NFC (Near Field Communication) device and human-computer interface device comprising same

Abstract

An NFC device and a human-computer interface device including the same are provided. The NFC equipment comprises an NFC transmitting end which comprises a transmitting end control circuit and a transmitting end antenna; the NFC receiving end comprises a receiving end control circuit, a receiving end antenna, a rectifying circuit, an energy storage capacitor and a voltage stabilizing circuit, the transmitting end control circuit transmits radio-frequency signals through the transmitting end antenna, the receiving end control circuit receives the radio-frequency signals through the receiving end antenna, and direct current is generated based on the radio-frequency signals and can be used in the receiving end control circuit; the rectifying circuit rectifies a radio frequency signal received by a receiving end antenna, the energy storage capacitor is connected to the output end of the rectifying circuit to be charged, and the voltage stabilizing circuit is connected with the energy storage capacitor in parallel to maintain the voltage at the two ends of the energy storage capacitor to be not higher than a first threshold value. The receiving end control circuit senses voltage values at the two ends of the energy storage capacitor and sends the voltage values to the transmitting end control circuit, and the transmitting end control circuit continuously transmits radio frequency signals on the basis that the voltage values are lower than a first threshold value.

Description

Technical Field

[0001] The present disclosure relates to an NFC device and a human-machine interface device including the NFC device. Background Art

[0002] Near Field Communication (NFC) technology has been rapidly developed and widely used in recent years. At first, NFC technology was applied to simple scenarios such as access cards and transportation cards. The NFC receiving end (also known as the card end, TAG end) was passive and did not need to be powered. As the scope of application expands, the NFC receiving end begins to carry or connect to loads such as displays, indicator lights, speakers, etc., which require power. There are currently two ways to power these loads. The first way is to configure a rechargeable battery at the NFC receiving end, and use the NFC transmitting end to transmit radio frequency signals to transfer electrical energy to the NFC receiving end. The NFC receiving end uses this electrical energy to charge the rechargeable battery and then drive these loads. The second way is that the NFC receiving end is not equipped with a rechargeable battery, and only drives these loads by collecting wireless carrier energy during the NFC communication process. However, both methods have their own shortcomings. Due to the introduction of rechargeable batteries in the first way, the safety, life, temperature, etc. of rechargeable batteries must be considered in certain application scenarios (for example, electrical systems), which increases complexity. In the second method, since the collected wireless carrier energy is very small and short-lived, it can only power low-power loads in a short period of time, but cannot continuously power high-power loads (eg, human-machine interfaces). Summary of the invention

[0003] One aspect of the present disclosure provides an NFC device, including: an NFC transmitter, including a transmitter control circuit and a transmitter antenna; and an NFC receiver, including a receiver control circuit, a receiver antenna, a rectifier circuit, an energy storage capacitor, and a voltage stabilizing circuit, wherein the transmitter control circuit transmits a radio frequency signal via the transmitter antenna, the receiver control circuit receives the radio frequency signal via the receiver antenna, generates direct current based on the radio frequency signal for internal use by the receiver control circuit, the rectifier circuit rectifies the radio frequency signal received by the receiver antenna, the energy storage capacitor is connected to the output end of the rectifier circuit to be charged, the voltage stabilizing circuit is connected in parallel with the energy storage capacitor to maintain a voltage across the energy storage capacitor not higher than a first threshold, the receiver control circuit senses a voltage value across the energy storage capacitor and sends the voltage value to the transmitter control circuit, and the transmitter control circuit continues to transmit the radio frequency signal based on the voltage value being lower than the first threshold.

[0004] Optionally, the NFC receiving end further includes a switch and a switch control circuit, the switch is connected between the output end of the rectifier circuit and the load, the switch control circuit is connected to the energy storage capacitor and the switch, the switch is closed when the voltage across the energy storage capacitor is higher than a second threshold, and the switch is opened when the voltage across the energy storage capacitor is lower than the second threshold, and the first threshold is higher than the second threshold but lower than the voltage when the energy storage capacitor is charged to a saturated state.

[0005] Optionally, the energy storage capacitor includes a first capacitor, a first end of the first capacitor is connected to the output end of the rectifier circuit, and a second end of the first capacitor is connected to the reference voltage.

[0006] Optionally, the voltage stabilizing circuit includes a voltage stabilizing diode connected in parallel with the first capacitor.

[0007] Optionally, the switch comprises a first semiconductor switch, a first end of the first semiconductor switch is connected to the first end of the first capacitor, a second end of the first semiconductor switch is connected to the load, and a control end of the first semiconductor switch is connected to the switch control circuit.

