Electronic device for non-contact communication and control method

Abstract

The embodiment of the invention discloses an electronic device for non-contact communication and a control method. In the scheme, the electronic device comprises an antenna, a communication chip and a load adjusting circuit; wherein the antenna is connected with the load adjusting circuit, and the load adjusting circuit is connected with the communication chip; the load adjusting 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; and if the electronic device obtains a low power consumption card detection (LPCD) signal sent by card reader equipment, the communication chip is used for controlling the load adjustment circuit to be switched from the first state to the second state, so that the card reader equipment is switched to a normal card detection mode.

Description

Technical Field

[0001] The present application relates to the technical field of contactless communication, and in particular to an electronic device and a control method for contactless communication. Background Art

[0002] 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 within a few centimeters. Its typical application scenarios include mobile payment, access control, smart posters, product authentication, and interconnection between Internet of Things (IoT) devices.

[0003] In actual applications, mobile terminal devices such as smartphones can be used as NFC card reader devices to communicate with NFC slave devices such as NFC cards, NFC tags, and NFC devices with radio frequency circuits. In order to save power, NFC card reader devices can be in low power mode, so that the card reader device can also be in low power card detection (LPCD) mode to detect nearby NFC cards. However, the card reader device in LPCD mode has reduced sensitivity to slave devices, which significantly reduces the success rate of the card reader device sensing slave devices, affecting the user experience.

[0004] Therefore, how to improve the success rate of card inspection is a technical problem that needs to be solved urgently. Summary of the invention

[0005] The embodiments of the present specification provide an electronic device for contactless communication and a control method to solve the problem of low card checking success rate of existing card reader devices.

[0006] To solve the above technical problems, the embodiments of this specification are implemented as follows.

[0007] An embodiment of the present specification provides 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 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 obtains a low power card detection LPCD signal sent by a card reader device, the communication chip is used to control 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 inspection mode.

[0008] An NFC tag provided in an embodiment of the present specification includes the above-mentioned electronic device.

[0009] A contactless communication control method provided in an embodiment of the present specification is applied to the above-mentioned electronic device, including: obtaining 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 switches 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.

[0010] At least one embodiment of this specification can achieve the following beneficial effects: The electronic device provided in the embodiments of the present 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 may be adjusted to switch from the first state to the 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. By changing the load impedance of the electronic device, the amplitude or phase of the signal emitted by the card reader device may be greatly changed after encountering the electronic device, thereby promoting the card reader device to enter the normal card inspection mode from the LPCD mode, thereby improving the recognition probability of contactless communication and the probability of successful card inspection by the card reader device. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0012] Figure 1A schematic diagram of the structure of an electronic device for contactless communication provided in an embodiment of this specification; Figure 2 A schematic diagram of an electronic device provided in an embodiment of this specification; Figure 3 A schematic diagram of an electronic device provided in an embodiment of this specification; Figure 4 A schematic diagram of an electronic device provided in an embodiment of this specification; Figure 5 A schematic diagram of an electronic device provided in an embodiment of this specification; Figure 6 A schematic diagram of an electronic device provided in an embodiment of this specification; Figure 7 A control method for contactless communication is provided in an embodiment of this specification. DETAILED DESCRIPTION

[0013] In order to make the purpose, 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 combination with the specific embodiments of this specification and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of one or more embodiments of this specification.

[0014] Many specific details are described in the following description to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present application, so the present application is not limited by the specific implementation disclosed below.

[0015] The terms used in one or more embodiments of the present application are only for the purpose of describing a specific embodiment, and are not intended to limit one or more embodiments of the present application. The singular forms of "a", "said" and "the" used in one or more embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used in one or more embodiments of the present 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 the present application, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of one or more embodiments of the present application, the first may also be referred to as the second, and similarly, the second may also be referred to as the first. Depending on the context, the word "if" as used herein can be interpreted as "at the time of..." or "when..." or "in response to determination".

[0016] First, the terms involved in one or more embodiments of the present application are explained.

[0017] Contactless communication refers to the technology of transmitting information without direct physical contact. It uses electromagnetic waves or other wireless signals to achieve data transmission and communication, avoiding the safety risks brought by 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, thereby completing the data transmission. Common contactless communication technologies mainly include near field communication (NFC), radio frequency identification (RFID) and wireless charging.

[0018] RFID (Radio Frequency Identification): The principle is to conduct non-contact data communication between the reader and the tag to achieve the purpose of identifying the target. There are different types of frequencies, such as low frequency, high frequency, ultra-high frequency, etc.

[0019] NFC (Near Field Communication) is a short-range wireless communication technology that can realize near-field communication between two devices, and realize data transmission, writing and reading, etc. It is usually used at a high frequency of 13.56MHz. NFC near-field communication is developed based on RFID radio frequency identification technology. NFC can be regarded as a subset of RFID, or NFC can be regarded as a special form of RFID.

[0020] NFC technology mainly includes three communication modes: Reader / Writer Mode, Card Emulation Mode, and Peer-to-Peer Mode.

[0021] Reader / Writer Mode is a common working 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 a payment scenario, a mobile phone can be in reader / writer mode to obtain payment information from the payment device for payment. Devices in this mode can be called card reader devices.

[0022] Card Emulation Mode In this mode, the NFC device can simulate a smart card, allowing it to be used as a payment card, access card, or other types of cards. The device can interact with existing contactless infrastructure, such as POS machines or access control systems. For example, use a mobile phone as a bank card to pay in a store; use a mobile phone as an access card in a company or residential area; use a mobile phone as a transportation card to take public transportation. A device in this mode can be called a slave device.

[0023] Peer-to-Peer Mode: In this mode, two NFC devices can exchange data with each other. Both devices must be active and able to send and receive data. It is mainly used for file transfer, social networking, game interaction, etc. For example, quickly pairing Bluetooth or Wi-Fi connection through NFC, and then transferring files or photos; for example, exchanging business cards, contact information or social media links by tapping two mobile phones; for example, character exchange or prop sharing in multiplayer games, etc.

[0024] An NFC tag is a small electronic chip with a built-in antenna that can communicate with NFC-enabled devices (such as smartphones) over short distances via radio waves. These tags are usually very thin and small and can be embedded in a variety of items, such as posters, business cards, product packaging, equipment, etc.

[0025] LPCD (Low Power Card Detection) mode: that is, low power card detection mode or low power card search mode. LPCD is a technology used in radio frequency technology to efficiently detect nearby contactless smart cards or tags. It is mainly used to reduce the power consumption of the card reader device when waiting for the smart card or tag to approach. The card reader device in LPCD mode can periodically send low power pulses. When the card reader device detects that the signal amplitude on the antenna changes and exceeds the preset threshold, it can determine that a card is approaching to initiate further interaction. Specifically, when a card enters the radio frequency field, the presence of the card will cause the amplitude and phase of the signal to change. The LPCD mode can use a software-based card detection mechanism to detect these changes using the LPCD algorithm to determine whether a card is approaching, thereby triggering further communication. In portable devices such as mobile phones, the LPCD mode is particularly important, and its main advantage is its low power consumption. Mobile phones usually need to be on standby for a long time, and frequent activation of functions such as NFC near-field communication may significantly consume the battery. LPCD mode allows the phone to continuously detect near-field communication signals in the background while maintaining a low energy consumption level. Once a card is detected, the phone can quickly switch from a low-power state to a full-function state to perform a transaction or exchange data.

[0026] Standard card inspection mode: also known as normal card inspection mode or normal card search mode. In order to improve the speed and success rate of contactless communication, under normal circumstances, the card reader device can be in a fully functional state when communicating, that is, standard card inspection mode. In actual applications, in LPCD mode and standard card inspection mode, the card reader device (for example, mobile terminal devices such as mobile phones) will send out a signal of a preset frequency. For example, in the NFC near-field communication scenario, the card reader device can send out a 13.56MHz sine wave in both LPCD mode and standard card inspection mode. The difference is that the transmission time and amplitude of the sine wave in LPCD mode and standard card inspection mode are different. For example, in LPCD mode, the pulse width is usually in the us level, while in standard card inspection mode, the pulse width is usually in the tens of ms level.

