An electronic price tag

Abstract

The application discloses an electronic price tag, which comprises a card reader chip, a label chip, a common coil and at least one isolator, the first transmitting end of the card reader chip is electrically connected with the first end of the common coil, the first pin of the label chip is electrically connected with the first end, the second pin of the label chip is electrically connected with the second end of the common coil, the isolator is arranged in series between the first pin and the first end, and / or the isolator is arranged in series between the second pin and the second end. According to the technical scheme, the card reader chip and the label chip are electrically connected with the common coil, and the isolator is arranged on the loop of the label chip and the common coil, so that the mutual coupling and mutual interference between the card reader coil and the label coil in the prior art are solved, and the normal work of the card reader chip and the label chip is ensured.

Description

Technical Field

[0001] This invention relates to the field of electronic price tag technology, and more particularly to an electronic price tag. Background Technology

[0002] Currently, electronic shelf labels all integrate Near Field Communication (NFC) functionality. The main application scenarios for electronic shelf labels include: communicating with external card readers as NFC tags, or communicating with external NFC tags as NFC card readers. When an external card reader triggers the NFC tag on the electronic shelf label, it can control the electronic shelf label to flash its lights, swipe its screen, and upload information; when the electronic shelf label reads an external NFC tag through an NFC card reader, it can obtain the external NFC tag's identity information and internally stored data, and by processing the obtained information, it can achieve functions such as location tracking.

[0003] With the improvement of electronic shelf label functions and the expansion of application scenarios, it is sometimes necessary to integrate NFC tags and NFC readers into electronic shelf labels. However, if the NFC reader coil in the NFC reader and the NFC tag coil in the NFC tag are close together or overlap, there will be mutual coupling between the coils, resulting in mutual inductance. Mutual inductance will change the inductance value of each coil, thus affecting the resonant point. The closer the resonant points of the coils are, the greater the mutual inductance, which leads to a greater offset of the resonant point of the coils. Therefore, it is impossible to ensure that both coils work near the resonant point. Therefore, how to reduce mutual interference has become an urgent problem to be solved in this field. Summary of the Invention

[0004] This invention provides an electronic price tag to solve the problem of mutual interference between the NFC reader coil and the NFC tag coil when integrating an NFC tag and an NFC reader into an electronic price tag in the prior art.

[0005] An electronic shelf label according to the present invention includes: a card reader chip, a tag chip, a common coil, and at least one isolator; The first transmitter of the card reader chip is electrically connected to the first end of the shared coil; The first pin of the tag chip is electrically connected to the first terminal, and the second pin of the tag chip is electrically connected to the second terminal of the common coil. An isolator is connected in series between the first pin and the first terminal; and / or, an isolator is connected in series between the second pin and the second terminal.

[0006] Optionally, the isolator is an isolation capacitor.

[0007] Optionally, it may also include at least one ground switch; The ground switch is located in the circuit between the isolator and the first pin and is electrically connected to the first pin, and / or is located in the circuit between the isolator and the second pin and is electrically connected to the second pin.

[0008] Optionally, the card reader chip may also include a second transmitter; The second transmitting end is electrically connected to the second end of the common coil; The electronic price tag also includes a first capacitor, a second capacitor, a third capacitor, and a fourth capacitor; The third capacitor is connected in series between the first transmitter and the first terminal; the fourth capacitor is connected in series between the second transmitter and the second terminal. The first capacitor is connected in series between the first transmitter and the ground terminal; the second capacitor is connected in series between the second transmitter and the ground terminal.

[0009] Optionally, the electronic price tag may also include a first inductor and a second inductor; The first inductor is connected in series between the first emitter and the first capacitor, and is also connected in series between the first emitter and the third capacitor; the second inductor is connected in series between the second emitter and the second capacitor, and is also connected in series between the second emitter and the fourth capacitor.

[0010] Optionally, it may also include a first disconnect switch and a second disconnect switch; The first disconnecting switch is located between the first inductor and the third capacitor and is connected in parallel with the first capacitor; The second disconnecting switch is located between the second inductor and the fourth capacitor and is connected in parallel with the second capacitor.

[0011] Optionally, a third disconnect switch and a fourth disconnect switch may also be included; The third disconnecting switch is connected in series between the first inductor and the first capacitor; The fourth disconnecting switch is connected in series between the second inductor and the second capacitor.

[0012] Optionally, both the first disconnect switch and the second disconnect switch include a first field-effect transistor and a second field-effect transistor; The first field-effect transistor includes a first source, a first gate, and a first drain; the second field-effect transistor includes a second source, a second gate, and a second drain; the first source and the second source are electrically connected; the first gate and the second gate are respectively electrically connected to the control unit of the electronic price tag; the second drain is electrically connected to the ground terminal; The first drain of the first disconnecting switch is electrically connected to the first inductor; the first drain of the second disconnecting switch is electrically connected to the second inductor.

[0013] Optionally, both the first field-effect transistor and the second field-effect transistor are N-type metal-oxide-semiconductor transistors.

[0014] Optionally, the second terminal is grounded; Electronic price tags also include a first capacitor and a third capacitor; The first capacitor is connected in series between the first transmitter and the ground terminal; the third capacitor is connected in series between the first transmitter and the first terminal.

