatively, the signal type can be determined by detecting the antenna induced voltage or demodulation threshold. The specific determination method is not limited here; existing methods can also be referenced.

[0127] Step 706: Based on the first control signal, the electronic device switches from the first state to the second state so that the card reader device switches to normal card detection mode.

[0128] The load impedance of the electronic device in the first state is different from that in the second state.

[0129] The first control signal can be a signal used to control the state of the load adjustment circuit. Specifically, it can be an analog signal or a digital signal. If the card reader device sends an LPCD signal, the electronic components can be triggered to adjust the load impedance of the electronic components after receiving the LPCD signal, thus prompting the card reader device to switch to normal card detection mode.

[0130] The load impedance of the electronic device in the first state can be greater than the load impedance of the electronic device in the second state, or the load impedance of the electronic device in the first state can be less than the load impedance of the electronic device in the second state.

[0131] The Low Power Card Detection (LPCD) signal indicates that the card reader is emitting a signal in LPCD mode, which can be one or more pulse signals. In practical applications, after determining that the card reader is in LPCD mode, the electronic device can switch states immediately or after a short interval.

[0132] The timing of state switching can also be set according to actual needs. For example, the state switch can occur at the beginning of an LPCD pulse signal emitted by the card reader, allowing the electronic device in the second state to influence the entire process or the initial part of this LPCD pulse signal. Suppose that the electronic device determines the card reader is in LPCD mode based on the nth LPCD pulse signal emitted by the card reader, the electronic device can switch from the first state to the second state when the card reader emits the (n+1)th LPCD pulse signal. The electronic device in the second state can influence the card reader to emit the (n+1)th LPCD pulse signal, or it can influence one or more pulse signals after the (n+1)th pulse signal. Alternatively, after the (n+1)th LPCD pulse signal ends, the electronic device can return to the first state.

[0133] For example, electronic devices can switch states at a certain point in the middle of an LPCD pulse signal emitted by the card reader, allowing the electronic devices in the second state to influence the latter half or subsequent parts of the LPCD pulse signal. For instance, assuming an LPCD pulse signal is 25μs long, after the card reader emits this signal, the electronic devices can be in the first state for the first 8μs and in the second state for the next 17μs; or, the electronic devices can be in the first state for the first 8μs, in the second state for the middle 10μs, and then return to the first state for the next 7μs.

[0134] In practical applications, the state of electronic devices can be set according to actual needs. During the normal card detection mode of a card reader device, the electronic device can perform one state transition or multiple state transitions. For example, after acquiring an LPCD signal, the electronic device can switch from a first state to a second state, and then remain in the second state until the communication ends or the card reader device wakes up the normal card detection mode. Alternatively, after acquiring an LPCD signal, the electronic device can switch from a first state to a second state, which can maintain the length of one or more LPCD pulse signals or a length shorter than one LPCD pulse signal, and then switch back to the first state, which can also maintain the length of one or more LPCD pulse signals or a length shorter than one LPCD pulse signal, repeating this state switching process until the communication ends or the card reader device wakes up the normal card detection mode.

[0135] It is understandable that the signals emitted by card reader devices in LPCD mode also conform to certain patterns, such as fixed transmission cycles and signal lengths. After receiving the LPCD signal emitted by the card reader device, electronic components can determine the parameters of the LPCD signal emitted by the card reader device, generate corresponding control signals for controlling state switching, and control or adjust the timing of state switching.

[0136] In practical applications, before acquiring the Low Power Card Detection (LPCD) signal, the electronic device can be in a first state. After acquiring the LPCD signal, the electronic device can switch from the first state to a second state. In the embodiments of this specification, the card reader can switch from the LPCD detection mode to the normal card detection mode by adjusting the load impedance of the electronic device. This can influence the card reader by adjusting its load, without requiring overly complex design, resulting in low cost and ease of implementation.

[0137] It should be understood that the order of some steps in the methods described in one or more embodiments of this specification may be interchanged according to actual needs, or some steps may be omitted or deleted.