[0027] At present, mobile devices such as mobile phones are increasingly used as active devices for contactless communications such as NFC near-field communication. However, mobile devices are usually powered by batteries. In order to control power consumption, they usually make many low-power designs for the transmission power of their own card readers, such as setting the LPCD mode. For example, when the screen of a mobile phone is off, the card reading function is usually turned off, and most mobile phones will automatically enter the LPCD mode after a period of time after the screen is turned on. When a mobile device in LPCD mode approaches an NFC target device at the opposite end, such as an NFC tag or an NFC slave device, it can be switched to the standard card detection mode. In actual applications, when the mobile device senses that the intensity change of the radio frequency signal it transmits when being sensed by the NFC target device at the opposite end is greater than or equal to the preset threshold, the mobile device will be awakened from the LPCD mode and enter the standard card detection mode. However, in LPCD mode, the signal strength emitted by the mobile device is weak, and the amplitude of the emitted RF signal is lower than that in the standard card detection mode. Therefore, the amplitude change caused by the influence of the NFC target device on the signal at the other end will also be reduced accordingly, making 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, which in turn causes the mobile device to be unable to switch to the standard card detection mode, and the success rate of the mobile device sensing the NFC target device is significantly reduced, thereby affecting the success rate of near-field communication and the user experience.

[0028] The technical solutions provided by the embodiments of this specification are described in detail below in conjunction with the accompanying drawings.

[0029] Figure 1 Schematic diagram of the structure of an electronic device for contactless communication provided in an embodiment 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. The electronic device can be used as a slave device or a passive device for contactless communication, or a part of a slave device or a passive device to communicate with a card reader device. Specifically, the electronic device can be a contactless tag, such as an NFC tag, or the electronic device can also be used as a slave device or a passive device for contactless communication. For example, contactless communication may include NFC near-field communication, and the electronic device is used as a part of an NFC device with an NFC tag function.

[0030] The antenna 102 may include a metal coil, specifically a conventional NFC antenna or other antenna for receiving radio frequency signals, and may be used to receive signals from a card reader device. The specific shape or size of the antenna may be consistent with or close to the shape or size of the antenna coil of the card reader device, so as to achieve a better coupling effect with the card reader device. The antenna 102 may be a pure coil, or may be an antenna containing some electronic components, for example, the antenna may contain a coil and a capacitor connected in parallel with the coil, etc., which is not specifically limited here.

[0031] The communication chip 104 can be a conventional NFC TAG chip, which can absorb energy through the radio frequency field provided by the card reader device to complete communication and other related tasks. For example, the communication chip can be an Ntag series IC chip, such as Ntag213, Ntag215, Ntag216, etc.; or, the communication chip can be a Mifare series IC chip, such as Mifare1 S50, Mifare1 S70 and Mifare Ultralight, etc.; or, the communication chip can be an I-CODE series IC chip, such as I-CODE2, etc.; or, the communication chip can be an FM series IC chip, such as FM11RF08, etc.; or, the communication chip can be 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 can include components such as a control circuit and a memory.

[0032] The communication chip 104 may directly or indirectly control the state of the load adjustment circuit 106 , and specifically may control parameter information of components in the load adjustment circuit, or may also be expressed as parameter information of controlling the load impedance in the load adjustment circuit.

[0033] The load adjustment circuit may include a first state and a second state, and 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 obtains a low power card detection LPCD signal sent by the card reader device, the communication chip is used to control 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.

[0034] In actual applications, the electronic device performs contactless communication such as NFC with the card reader device. The card reader device, as an active device, can provide the energy required for communication. The electronic device can be equivalent to the load of the card reader device. When the load impedance characteristics of the electronic device change, the feedback signal obtained by the corresponding card reader device will also change. The electronic device in the embodiments of this specification can be used in NFC tags in NFC communication, and can also be used in other contactless communication tags. As long as the card reader device corresponding to the contactless communication tag has the need to switch from LPCD mode to normal card inspection mode, the contactless communication tag can include the electronic device provided in this specification.

[0035] The electronic device provided in the embodiments of the present 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 may be adjusted to switch from the first state to the 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. By changing the load impedance of the electronic device, the amplitude or phase of the signal emitted by the card reader device may be greatly changed after encountering the electronic device, thereby promoting the card reader device to enter the normal card inspection mode from the LPCD mode, thereby improving the recognition probability of contactless communication and the probability of successful card inspection by the card reader device.

[0036] In actual applications, the card reader device sends a radio frequency signal. After the antenna in the electronic device senses the radio frequency signal, it will affect the radio frequency signal sent by the card reader. The card reader device can detect the change in the signal, such as the change in parameters such as amplitude and phase. The existing NFC tags have a fixed degree of influence on each signal sent by the card reader device. For example, the card reader device sends multiple signals in LPCD mode, and the difference sensed by the card reader for these multiple signals is unchanged. The card reader device will have anti-fatigue actions and cannot switch to the normal card inspection 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 inspection process, so that the card reader device can reflect different changes and promote the card reader device to switch to the normal card inspection mode.

[0037] As an implementation method, the load impedance of the circuit can be adjusted by adjusting the resonance point of the circuit. In the embodiments of this specification, the load adjustment circuit can be a tuning circuit (Tuning Circuit), which can also be called a resonant circuit or an LC circuit, and 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 to form a circuit capable of adjusting the resonant frequency. The load adjustment circuit 106 may include a first state and a second state. The inductance value or capacitance value of the load adjustment circuit in the first state is different from that of the load adjustment circuit in the second state, so that the resonance points of the load adjustment circuits in the two states are different, which can also be manifested as different load impedances.

[0038] As an implementation, in the first state, the resonance point of the electronic device may conform to the preset resonance point. For example, in the first state, the resonance frequency of the electronic device may be equal to the preset resonance frequency or have a smaller difference from the preset resonance frequency. In the second state, the resonance point of the electronic device may deviate from the preset resonance point. For example, in the second state, the resonance frequency of the electronic device may be greater than or less than the preset resonance frequency of the preset resonance point.

[0039] As another implementation, the resonance point of the electronic device in the first state may deviate from the preset resonance point, and the resonance point of the electronic device in the second state may conform to the preset resonance point.

[0040] The resonance point may represent the point at which the resonant circuit exhibits maximum response or minimum impedance at a specific frequency. The resonance point of the electronic device in the embodiment of this specification may represent the resonance point of the resonant circuit including the load adjustment circuit in the electronic device. The preset resonance point may be the resonance point corresponding to the working carrier frequency band of the card reader device, and the preset resonance point may also be represented by the resonance frequency. The working frequency of the card reader device may be the resonance frequency of the card reader device so as to be recognized by the slave device.

[0041] For example, the operating carrier frequency band of a commonly used NFC communication card reader device is about 13.56 MHz, for example, it can operate within the range of 13.56±0.7 MHz. The preset resonance point can be the point of maximum response or minimum impedance exhibited in the operating carrier frequency band, and the preset resonance frequency can be 13.56 MHz, or a frequency within the range of 13.56±0.7 MHz.

[0042] In the embodiment of this specification, the communication chip 104 can be used to control the load adjustment circuit 106 to be in the first state or the second state. Specifically, if the electronic device obtains the 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, and promote the card reader device to exit the low power card detection LPCD mode by adjusting the resonance point, so that the card reader device switches to the normal card detection mode.

[0043] The low power card detection LPCD signal may be a signal sent by the card reader device in a low power card detection LPCD mode.

[0044] The card reader device can be a mobile phone, smart watch, computer, POS machine, etc. that can be used as an active device for contactless communication, such as an NFC card reader device. The electronic device provided in the embodiments of this specification can be a slave device or component of contactless communication. For example, the electronic device provided in the embodiments of this specification can be a part of an active or passive NFC tag or NFC card, or can also be a part of an electronic device that serves as an NFC slave device.

[0045] Taking NFC near-field communication as an example, the card reader device can actively send out electromagnetic signals, for example, actively send out 13.56MHz signals in LPCD mode. The antenna contained in the electronic device provided in this specification can sense the electromagnetic signal sent by the card reader device. The electronic device in this specification can sense whether there is a card reader device through the antenna. If the electronic device detects a signal sent by a card reader device in the low-power card detection LPCD mode, the load adjustment circuit can be switched to a state, prompting the card reader device to switch from the LPCD mode to the normal card detection mode.