[0008] Optionally, the switch control circuit includes a first resistor, a second resistor and a second semiconductor switch. The first resistor and the second resistor are connected in series and then in parallel with the first capacitor. The first end of the second semiconductor switch is connected to the control end of the first semiconductor switch, the second end is connected to a reference voltage, and the control end is connected between the first resistor and the second resistor.

[0009] Optionally, the NFC receiving end further includes a third resistor, and the third resistor is connected between the first end and the control end of the first semiconductor switch.

[0010] Optionally, the NFC receiving end further includes a second capacitor, a first end of the second capacitor is connected to the second end of the first semiconductor switch, and a second end of the second capacitor is connected to a reference voltage.

[0011] Optionally, the voltage stabilization circuit further includes a three-terminal voltage stabilizer.

[0012] Optionally, the NFC receiving end further includes a first inductor and a first diode, the first inductor is connected between the first semiconductor switch and the load, the cathode of the first diode is connected to the second end of the first semiconductor switch, and the anode of the first diode is connected to the reference voltage.

[0013] Another aspect of the present disclosure provides a human-machine interface device, comprising the NFC device according to any one of the preceding claims 1 to 10 .

[0014] An NFC device according to the present disclosure can continuously power low power consumption and / or high power consumption loads without requiring a rechargeable battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The aspects, features and advantages of the present disclosure will become clearer and easier to understand through the following description of the embodiments of the present disclosure in conjunction with the accompanying drawings, in which:

[0016] Figure 1 and Figure 2 is an exemplary block diagram of an NFC device according to the prior art;

[0017] Figure 3 is an exemplary block diagram of an NFC device according to an embodiment of the present disclosure;

[0018] Figure 4 is an exemplary block diagram of an NFC device according to another embodiment of the present disclosure;

[0019] Figure 5 is an exemplary circuit diagram of an NFC receiving terminal of an NFC device according to another embodiment of the present disclosure;

[0020] Figure 6 is another exemplary circuit diagram of an NFC receiving terminal of an NFC device according to another embodiment of the present disclosure; and

[0021] Figure 7 is an exemplary block diagram of a human-machine interface device according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0022] The present disclosure will be described in detail below with reference to exemplary embodiments of the present disclosure. However, the present disclosure is not limited to the embodiments described herein, and it can be implemented in many different forms. The described embodiments are only used to make the present disclosure thorough and complete, and to fully convey the concept of the present disclosure to those skilled in the art. The features of the various embodiments described can be combined or replaced with each other, unless explicitly excluded or should be excluded according to the context.

[0023] Unless otherwise defined, the technical terms or scientific terms used in this disclosure should be understood by people with ordinary skills in the field to which this disclosure belongs. "First", "second" and similar words used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. "Including" or "comprising" and similar words used in this disclosure mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect", "connect" or "connected" and similar words used in this disclosure are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0024] In the drawings, the same reference numerals denote components having the same or similar structures or functions, and repeated descriptions thereof will be omitted in the following description.

[0025] Figure 1 and Figure 2 is an exemplary block diagram of an NFC device according to the prior art.

[0026] Reference Figure 1 According to the prior art, an NFC device 1 includes an NFC transmitter and an NFC receiver. The NFC transmitter includes a transmitter control circuit and a transmitter antenna. The transmitter control circuit transmits a radio frequency signal through the transmitter antenna, and the radio frequency signal includes communication data to be sent to the NFC receiver. The NFC receiver includes a receiver control circuit, a receiver antenna and a rechargeable battery. The receiver control circuit receives the radio frequency signal through the receiver antenna, reads the communication data therein, and converts the energy of the radio frequency signal into electrical energy. The receiver control circuit has a charging interface connected to the rechargeable battery and a load interface connected to the load. The rechargeable battery is also connected to the load. The load can be integrated with the NFC receiver, or it can be located outside the NFC receiver and connected to it (for example, connected to the load interface of the receiver control circuit). The receiver control circuit also has a communication interface, and the communication interface is connected to the load via a communication bus.

[0027] When the NFC transmitter is close to the NFC receiver, the receiver control circuit uses the power converted from the radio frequency signal transmitted by the NFC transmitter to charge the rechargeable battery through the charging interface, and supplies power to the load through the load interface. When the rechargeable battery is charged to a saturated state (for example, the receiver control circuit senses that the voltage at its charging interface exceeds the voltage value when the rechargeable battery is charged to a saturated state), or when the NFC transmitter is far away from the NFC receiver, or when an abnormality occurs in the load (for example, the receiver control circuit senses that the voltage at its charging interface is zero, for example, the load is short-circuited), the transmitter control circuit stops transmitting the radio frequency signal, and the load is powered by the rechargeable battery.