[0015] Optionally, the electronic price tag may also include a first inductor; The first inductor is connected in series between the first emitter and the first capacitor, and is also connected in series between the first emitter and the third capacitor.

[0016] Optionally, the electronic price tag may also include a fifth disconnect switch; The fifth disconnecting switch is connected in series between the grounding terminal and the second terminal.

[0017] Optionally, the common coil may also include a third terminal; The third terminal is located between the first and second terminals and in the middle of the common coil; the third terminal is grounded. Electronic price tags also include a first capacitor and a third capacitor; The first capacitor is connected in series between the first transmitter and the ground terminal; the third capacitor is connected in series between the first transmitter and the first terminal.

[0018] Optionally, the electronic price tag may also include a first inductor; The first inductor is connected in series between the first emitter and the first capacitor, and is also connected in series between the first emitter and the third capacitor.

[0019] Optionally, the electronic price tag may also include a sixth disconnect switch; The sixth disconnecting switch is connected in series between the first inductor and the third capacitor; or, the sixth disconnecting switch is connected in series between the first inductor and the ground terminal and in parallel with the first capacitor.

[0020] Optionally, the isolator is a disconnect switch. The technical solution of this invention, by setting a common coil, ensures that the reader chip and the tag chip are electrically connected to the common coil respectively. Simultaneously, to ensure the independent operation of the reader chip and the tag chip, an isolator is set in the circuit between the tag chip and the common coil. This solves the problem of mutual coupling and interference between the reader coil and the tag coil due to their close proximity in the prior art, thus ensuring the normal operation of the reader chip and the tag chip.

[0021] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a partial circuit diagram of an NFC reader module in the prior art; Figure 2 This is a partial circuit diagram of an NFC tag module in existing technology; Figure 3 This is a partial circuit diagram of the first type of electronic price tag provided according to an embodiment of the present invention; Figure 4 This is a partial circuit diagram of the second type of electronic price tag provided according to an embodiment of the present invention; Figure 5 This is a partial circuit diagram of the third type of electronic price tag provided according to an embodiment of the present invention; Figure 6 This is a partial circuit diagram of the fourth type of electronic price tag provided according to an embodiment of the present invention; Figure 7 This is a partial circuit diagram of the fifth type of electronic price tag provided according to an embodiment of the present invention; Figure 8 This is a partial circuit diagram of the sixth type of electronic price tag provided according to an embodiment of the present invention; Figure 9 This is a schematic diagram of the structure of a disconnecting switch according to an embodiment of the present invention; Figure 10 This is a partial circuit diagram of the seventh type of electronic price tag provided according to an embodiment of the present invention; Figure 11 This is a partial circuit diagram of the eighth type of electronic price tag provided according to an embodiment of the present invention; Figure 12 This is a partial circuit diagram of the ninth type of electronic price tag provided according to an embodiment of the present invention; Figure 13 This is a partial circuit diagram of the tenth type of electronic price tag provided according to an embodiment of the present invention; Figure 14 This is a partial circuit diagram of the eleventh type of electronic price tag provided according to an embodiment of the present invention. Detailed Implementation

[0024] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0025] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0026] In existing technologies, to achieve a more convenient interactive experience, customers can quickly send commands to electronic shelf labels using NFC on a handheld device. Therefore, NFC tag functionality needs to be integrated into the electronic shelf label. To achieve intelligent operation of the electronic shelf label, enabling it to accurately identify the corresponding product and display product information, an NFC reader needs to be integrated. This reader uses the NFC protocol to query nearby NFC tags, obtains the tag's identity and storage information, and uploads it to the backend system. The backend system queries the location address corresponding to this identity information, associates it with the product at that location, and sends the product information back to the electronic shelf label. The electronic shelf label then displays the obtained product information on an e-ink screen. Therefore, both the NFC reader and NFC tag are integrated within the electronic shelf label. Such electronic shelf labels typically include an NFC reader module, an NFC reader coil, an NFC tag module, an NFC tag coil, and a control unit. Both the NFC reader module and the NFC tag module are connected to the control unit. The NFC reader module includes: an NFC reader chip, a peripheral power supply circuit, a communication and control circuit with the control unit, a crystal, and a matching circuit. Figure 1 This is a partial circuit diagram of an NFC reader module in existing technology, such as... Figure 1 As shown, the NFC reader chip 01 is connected to the NFC reader coil 02 via a matching circuit. The NFC tag module includes: an NFC tag chip, a chip peripheral power supply circuit, a communication and control circuit with the control unit, a matching circuit, etc. Figure 2This is a partial circuit diagram of an NFC tag module in existing technology, such as... Figure 2 As shown, the NFC tag chip 03 is connected to the NFC tag coil 04 via a matching circuit. However, when the NFC reader coil 02 and the NFC tag coil 04 are close together or overlap, mutual coupling will occur between the coils, generating mutual inductance. This mutual inductance will change the inductance value of each coil, thus affecting the resonant point. The closer the resonant points of the coils are, the greater the mutual inductance, resulting in a greater offset of the resonant points, making it impossible to guarantee that both coils operate near their resonant points. Therefore, this embodiment of the invention provides an electronic price tag in which the reader chip circuit can be a single-ended circuit or a differential circuit. Figure 3 This is a partial circuit diagram of the first type of electronic price tag provided according to an embodiment of the present invention. Figure 3 The following explanation uses a differential circuit as an example. Figure 3 As shown, the electronic price tag includes: Card reader chip 1, tag chip 2, common coil 3, and at least one isolator 4; The first transmitter TX1 of the card reader chip 1 is electrically connected to the first terminal 31 of the common coil 3; The first pin 21 of the tag chip 2 is electrically connected to the first terminal 31, and the second pin 22 of the tag chip 2 is electrically connected to the second terminal 32 of the common coil 3. An isolator 4 is connected in series between the first pin 21 and the first terminal 31; and / or, an isolator 4 is connected in series between the second pin 22 and the second terminal 32.