[0046] As an implementation method, when the electronic device is not in operation, it can also represent the initial state of the electronic device, or when there is no card reader device near the electronic device and the radio frequency signal emitted by the card reader device is not detected, the electronic device can be in the first state, and the resonance point of the electronic device can meet the preset resonance point, for example, the resonance frequency is 13.56MHz. If a card reader device approaches, the electronic device or the antenna in the electronic device senses the low-power card detection LPCD signal sent by the card reader device, and the communication chip can control the electronic device to switch from the first state to the second state. The resonance point of the electronic device in the second state can deviate from the preset resonance point, such as the resonance frequency is 11MHz, 12MHz, 15MHz, etc. The operating frequency of the card reader device is 13.56MHz. By adjusting the resonance point, the change in the amplitude or phase of the feedback signal obtained by the card reader device under the influence of the electronic device can be increased, which promotes the card reader device to evoke the normal card inspection mode. In actual applications, if the card reader device switches from LPCD mode to normal card inspection mode and uses the normal card inspection mode to transmit signals, after the electronic device obtains the signal sent by the card reader device in normal card inspection mode, it can also adjust the resonance point of the electronic device to a resonance point that meets the operation of the card reader, such as restoring from the second state to the first state to ensure communication efficiency, and also prepare for the next time the card reader device in LPCD mode is awakened.

[0047] As another implementation, in the first state, the resonance point of the electronic device can deviate from the preset resonance point. If a card reader device approaches, the electronic device or the antenna in the electronic device senses the low-power card detection LPCD signal sent by the card reader device, and the communication chip can control the electronic device to switch from the first state to the second state, and the resonance point of the electronic device in the second state can meet the preset resonance point. By adjusting the resonance point, the change in the amplitude or phase of the feedback signal obtained by the card reader device under the influence of the electronic device can be increased, which promotes the card reader device to evoke the normal card inspection mode. In practical applications, if the card reader device switches from the LPCD mode to the normal card inspection mode, the signal is transmitted in the normal card inspection mode. After the electronic device obtains the signal sent by the card reader device in the normal card inspection mode, or after the communication with the card reader device is completed, the resonance point of the electronic device can also be adjusted to deviate from the resonance point of the card reader operation, such as being restored from the second state to the first state, to prepare for the next awakening of the card reader device in the LPCD mode.

[0048] The electronic device provided in the embodiment of this specification can adjust the load adjustment circuit after detecting the signal emitted by the card reader device in LPCD mode, so that the amplitude or phase of the signal emitted by the card reader device undergoes a significant change after hitting the electronic device, which can promote the card reader device to enter the normal card inspection mode from the LPCD mode, improve the recognition probability of contactless communication, and improve the probability of successful card inspection by the card reader device.

[0049] In some related technologies, an ALM mode (Always Listen Mode) tag chip powered by an additional power supply is used to increase the card inspection success rate of the mobile terminal. In ALM mode, the tag chip can continuously listen to the signal from the reader with extremely low power consumption, and respond quickly when receiving a valid signal. In some other related technologies, an active signal wake-up circuit is separately set to prompt the mobile terminal to exit the LPCD mode. It can be seen that the methods used in the related technologies are complex and costly, which is not conducive to implementation in practical applications.

[0050] The electronic device provided in the embodiments of this specification has a simple structure, does not require an overly complex circuit, does not require an additional power supply, is low in cost, and is more conducive to implementation in practical applications.

[0051] Taking the NFC frequency working at 13.56MHz as an example, its resonant frequency is ; Its impedance value: ,in is the inductive reactance value, is the capacitive reactance value; the frequency angle is: .

[0052] Through the 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.

[0053] The electronic device provided in the embodiments of this specification can affect the signal sent by the card reader device from the perspective of changing the capacitance value or the inductance value, so that the card reader device can smoothly switch from the LPCD mode to the normal card inspection mode. From the perspective of the card reader device, the electronic device provided in this specification can be used as a load of the card reader device, and in this specification, the card reader device can be smoothly switched from the LPCD mode to the normal card inspection mode from the perspective of adjusting the load parameters.

[0054] As an implementation mode, 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 end 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 condition obtained by the antenna.

[0055] Specifically, the inductance value of the first adjustable inductor in the first state is a first inductance value, and the inductance value of the first adjustable inductor in the second state 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. 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, 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, the first inductance value is greater than the second inductance value.

[0056] As an implementation method, 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. Assume that the resonant frequency of the electronic device in the first state is the working resonant frequency of the card reader device, and the resonant frequency of the electronic device in the second state is less than the working resonant frequency of the card reader device; or, the resonant frequency of the electronic device in the first state is greater than the working resonant frequency of the card reader device, and the resonant frequency of the electronic device in the second state is equal to the working resonant frequency of the card reader device, which can be expressed as 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. In this case, the resonant frequency of the electronic device can be lowered, and the load adjustment circuit is switched 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, that is, the first inductance value can be less than the second inductance value.

[0057] As another implementation, 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. Assuming that the resonant frequency of the electronic device in the first state is equal to the working resonant frequency of the card reader device, and the resonant frequency of the electronic device in the second state is greater than the working resonant frequency of the card reader device; or, the resonant frequency of the electronic device in the first state is less than the working resonant frequency of the card reader device, and the resonant frequency of the electronic device in the second state is equal to the working resonant frequency of the card reader device, it can be expressed as 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. 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, that is, the first inductance value is greater than the second inductance value.

[0058] Figure 2 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 and the first capacitor C1 can also be represented as the first adjustable inductor L1 and the antenna 102 are connected in series.

[0059] Specifically, one end A of the 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 an input end IN1 of the communication chip 104. Another input end IN2 of the communication chip 104 can be connected to the other end B of the antenna 102. The adjustable end c of the first adjustable inductor L1 can be connected to the signal control end GPO of the communication chip 104. The communication chip 104 can output an analog or digital control signal 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 the antenna 102.

[0060] In this embodiment, the load adjustment circuit includes an adjustable inductor in series and a capacitor in parallel, which together with the inductance L0 of the antenna coil body form a resonant circuit. The adjustable inductor may be an inductor whose inductance value can be adjusted or changed, and may also be called a variable inductor.

[0061] As an implementation method, when the adjustable inductor is in an idle state, such as when the antenna does not sense a signal sent by a card reader device, there is no card reader device sending a near-field communication signal nearby, or contactless data transmission is completed with the card reader device, the load adjustment circuit may be in a first state. In this case, the resonance point of the resonant circuit including the first capacitor and the first adjustable inductor in the electronic device may deviate from a preset resonance point, such as from 13.56 MHz, and the impedance is relatively high. Relative to the card reader device, the load is large, and the change in the signal sensed back by the card reader device is large. When a field approaches, the antenna senses the radio frequency signal sent by the card reader device, converts the radio frequency signal into electrical energy and supplies it to the communication chip. The communication chip can determine that there is a card reader device that sends a low-power card detection signal nearby, and can send a control signal to the first adjustable inductor, so that the inductance value of the first adjustable inductor increases or decreases, and the load adjustment circuit can switch from the first state to the second state. In this case, the resonance point of the resonant circuit including the first capacitor C1 and the first adjustable inductor L1 in the electronic device will meet the preset resonance point, such as 13.56MHz, and the impedance is low. Relative to the card reader device, the load becomes smaller, and the change of the signal sensed by the card reader device is small, but relative to the continuous signal change, it will become larger, which can effectively solve the problem that the card reader device does not trigger the normal card detection function due to the continuous acquisition of the same change value. Furthermore, 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.

[0062] Similarly, as another implementation method, in the idle state, the load adjustment circuit is in the first state. In the first state, the resonance point of the electronic device can be the same as the preset resonance point, with small impedance and small return loss. Relative to the card reader device, the load is small, and the change of the signal sensed by the card reader device is small. When a field is approaching, the antenna senses the radio frequency signal sent by the card reader device. After determining that the radio frequency signal is a low-power card detection LPCD signal, the communication chip can adjust the load adjustment circuit from the first state to the second state. The load adjustment circuit in the second state can deviate from the preset resonance point, with large impedance and large return loss. Relative to the card reader device, the load is large, and the change of the signal sensed by the card reader device becomes large, which can trigger the normal card detection mode of the card reader device.

[0063] In the embodiments of this specification, the resonance 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 the normal card inspection mode. As an implementation method, the load adjustment circuit can include an adjustable capacitor, which forms an LC resonant circuit with adjustable parameters with the antenna. Optionally, the load adjustment circuit can include at least a first adjustable capacitor. The first adjustable capacitor is connected in parallel with the antenna; the adjustable end of the first adjustable capacitor is connected to the communication chip so that the communication chip can adjust the capacitance value of the capacitor according to the signal obtained by the antenna.

[0064] 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. 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, 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, the first capacitance value is greater than the second capacitance value.