[0028] Although the NFC device 1 according to the prior art can continuously supply power to the load, it must be equipped with a rechargeable battery. If there is no rechargeable battery, the transmitter control circuit will consider that there is no need for charging and stop transmitting power.

[0029] Reference Figure 2 , the NFC device 2 according to the prior art is different from the NFC device 1 in that its NFC receiving end does not include a rechargeable battery, but instead includes an energy storage capacitor. When the NFC transmitting end is close to the NFC receiving end and performs NFC communication with it, the receiving end circuit collects the energy of the RF signal in this process, stores the energy in the energy storage capacitor, and then drives the load. When the NFC communication process ends, the RF signal disappears, and the receiving end circuit stops collecting energy.

[0030] Although the NFC device 2 according to the prior art does not require a rechargeable battery, due to the limited capacity of the energy storage capacitor, the power that can be collected by the receiving end circuit is very small (for example, only a few milliwatts), which is not enough to power a load with slightly higher power consumption. Therefore, the NFC device 2 can only temporarily power a low-power load, but cannot continuously or power a high-power load (for example, a human-machine interface).

[0031] The following describes an NFC device 3 according to an embodiment of the present disclosure, which does not require a rechargeable battery and can continuously power low and / or high power consumption loads. The NFC device 3 can be regarded as an improved circuit design of the NFC receiving end based on the NFC device 1.

[0032] Figure 3 is an exemplary block diagram of an NFC device according to an embodiment of the present disclosure.

[0033] Reference Figure 3 According to an embodiment of the present disclosure, the NFC device 3 includes an NFC transmitter 310 and an NFC receiver 320. The NFC transmitter 310 includes a transmitter control circuit 311 and a transmitter antenna 312. The NFC transmitter 310 transmits a radio frequency signal through the transmitter antenna 312. The NFC receiver 320 includes a receiver control circuit 321, a receiver antenna 322, a rectifier circuit 323, a storage capacitor 324, and a voltage regulator circuit 325. The load can be integrated with the NFC receiver, or it can be located outside the NFC receiver and connected to it (for example, connected to the voltage regulator circuit 325) to draw power from it, for example, the power-drawing voltage shown in the figure is Vcc.

[0034] The transmitting end control circuit 311 transmits a radio frequency signal via the transmitting end antenna 312. The radio frequency signal includes communication data to be sent to the NFC receiving end 320. The receiving end control circuit 321 receives the radio frequency signal through the receiving end antenna 322, reads the communication data therein, and generates direct current based on the radio frequency signal for internal use by the receiving end control circuit 321. The rectifier circuit 323 rectifies the radio frequency signal received by the receiving end antenna 322.

[0035] The energy storage capacitor 324 is connected to the output end of the rectifier circuit 323 to be charged. For example, the energy storage capacitor 324 may include one capacitor, multiple capacitors in parallel, multiple capacitors in series, etc. Further, the one capacitor, multiple capacitors in parallel, multiple capacitors in series have a smaller equivalent capacitance value (e.g., 1 microfarad, 2 microfarad, etc.) so that they can be quickly charged to quickly establish the supply voltage Vcc provided to the load.

[0036] The charging interface of the receiving end control circuit 321 is connected to the energy storage capacitor 324 to sense the voltage across the energy storage capacitor 324 in real time and send the sensed voltage value to the transmitting end control circuit 321 via the receiving end antenna 322. When the voltage value is higher than the preset voltage when the energy storage capacitor 324 is charged to a saturated state, or when the voltage value indicates that the load is abnormal (for example, when the load is short-circuited, the voltage value is zero), the transmitting end control circuit 321 stops transmitting the RF signal. The receiving end control circuit 321 is also connected to the load via a communication bus to receive communication data to be transmitted to the NFC transmitting end 310 from the load. The communication bus can be based on an Inter-Integrated Circuit (IC). 2 C), Serial Peripheral Interface (SPI), Universal Asynchronous Receiver / Transmitter (UART), etc.

[0037] The voltage stabilizing circuit 325 is connected in parallel with the energy storage capacitor 324 to maintain the voltage across the energy storage capacitor 324 at a level not higher than a first threshold value T1. The first threshold value T1 is lower than the preset voltage of the energy storage capacitor 324 when it is charged to a saturated state, so as to prevent the voltage across the energy storage capacitor 324 from rising to the charging saturation voltage, so that the transmitting end circuit 311 does not reduce or stop transmitting the RF signal, but continues to transmit the RF signal.