[0027] The reader chip 1 can be an NFC reader chip 1. The first transmitting terminal TX1 of the reader chip 1 is electrically connected to the first terminal 31 of the common coil 3, enabling the reader chip 1 to transmit or receive NFC signals using the common coil 3. The tag chip 2 can be an NFC tag chip 2. The first pin 21 of the tag chip 2 is electrically connected to the first terminal 31 of the common coil 3, and the second pin 22 is electrically connected to the second terminal 32 of the common coil 3, realizing the connection between the tag chip 2 and the common coil 3.

[0028] It is understood that, in order to avoid the mutual interference problem between the NFC reader coil and the NFC tag coil in the prior art, the embodiments of the present invention reuse the NFC reader coil as the NFC tag coil, or reuse the NFC tag coil as the NFC reader coil, i.e., the aforementioned shared coil 3. The reader chip 1 is electrically connected to the shared coil 3, and the tag chip 2 is also electrically connected to the shared coil 3, thereby avoiding the problem of mutual interference between the coils. At the same time, in order to ensure the normal operation of the reader chip 1 and the tag chip 2, an isolator 4 is also provided. The isolator 4 is provided in the connection circuit between the tag chip 2 and the shared coil 3. The isolator 4 includes at least one, which is connected in series between the first pin 21 and the first terminal 31 and / or connected in series between the second pin 22 and the second terminal 32. Figure 3 The diagram shows that isolators 4 include two units: one connected in series between the first pin 21 and the first terminal 31, and the other connected in series between the second pin 22 and the second terminal 32. When the card reader chip 1 is in the working state, isolators 4 isolate the first pin 21 and the first terminal 31 and / or the second pin 22 and the second terminal 32, allowing the energy output from the card reader chip 1 to be concentrated into the common coil 3. Simultaneously, when the card reader chip 1 is in the non-working state, the energy received by the common coil 3 can effectively activate the tag chip 2.

[0029] Furthermore, when reader chip 1 is working, to ensure that it has sufficient energy to read external tags, its voltage is generally required to be adjustable to a relatively large value, such as above 12V. Tag chip 2, however, requires a smaller voltage, such as 3.3V. To prevent tag chip 2 from being burned out by a large external voltage, a clamping voltage, such as 3.6V, is usually set internally in tag chip 2. This ensures that even if a large external voltage exists, the potential difference between the first pin 21 and the second pin 22 of tag chip 2 will not exceed 3.6V. In the electronic price tag circuit structure of this embodiment, since reader chip 1 and tag chip 2 are connected in parallel, without isolator 4, the voltage of reader chip 1 is the same as the voltage of tag chip 2. If, in order to better read external tags, it is desired to adjust the voltage of reader chip 1 to a relatively large value, then due to the clamping voltage of tag chip 2, the adjusted voltage of reader chip 1 cannot exceed the clamping voltage. Therefore, in order to adjust the voltage of the card reader chip 1 to a larger value, such as 12V, an isolator 4 needs to be set between the first pin 21 and the first terminal 31, and / or between the second pin 22 and the second terminal 32.

[0030] For example, such as Figure 3As shown, the first transmitter TX1 of the card reader chip 1 is electrically connected to the first end 31 of the common coil 3, the first pin 21 of the tag chip 2 is electrically connected to the first end 31 of the common coil 3, the second pin 22 is electrically connected to the second end 32 of the common coil 3, an isolator 4 is connected in series between the first pin 21 and the first end 31, and another isolator 4 is connected in series between the second pin 22 and the second end 32.

[0031] The technical solution of this invention, by setting a common coil, allows the reader chip and the tag chip to be electrically connected to the common coil respectively. At the same time, in order to ensure that the reader chip and the tag chip work independently, an isolator is set in the circuit between the tag chip and the common coil. This solves the problem of mutual coupling and interference between the reader coil and the tag coil due to their close proximity in the prior art, and ensures that both the reader chip and the tag chip can reach the ideal potential, thus realizing the normal operation of the reader chip and the tag chip.

[0032] Optional, Figure 4 This is a partial circuit diagram of the second type of electronic price tag provided according to an embodiment of the present invention. Figure 4 The following explanation will also use a differential circuit as an example. Figure 4 As shown, isolator 4 is an isolation capacitor.