[0065] As an implementation mode, assuming that the resonance point of the electronic device in the first state is equal to the preset resonance point, and the resonance point of the electronic device in the second state is lower than the preset resonance point, it can also be expressed as the resonance frequency of the electronic device is lower than the preset resonance frequency; or, the resonance point of the electronic device in the first state is greater than the preset resonance point, and the resonance of the electronic device in the second state is equal to the preset resonance 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 smaller than the second capacitance value.

[0066] As another implementation, assuming that the resonance point of the electronic device in the first state is equal to the preset resonance point, and the resonance point of the electronic device in the second state is higher than the preset resonance point, it can also be expressed as the resonance frequency of the electronic device is higher than the preset resonance frequency; or, the resonance point of the electronic device in the first state is less than the preset resonance point, and the resonance of the electronic device in the second state is equal to the preset resonance 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.

[0067] Figure 3 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 may be connected to one end A of the antenna 102, and the other end g of the first adjustable capacitor C2 may be connected to the other end B of the antenna 102. The adjustable end h of the first adjustable capacitor C2 may be connected to the signal control end GPO of the communication chip, and the communication chip 104 may output an analog or digital control signal 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 may be fixed ends of the adjustable capacitor, such as a fixed pin; the adjustable end h of the first adjustable capacitor C2 may be a movable end of the adjustable capacitor, such as a fixed pin.

[0068] Among them, the antenna 102 can also be connected to the communication chip 104. Specifically, one end A of the antenna 102 can be connected to an 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.

[0069] In this embodiment, the load adjustment circuit includes a first adjustable capacitor C2 connected in parallel, and the first adjustable capacitor C2 and the inductance L0 of the coil body of the antenna can form a resonant circuit. The adjustable capacitor can be a capacitor that can adjust or change the capacitance value, and can also be called a variable capacitor.

[0070] In this embodiment, the resonant frequency of the electronic device can be adjusted by adjusting the capacitance value, so as to promote the card reader device to enter the normal card detection mode. As an implementation method, in an idle state, the load adjustment circuit can be in a first state where the resonance point deviates from the preset resonance point, the inductance of the first adjustable capacitor is C20, and the resonance point of the resonant circuit including the first adjustable capacitor C2 and the antenna coil can deviate from the preset resonance point, such as deviating from 13.56MHz, and the impedance is high. Relative to the card reader device, the load is large, and the change of the signal sensed back by the card reader device is large. When a field approaches, the communication chip determines that there is a card reader device that sends a low-power card detection signal nearby, and can send a control signal to the first adjustable capacitor C2, and adjust the inductance value to increase or decrease through the adjustable end of the first adjustable capacitor C2. In this state, the inductance of the first adjustable capacitor is C21, which can form a resonant circuit with the coil body of the antenna. The resonance point of the resonant circuit meets the preset resonance point, such as 13.56MHz, and the impedance is low. Relative to the card reader device, the load becomes smaller, and the change of the signal sensed by the card reader device is small, but relative to the continuous signal change, it will become larger, which can effectively solve the problem that the card reader device does not trigger the normal card detection function due to the continuous acquisition of the same change value. Furthermore, 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.

[0071] Similarly, as an implementation method, in an idle state, the load adjustment circuit can be in a first state where the resonance point meets the preset resonance point. When the LPCD signal is detected, the load adjustment circuit can be in a second state where the resonance point deviates from the preset resonance point by adjusting the first adjustable capacitor. Changing the resonance frequency of the electronic device can also be expressed as changing the load parameters, which can promote the card reader device to enter the normal card inspection mode. The specific principle can be found in the above embodiment, which will not be repeated here.

[0072] In the embodiments of this specification, the fixed capacitor can also be made to function as an adjustable capacitor by providing a switch to adjust the resonance point of the electronic device and promote the card reader device to start the normal card inspection mode. Optionally, the load adjustment circuit 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 connected 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.

[0073] 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, the first controllable switch in the first state may be in an open state, and the first controllable switch in the second state may be in a closed state, so that the capacitance value of the electronic device in the first state may 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, the first controllable switch in the first state is in a closed state, and the first controllable switch in the second state is in an open state, so that the capacitance value of the electronic device in the first state may be greater than the capacitance value of the electronic device in the second state.

[0074] Figure 4 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. Among them, one end p of the second capacitor C4 may be connected to one end A of the antenna 102, and the other end q of the second capacitor C4 may be connected to the other end B of the antenna 102. One end n of the third capacitor C3 may be connected to one end A of the antenna 102, the other end m of the third capacitor C3 may be connected to one end s1 of the first controllable switch K1, and the other end t1 of the first controllable switch K1 may be connected to the other end B of the antenna 102. The control end r1 of the first controllable switch K1 may be connected to the signal control end GPO of the communication chip 104, so that the communication chip 104 can control the switch state of the first controllable switch K1 to adjust the resonance point of the load adjustment circuit.

[0075] In practical applications, the first controllable switch K1 may be a switch whose switch state can be controlled by an analog signal or a digital signal. For example, a switch that can be controlled by a pulse signal, a voltage signal, a current signal, or the like. The specific first controllable switch may be an electronic unit including a thyristor, or may be an integrated electronic component, such as a 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 the function of adjusting the capacitance value can be achieved.

[0076] Among them, the antenna 102 can also be connected to the communication chip 104. Specifically, one end A of the antenna 102 can be connected to an 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.

[0077] In this embodiment, the available capacitance value in the load adjustment circuit is adjusted by the first controllable switch. The specific working principle can be found in the above embodiments and will not be described again here.

[0078] In practical applications, the load impedance of the electronic device can also be expressed as the quality factor Q value of the electronic device. The Q value represents the ratio of energy storage to energy loss in the resonant circuit. Similar to the principles of the above embodiments, in the embodiments of this specification, the resistance value of the electronic device can be adjusted to adjust the Q value and the load impedance, thereby facilitating the card reader device to switch from the low-power LPCD mode to the normal card inspection mode.

[0079] Optionally, in an embodiment of the present specification, 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, which may specifically include: the resistance value of the electronic device in the first state is different from the resistance value of the electronic device in the second state.

[0080] By adjusting the resistance value of the electronic device, the load impedance can also be changed, which can effectively prevent the card reader device from being unable to awaken the normal card inspection mode due to anti-fatigue and other reasons.

[0081] As an implementation mode, 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 is connected in series with the second controllable switch 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.

[0082] Figure 5 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, the other end w2 of the fourth capacitor C5 can be connected to the other end B of the antenna, and 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, 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, and the first resistor R1 is connected in series with the second controllable switch K2 and then parallel to the antenna 102. The controllable end r2 of the second controllable switch K2 can be connected to the signal control end GPO of the communication chip 102, so that the communication chip 102 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.

[0083] Among them, the antenna 102 can also be connected to the communication chip 104. Specifically, one end A of the antenna 102 can be connected to an 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.

[0084] 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 a closed state, and in the second state, the second controllable switch can be in an open state; or, in the first state, the second controllable switch can be in an open state, and in the second state, the second controllable switch can be in a closed state.

[0085] Assuming that the electronic device is in an idle state, the electronic device is in a first state, and assuming that the second controllable switch is in a closed state in the first state, after detecting the LPCD signal sent by the card reader device, the second controllable switch can be switched to an open state, and the resistance value of the electronic device changes, the Q value changes, and the load impedance changes, which promotes the card reader device to enter the normal card inspection mode from the LPCD mode. In order to ensure the efficiency of information transmission later, the electronic device can be restored to the first state after the card reader device enters the normal card inspection mode, such as reclosing the second controllable switch. Similarly, if the second controllable switch is in an open state in the first state, after detecting the LPCD signal sent by the card reader device, the second controllable switch can be switched to a closed state, which can also promote the card reader device to enter the normal card inspection mode.

[0086] In practical applications, when the electronic device is in an idle state, the Q value of the electronic device may be within a preset range, which may represent the Q value of the electronic device after the card reader device starts the normal card inspection mode or obtains the tag information by polling. Alternatively, when the electronic device is in an idle state, the Q value of the electronic device may deviate from the preset range, such as the Q value is too large or too small. The specific parameters can be set according to actual needs and are not limited here.

[0087] As 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 end 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.

[0088] Figure 6 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. Among them, 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, and 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 an input end IN1 of the communication chip 104, and the adjustable end of the first adjustable resistor R2 can be connected to the signal control end GPO of the communication chip 102. The other end B of the antenna 102 can be connected to another input end 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.

[0089] In the first state, the resistance value of the first adjustable resistor R2 is a first resistance value, and in the second state, the resistance value of the first adjustable resistor is a second resistance value, and the first resistance value is different from the second resistance value.