[0138] In practical applications, the load impedance of electronic devices can also be reflected in parameters such as resonant frequency and circuit resistance.

[0139] As one implementation method, to facilitate the card reader device switching to normal card detection mode, the electronic device can switch from a state where its resonant point matches the card reader device's operating resonant point to a state deviating from that operating resonant point, or vice versa. Here, deviating from the resonant point can be expressed as a resonant frequency greater than or less than the card reader device's resonant frequency. Optionally, the load impedance of the electronic device in the first state differs from that in the second state. Specifically, this can include: the resonant point of the electronic device in the first state matches a preset resonant point; the resonant point of the electronic device in the second state deviates from the preset resonant point; the preset resonant point is the card reader device's operating resonant point; or, the resonant point of the electronic device in the first state deviates from the preset resonant point, while the resonant point of the electronic device in the second state matches the preset resonant point.

[0140] In the embodiments of this specification, the resonant point of the electronic device can be adjusted by adjusting the inductance and / or capacitance values, thereby influencing the card reader device. As one implementation, in the first state, the inductance value of the load adjustment circuit of the electronic device is a first inductance value, and in the second state, the inductance value is a second inductance value. If the resonant frequency of the electronic device in the second state is less than the resonant frequency of the electronic device in the first state, then the first inductance value is less than the second inductance value; if the resonant frequency of the electronic device in the second state is greater than the resonant frequency of the electronic device in the first state, then the first inductance value is greater than the second inductance value.

[0141] In the embodiments described in this specification, the resonant frequency of the electronic device in the second state can be greater than the resonant frequency of the card reader device, or it can be less than the resonant frequency of the card reader device.

[0142] Before receiving the LPCD signal from the card reader, the electronic device is in a first state where its resonant point matches the resonant point of the card reader. After receiving the LPCD signal, the electronic device can be adjusted to a second state where its resonant point deviates from the resonant point of the card reader. Specifically, the inductance value of the load adjustment circuit in the electronic device can be increased, making the resonant frequency of the electronic device lower than that of the card reader; or the inductance value of the load adjustment circuit can be decreased, making the resonant frequency of the electronic device higher than that of the card reader.

[0143] If the electronic device is in a first state where its resonant point deviates from the resonant point of the card reader before receiving the LPCD signal, it can be adjusted to a second state after receiving the LPCD signal, thus bringing its resonant point closer to the card reader's resonant point. Specifically, assuming the electronic device's resonant frequency in the first state is higher than the card reader's resonant frequency, after receiving the LPCD signal, the inductance value of the load adjustment circuit in the electronic device can be increased to lower the resonant frequency, bringing the electronic device's resonant point closer to the card reader's resonant point. Conversely, assuming the electronic device's resonant frequency in the first state is lower than the card reader's resonant frequency, after receiving the LPCD signal, the inductance value of the load adjustment circuit in the electronic device can be decreased to increase the resonant frequency, bringing the electronic device's resonant point closer to the card reader's resonant point.

[0144] As in at least one of the foregoing embodiments, the load adjustment circuit of the electronic device may include a first adjustable inductor capable of adjusting its inductance value. By adjusting this inductor, the resonant point of the electronic device can be adjusted. Specific circuit structures and adjustment methods can be found in at least one of the foregoing embodiments, or other circuits capable of adjusting the resonant point of the circuit by adjusting the inductance value, which will not be elaborated here.

[0145] As another implementation, the resonant point of the electronic device can be adjusted by adjusting the capacitance value. Optionally, in the embodiments of this specification, the capacitance value of the load adjustment circuit of the electronic device in the first state is a first capacitance value, and the capacitance value of the load adjustment circuit of the electronic device in the second state is a second capacitance value; if the resonant frequency of the electronic device in the second state is less than the resonant frequency of the electronic device in the first state, then the first capacitance value is less than the second capacitance value; if the resonant frequency of the electronic device in the second state is greater than the resonant frequency of the electronic device in the first state, then the first capacitance value is greater than the second capacitance value.