[0033] An isolation capacitor can be placed in the circuit between the tag chip 2 and the common coil 3. When the isolator 4 is the isolation capacitor, most of the energy emitted by the reader chip 1 when it is in operation can be input into the common coil 3. When an external reader needs to read the tag chip 2, since the isolation capacitor is connected in series in the circuit between the tag chip 2 and the common coil 3, the resonant point of the common coil 3 can be adjusted by adjusting the isolation capacitor, thus distributing the energy appropriately. Specifically, increasing the isolation capacitor increases the energy allocated to the tag chip 2, and decreasing the isolation capacitor decreases the energy allocated to the tag chip 2.

[0034] For example, such as Figure 4 As shown, isolation capacitors C9 and C10 are set. By adjusting the capacitance of C9 and C10, the resonant point of the common coil 3 can be adjusted, and the energy can be reasonably distributed.

[0035] The technical solution of this invention, by selecting an appropriate isolation capacitor as an isolator, ensures that most of the energy emitted by the card reader chip can be output to the common coil when the card reader chip is working, and ensures that the external energy received from the common coil can smoothly enter the tag chip when an external card reader is needed to read the tag chip.

[0036] Optional, Figure 5 This is a partial circuit diagram of the third type of electronic price tag provided according to an embodiment of the present invention. Figure 5The following explanation will also use a differential circuit as an example. Figure 5 As shown, it also includes at least one ground switch 5; The ground switch 5 is disposed on the circuit between the isolator 4 and the first pin 21 and is electrically connected to the first pin 21, and / or disposed on the circuit between the isolator 4 and the second pin 22 and is electrically connected to the second pin 22.

[0037] In order to improve the isolation function of isolator 4, a grounding switch 5 is installed.

[0038] For example, isolator 4 is an isolation capacitor, and ground switches 5 are added between the two isolation capacitors and the tag chip 2 respectively. When the card reader chip 1 is working, the ground switch 5 is short-circuited to ground, which is equivalent to disconnecting the connection between the card reader chip 1 and the tag chip 2, preventing the tag chip 2 from diverting the output energy of the card reader; when the tag chip 2 is working, the ground switch 5 is disconnected to ground, and the energy of the shared coil 3 can enter the tag chip 2 through the isolation capacitor.

[0039] The technical solution of this invention improves the isolation effect of the isolation capacitor by setting a ground switch, thus ensuring the normal operation of the card reader chip and the tag chip.

[0040] Optionally, the isolator is a disconnect switch (not shown in the figure).

[0041] Specifically, when the card reader chip 1 is working, the isolation switch is open, which is equivalent to disconnecting the connection between the card reader chip 1 and the tag chip 2, preventing the tag chip 2 from diverting the output energy of the card reader chip 1; when an external card reader needs to read the tag chip 2, the isolation switch is closed, and the energy of the shared coil 3 can directly enter the tag chip 2.

[0042] Understandably, the operating frequency of the disconnecting switch needs to cover the operating frequency of the electronic price tag, that is, to ensure that the switch has good conduction and isolation characteristics near the resonant point, so as to ensure the normal operation of the electronic price tag.

[0043] Optional, continue to refer to Figure 3 As shown, the card reader chip 1 also includes a second transmitter TX2; The second transmitting terminal TX2 is electrically connected to the second terminal 32 of the common coil 3; The electronic price tag also includes a first capacitor C1, a second capacitor C2, a third capacitor C3, and a fourth capacitor C4; The third capacitor C3 is connected in series between the first transmitter TX1 and the first terminal 31; the fourth capacitor C4 is connected in series between the second transmitter TX2 and the second terminal 32. The first capacitor C1 is connected in series between the first transmitter TX1 and the ground terminal; the second capacitor C2 is connected in series between the second transmitter TX2 and the ground terminal.

[0044] The circuit corresponding to the card reader chip 1 can be a differential circuit, that is, it includes two transmitters, a first transmitter TX1 and a second transmitter TX2. The first transmitter TX1 is connected to the first terminal 31, and the second transmitter TX2 is connected to the second terminal 32.

[0045] When the transmit signal voltage of reader chip 1 is low, and the harmonics and high-frequency noise radiated by the signal meet the regulatory requirements, no inductor is required at the transmitter of reader chip 1. This can mean that either the first transmitter TX1 or the second transmitter TX2 of reader chip 1 does not need an inductor, or that neither the first transmitter TX1 nor the second transmitter TX2 needs an inductor. A first capacitor C1 and a second capacitor C2 can be directly incorporated into the electronic tag; these capacitors can be used to filter harmonics. A third capacitor C3 is connected in series between the first transmitter TX1 and the first terminal 31; a fourth capacitor C4 is connected in series between the second transmitter TX2 and the second terminal 32. By adjusting the values ​​of the first capacitor C1, the second capacitor C2, the third capacitor C3, and the fourth capacitor C4, the resonant points of the reader and the tag can be made to be around 13.56MHz.

