Antenna coupling power supply circuit and NFC tag comprising same

Abstract

The embodiment of the utility model relates to the technical field of near field communication, and discloses an antenna coupling power supply circuit and an NFC tag comprising the same. The antenna coupling power supply circuit comprises a first antenna loop and a second antenna loop. The first antenna loop is configured to work at a preset frequency band, has a set signal attenuation capability, and is used for receiving and forwarding an external signal and attenuating the power of the forwarded signal; and the second antenna loop is configured to receive the signal forwarded by the first antenna loop to realize near field communication. According to the embodiment of the utility model, the external signal is received and forwarded through the additionally arranged antenna coupling loop, the forwarded signal is attenuated to meet the power supply requirement required by the safe work of the NFC chip, and the antenna loop where the NFC chip is located works based on the attenuated signal, so that the NFC card can be safely used in a high-power wireless environment, and the safety of the NFC card is improved. And meanwhile, the communication function of the NFC card is met.

Description

Technical Field

[0001] The present invention relates to the field of near field communication technology, and more particularly to an antenna coupling power supply circuit and an NFC tag comprising the same. Background Art

[0002] Mobile phone wireless charging technology has been widely used in daily life, especially in new energy vehicles. Proximity IC cards, such as NFC (Near Field Communication) cards, have been widely used in transportation cards, access control cards, electronic consumer cards, bank cards and other fields. At the same time, proximity IC cards are used as access control cards for new energy vehicles as a new business model, bringing users a perfect experience. Furthermore, the cost difference between NFC door cards and remote control car keys is huge, making more vehicle manufacturers willing to use NFC door cards instead of remote control car keys.

[0003] During use, many users are accustomed to sticking the NFC door card with their mobile phones, and at the same time put the mobile phone on the wireless charger in the car to charge, so that the antenna of the NFC card is placed in the wireless charging electric field, so that the NFC card obtains power through its NFC antenna and L / C oscillation circuit and directly loads it onto the NFC chip, and the NFC chip is continuously powered until the card leaves the wireless charging electric field. Since the charging power of the current mobile phone wireless charger has reached 50W or above, and the wireless charging current emitted is close to 10A, such a large current generates a strong radio field, and the intensity of this electric field far exceeds the electric field intensity required for NFC card data interaction. Such a high electric field receives power through the NFC card antenna to generate a large current loop acting on both ends of the NFC chip. Under the continuous high current loading, the chip is easy to heat up, causing the chip to burn out and the surface of the PVC card to burn, and even worse, it may induce a fire. Utility Model Content

[0004] The embodiment of the utility model provides an antenna coupling power supply circuit and an NFC tag including the same, which receives and forwards external signals through an additional antenna coupling loop, and attenuates the forwarded signal to the power supply requirement for the safe operation of the NFC chip, and enables the antenna loop where the NFC chip is located to operate based on the attenuated signal, thereby enabling the NFC card to be safely used in a high-power wireless environment while satisfying the communication function of the NFC card.

[0005] In a first aspect, an embodiment of the utility model provides an antenna coupling power supply circuit, comprising: a first antenna loop and a second antenna loop;

[0006] The first antenna loop is configured to operate in a preset frequency band and has a set signal attenuation capability, and the first antenna loop is used to receive and forward external signals and attenuate the power of the forwarded signals;

[0007] The second antenna loop is configured to receive a signal forwarded by the first antenna loop to implement near field communication.

[0008] As an embodiment, the first antenna loop includes: a receiving antenna ANT1, a forwarding antenna ANT1-2 and a capacitor C1, wherein the ANT1 and the C1 are connected in parallel to form a first L / C oscillation circuit for partially receiving external signal power;

[0009] The ANT1 - 2 is connected in parallel with the C1 to form a second L / C oscillation circuit for forwarding the signal received by the first L / C oscillation circuit.

[0010] As an embodiment, the second antenna loop includes: a transceiver antenna ANT2 and an NFC chip, wherein the ANT2 is connected to the NFC chip, and the ANT2 is configured to receive the signal forwarded by the ANT1-2 to realize the near field communication.

[0011] As an embodiment, the antenna coils corresponding to ANT1 and ANT1-2 are both multi-turn, and the number of turns of the coil of ANT1-2 is greater than the number of turns of the coil of ANT1, and the coil of ANT1-2 is located inside the coil of ANT1; the coil of ANT2 is located inside the coil of ANT1-2.

[0012] As an embodiment, the ANT1 and the ANT1-2 are wound with an integral wire, one end of the integral wire is connected to one end of the C1, and is wound from the outside to the inside on a plane into a plurality of large rectangular coils, and then is further wound from the inside to the outside inside the large rectangular coil into a plurality of small rectangular coils, and then the other end of the integral wire is connected to the C1; wherein the large rectangular coil forms the ANT1, the small rectangular coil forms the ANT1-2, and the small rectangular coil is located inside the large rectangular coil.