[0146] In the embodiments of this specification, if an LPCD signal emitted by a card reader device is detected, the electronic device can switch from a first state to a second state, or vice versa. Specifically, if the electronic device is in the first state before acquiring the LPCD signal emitted by the card reader device, its resonant point matches the resonant point of the card reader device. After acquiring the LPCD signal emitted by the card reader device, the electronic device can be adjusted to the second state, where its resonant point deviates from the resonant point of the card reader device. Specifically, the capacitance value of the load adjustment circuit in the electronic device can be increased, making the resonant frequency of the electronic device lower than the resonant frequency of the card reader device; or the capacitance value of the load adjustment circuit in the electronic device can be decreased, making the resonant frequency of the electronic device higher than the resonant frequency of the card reader device.

[0147] If the electronic device is in its second state before receiving the LPCD signal from the card reader, its resonant point deviates from the card reader's resonant point. After receiving the LPCD signal, the electronic device can be adjusted to its first state, bringing its resonant point closer to the card reader's resonant point. Specifically, assuming the electronic device's resonant frequency in the second state is higher than the card reader's resonant frequency, after receiving the LPCD signal, the capacitance of the load adjustment circuit in the electronic device can be increased to lower the resonant frequency, bringing the electronic device's resonant point closer to the card reader's resonant point. Conversely, assuming the electronic device's resonant frequency in the second state is lower than the card reader's resonant frequency, after receiving the LPCD signal, the capacitance of the load adjustment circuit in the electronic device can be decreased to increase the resonant frequency, bringing the electronic device's resonant point closer to the card reader's resonant point.

[0148] As in at least one of the foregoing embodiments, the resonant point of the electronic device can be adjusted by adjusting the capacitance value in the load adjustment circuit, such as by using an adjustable capacitor or by controlling the number of capacitors connected in parallel in the circuit using a first controllable switch. The specific method for adjusting the capacitance value in the circuit is not limited here.

[0149] In one implementation, the resistance value of the electronic device in the first state is a first resistance value, and the resistance value of the electronic device in the second state is a second resistance value, wherein the first resistance value is not equal to the second resistance value.

[0150] In the embodiments described in this specification, the load impedance can also be adjusted by changing the resistance value of the electronic components, thereby facilitating the card reader device to enter normal card detection mode. For the specific working principle and implementation method, please refer to at least one of the foregoing embodiments, which will not be repeated here.

[0151] In the embodiments of this specification, if an LPCD signal emitted by the card reader device is detected, the electronic device can switch from a first state to a second state. For example, the resonant point can switch from 13.56MHz to 11.5MHz, that is, by shifting the resonant point, the electronic device can be encouraged to activate the normal card detection mode. Alternatively, the Q value can switch from a preset range to a range deviating from the preset range, that is, by changing the Q value, the electronic device can be encouraged to activate the normal card detection mode. The closer the resonant point of the electronic device matches the resonant point of the card reader device, or the closer the Q value is to the preset range, the more beneficial it is for the electronic device to send tag information to the card reader device. To ensure communication quality, optionally, the method in the embodiments of this specification may further include: after the electronic device switches from the first state to the second state, if it is detected that the card reader device is already in the normal card detection mode, the electronic device can be restored from the second state to the first state.

[0152] In practical applications, electronic devices can determine whether a card reader is sending a normal card detection signal by detecting signal parameters such as amplitude, time interval, and signal content. If the card reader is sending a normal card detection signal, it can be confirmed that the card reader has switched to normal card detection mode, and subsequent information transmission can proceed after successful card detection. As one implementation method, if the electronic device is in a first state before detecting the LPCD signal from the card reader, and switches to a second state after detecting the LPCD signal, then upon subsequently detecting a normal card detection signal from the card reader, the communication chip can send a second control signal to the load adjustment circuit. This causes the load adjustment circuit to switch back to the first state, allowing the electronic device and the card reader to transmit information via contactless communication. This also prepares for the next switch from LPCD mode to normal card detection mode.