[0046] In some embodiments, Figure 6 This is a partial circuit diagram of the fourth type of electronic price tag provided according to an embodiment of the present invention, such as... Figure 6 As shown, when the transmit signal voltage of the card reader chip 1 is high and the harmonics and high-frequency noise radiated by the signal do not meet the requirements of the regulations, a first inductor L1 and a second inductor L2 can also be set in the electronic price tag; the first inductor L1 is connected in series between the first transmitting terminal TX1 and the first capacitor C1 and is also connected in series between the first transmitting terminal TX1 and the third capacitor C3; the second inductor L2 is connected in series between the second transmitting terminal TX2 and the second capacitor C2 and is also connected in series between the second transmitting terminal TX2 and the fourth capacitor C4.

[0047] In some embodiments, continue to refer to Figure 6 As shown, to accurately adjust the resonant point, a fifth capacitor C5 can be placed between the third capacitor C3 and the common coil 3, and the fifth capacitor C5 can be connected in series between the third capacitor C3 and the ground terminal. A sixth capacitor C6 can be placed between the fourth capacitor C4 and the common coil 3, and the sixth capacitor C6 can be connected in series between the fourth capacitor C4 and the ground terminal. Additionally, a seventh capacitor C7 can be connected in parallel with the fifth capacitor C5, and an eighth capacitor C8 can be connected in parallel with the sixth capacitor C6.

[0048] In some embodiments, the card reader chip 1 may include one receiving terminal. The circuit between the card reader chip 1 and the common coil 3 further includes resistors R2 and R4 for voltage division, capacitor C12 for DC isolation, and decoupling capacitor C13. Resistors R2 and R4 and capacitor C12 are connected in series at this receiving terminal of the card reader chip 1, and decoupling capacitor C13 is connected in parallel at this receiving terminal of the card reader chip 1, with one end grounded. In some embodiments, the receiving terminal may also include two terminals. The other receiving terminal includes resistors R1 and R3, and capacitor C11 for DC isolation. Resistors R1 and R3 and capacitor C11 are connected in series at the other receiving terminal of the card reader chip 1.

[0049] In some embodiments, continue to refer to Figure 6 As shown, the circuit between tag chip 2 and common coil 3 also includes capacitors C91 and C92 connected in parallel with common coil 3. Additionally, to precisely adjust the resonant point, an inductor L3 can be added, connected in parallel with capacitors C91 and C92.

[0050] Optional, Figure 7 This is a partial circuit diagram of the fifth type of electronic price tag provided according to an embodiment of the present invention, such as... Figure 7 As shown, it also includes a first disconnect switch 61 and a second disconnect switch 62; The first disconnecting switch 61 is disposed between the first inductor L1 and the third capacitor C3 and is connected in parallel with the first capacitor C1; The second disconnecting switch 62 is located between the second inductor L2 and the fourth capacitor C4 and is connected in parallel with the second capacitor C2.

[0051] The internal resistance of the first transmitter TX1 and the second transmitter TX2 may change with the operating state. For example, when operating in card reader mode, the first transmitter TX1 and the second transmitter TX2 exhibit certain impedance characteristics, and the impedance changes with the transmission level. When exiting card reader mode, the two pins are grounded through a very small internal resistance. Due to the change in the internal impedance of the pins, the resonant circuits of the card reader chip 1 and the tag chip 2 are different. To address this issue, a first isolation switch 61 and a second isolation switch 62 are provided. The first isolation switch 61 is located between the first inductor L1 and the third capacitor C3 and is connected in parallel with the first capacitor C1. The second isolation switch 62 is located between the second inductor L2 and the fourth capacitor C4 and is connected in parallel with the second capacitor C2.

[0052] Specifically, when the card reader chip 1 is working, the first isolation switch 61 and the second isolation switch 62 are disconnected; when the external card reader needs to read the tag chip 2, the first isolation switch 61 and the second isolation switch 62 are turned on. This setting ensures that changes in the internal impedance of the card reader will not affect the resonant point of the tag chip 2.

[0053] In some embodiments, in order to make the resonant points of the reader chip 1 and the tag chip 2 close to 13.56MHz, C1 and C2 are given larger capacitance values, while C3 and C4 are given smaller capacitance values.

[0054] In some embodiments, the isolating switch may be a high-frequency switch, a radio frequency switch, or a field-effect transistor, etc. When the isolating switch is a high-frequency switch, the operating frequency range of the high-frequency switch is 3MHz-30MHz; when the isolating switch is a radio frequency switch, the operating frequency range of the radio frequency switch is 300K-300GHz.

[0055] It is understood that while setting the first isolating switch 61 and the second isolating switch 62, an isolator 4 can also be set on the circuit of the tag chip 2. The isolator 4 can be in the form of a capacitor or a switch, and the embodiments of the present invention do not limit this.

[0056] The technical solution of this invention, by setting a first isolation switch and a second isolation switch, ensures that both the card reader mode and the tag mode are close to the resonance point, thus ensuring the normal operation of the electronic price tag.

[0057] Optional, Figure 8 This is a partial circuit diagram of the sixth type of electronic price tag provided according to an embodiment of the present invention, such as... Figure 8 As shown, it also includes a third disconnecting switch 63 and a fourth disconnecting switch 64; The third disconnector 63 is connected in series between the first inductor L1 and the ground terminal; The fourth disconnecting switch 64 is connected in series between the second inductor L2 and the ground terminal.