[0013] As an embodiment, the number of turns of the ANT1 coil is 3, and the number of turns of the ANT1-2 coil is 8.

[0014] As an embodiment, the capacitance of C1 is 20pf~50pf.

[0015] As an embodiment, the frequency range of the preset frequency band is 12.5~14.5MHZ.

[0016] In a second aspect, an embodiment of the present invention provides an NFC tag, comprising the antenna coupling power supply circuit as described in the first aspect.

[0017] Compared with the prior art, the technical solution provided by the embodiment of the utility model has at least the following positive effects:

[0018] In the technical solution of the embodiment of the utility model, the first antenna loop is configured to operate in a preset frequency band and has a set signal attenuation capability. The first antenna loop is used to receive and forward external signals, and the power of the forwarded signal is attenuated so that the forwarded signal is attenuated to a range in which the NFC chip can operate safely. The signal forwarded by the first antenna loop is then received through the second antenna loop to realize the communication of the NFC chip, thereby ensuring the safety of the NFC card when used in a high-power wireless environment, preventing the NFC card from being burned or causing a fire, and ensuring the communication performance of the NFC tag. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 A schematic diagram of the structure of an antenna coupling power supply circuit provided in Embodiment 1 of the present utility model;

[0021] Figure 2 A schematic diagram of the structure of a first antenna loop in an antenna coupling power supply circuit provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only the parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0023] The antenna coupling power supply circuit and the NFC tag including the same according to the embodiments of the present application are described below with reference to the accompanying drawings.

[0024] In response to the problem mentioned in the background technology that when the NFC door card is placed in a high-power wireless charging environment, the large current generated by the charging signal is directly loaded on the NFC chip, which may easily cause the NFC chip to burn out, posing a serious safety hazard. The external signal is received through the first antenna loop and the received external signal is forwarded. The first antenna loop has a set attenuation capability, which can make the high-power wireless charging signal of the mobile phone, etc. attenuate to the safe use range of the NFC card after forwarding, and then receive the forwarded external signal through the second antenna loop to power the NFC card, so that the NFC card meets the communication performance requirements. The embodiment of the utility model attenuates the external signal through the first antenna loop, and uses the attenuated signal to power the NFC chip through coupling with the second antenna loop (that is, the antenna loop where the NFC chip is located), thereby avoiding the external signal directly acting on the NFC chip to cause damage to it, ensuring the power supply safety of the NFC chip, avoiding the NFC chip from being burned, and also meeting the communication performance requirements of the NFC card.

[0025] Specifically, Figure 1 A schematic diagram of the structure of an antenna coupling power supply circuit provided in the first embodiment of the present application can be used for a proximity card, such as a power supply circuit of an NFC tag.

[0026] like Figure 1 , 2 As shown, the antenna coupling power supply circuit of the embodiment of the present application includes: a first antenna loop and a second antenna loop.

[0027] The first antenna loop is configured to operate in a preset frequency band and has a set signal attenuation capability. The first antenna loop is used to receive and forward external signals and attenuate the power of the forwarded signals. The second antenna loop is configured to receive the signal forwarded by the first antenna loop to achieve near field communication.

[0028] As an example but not a limitation, the preset frequency band is the frequency band where the 13.56 MHz frequency is located. The frequency range of the preset frequency band is, for example, 12.5~14.5 MHZ. The preset frequency band can well meet the communication requirements of the NFC card and no excessive restrictions are made here.

[0029] The design of the first antenna loop should be able to receive external signals in the NFC frequency band and have appropriate power attenuation capability, that is, the power of the external signal it receives should be reduced at a certain degree of attenuation, and the received external signal should be forwarded. The signal attenuation capability of the first antenna loop can make the forwarded signal power attenuate to a certain degree, for example, a 50-watt wireless signal can be attenuated to 1 watt or lower, thereby meeting the use requirements of the NFC chip.

[0030] The second antenna loop should be designed to receive the external signal forwarded by the first antenna loop and meet the communication capabilities of the NFC chip, such as meeting the card reading distance requirements of the NFC card reader. The second antenna loop uses the external signal forwarded by the first antenna loop to power the NFC chip, so that the NFC card can work, and respond to the request of the card reader device for data interaction.

[0031] Therefore, when the NFC card using the power supply circuit of this embodiment is placed in a high-power wireless charging environment, the first antenna loop receives the external signal with power attenuation and then forwards it, so that the power of the forwarded signal decreases rapidly, meeting the safe power supply requirements of the NFC chip. The second antenna loop receives the signal forwarded by the first antenna loop to power the NFC chip, which, on the one hand, prevents the external high-power signal from directly acting on the NFC chip and preventing the NFC chip from being burned, that is, the safety barrier provided by the first antenna loop protects the NFC chip, and at the same time, it can provide the required power supply capacity for the NFC chip, so that the NFC card has good communication capabilities.