[0038] The working principle of the NFC device 3 is as follows. When the NFC transmitter 310 is turned on and the NFC transmitter 310 is close to the NFC receiver 320, the NFC transmitter 310 transmits a radio frequency signal. The NFC receiver 320 receives the radio frequency signal and starts the communication response procedure with the NFC transmitter 310. At the same time, the rectifier circuit 323 converts the received radio frequency signal into a DC voltage. The DC voltage charges the energy storage capacitor 324 and supplies power to the load. The charging interface of the receiving end control circuit 321 senses the voltage across the energy storage capacitor 324 in real time and transmits it to the transmitting end control circuit 311. Due to the presence of the voltage stabilizing circuit 325, the voltage across the energy storage capacitor 324 is maintained at no more than the first threshold value T1. The transmitting end control circuit 311 will consider that the charging of the NFC receiver 320 has not reached the saturation state and continue to transmit the radio frequency signal. The load is continuously powered.

[0039] As such, the NFC device 3 according to the embodiment of the present disclosure can continuously supply power to a low power consumption or high power consumption load without requiring a rechargeable battery.

[0040] Furthermore, considering the case where the load power consumption is high, since the charging of the energy storage capacitor 324 and the power supply to the load are started at the same time, the NFC device 3 may take a long time to establish the power supply voltage Vcc provided to the load, and the power supply of the load may be unstable before the power supply voltage Vcc is established. To avoid this situation, the NFC device 4 according to another embodiment of the present disclosure is further introduced below.

[0041] Figure 4 is an exemplary block diagram of an NFC device according to another embodiment of the present disclosure.

[0042] Reference Figure 4 , the NFC device 4 is Figure 3 The NFC device 3 shown in the figure is further provided with a switch 326 and a switch control circuit 327. The switch 326 is connected between the output terminal of the rectifier circuit 323 and the load to switch the load on or off. The switch 326 may include a single-pole single-throw switch, a single-pole double-throw switch, a contactor, a relay, a semiconductor switch, or a combination thereof.

[0043] The switch control circuit 327 is designed to open the switch 326 when the voltage across the energy storage capacitor 324 is lower than the second threshold T2, and close the switch 326 when the voltage across the energy storage capacitor 324 is higher than the second threshold T2. The second threshold T2 is greater than zero and less than the first threshold T1.

[0044] The function of the switch 326 and the switch control circuit 327 is to start charging the energy storage capacitor 324 first, and then start the power supply to the load after the power supply voltage Vcc to the load is established, instead of starting charging the energy storage capacitor 324 and powering the load at the same time as the NFC device 3. In this way, the power supply voltage Vcc to the load can be established faster and more stably.

[0045] The working principle of the NFC device 4 is as follows. When the NFC transmitter 310 is turned on and the NFC transmitter 310 is close to the NFC receiver 320, the NFC transmitter 310 transmits a radio frequency signal. The NFC receiver 320 receives the radio frequency signal and starts the communication response procedure with the NFC transmitter 310. At the same time, the rectifier circuit 323 converts the received radio frequency signal into a DC voltage. The DC voltage charges the energy storage capacitor 324. Initially, the voltage across the energy storage capacitor 324 is zero and has not yet reached the second threshold value T2, and the switch control circuit 327 keeps the switch 326 open. Afterwards, since the load has not yet been connected and does not consume power and the capacitance of the energy storage capacitor 324 is very small (for example, 1 microfarad, a few microfarads, etc.), the energy storage capacitor 324 is quickly charged until the voltage across the two ends reaches the second threshold value T2, the power supply voltage Vcc for the load is established, and the switch control circuit 327 controls the switch 326 to close to connect the load. The charging interface of the receiving end control circuit 321 senses the voltage across the energy storage capacitor 324 in real time and transmits it to the transmitting end control circuit 311. Due to the existence of the voltage stabilizing circuit 325, the voltage across the energy storage capacitor 324 is maintained at no more than the first threshold value T1. The transmitting end control circuit 311 will consider that the charging of the NFC receiving end 320 has not reached the saturation state and continue to transmit the RF signal, and the load is continuously powered.

[0046] In this way, the NFC device 4 according to the embodiment of the present disclosure can continuously supply power to a low-power or high-power load without the need for a rechargeable battery. Moreover, due to the addition of a switch and a switch control circuit, even when the load power consumption is high, the NFC device 4 can establish the power supply voltage of the load in a short time and provide a stable power supply to the load.