[0058] The internal resistance of the first transmitter TX1 and the second transmitter TX2 may change with the operating state. For example, when operating in card reader mode, the first transmitter TX1 and the second transmitter TX2 exhibit certain impedance characteristics, and the impedance changes with the transmission level. When exiting card reader mode, the two pins are grounded through a very small internal resistance. Due to the change in the internal impedance of the pins, the resonant circuits of the card reader chip 1 and the tag chip 2 are different. To address this issue, a third isolation switch 63 and a fourth isolation switch 64 are provided. The third isolation switch 63 is located between the first inductor L1 and the ground terminal and is connected in parallel with the first capacitor C1. The fourth isolation switch 64 is located between the second inductor L2 and the ground terminal and is connected in parallel with the second capacitor C2.

[0059] Specifically, when the card reader chip 1 is working, the third isolation switch 63 and the fourth isolation switch 64 are turned on; when the external card reader needs to read the tag chip 2, the third isolation switch 63 and the fourth isolation switch 64 are turned off. This setting ensures that changes in the internal impedance of the card reader will not affect the resonant point of the tag.

[0060] It is understood that while setting the third isolating switch 63 and the fourth isolating switch 64, an isolator 4 can also be set on the circuit of the tag chip 2. The isolator 4 can be in the form of a capacitor or a switch, and the embodiments of the present invention do not limit this.

[0061] Optional, Figure 9 This is a schematic diagram of the structure of a disconnecting switch according to an embodiment of the present invention, combined with... Figure 7 and Figure 9 As shown, both the first disconnect switch 61 and the second disconnect switch 62 include a first field-effect transistor and a second field-effect transistor. The first field-effect transistor includes a first source S1, a first gate G1, and a first drain D1; the second field-effect transistor includes a second source S2, a second gate G2, and a second drain D2; the first source S1 and the second source S2 are electrically connected; the first gate G1 and the second gate G2 are respectively electrically connected to the control unit of the electronic price tag; the second drain D2 is electrically connected to the ground terminal. The first drain D1 of the first disconnecting switch 61 is electrically connected to the first inductor L1; the first drain D1 of the second disconnecting switch 62 is electrically connected to the second inductor L2.

[0062] Combination Figure 7 and Figure 9 As shown, the first source S1 and the second source S2 of the first disconnecting switch 61 are electrically connected, the first drain D1 is electrically connected to the first inductor L1, the second drain D2 is connected to the ground terminal, and the first gate G1 and the second gate G2 are electrically connected to the control unit of the electronic price tag, respectively. The voltage value output by the control unit controls the conduction and turn-off of the first field-effect transistor and the second field-effect transistor.

[0063] Combination Figure 7 and Figure 9 As shown, the first source S1 and the second source S2 of the second disconnecting switch 62 are electrically connected, the first drain D1 is electrically connected to the second inductor L2, the second drain D2 is connected to the ground terminal, and the first gate G1 and the second gate G2 are electrically connected to the control unit of the electronic price tag, respectively. The voltage value output by the control unit controls the conduction and turn-off of the first field-effect transistor and the second field-effect transistor.

[0064] In some embodiments, such as Figure 9 As shown, both the first and second field-effect transistors are N-type metal-oxide-semiconductor transistors.

[0065] For example, when both the first field-effect transistor and the second field-effect transistor are N-type metal-oxide-semiconductor (NMOS) transistors, such as Figure 9 As shown, the voltage value output by the control unit is determined by the magnitude of the voltage at the first drain terminal.

[0066] The technical solution of this invention uses a dual field-effect transistor to ensure effective disconnection during AC operation, so that both the reader chip and the tag chip are close to the resonant point.

[0067] Optional, Figure 10 This is a partial circuit diagram of the seventh type of electronic price tag provided according to an embodiment of the present invention, such as... Figure 10 As shown, the second terminal 32 is grounded; The electronic price tag also includes a first capacitor C1 and a third capacitor C3; The first capacitor C1 is connected in series between the first transmitter TX1 and the ground terminal; the third capacitor C3 is connected in series between the first transmitter TX1 and the first terminal 31.

[0068] The circuit corresponding to the card reader chip 1 can be a single-ended circuit, that is, it only includes one transmitting end, and the second end 32 of the common coil 3 is grounded, thus forming a loop.

[0069] Specifically, when the transmit signal voltage of reader chip 1 is low, and the harmonics and high-frequency noise radiated by the signal meet the regulatory requirements, an inductor is not required at the transmitter of reader chip 1. This can mean that either the first transmitter TX1 or the second transmitter TX2 of reader chip 1 does not need an inductor, or both the first transmitter TX1 and the second transmitter TX2 do not need an inductor. A first capacitor C1 and a second capacitor C3 can be directly incorporated into the electronic price tag. The first capacitor C1 can act as a filter. The first capacitor C1 and the third capacitor C3 can also work together to achieve resonant matching.

[0070] In some embodiments, Figure 11 This is a partial circuit diagram of the eighth type of electronic price tag provided according to an embodiment of the present invention, such as... Figure 11 As shown, when the transmit signal voltage of the card reader chip 1 is high and the harmonics and high-frequency noise radiated by the signal do not meet the requirements of the regulations, the electronic price tag also includes a first inductor L1; the first inductor L1 is connected in series between the first transmitting terminal TX1 and the first capacitor C1 and is also connected in series between the first transmitting terminal TX1 and the third capacitor C3.