[0090] In practical applications, the first resistance value and the second resistance value can be set according to actual needs. Figure 5 The circuit principle shown is similar, using Figure 6 The electronic device shown can also facilitate the card reader device to start the normal card checking mode.

[0091] It can be understood that the above embodiments mainly describe the circuit parts that play a major role. In practical applications, required electronic components can be added to the circuits shown in the above embodiments according to actual needs, or the connection order of the components can be adjusted. Figures 2 to 6 In the circuit shown, electronic components such as resistors and inductors can also be connected in series, or electronic components such as capacitors can be connected in parallel. Figures 2 to 6 The schematic diagram provided in this specification is only for the purpose of more clearly illustrating the electronic device. 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.

[0092] In order to improve the stability of the electronic device, the communication chip in the embodiment of this specification can optionally be a chip with energy recovery function and energy output function. The power output end of the communication chip can be connected to the power input end of the load adjustment circuit to provide power supply for the state conversion of the load adjustment circuit.

[0093] For example, the first adjustable capacitor, the first adjustable inductor, the first adjustable resistor, the first controllable switch or the second controllable switch may be a component with a power input terminal, and the communication chip may provide the electric energy required for adjustment, which may be short-term electric energy, for example, to provide instantaneous electric energy for starting the circuit of the component. As an implementation mode, the power output terminal of the communication chip may be connected to the power input terminal of the first controllable switch and / or the second controllable switch to provide electric energy for the first controllable switch and / or the second controllable switch.

[0094] In practical applications, a passive NFC tag, or the main circuit part of a passive NFC tag, can be formed by using a communication chip with energy recovery function and energy output function, as well as the above-mentioned antenna and load adjustment circuit.

[0095] In practical applications, an external power supply may also be used to power the electronic device or the load adjustment circuit in the electronic device. Optionally, the electronic device may include a power input terminal for connecting to a power supply outside the electronic device so that the power supply provides power to the electronic device.

[0096] As an implementation mode, the power input terminal of the electronic device may represent the power input terminal of the load adjustment circuit and / or the communication chip, and the external power supply may provide working power for the load adjustment circuit and / or the communication chip.

[0097] The power source outside the electronic device may be a power source located outside the electronic device, such as a battery, a power module, etc. The specific form of the power source is not limited here, and the specific parameters of the power source may be set according to actual circuit requirements.

[0098] As another embodiment, the power supply device may also include a power supply element, such as a battery. The power supply element may be connected to a load adjustment circuit and / or a communication chip to provide power for the electronic device. The power supply element may be fixed or integrated with the communication chip, the load adjustment circuit, etc. in the same circuit board, or may be placed separately, which is not limited here.

[0099] In actual applications, the load adjustment circuit can be a circuit controlled by a digital signal level. To facilitate the control of the load adjustment circuit, the communication chip in the embodiment of this specification can have the function of outputting the digital signal level. The above-mentioned load adjustment circuit is connected to the communication chip, and specifically may include: the digital signal level output pin of the communication chip is connected to the digital signal input end communication chip of the load adjustment circuit.

[0100] The digital signal level output pin of the communication chip can represent the signal control end of the communication chip. The pin can be connected to the adjustable end for controlling the capacitor or inductor in the load adjustment circuit. For example, it can be connected to at least one of the adjustable end of the first adjustable inductor, the adjustable end of the first adjustable capacitor, and the control end of the controllable switch.

[0101] In practical applications, the electronic device may also include a power supply device or use an external power supply device connected to the communication chip, so that the communication chip can generate a digital signal level for controlling the load adjustment circuit based on the power supply element or the power provided by the external power supply device.

[0102] In practical applications, a signal for controlling the load adjustment circuit can also be provided through an external digital signal circuit. Optionally, the electronic device in the embodiment of this specification may also include a digital signal conversion unit; the load adjustment circuit is connected to the communication chip, specifically including: the input end of the digital signal conversion unit is connected to the antenna, used to obtain the radio frequency signal obtained by the antenna; the output end of the digital signal conversion unit is connected to the load adjustment circuit, used to provide a digital signal level to the load adjustment circuit, so that the load adjustment circuit switches from the first state to the second state.

[0103] The digital signal conversion unit may be a unit that can process a sine wave signal to generate a controllable digital signal level, such as an envelope detection circuit, a half-wave rectifier circuit, etc. The specific circuit design of the digital signal conversion unit is not limited here.

[0104] In practical applications, the digital signal conversion unit may also be connected to the communication chip, and when the communication chip determines that the RF signal acquired by the antenna is an LPCD signal, the digital signal conversion unit may generate a digital signal level. Alternatively, the digital signal level generated by the digital signal conversion unit may be provided to the load adjustment circuit through the communication chip, and the communication chip may provide the digital signal level to the load adjustment circuit according to actual needs. For example, when the communication chip determines that the RF signal acquired by the antenna is an LPCD signal, the communication chip may provide the digital signal level generated by the digital signal conversion unit to the load adjustment circuit, or, after the communication with the card reader device is completed or the normal card inspection function of the card reader device is successfully aroused, the communication chip may stop providing the digital signal level to the load adjustment circuit so that the load adjustment circuit can be restored to its previous state.

[0105] It is understandable that the circuits or electronic components provided in the above embodiments can be used independently or in combination. Figures 2 to 6The load adjustment circuits shown in the figure can be used individually or multiple of them can be used at the same time, which is not specifically limited here. If multiple load adjustment circuits are used, the electronic components in different load adjustment circuits can be shared, such as the first capacitor and the second capacitor can be the same capacitor. Of course, the electronic components in different load adjustment circuits can also be used independently, which is not limited here either.

[0106] In actual applications, the degree to which the resonance point of the electronic device deviates from the preset resonance point or the degree to which the Q value deviates from the preset range in the first state or the second state of the above-mentioned load adjustment circuits may be the same or different. For an electronic device, if two or more of the above-mentioned load adjustment circuits are set in the electronic device, if the LPCD signal emitted by the card reader device is obtained, these multiple load adjustment circuits can be triggered to work at the same time, or one of the load adjustment circuits can be selected to work, or multiple load adjustment circuits can be used in a decreasing manner. In order to achieve the first state or the second state, it can be achieved by one of the above-mentioned load adjustment circuits, or by multiple load adjustment circuits, and it can be set according to actual needs, and is not limited here.

[0107] In practical applications, the load adjustment circuit can also be set to a circuit that can be adjusted in multiple gears. For example, the above-mentioned state indicating deviation from the preset resonance point can include multiple sub-states, and the difference between different sub-states can be different degrees of deviation from the preset resonance point. Alternatively, it can also be understood that the load adjustment circuit can include not only the above-mentioned first state and second state, but also a third state, or even a fourth state, etc. Among them, the third state and / or the fourth state are different from the second state in the degree of deviation from the preset resonance point. For example, the degree of deviation of the electronic device from the preset resonance point in the third state can be greater than that in the second state. In practical applications, assuming that it is necessary to promote the card reader device to start the normal card inspection mode by switching the load adjustment circuit from the first state to the second state, if the card reader device still does not start the normal card inspection mode within the preset time length 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 inspection mode. The specific setting of the load adjustment circuit is not limited here.

[0108] Based on the same idea, an NFC tag is also provided in the embodiments of this specification, and the NFC tag includes the electronic device provided above.

[0109] NFC tags can be broadly understood as the other party that can perform NFC near-field communication with the card reader device, and can also be called the passive party of NFC communication. They can use the energy provided by the card reader device to send tag information to the card reader device. The communication process or principle between NFC tags and card reader devices can be found in the relevant technical introduction, which will not be repeated here.

[0110] The specific form of the NFC tag can be a card, sticker, label, etc., or a keychain, pendant, etc., or a wristband, bracelet, badge, badge, flexible label, etc. Or the NFC tag can also be embedded in an object, such as integrated into a toy, furniture, equipment, etc., such as an electronic device with an NFC tag. The NFC tag can be a passive tag or an active tag. This does not limit the specific form of the NFC tag.

[0111] It should be understood that the connection order of some components of the electronic device described in one or more embodiments of this specification can be interchanged according to actual needs, or some components can be omitted or deleted.

[0112] Based on the same idea, the embodiments of this specification also provide a control method based on the above electronic device. Figure 7 A contactless communication control method provided in the embodiments of this specification can be applied to the above-mentioned electronic device. The specific contents of the electronic device can be referred to the above-mentioned embodiments, which will not be described here. Figure 7 As shown, the control method may include: Step 702: Acquire a detection signal sent by a card reader device.