[0032] like Figure 2 As shown, as a preferred embodiment, the first antenna loop may include: a receiving antenna ANT1, a forwarding antenna ANT1-2 and a capacitor C1. ANT1 and C1 are connected in parallel to form a first L / C oscillator circuit for partially receiving external signal power. ANT1-2 and C1 are connected in parallel to form a second L / C oscillator circuit for forwarding the signal power received by the first L / C oscillator circuit. The first L / C oscillator circuit is configured to have a certain power reception attenuation capability, so that the external signal is attenuated to a certain extent after being received by the first L / C oscillator circuit and forwarded by the second L / C oscillator circuit, for example, a 50W wireless charging signal is attenuated to less than 1 watt.

[0033] The second antenna loop may include: a transceiver antenna ANT2 and an NFC chip, wherein ANT2 is connected to the NFC chip, and ANT2 is configured to receive a signal forwarded by ANT1 - 2 to achieve near field communication.

[0034] ANT1 is the main coil for obtaining external electrical energy. It obtains energy from the outside through the first L / C oscillation circuit and then transmits it through ATN1-2. Based on this working principle, the following should be considered: 1) The gain of the ANT1 antenna should not be too high, so that too much energy is accumulated at both ends of the capacitor C1 and the capacitor is burned; 2) The antenna design of ANT1-2 aims to transmit the energy converted on ANT1 through ANT1-2 as much as possible; 3) The coupling frequency of the first L / C oscillation circuit composed of ANT1 and C1 must be a reasonable value, and the frequency of the third L / C oscillation circuit composed of ANT2 and the NFC chip must be taken into account.

[0035] As a preferred embodiment of the first antenna loop, the antenna coils corresponding to ANT1 and ANT1-2 are both multi-turn, and the number of turns of the coil of ANT1-2 is greater than the number of turns of the coil of ANT1, and the coil of ANT1-2 is located inside the coil of ANT1; the coil of ANT2 is located inside the coil of ANT1-2.

[0036] Furthermore, ANT1 and ANT1-2 are wound with an integrated wire, one end of which is connected to one end of C1, and then wound from outside to inside on a plane into a plurality of large rectangular coils, and then wound from inside to outside in the large rectangular coil into a plurality of small rectangular coils, and then the other end of the integrated wire is connected to C1. The large rectangular coil forms ANT1, and the small rectangular coil forms ANT1-2.

[0037] Exemplarily, the first L / C oscillation circuit and the second L / C oscillation circuit have the same operating frequency band, and the operating frequency range is 12.5~14.5MHZ. The capacitance of capacitor C1 is 20pf~50pf. In order to make the first L / C oscillation circuit work within the preset frequency band and have the required signal reception and forwarding attenuation capability, the parameters can be debugged according to the number of turns of the ANT1 coil, the spacing between the coils, the shape, etc. For example, the number of turns of the coil of ANT1 is 3, and the number of turns of the coil of ANT1-2 is 8. As long as the first antenna loop meets the design requirements, this embodiment does not impose excessive restrictions on the parameters of the components of the first antenna loop.

[0038] The coil corresponding to ANT2 is located inside the coil of ANT1-2, so that ANT2 can better receive the signal transmitted by ANT1-2, and avoid ANT2 directly receiving external signals. Antenna design principle of ANT2: The built-in capacitor of antenna ANT2 and NFC chip 1 form a third L / C oscillation circuit, and obtain the external signal power forwarded by it from the ANT1-2 antenna, and enable the NFC chip to communicate with the card reader at a frequency of 13.56Mhz. When designing, it should be considered that the energy obtained by ANT2 should not be too large to avoid burning the NFC chip. At the same time, the working energy of the NFC chip can be adjusted by the difference frequency method, that is, the working frequency of the first antenna loop and the second antenna loop is adjusted through repeated tests, so that the NFC chip obtains appropriate working energy. It is understandable that those skilled in the art can design parameters for ANT2 so that the NFC card can communicate with the card reader within an appropriate card reading distance.

[0039] The working principle of the antenna coupling power supply circuit of the embodiment of the utility model is as follows:

[0040] The large antenna ANT1 with a frequency of 1 generated by the first L / C oscillation circuit receives external wireless signals and forwards them outward through the ANT1-2 antenna. The L / C oscillation loop composed of a small antenna ANT2 and the NFC chip receives the 13.56Mhz frequency band electric field emitted by the large antenna ANT1-2 to obtain power and establish communication with the external card reader.