[0071] In addition, continue to refer to Figure 11As shown, a fifth capacitor C5 and a seventh capacitor C7 can also be placed between the third capacitor C3 and the first end 31 of the common coil 3. C5 and C7 are connected in parallel and in series between the third capacitor C3 and the ground terminal. By setting the fifth capacitor C5 and the seventh capacitor C7, the resonance matching is further optimized.

[0072] In some embodiments, when there is a change in pin impedance between the card reader's working and non-working states, in order to ensure that the working resonant points of the card reader chip 1 and the tag chip 2 are close to the working resonant points and to improve the communication efficiency when the external card reader reads the tag chip, the electronic price tag also includes a fifth isolation switch 65; the fifth isolation switch 65 is connected in series between the ground terminal and the second terminal 32, so that the tag chip 2 avoids the second terminal 32 of the shared coil 3 being grounded when it is read, thereby improving the communication efficiency.

[0073] Specifically, when the card reader chip 1 is working, the fifth isolation switch 65 is turned on; when the external card reader reads the tag chip 2, the fifth isolation switch 65 is turned off, thus improving communication efficiency.

[0074] Optional, Figure 12 This is a partial circuit diagram of the ninth type of electronic price tag provided according to an embodiment of the present invention, such as... Figure 12 As shown, the common coil 3 also includes a third terminal 33; The third terminal 33 is located between the first terminal 31 and the second terminal 32 and is located in the middle of the common coil 3; the third terminal 33 is grounded; The electronic price tag also includes a first capacitor C1 and a third capacitor C3; The first capacitor C1 is connected in series between the first transmitter TX1 and the ground terminal; the third capacitor C3 is connected in series between the first transmitter TX1 and the first terminal 31.

[0075] In this configuration, the middle position of the common coil 3, i.e., the third end 33, can be grounded. The first transmitting end TX1, the first end 31, and the third end 33 form a loop. The first pin 21 is electrically connected to the first end 31, and the second pin 22 is electrically connected to the second end 32. A loop is formed between the first end 31, the second end 32, the first pin 21, and the second pin 22.

[0076] Specifically, when the transmit signal voltage of reader chip 1 is low, and the harmonics and high-frequency noise radiated by the signal meet the regulatory requirements, an inductor is not required at the transmitter of reader chip 1. This can mean that either the first transmitter TX1 or the second transmitter TX2 of reader chip 1 does not need an inductor, or both the first transmitter TX1 and the second transmitter TX2 do not need an inductor. A first capacitor C1 and a second capacitor C3 can be directly incorporated into the electronic price tag. The first capacitor C1 can act as a filter. The first capacitor C1 and the third capacitor C3 can also work together to achieve resonant matching.

[0077] In some embodiments, Figure 13 This is a partial circuit diagram of the tenth type of electronic price tag provided according to an embodiment of the present invention, such as... Figure 13 As shown, when the transmit signal voltage of the card reader chip 1 is high and the harmonics and high-frequency noise radiated by the signal do not meet the requirements of the regulations, the electronic price tag also includes a first inductor L1; the first inductor L1 is connected in series between the first transmitting terminal TX1 and the first capacitor C1 and is also connected in series between the first transmitting terminal TX1 and the third capacitor C3.

[0078] In some embodiments, continue to refer to Figure 13 As shown, the electronic price tag also includes a sixth disconnector switch 66; The sixth disconnecting switch 66 is connected in series between the first inductor L1 and the third capacitor C3; or, Figure 14 This is a partial circuit diagram of the eleventh type of electronic price tag provided according to an embodiment of the present invention, such as... Figure 14 As shown, the sixth disconnecting switch 66 is connected in series between the first inductor L1 and the ground terminal and in parallel with the first capacitor C1.

[0079] Specifically, when the sixth isolating switch 66 is connected in series between the first inductor L1 and the third capacitor C3, the sixth isolating switch 66 is turned on when the card reader chip 1 is working; when the external card reader reads the tag chip 2, the sixth isolating switch 66 is turned off. When the sixth isolating switch 66 is located between the first inductor L1 and the ground terminal and in parallel with the first capacitor C1, the sixth isolating switch 66 is turned off when the card reader chip 1 is working; when the external card reader reads the tag chip 2, the sixth isolating switch 66 is turned on. This arrangement ensures that changes in the internal impedance of the card reader will not affect the resonant point of the tag.

[0080] In some embodiments, the specific application scenarios of electronic shelf labels are as follows: Electronic shelf labels are detachably mounted on shelf rails, and multiple electronic tags with known locations, such as NFC electronic tags, are fixedly mounted on the bottom surface of the shelf rails. When the reader chip 1 of the electronic shelf label is working, due to the action of the isolator, the energy output by the reader chip 1 can be concentrated into the common coil 3, and the energy is radiated outward through the common coil 3 to activate the electronic tag with the known location closest to its own installation position, and read the ID information of the electronic tag. After reading the ID information, the electronic shelf label transmits the ID information to the backend server. Based on the ID information and the association between the known ID information and the specific location on the shelf, the backend server can obtain the specific location of the electronic shelf label on the shelf. In addition, since the electronic shelf label stores product information, there is a need for it to be wirelessly read and written by other wireless reading and writing devices (such as NFC reading and writing devices). For example, it may be activated by the handheld terminal of supermarket employees, or have product information written or modified. Therefore, when the shared coil 3 receives energy from other wireless reading and writing devices, the tag chip 2 is effectively activated, and other wireless reading and writing devices can perform operations such as reading and writing the internal information of the electronic shelf label and refreshing the screen.