[0113] In actual applications, the card reader device can actively send out a detection signal to detect nearby passive communication devices. The card reader device can be a mobile phone, computer, smart watch, POS machine and other terminal devices.

[0114] The electronic device provided in the embodiments of this specification can be an NFC tag used in NFC near-field communication scenarios, or an electronic device used in other radio frequency communication scenarios, such as a passive device used in RFID radio frequency identification scenarios, such as ETC identification, etc. Specific actual scenarios may include payment, transportation, access control, information promotion, management and other scenarios.

[0115] The antenna of the electronic device can obtain the detection signal sent by the card reader device and send it to the communication chip or signal analysis component for signal analysis.

[0116] Step 704: If the detection signal is a low power card detection LPCD signal, generate a first control signal.

[0117] The communication chip in the electronic device can be a chip with LPCD detection function, which can be used to detect whether the signal obtained by the antenna is a low-power card detection LPCD signal. Alternatively, it is also possible to determine whether the detection signal is a low-power card detection LPCD signal by time characteristic analysis, instruction parsing, etc. For example, the LPCD signal is manifested as a short and periodic RF field pulse, such as sending an extremely short activation signal every 500ms, such as a 25μs pulse signal. The RF field of a normal signal persists until the data exchange is completed. The communication chip can determine the duration of the field strength through an internal timer, and then determine whether the detection signal is a low-power card detection LPCD signal. For example, the signal type can be determined by detecting the antenna induced voltage or the demodulation threshold. The specific judgment method is not limited here, and some existing judgment methods can also be referred to.

[0118] 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 the normal card inspection mode.

[0119] 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.

[0120] The first control signal may be a signal for controlling the state of the load adjustment circuit. Specifically, it may be an analog signal or a digital signal. If the card reader device sends an LPCD signal, the electronic device may trigger the adjustment of the load impedance of the electronic device after acquiring the LPCD signal, thereby facilitating the card reader device to switch to the normal card inspection mode.

[0121] The load impedance of the electronic device in the first state may 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 may be smaller than the load impedance of the electronic device in the second state.

[0122] The low power card detection LPCD signal may indicate that the card reader device sends a signal in the low power card detection LPCD mode, which may specifically be one or more pulse signals. In practical applications, after the electronic device determines that the card reader device is in the LPCD mode, it may switch the state immediately, or it may switch the state after a short interval.

[0123] The timing of state switching can also be set according to actual needs. For example, the state switching can be performed at the beginning of the card reader sending a LPCD pulse signal, so that the electronic device in the second state can affect the entire process or the first part of the LPCD pulse signal. Assuming that the electronic device determines that the card reader device is in LPCD mode according to the nth LPCD pulse signal sent by the card reader device, the electronic device can switch from the first state to the second state when the card reader sends the n+1th LPCD pulse signal. The electronic device in the second state can affect the card reader to send the n+1th LPCD pulse signal, or it can also affect one or more pulse signals after the n+1th. Alternatively, after the n+1th LPCD pulse signal ends, the electronic device can also be restored to the first state.

[0124] For another example, the electronic device can also switch states at a certain moment in the middle of an LPCD pulse signal sent by the card reader, so that the electronic device in the second state can affect the second half of the LPCD pulse signal or the subsequent signal. For example, assuming that an LPCD pulse signal is a 25μs pulse signal, after the card reader device sends the signal, the electronic device can be in the first state for the first 8μs and in the second state for the last 17μs; or, the electronic device can be in the first state for the first 8μs, in the second state for the middle 10μs, and in the first state for the last 7μs.

[0125] In actual application, the state of the electronic device can be set according to actual needs. In the process of waking up the normal card inspection mode of the card reader device once, the electronic device can perform one state transition, or it can also perform multiple state transitions. For example, after the electronic device obtains the LPCD signal, it can switch from the first state to the second state, and then maintain the second state until the communication ends or the card reader device wakes up the normal card inspection mode. For another example, after the electronic device obtains the LPCD signal, it can switch from the first state to the second state, and the second state can maintain the length of one or more LPCD pulse signals or maintain a length less than one LPCD pulse signal, and then switch to the first state, and the first state can also maintain the length of one or more LPCD pulse signals or maintain a length less than one LPCD pulse signal, and the state switching is repeated until the communication ends or the card reader device wakes up the normal card inspection mode.

[0126] It is understandable that the signal sent by the card reader device in LPCD mode is also a signal that conforms to certain rules, such as the sending period, signal length, etc. can be fixed. After acquiring the LPCD signal sent by the card reader device, the electronic device can determine the parameters of the LPCD signal sent by the card reader device, generate a corresponding control signal for controlling the state switching, and control or adjust the timing of the state switching.

[0127] In practical applications, before obtaining the low power card detection LPCD signal, the electronic device can be in the first state, and after obtaining the low power card detection LPCD signal, the electronic device can be switched from the first state to the second state. In the embodiments of this specification, the load impedance of the electronic device can be adjusted to promote the card reader device to switch from the low power card detection LPCD mode to the normal card detection mode, and the card reader device can be affected from the perspective of adjusting the load of the card reader device, without the need for overly complex design, low cost, and easy implementation.

[0128] It should be understood that the order of some steps in the methods described in one or more embodiments of this specification can be interchanged according to actual needs, or some steps can be omitted or deleted.

[0129] In practical applications, the load impedance of electronic devices can also be reflected in parameters such as resonant frequency and circuit resistance.

[0130] As an implementation mode, in order to facilitate the card reader device to switch to the normal card inspection mode, the electronic device can be switched from a state where the resonance point conforms to the working resonance point of the card reader device to a state deviating from the working resonance point, or the electronic device can be switched from a state where the resonance point deviates from the working resonance point of the card reader device to a state conforming to the working resonance point. The deviation from the resonance point can be expressed as a resonance frequency greater than or less than the resonance frequency of the card reader device. Optionally, 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, which may specifically include: the resonance point of the electronic device in the first state conforms to a preset resonance point; the resonance point of the electronic device in the second state deviates from the preset resonance point; the preset resonance point is the working resonance point of the card reader device; or, the resonance point of the electronic device in the first state deviates from the preset resonance point, and the resonance point of the electronic device in the second state conforms to the preset resonance point.

[0131] In the embodiments of this specification, the resonance point of the electronic device can be adjusted by adjusting the inductance value and / or capacitance value of the electronic device, so that it can affect the card reader device. As an implementation mode, in the embodiments of this specification, 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, 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, the first inductance value is greater than the second inductance value.

[0132] In the embodiments of this specification, the resonance frequency of the electronic device in the second state may be greater than the resonance frequency of the card reader device, or may be less than the resonance frequency of the card reader device.

[0133] If the electronic device is in a first state where the resonance point matches the resonance point of the card reader device before acquiring the LPCD signal emitted by the card reader device, after acquiring the LPCD signal emitted by the card reader device, the electronic device can be adjusted to a second state where the resonance point deviates from the resonance point of the card reader device. Specifically, the inductance value of the load adjustment circuit in the electronic device can be increased so that the resonance frequency of the electronic device is less than the resonance frequency of the card reader device; or the inductance value of the load adjustment circuit in the electronic device can be decreased so that the resonance frequency of the electronic device is greater than the resonance frequency of the card reader device.

[0134] If the electronic device is in the first state where the resonance point deviates from the resonance point of the card reader device before acquiring the LPCD signal emitted by 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 to pull the resonance point to the resonance point of the card reader device. Specifically, assuming that the resonance frequency of the electronic device in the first state is greater than the resonance frequency of the card reader device, after acquiring the LPCD signal emitted by the card reader device, the inductance value of the load adjustment circuit in the electronic device can be increased to reduce the resonance frequency, and the resonance point of the electronic device can be pulled to the resonance point of the card reader device. Assuming that the resonance frequency of the electronic device in the first state is less than the resonance frequency of the card reader device, after acquiring the LPCD signal emitted by the card reader device, the inductance value of the load adjustment circuit in the electronic device can be adjusted to reduce the resonance frequency, and the resonance point of the electronic device can be pulled to the resonance point of the card reader device.

[0135] As in at least one of the aforementioned embodiments, the load adjustment circuit of the electronic device may include a first adjustable inductor capable of adjusting the inductance value, and the first adjustable inductor can be adjusted to adjust the resonance point of the electronic device. The specific circuit structure and adjustment method can refer to at least one of the aforementioned embodiments, or other circuits capable of adjusting the resonance point of the circuit by adjusting the inductance value, which will not be described in detail here.