[0153] In the embodiments of this specification, the first state can also represent a state deviating from a preset resonant point or a Q value deviating from a preset range. After the electronic device receives the LPCD signal emitted by the card reader device, it can switch from the first state to the second state, that is, by correcting the resonant point or Q value, it can promote the card reader device to activate the normal card detection mode. To ensure that it can continue to promote the card reader device to activate the normal card detection mode, the electronic device can also switch back to the first state. Optionally, the method in the embodiments of this specification may further include: after the electronic device switches from the first state to the second state, if the communication between the electronic device and the card reader device ends, the electronic device is restored from the second state to the first state.

[0154] As one implementation, if the electronic device is in a first state deviating from a preset resonant point or its Q value deviating from a preset range before detecting the LPCD signal emitted by the card reader, it switches to a second state that conforms to the preset resonant point or its Q value conforms to the preset range after detecting the LPCD signal. It can then continuously communicate with the card reader in the second state, for example, by sending stored tag information to the card reader using the circuitry in the second state. After communication between the electronic device and the card reader ends, such as when the electronic device completes sending the tag information or when the electronic device and the card reader are far apart and can no longer communicate in the near field, the communication chip can send a third control signal to the load adjustment circuit. This causes the load adjustment circuit to switch back to the first state, preparing for the next switch of the card reader from LPCD mode to normal card detection mode.

[0155] In the embodiments of this specification, analog or digital signals can be used to control the state changes of electronic devices. Optionally, the first control signal mentioned above can be a digital pulse signal.

[0156] As in at least one of the embodiments described above, the communication chip can be a chip capable of generating digital pulse signals, or a digital pulse signal can be generated using an external digital signal conversion circuit.

[0157] In one implementation, the length of the digital pulse signal can be equal to the length of the LPCD signal sent by the card reader device.

[0158] In practical applications, card reader devices can send multiple short pulse signals in LPCD mode. The length of the LPCD signal can represent the length of a single pulse signal, which can be on the order of tens of microseconds, such as 35μs or 25μs. For example, after receiving the LPCD signal from the card reader device, electronic devices can generate a digital pulse signal with the same length as the LPCD signal. This can affect the entire pulse duration of the LPCD signal emitted by the card reader device, thereby prompting the card reader device to switch to normal card detection mode.

[0159] In one implementation, the length of the digital pulse signal can also be shorter than the length of the LPCD signal sent by the card reader device. For example, the length of the digital pulse signal can be equal to one-third, one-half, or two-thirds of the length of the LPCD signal sent by the card reader device. In practical applications, different card reader devices may have different signal analysis capabilities or signal sensitivity due to differences in hardware or software configurations; or the parameters or number of electronic components such as capacitors, resistors, and inductors contained in the electronic devices may differ, and the amount of signal change generated by different configurations of electronic devices for the card reader device may also be different. In practical applications, for some card reader devices with strong computing power, or for electronic devices that are greatly affected by signal changes, the electronic devices can adjust their state by using digital pulse signals with a length shorter than the LPCD signal length, which can also promote the card reader device to switch to normal card detection mode. For example, assuming the LPCD signal length is 25μs, a 10μs pulse signal can be generated. For a single LPCD pulse signal emitted by the card reader, the electronic devices can be in the second state for the first 10μs and in the first state for the last 15μs, which can also prompt the card reader to switch to normal card detection mode. The actual signal length can be set according to the specific parameters of the card reader, and is not specifically limited here.

[0160] In the embodiments of this specification, the duration for which the electronic device is in the first or second state can also be controlled by the length of the digital pulse signal. For example, if the electronic device is in the first state before detecting the LPCD signal emitted by the card reader device, upon acquiring the LPCD signal, it can generate a digital pulse signal to switch from the first state to the second state. When the digital pulse signal disappears or ends, the electronic device can return from the second state to the first state.

[0161] It is understood that the above embodiments describe the solutions from multiple perspectives. In practical applications, one or more of the contents described in the embodiments can be adopted according to actual needs, and multiple embodiments can be superimposed or adjusted according to actual needs. These will not be elaborated here.