[0081] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. An electronic price tag, characterized in that, include: Card reader chip, tag chip, common coil, and at least one isolator; The first transmitting end of the card reader chip is electrically connected to the first end of the shared coil; The first pin of the tag chip is electrically connected to the first terminal, and the second pin of the tag chip is electrically connected to the second terminal of the common coil; The isolator is connected in series between the first pin and the first terminal; and / or, the isolator is connected in series between the second pin and the second terminal.

2. The electronic price tag according to claim 1, characterized in that, The isolator is an isolation capacitor.

3. The electronic price tag according to claim 2, characterized in that, It also includes at least one ground switch; The grounding switch is disposed on the circuit between the isolator and the first pin and is electrically connected to the first pin, and / or disposed on the circuit between the isolator and the second pin and is electrically connected to the second pin.

4. The electronic price tag according to claim 1, characterized in that, The card reader chip also includes a second transmitter; The second transmitting end is electrically connected to the second end of the common coil; The electronic price tag also includes a first capacitor, a second capacitor, a third capacitor, and a fourth capacitor; The third capacitor is connected in series between the first transmitting end and the first end; the fourth capacitor is connected in series between the second transmitting end and the second end. The first capacitor is connected in series between the first transmitting end and the ground end; the second capacitor is connected in series between the second transmitting end and the ground end.

5. The electronic price tag according to claim 4, characterized in that, The electronic price tag also includes a first inductor and a second inductor; The first inductor is connected in series between the first transmitter and the first capacitor, and is also connected in series between the first transmitter and the third capacitor; the second inductor is connected in series between the second transmitter and the second capacitor, and is also connected in series between the second transmitter and the fourth capacitor.

6. The electronic price tag according to claim 5, characterized in that, It also includes a first disconnect switch and a second disconnect switch; The first disconnecting switch is disposed between the first inductor and the third capacitor and is connected in parallel with the first capacitor; The second disconnecting switch is disposed between the second inductor and the fourth capacitor and is connected in parallel with the second capacitor.

7. The electronic price tag according to claim 5, characterized in that, It also includes a third disconnect switch and a fourth disconnect switch; The third disconnecting switch is connected in series between the first inductor and the first capacitor; The fourth disconnecting switch is connected in series between the second inductor and the second capacitor.

8. The electronic price tag according to claim 6, characterized in that, Both the first disconnect switch and the second disconnect switch include a first field-effect transistor and a second field-effect transistor; The first field-effect transistor includes a first source, a first gate, and a first drain; the second field-effect transistor includes a second source, a second gate, and a second drain; the first source and the second source are electrically connected; the first gate and the second gate are respectively electrically connected to the control unit of the electronic price tag; the second drain is electrically connected to the ground terminal; The first drain of the first disconnecting switch is electrically connected to the first inductor; the first drain of the second disconnecting switch is electrically connected to the second inductor.

9. The electronic price tag according to claim 8, characterized in that, Both the first field-effect transistor and the second field-effect transistor are N-type metal-oxide-semiconductor transistors.

10. The electronic price tag according to claim 1, characterized in that, The second terminal is grounded; The electronic price tag also includes a first capacitor and a third capacitor; The first capacitor is connected in series between the first transmitting end and the ground end; the third capacitor is connected in series between the first transmitting end and the first end.

11. The electronic price tag according to claim 10, characterized in that, The electronic price tag also includes a first inductor; The first inductor is connected in series between the first transmitter and the first capacitor, and is also connected in series between the first transmitter and the third capacitor.

12. The electronic price tag according to claim 11, characterized in that, The electronic price tag also includes a fifth disconnect switch; The fifth disconnecting switch is connected in series between the grounding terminal and the second terminal.

13. The electronic price tag according to claim 1, characterized in that, The common coil also includes a third terminal; The third terminal is located between the first terminal and the second terminal and in the middle of the common coil; the third terminal is grounded. The electronic price tag also includes a first capacitor and a third capacitor; The first capacitor is connected in series between the first transmitting end and the ground end; the third capacitor is connected in series between the first transmitting end and the first end.

14. The electronic price tag according to claim 13, characterized in that, The electronic price tag also includes a first inductor; The first inductor is connected in series between the first transmitter and the first capacitor, and is also connected in series between the first transmitter and the third capacitor.

15. The electronic price tag according to claim 14, characterized in that, The electronic price tag also includes a sixth isolating switch; The sixth disconnecting switch is connected in series between the first inductor and the third capacitor; or, the sixth disconnecting switch is connected in series between the first inductor and the ground terminal and in parallel with the first capacitor.

16. The electronic price tag according to claim 1, characterized in that, The isolator is an isolating switch.

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