[0136] As another implementation, the resonance point of the electronic device can be adjusted by adjusting the capacitance value. Optionally, in the embodiment 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.

[0137] In the embodiments of this specification, if an LPCD signal emitted by a card reader device is detected, the electronic device can be switched from a first state to a second state, or from a first state to a second state. Specifically, if the electronic device is in the first state before acquiring the LPCD signal emitted by the card reader device, the resonance point matches the resonance 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, and the resonance point deviates from the resonance point of the card reader device. Specifically, the capacitance value of the load adjustment circuit in the electronic device can be increased so that the resonance frequency of the electronic device is less than the resonance frequency of the card reader device; or the capacitance value of the load adjustment circuit in the electronic device can be decreased so that the resonance frequency of the electronic device is greater than the resonance frequency of the card reader device.

[0138] If the electronic device is in the second state before acquiring the LPCD signal emitted by the card reader device, the resonance point deviates from the resonance 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 first state, and the resonance point can be pulled to the resonance point of the card reader device. Specifically, assuming that the resonance frequency of the electronic device in the second state is greater than the resonance frequency of the card reader device, after acquiring the LPCD signal emitted by the card reader device, the capacitance value of the load adjustment circuit in the electronic device can be increased to reduce the resonance frequency, and the resonance point of the electronic device can be pulled to the resonance point of the card reader device. Assuming that the resonance frequency of the electronic device in the second state is less than the resonance frequency of the card reader device, after acquiring the LPCD signal emitted by the card reader device, the capacitance value of the load adjustment circuit in the electronic device can be adjusted to increase the resonance frequency, and the resonance point of the electronic device can be pulled to the resonance point of the card reader device.

[0139] As in at least one of the foregoing embodiments, the resonance 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 through a first controllable switch, etc. The specific method for adjusting the capacitance value in the circuit is not limited here.

[0140] As an implementation manner, the resistance value of the electronic device in the first state is a first resistance value, the resistance value of the electronic device in the second state is a second resistance value, and the first resistance value is not equal to the second resistance value.

[0141] In the embodiments of this specification, the load impedance can also be adjusted by adjusting the resistance value of the electronic device to promote the card reader device to enter the normal card detection mode. The specific working principle and implementation method can refer to at least one embodiment of the above embodiments, and will not be repeated.

[0142] In the embodiments of this specification, if an LPCD signal emitted by a card reader device is detected, the electronic device can be switched from a first state to a second state, for example, the resonance point is switched from 13.56MHz to 11.5MHz, that is, the resonance point is pulled away to promote the card reader device to awaken the normal card detection mode; or the Q value is switched from a preset range to a range that deviates from the preset range, that is, the change of the Q value promotes the card reader device to awaken the normal card detection mode. The more the resonance point of the electronic device matches the resonance point of the card reader device or the more the Q value conforms to the preset range, the more conducive it is for the electronic device to send tag information to the card reader device. In order to ensure the quality of communication, optionally, the method in the embodiments of this specification may also 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 is restored from the second state to the first state.

[0143] In actual applications, the electronic device can determine whether the signal emitted by the card reader device is a normal card detection signal through the signal parameters such as the amplitude, time interval, and signal content of the signal emitted by the card reader device detected by the antenna. If the card reader device emits a normal card detection signal, it can be determined that the card reader device has switched to the normal card detection mode, and the information transmission process can be carried out after the card detection is successful. As an implementation method, if the electronic device is in the first state before detecting the LPCD signal emitted by the card reader device, and switches to the second state after detecting the LPCD signal, after subsequently detecting that the card reader device emits a normal card detection signal, the communication chip can send a second control signal to the load adjustment circuit so that the load adjustment circuit switches back to the first state, so that the electronic device and the card reader device transmit information through a contactless communication method, and can also prepare for the next time to promote the card reader device to switch from the LPCD mode to the normal card detection mode.

[0144] In the embodiments of this specification, the first state may also represent a state in which a preset resonance point is deviated or a Q value is deviated from a preset range. After acquiring the LPCD signal emitted by the card reader device, the electronic device may switch from the first state to the second state, that is, by pulling the resonance point or Q value to the positive position to promote the card reader device to wake up the normal card inspection mode. In order to ensure that the card reader device can continue to be promoted to wake up the normal card inspection mode in the future, the electronic device may also switch back to the first state. Optionally, the method in the embodiments of this specification may also 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 is terminated, the electronic device is restored from the second state to the first state.

[0145] As an implementation method, if the electronic device is in a first state that deviates from a preset resonance point or a Q value deviates from a preset range before detecting the LPCD signal emitted by the card reader device, and switches to a second state that meets the preset resonance point or the Q value meets the preset range after detecting the LPCD signal, it can continue to perform contactless communication with the card reader device in the second state, for example, the electronic device can send the stored tag information to the card reader device in the circuit of the second state. After the electronic device and the card reader device have completed the communication, for example, the electronic device has completed the sending of the tag information, or the electronic device and the card reader device are far away and can no longer perform near-field communication, the communication chip can send a third control signal to the load adjustment circuit so that the load adjustment circuit switches back to the first state, so as to prepare for the next time to promote the card reader device to switch from the LPCD mode to the normal card inspection mode.

[0146] In the embodiments of this specification, analog signals or digital signals can be used to control the state change of the electronic device. Optionally, the first control signal can be a digital pulse signal.

[0147] As in at least one of the above embodiments, the communication chip may be a chip capable of generating a digital pulse signal, or an external digital signal conversion circuit may be used to generate a digital pulse signal.

[0148] In one implementation, the length of the digital pulse signal may be equal to the length of the LPCD signal sent by the card reader device.

[0149] In practical applications, the card reader device 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 in the order of tens of microseconds. For example, 35μs, 25μs, etc. For example, after the electronic device obtains the LPCD signal sent by the card reader device, it can generate a digital pulse signal equal to the length of the LPCD signal, which can affect the entire single pulse time period of the LPCD signal sent by the card reader device, thereby promoting the card reader device to switch to the normal card inspection mode.

[0150] In one implementation, the length of the digital pulse signal may also be less than the length of the LPCD signal sent by the card reader device. For example, the length of the digital pulse signal may be equal to one-third, one-half, two-thirds, etc. of the length of the LPCD signal sent by the card reader device. In actual applications, different card reader devices may have different signal analysis capabilities or signal sensitivities due to differences in hardware or software configurations; or the parameters or quantity of electronic components such as capacitors, resistors, and inductors contained in the electronic devices are different, and the signal changes generated by electronic devices with different configurations for the card reader device may also be different. In actual applications, for some card reader devices with strong computing capabilities, or electronic devices that have a greater impact on signal changes, the electronic devices can adjust the state of the electronic devices through digital pulse signals with a length less than the length of the LPCD signal, which can also promote the card reader device to switch to the normal card inspection mode. For example, assuming that the length of the LPCD signal is 25 μs, a pulse signal with a length of 10 μs can be generated. For a single LPCD pulse signal sent by the card reader device, the electronic device can be in the second state in the first 10 μs of the signal and in the first state in the last 15 μs, which can also promote the card reader device to switch to the normal card inspection mode. The actual signal length can be set by the specific parameters of the card reader device and is not specifically limited here.

[0151] In the embodiments of this specification, the length of the digital pulse signal can also be used to control the duration of the electronic device in the first state or the second state. For example, if the electronic device is in the first state before detecting the LPCD signal sent by the card reader device, after obtaining the LPCD signal, a digital pulse signal can be generated to switch from the first state to the second state. When the digital pulse signal disappears or ends, the electronic device can be restored from the second state to the first state.

[0152] It can be understood that the above-mentioned embodiments describe the solutions from multiple perspectives. In practical applications, the contents described in one or more embodiments can be adopted according to actual needs, and multiple embodiments can be superimposed or adjusted and implemented according to actual needs, which will not be described one by one here.

[0153] The components in the embodiments of this specification are only functionally described, and specific parameters or quantities can be set according to actual needs. For example, the first adjustable inductor can be an inductive component that can adjust the inductance value, for example, it can be a single adjustable inductor, or it can be a combined inductor including multiple single adjustable inductors, or it can be other inductive components. The first adjustable capacitor can be a capacitive component that can adjust the capacitance value, for example, it can be a single capacitor, or it can be a combined capacitor including one or more single capacitors, or it can be other capacitive components. The first capacitor, the second capacitor, the third capacitor, the fourth capacitor, the fifth capacitor, etc. can be capacitive elements, for example, they can be capacitors with fixed capacitance values, they can be single capacitors, they can be combined capacitors including multiple single capacitors, or they can be 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 resonance point is achieved.