[0162] The components described in the embodiments of this specification are only functional descriptions. Specific parameters or quantities can be set according to actual needs. For example, the first adjustable inductor can be an inductive component capable of adjusting its inductance value; it can be a single adjustable inductor, a combination inductor including multiple single adjustable inductors, or other inductive components. The first adjustable capacitor can be a capacitive component capable of adjusting its capacitance value; it can be a single capacitor, a combination capacitor including one or more single capacitors, or other capacitive components. The first capacitor, second capacitor, third capacitor, fourth capacitor, fifth capacitor, etc., can be capacitive elements; for example, they can be capacitors with fixed capacitance values, single capacitors, combination capacitors including multiple single capacitors, or other capacitive components. The specific form, type, and quantity of each electronic component are not limited here, as long as the function of adjusting the resonant point is achieved.

[0163] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0164] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties. Furthermore, the collection, use and processing of the relevant data must comply with the relevant laws, regulations and standards of the relevant regions, and corresponding operation portals are provided for users to choose to authorize or refuse.

[0165] In the 1990s, improvements to a technology could be clearly distinguished as either hardware improvements (e.g., improvements to the circuit structure of diodes, transistors, switches, etc.) or software improvements (improvements to the methodology). However, with technological advancements, many methodological improvements today can be considered direct improvements to the hardware circuit structure. Designers almost always obtain the corresponding hardware circuit structure by programming the improved methodology into the hardware circuit. Therefore, it cannot be said that a methodological improvement cannot be implemented using hardware physical modules. For example, a Programmable Logic Device (PLD) (such as a Field Programmable Gate Array (FPGA)) is such an integrated circuit whose logic function is determined by the user programming the device. Designers can program and "integrate" a digital system onto a PLD themselves, without needing chip manufacturers to design and manufacture dedicated integrated circuit chips. Furthermore, nowadays, instead of manually manufacturing integrated circuit chips, this programming is mostly implemented using "logic compiler" software. Similar to the software compiler used in program development, the original code before compilation must be written in a specific programming language, called a Hardware Description Language (HDL). There are many HDLs, such as ABEL (Advanced Boolean Expression Language), AHDL (Altera Hardware Description Language), Confluence, CUPL (Cornell University Programming Language), HDCal, JHDL (Java Hardware Description Language), Lava, Lola, MyHDL, PALASM, and RHDL (Ruby Hardware Description Language). Currently, the most commonly used are VHDL (Very-High-Speed ​​Integrated Circuit Hardware Description Language) and Verilog. Those skilled in the art should understand that by simply performing some logic programming on the method flow using one of these hardware description languages ​​and programming it into an integrated circuit, the hardware circuit implementing the logical method flow can be easily obtained.

[0166] The controller can be implemented in any suitable manner. For example, it can take the form of a microprocessor or processor and a computer-readable medium storing computer-readable program code (e.g., software or firmware) executable by the (micro)processor, logic gates, switches, application-specific integrated circuits (ASICs), programmable logic controllers, and embedded microcontrollers. Examples of controllers include, but are not limited to, the following microcontrollers: ARC 625D, Atmel AT91SAM, Microchip PIC18F26K20, and Silicon Labs C8051F320. A memory controller can also be implemented as part of the control logic of the memory. Those skilled in the art will also recognize that, in addition to implementing the controller in purely computer-readable program code form, the same functionality can be achieved by logically programming the method steps to make the controller take the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers. Therefore, such a controller can be considered a hardware component, and the means included therein for implementing various functions can also be considered as structures within the hardware component. Alternatively, the means for implementing various functions can be considered as both software modules implementing the method and structures within the hardware component.

[0167] The systems, devices, modules, or units described in the above embodiments can be implemented by computer chips or physical entities, or by products with certain functions. A typical implementation device is a computer. Specifically, a computer can be, for example, a personal computer, laptop computer, cellular phone, camera phone, smartphone, personal digital assistant, media player, navigation device, email device, game console, tablet computer, wearable device, or any combination of these devices. For ease of description, the above devices are described separately by function as various units. Of course, in implementing this application, the functions of each unit can be implemented in one or more software and / or hardware.