[0041] exist Figure 1 Under the action of the strong electric field E1 (such as the external interference electric field generated by wireless charging), the first L / C oscillation circuit composed of antenna ANT1 and capacitor C1 obtains external signal energy. Due to the high intensity of the electric field E1, after attenuation by the small antenna ANT1-2, a small transmitting electric field E2 is generated through the inductor coil ANT1-2. Then, the electric field of E2 is obtained by ANT2 in a contactless manner to power on the NFC chip on ANT2 and exchange data with the card reader at the communication frequency of 13.56Mhz. In this way, the electric energy obtained on ANT2 is greatly reduced, which basically meets the communication requirements of ISO14443 / 15693.

[0042] After experimental verification, the NFC card of the embodiment of the utility model displays the UID number of the NFC chip after the card is successfully found on the contactless card reader. At the same time, the NFC card is read and charged continuously for 8 hours on the car mobile phone wireless charger without burning the NFC card, which fully meets the use needs of car manufacturers.

[0043] Compared with the prior art, the embodiment of the utility model has the following advantages:

[0044] 1. Compared with the single-antenna linked NFC chip card design, the NFC card powered by the coupled antenna can be safely used for 50W mobile phone wireless charging.

[0045] Second, the utility model provides a safety barrier by coupling antenna power supply, and cleverly solves the problem of NFC card chip resisting interference from external uncontrollable electric fields.

[0046] 3. Wide range of applications: The utility model can be used on all NFC card products, expanding the application range of NFC card products.

[0047] Embodiment 2 of the present application provides an NFC tag, including the antenna coupling power supply circuit as described in the above embodiment.

[0048] Compared with the prior art, the NFC tag of the embodiment of the utility model attenuates and forwards the external signal through the first antenna loop, and uses the attenuated signal to power the NFC chip through coupling, thereby avoiding the external signal from directly acting on the NFC chip and causing damage to it, ensuring the power supply security of the NFC chip and preventing the NFC chip from being burned, and also meeting the communication performance requirements of the NFC card.

[0049] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention is described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. An antenna coupling power supply circuit, characterized in that: include: a first antenna loop and a second antenna loop; The first antenna loop is configured to operate in a preset frequency band and has a set signal attenuation capability, and the first antenna loop is used to receive and forward external signals and attenuate the power of the forwarded signals; The second antenna loop is configured to receive a signal forwarded by the first antenna loop to implement near field communication.

2. The antenna coupling power supply circuit according to claim 1, characterized in that: The first antenna loop includes: a receiving antenna ANT1, a forwarding antenna ANT1-2 and a capacitor C1, wherein the ANT1 and the C1 are connected in parallel to form a first L / C oscillating circuit for partially receiving external signal power; The ANT1 - 2 is connected in parallel with the C1 to form a second L / C oscillation circuit for forwarding the signal received by the first L / C oscillation circuit.

3. The antenna coupling power supply circuit according to claim 2, characterized in that: The second antenna loop includes: a transceiver antenna ANT2 and an NFC chip, wherein the ANT2 is connected to the NFC chip, and the ANT2 is configured to receive the signal forwarded by the ANT1-2 to realize the near field communication.

4. The antenna coupling power supply circuit according to claim 3, characterized in that: The antenna coils corresponding to ANT1 and ANT1-2 are both multi-turn, and the number of turns of the coil of ANT1-2 is greater than the number of turns of the coil of ANT1. The coil of ANT1-2 is located inside the coil of ANT1; the coil of ANT2 is located inside the coil of ANT1-2.

5. The antenna coupling power supply circuit according to claim 4, characterized in that: The ANT1 and the ANT1-2 are wound with an integral wire, one end of the integral wire is connected to one end of the C1, and is wound from the outside to the inside on a plane into a plurality of large rectangular coils, and then is further wound from the inside to the outside inside the large rectangular coil into a plurality of small rectangular coils, and then the other end of the integral wire is connected to the C1; wherein the large rectangular coil forms the ANT1, the small rectangular coil forms the ANT1-2, and the small rectangular coil is located inside the large rectangular coil.

6. The antenna coupling power supply circuit according to claim 5, characterized in that: The number of turns of the ANT1 coil is 3, and the number of turns of the ANT1-2 coil is 8.

7. The antenna coupling power supply circuit according to claim 3, characterized in that: The NFC chip uses difference frequency to control the transmission and reception energy.

8. The antenna coupling power supply circuit according to claim 2, characterized in that: The capacitance of C1 is 20pf to 50pf.

9. The antenna coupling power supply circuit according to claim 1, characterized in that: The frequency range of the preset frequency band is 12.5-14.5 MHZ.

10. An NFC tag, characterized in that: The invention comprises the antenna coupling power supply circuit as claimed in any one of claims 1 to 8.

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