[0154] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0155] 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, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant laws, regulations and standards in the relevant regions, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0156] In the 1990s, it was very clear whether the improvement of a technology was hardware improvement (for example, improvement of the circuit structure of diodes, transistors, switches, etc.) or software improvement (improvement of the method flow). However, with the development of technology, many improvements of the method flow today can be regarded as direct improvements of the hardware circuit structure. Designers almost always obtain the corresponding hardware circuit structure by programming the improved method flow into the hardware circuit. Therefore, it cannot be said that the improvement of a method flow cannot be implemented with hardware entity modules. For example, a programmable logic device (PLD) (such as a field programmable gate array (FPGA)) is such an integrated circuit whose logical function is determined by the user's programming of the device. Designers can "integrate" a digital system on a PLD by programming it themselves, without having to ask chip manufacturers to design and make dedicated integrated circuit chips. Moreover, nowadays, instead of manually making integrated circuit chips, this kind of programming is mostly implemented by "logic compiler" software, which is similar to the software compiler used when developing and writing programs, and the original code before compilation must also be written in a specific programming language, which is called hardware description language (HDL). There is not only one kind of HDL, but many kinds, 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, RHDL (Ruby Hardware Description Language), etc. The most commonly used ones are VHDL (Very-High-Speed ​​Integrated Circuit Hardware Description Language) and Verilog. Those skilled in the art should also know that it is only necessary to program the method flow slightly in the above-mentioned hardware description languages ​​and program it into the integrated circuit, and then it is easy to obtain the hardware circuit that implements the logic method flow.

[0157] The controller may be implemented in any suitable manner, for example, the controller may take the form of a microprocessor or processor and a computer-readable medium storing a computer-readable program code (e.g., software or firmware) executable by the (micro)processor, a logic gate, a switch, an application-specific integrated circuit (ASIC), a programmable logic controller, and an embedded microcontroller, examples of which include but are not limited to the following microcontrollers: ARC 625D, Atmel AT91SAM, Microchip PIC18F26K20, and Silicone Labs C8051F320, and the memory controller may also be implemented as part of the control logic of the memory. It is also known to those skilled in the art that, in addition to implementing the controller in a purely computer-readable program code manner, the controller may be implemented in the form of a logic gate, a switch, an application-specific integrated circuit, a programmable logic controller, and an embedded microcontroller by logically programming the method steps. Therefore, such a controller may be considered as a hardware component, and the devices for implementing various functions included therein may also be considered as structures within the hardware component. Or even, the devices for implementing various functions may be considered as both software modules for implementing the method and structures within the hardware component.

[0158] The systems, devices, modules or units described in the above embodiments may be implemented by computer chips or entities, or by products having certain functions. A typical implementation device is a computer. Specifically, the computer may be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices. For the convenience of description, the above devices are described separately by function into various units. Of course, when implementing this application, the functions of each unit may be implemented in the same or more software and / or hardware.

[0159] Those skilled in the art should understand that the 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 complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention 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. The present invention is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present invention. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the functions in the process. Figure 1 A process or multiple processes and / or boxes Figure 1 These computer program instructions can also be stored in a computer-readable memory that can guide a computer or other programmable data processing device to work in a specific way, so that the instructions stored in the computer-readable memory produce a product including an instruction device, which implements the functions specified in the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0160] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0161] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory. Memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. Memory is an example of a computer-readable medium. Computer-readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. 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 technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. According to the definition in this article, computer-readable media does not include temporary computer-readable media (transitory media), such as modulated data signals and carrier waves.

[0162] It should also be noted that the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of further restrictions, the elements defined by the sentence "including one..." do not exclude the presence of other identical elements in the process, method, commodity or device including the elements. It should be understood by those skilled in the art that the embodiments of the present application can be provided as methods, systems or computer program products. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment or an embodiment combining software and hardware. Moreover, the present 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. The present application can be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The present application can also be practiced in distributed computing environments where tasks are performed by remote processing devices that are connected through a communications network. In a distributed computing environment, program modules may be located in local and remote computer storage media including memory storage devices.

[0163] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present 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; 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 obtains a low power card detection LPCD signal sent by the card reader device, the communication chip is used to control 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.

2. The electronic device according to claim 1, wherein 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, specifically comprising: The resonance point of the electronic device in the first state meets the preset resonance point; In the second state, the resonance point of the electronic device deviates from the preset resonance point; The preset resonance point is the working resonance point of the card reader device; Alternatively, the resonance point of the electronic device in the first state deviates from the preset resonance point, and the resonance point of the electronic device in the second state conforms to the preset resonance point.

3. The electronic device according to claim 2, wherein the load adjustment circuit comprises 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 end of the first adjustable inductor is connected to the communication chip; in, The inductance value of the first adjustable inductor in the first state is a first inductance value, and the inductance value of the first adjustable inductor in the second state is a second inductance value; If the resonant frequency of the electronic device in the second state is lower than the resonant frequency of the electronic device in the first state, the first inductance value is lower 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, the first inductance value is greater than the second inductance value.

4. The electronic device according to claim 2, wherein the load adjustment circuit comprises a first adjustable capacitor; the first adjustable capacitor is connected in parallel with the antenna; the adjustable end 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, and 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 lower than the resonant frequency of the electronic device in the first state, the first capacitance value is lower 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, the first capacitance value is greater than the second capacitance value.

5. The electronic device according to claim 2, 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 connected 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 lower than the resonant frequency of the electronic device in the first state, the first controllable switch is in an open state in the first state, and the first controllable switch is in a closed state in the second state; if the resonant frequency of the electronic device in the second state is higher than the resonant frequency of the electronic device in the first state, the first controllable switch is in a closed state in the first state, and the first controllable switch is in an open state in the second state.

6. The electronic device according to claim 1, wherein 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, specifically comprising: A resistance value of the electronic device in the first state is different from a resistance value of the electronic device in the second state.

7. 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 is connected in series with the second controllable switch 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 an open state in the first state, and is in a closed state in the second state.

8. The electronic device according to claim 7, wherein the load adjustment circuit comprises 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 end 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.

9. The electronic device according to claim 1, 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.

10. The electronic device according to claim 1, wherein the communication chip has a function of outputting a digital signal level; The load adjustment circuit is connected to the communication chip and specifically includes: The digital signal level output pin of the communication chip is connected to the digital signal input terminal communication chip of the load adjustment circuit.

11. The electronic device according to claim 1, further comprising a power input terminal for connecting to a power source outside the electronic device so that the power source provides electrical energy to the electronic device; Alternatively, the electronic device further includes a power supply element, and the power supply element is connected to the communication chip, so that the communication chip generates a digital signal level for controlling the load adjustment circuit based on the electric energy provided by the power supply element.

12. The electronic device according to claim 1, further comprising a digital signal conversion unit; The load adjustment circuit is connected to the communication chip and specifically includes: The input end of the digital signal conversion unit is connected to the antenna, and is used to obtain the radio frequency signal obtained by the antenna; The output end of the digital signal conversion unit is connected to the load adjustment circuit, and is used to provide a digital signal level to the load adjustment circuit, so that the load adjustment circuit switches from the first state to the second state.

13. An NFC tag, comprising the electronic device according to any one of claims 1 to 12.

14. A contactless communication control method, applied to the electronic device according to claim 1, comprising: Get the detection signal sent by the 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 switches from a first state to a second state so that the card reader device switches to a normal card inspection 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.

15. According to the method of claim 14, 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 of the load adjustment circuit of the electronic device 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.

16. According to the method of claim 14, 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, 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, the first capacitance value is greater than the second capacitance value. 17 . The method according to claim 14 , wherein the resistance value of the electronic device in the first state is a first resistance value, the resistance value of the electronic device in the second state is a second resistance value, and the first resistance value is not equal to the second resistance value.

18. The method according to claim 14, after the electronic device switches from the first state to the second state, further comprising: If it is detected that the card reader device is in a normal card checking mode, the electronic device is restored from the second state to the first state; Alternatively, if the communication between the electronic device and the card reader device is completed, the electronic device is restored from the second state to the first state. The method according to claim 14 , wherein the first control signal is a digital pulse signal.

20. The method according to claim 19, wherein 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.

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