[0168] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The present invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, produce implementations of the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 The computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0169] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0170] In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory. Memory may include non-persistent storage in computer-readable media, random access memory (RAM), and / or non-volatile memory such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media. Computer-readable media includes both permanent and non-persistent, removable and non-removable media that can store information by any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transfer medium that can be used to store information that can be accessed by the computing device. As defined in this article, computer-readable media do not include transient media, such as modulated data signals and carrier waves.

[0171] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. This application can be described in the general context of computer-executable instructions that are executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform a particular task or implement a particular abstract data type. This application can also be practiced in distributed computing environments, where tasks are performed by remote processing devices connected via a communication network. In a distributed computing environment, program modules can reside in local and remote computer storage media, including storage devices.

[0172] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. An electronic device for contactless communication, the electronic device comprising an antenna, a communication chip, and a load adjustment circuit; wherein, The antenna is connected to the load adjustment circuit, and the load adjustment circuit is connected to the communication chip; The load adjustment circuit includes a first state and a second state; in the first state, the load impedance of the electronic device is different from that in the second state; in the first state, the resonant point of the electronic device matches the operating resonant point of the card reader device or the quality factor Q value is within a preset range, while in the second state, the resonant point of the electronic device deviates from the operating resonant point of the card reader device or the quality factor Q value deviates from the preset range; or, in the first state, the resonant point of the electronic device deviates from the operating resonant point of the card reader device or the quality factor Q value deviates from the preset range, while in the second state, the resonant point of the electronic device matches the operating resonant point of the card reader device or the quality factor Q value is within the preset range. If the electronic device receives a low-power card detection LPCD signal sent by the card reader device, the communication chip controls the load adjustment circuit to switch from the first state to the second state, so that the amplitude or phase change of the feedback signal obtained by the card reader device under the influence of the electronic device increases, thereby exiting the low-power card detection LPCD mode and switching to the normal card detection mode. If the card reader device is detected to be in normal card detection mode or communication with the card reader device has ended, the electronic device is restored from the second state to the first state.

2. The electronic device according to claim 1, wherein in the first state, the resonant point of the electronic device matches the working resonant point of the card reader device or the quality factor Q value matches a preset range, and in the second state, the resonant point of the electronic device deviates from the working resonant point of the card reader device or the quality factor Q value deviates from a preset range, if it is detected that the card reader device is in normal card detection mode, the electronic device is restored from the second state to the first state; Alternatively, if the electronic device's resonant point deviates from the card reader's operating resonant point or its quality factor Q deviates from a preset range in the first state, and the electronic device's resonant point matches the card reader's operating resonant point or its quality factor Q matches a preset range in the second state, then if the electronic device's communication with the card reader ends, the electronic device will revert from the second state to the first state.

3. The electronic device according to claim 1, wherein at least one of the resistance value, inductance value, or capacitance value of the electronic device in the first state and the second state is different.

4. The electronic device according to claim 1, wherein the communication chip is a chip with LPCD detection function, and determines whether the detection signal is a low-power card detection LPCD signal through time feature analysis and / or instruction parsing; Alternatively, the shape or size of the antenna may be the same as or similar to the shape or size of the antenna coil of the card reader device.

5. The electronic device according to claim 1, wherein the operating resonant point includes a resonant frequency of 13.56 MHz.

6. The electronic device according to claim 1, wherein the operating resonant point includes a resonant frequency in the range of 13.56 ± 0.7 MHz.

7. The electronic device according to claim 1, wherein the load adjustment circuit includes a first capacitor and a first adjustable inductor; the first capacitor is connected in parallel with the antenna; the first adjustable inductor is connected in series with the antenna; and the adjustable terminal of the first adjustable inductor is connected to the communication chip. in, In the first state, the inductance value of the first adjustable inductor is the first inductance value, and in the second state, the inductance value of the first adjustable inductor is the second inductance value. If the resonant frequency of the electronic device in the second state is less than the resonant frequency of the electronic device in the first state, then the first inductance value is less than the second inductance value. If the resonant frequency of the electronic device in the second state is greater than the resonant frequency of the electronic device in the first state, then the first inductance value is greater than the second inductance value.

8. The electronic device according to claim 1, wherein the load adjustment circuit includes a first adjustable capacitor; the first adjustable capacitor is connected in parallel with the antenna; the adjustable terminal of the first adjustable capacitor is connected to the communication chip; wherein, In the first state, the first adjustable capacitor has a first capacitance value; in the second state, the first adjustable capacitor has a second capacitance value. If the resonant frequency of the electronic device in the second state is less than the resonant frequency of the electronic device in the first state, then the first capacitance value is less than the second capacitance value. If the resonant frequency of the electronic device in the second state is greater than the resonant frequency of the electronic device in the first state, then the first capacitance value is greater than the second capacitance value.

9. The electronic device according to claim 1, wherein the load adjustment circuit comprises a second capacitor, a third capacitor, and a first controllable switch; the second capacitor is connected in parallel with the antenna; the third capacitor is connected in series with the first controllable switch and then in parallel with the antenna; the first controllable switch is connected to the communication chip; If the resonant frequency of the electronic device in the second state is less than the resonant frequency of the electronic device in the first state, then the first controllable switch is in the open state in the first state and in the closed state in the second state; if the resonant frequency of the electronic device in the second state is greater than the resonant frequency of the electronic device in the first state, then the first controllable switch is in the closed state in the first state and in the open state in the second state.

10. The electronic device according to claim 9, wherein the first controllable switch is a switch whose switching state can be controlled by an analog signal or a digital signal; or, the first controllable switch is a switch controlled by at least one of a pulse signal, a voltage signal, and a current signal; Alternatively, the communication chip may be a chip with energy recovery and energy output functions, and the power output terminal of the communication chip may be connected to the power input terminal of the first controllable switch to provide power to the first controllable switch.

11. The electronic device according to claim 1, wherein the load adjustment circuit comprises a fourth capacitor, a first resistor, and a second controllable switch; the fourth capacitor is connected in parallel with the antenna; the first resistor and the second controllable switch are connected in series and then in parallel with the antenna; the second controllable switch is connected to the communication chip; In the first state, the second controllable switch is in a closed state, and in the second state, the second controllable switch is in an open state. Alternatively, the second controllable switch is in the open state in the first state, and in the closed state in the second state.

12. The electronic device according to claim 11, wherein the communication chip is a chip with energy recovery function and energy output function, and the power output terminal of the communication chip is connected to the power input terminal of the second controllable switch to provide power to the second controllable switch.

13. The electronic device according to claim 1, wherein the load adjustment circuit includes a first adjustable resistor and a fifth capacitor; the fifth capacitor is connected in parallel with the antenna; the first adjustable resistor is connected in series with the antenna; and the adjustable terminal of the first adjustable resistor is connected to the communication chip. In the first state, the resistance value of the first adjustable resistor is a first resistance value, and in the second state, the resistance value of the first adjustable resistor is a second resistance value.

14. The electronic device according to any one of claims 1 to 13, wherein the communication chip has an energy recovery function and an energy output function, and the power output terminal of the communication chip is connected to the power input terminal of the load adjustment circuit; Alternatively, the communication chip has the function of outputting digital signal levels; the digital signal level output pin of the communication chip is connected to the digital signal input terminal of the load adjustment circuit. Alternatively, the electronic device may further include a power input terminal for connecting to an external power source so that the power source provides electrical energy to the electronic device; Alternatively, the electronic device may further include a power supply element connected to the communication chip, so that the communication chip generates a digital signal level for controlling the load adjustment circuit based on the electrical energy provided by the power supply element. Alternatively, the electronic device may further include a digital signal conversion unit; the input terminal of the digital signal conversion unit is connected to the antenna for acquiring the radio frequency signal acquired by the antenna; the output terminal of the digital signal conversion unit is connected to the load adjustment circuit for providing a digital signal level to the load adjustment circuit so that the load adjustment circuit switches from the first state to the second state.

15. The electronic device according to any one of claims 1 to 13, wherein if the electronic device determines that the card reader is in LPCD mode based on the nth LPCD pulse signal emitted by the card reader, the electronic device can switch from the first state to the second state when the card reader emits the (n+1)th LPCD pulse signal, and the electronic device in the second state can influence the (n+1)th LPCD pulse signal emitted by the card reader, or influence one or more pulse signals after the (n+1)th pulse signal, or the electronic device returns to the first state after the (n+1)th LPCD pulse signal ends; Alternatively, the electronic device switches from the first state to the second state at a preset time in the middle of an LPCD pulse signal emitted by the card reader device; Alternatively, the electronic device may switch to the first state after being in the second state for a preset time, and this state switching may be repeated until the card reader device activates the normal card detection mode.

16. The electronic device according to any one of claims 1 to 13, the electronic device further comprising a digital signal conversion unit, wherein after the communication chip determines that the radio frequency signal acquired by the antenna is an LPCD signal, the communication chip is able to provide the digital signal level generated by the digital signal conversion unit to the load adjustment circuit, so that the load adjustment circuit switches from the first state to the second state; Alternatively, after the electronic device completes communication with the card reader or the normal card detection function of the card reader is successfully activated, the communication chip can stop providing digital signal levels to the load adjustment circuit so that the load adjustment circuit can be restored to the first state.

17. An NFC tag comprising the electronic device according to any one of claims 1 to 16.

18. The NFC tag according to claim 17, wherein the NFC tag is the other party to perform NFC communication with the card reader device; Alternatively, the NFC tag may be a passive tag or an active tag; Alternatively, the NFC tag may be at least one of the following forms: card, sticker, label, keychain, pendant, wristband, bracelet, badge, name tag, or flexible tag; Alternatively, the NFC tag may be embedded inside an object, which may include at least one of toys, furniture, or electronic devices.

19. A control method for contactless communication, applied to the electronic device of claim 1, comprising: Acquire the detection signal emitted by the card reader device; If the detection signal is a low-power card detection LPCD signal, then a first control signal is generated; Based on the first control signal, the electronic device switches from a first state to a second state so that the card reader device switches to normal card detection mode; the load impedance of the electronic device in the first state is different from that in the second state.

20. The method according to claim 19, wherein the inductance value of the load adjustment circuit of the electronic device in the first state is a first inductance value, and the inductance value of the load adjustment circuit of the electronic device in the second state is a second inductance value; if the resonant frequency of the electronic device in the second state is less than the resonant frequency of the electronic device in the first state, then the first inductance value is less than the second inductance value. If the resonant frequency of the electronic device in the second state is greater than the resonant frequency of the electronic device in the first state, then the first inductance value is greater than the second inductance value. Alternatively, in the first state, the capacitance value of the load adjustment circuit of the electronic device is a first capacitance value, and in the second state, the capacitance value of the load adjustment circuit of the electronic device is a second capacitance value; if the resonant frequency of the electronic device in the second state is less than the resonant frequency of the electronic device in the first state, then the first capacitance value is less than the second capacitance value. If the resonant frequency of the electronic device in the second state is greater than the resonant frequency of the electronic device in the first state, then the first capacitance value is greater than the second capacitance value. Alternatively, in the first state, the resistance value of the electronic device is a first resistance value, and in the second state, the resistance value of the electronic device is a second resistance value, wherein the first resistance value is not equal to the second resistance value.

21. The method according to any one of claims 19 to 20, wherein after the electronic device switches from the first state to the second state, it further comprises: If the card reader device is detected to be in normal card detection mode, the electronic device is restored from the second state to the first state; Alternatively, if the electronic device finishes communicating with the card reader device, the electronic device will revert from the second state to the first state.

22. The method according to any one of claims 19 to 20, wherein the first control signal is a digital pulse signal, and the length of the digital pulse signal is less than or equal to the length of the LPCD signal sent by the card reader device; Alternatively, the communication chip in the electronic device is a chip with LPCD detection function, which determines whether the detection signal is a low-power card detection LPCD signal through time feature analysis and / or instruction parsing.

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