[0047] Combine the following Figure 5 Describe the exemplary circuit of the NFC receiving end of the NFC device 4. According to the previous description, the circuit of the NFC device 3 can be obtained by removing the switch 326 and the switch control circuit 327 from the circuit of the NFC device 4, so the exemplary circuit of the NFC device 3 is not further described.

[0048] Figure 5 is an exemplary circuit diagram of an NFC receiving terminal of an NFC device according to another embodiment of the present disclosure.

[0049] Reference Figure 5 The rectifier circuit 323 may be a bridge rectifier circuit composed of a second diode D2, a third diode D3, a fourth diode D4 and a fifth diode D5. Since the bridge rectifier circuit is well known, it will not be described in detail here.

[0050] The energy storage capacitor 324 includes a first capacitor C1, for example, whose capacitance is 1 microfarad. The first end of the first capacitor C1 is connected to the output end of the rectifier circuit 323, and the second end is connected to the reference voltage VGND (e.g., ground).

[0051] The voltage stabilization circuit 325 includes a voltage stabilization diode Z1 connected in parallel with the first capacitor C1. For example, the anode of the voltage stabilization diode Z1 is connected to the reference voltage V GND , whose cathode is connected to the first end of the first capacitor C1. When the voltage across the first capacitor C1 is lower than the first threshold value T1 (for example, the first threshold value T1 may be the breakdown voltage of the Zener diode Z1), the Zener diode Z1 blocks the current from passing through, which is equivalent to being disconnected. When the voltage across the first capacitor C1 is higher than the first threshold value T1, the Zener diode Z1 is reversely broken down, allowing the current to pass through so as to maintain the voltage of the first capacitor C1 not higher than the first threshold value T1.

[0052] The switch 326 includes a first semiconductor switch M1, which is shown as a P-type metal oxide semiconductor field effect transistor (P-type MOS tube) in the figure. The first end (source) of the first semiconductor switch M1 is connected to the first end of the first capacitor C1, and the second end (drain) thereof is connected to the load. The switch control circuit 327 includes a first resistor R1, a second resistor R2, and a second semiconductor switch M2. The first resistor R1 and the second resistor R2 are connected in series and then in parallel with the first capacitor C1. The second semiconductor switch M2 is shown as an N-type MOS tube in the figure. The first end (drain) of the second semiconductor switch M2 is connected to the control end (gate) of the first semiconductor switch M1, and the second end thereof is connected to the reference voltage V GND , and its control terminal (gate) is connected between the first resistor R1 and the second resistor R2. The first resistor R1 and the second resistor R2 may have different resistances to achieve the threshold adjustment function of the first semiconductor switch M1.

[0053] The NFC receiving terminal 320 may further include a third resistor R3 connected between the first terminal (source) and the third terminal (gate) of the first semiconductor switch M1 to quickly turn off the first semiconductor switch M1 when the second semiconductor switch M2 is turned off.

[0054] The NFC receiving terminal 320 may further include a second capacitor C2, a first end of the second capacitor C2 being connected to the second end (drain) of the first semiconductor switch M1, and a second end of the second capacitor C2 being connected to a reference voltage V GND .

[0055] Figure 5 The working principle of the exemplary circuit of the NFC receiving end shown is as follows. The rectifier circuit converts the radio frequency signal received by the receiving end antenna 322 from the NFC transmitting end 310 into a DC voltage V NFC The DC voltage V NFCThe first capacitor C1 is charged. Initially, the voltage across the first capacitor C1 is zero and has not reached the second threshold value T2. The voltage across the second resistor R2 has not reached the turn-on voltage of the second semiconductor switch M2. The second semiconductor switch M2 is turned off, and then the first semiconductor switch M1 is turned off. Afterwards, since the load has not been connected and does not consume power and the capacitance of the first capacitor C1 is very small (for example, 1 microfarad), the first capacitor C1 is quickly charged until the voltage across the two ends reaches the second threshold value T2. The voltage across the second resistor R2 also reaches the turn-on voltage of the second semiconductor switch M2. The second semiconductor switch M2 is turned on, and then the first semiconductor switch M1 is turned on to turn on the load and start to power the load. The receiving end control circuit 321 senses the voltage across the first capacitor C1 in real time and transmits it to the transmitting end control circuit 311. Due to the presence of the voltage stabilizing diode Z1, the voltage across the first capacitor C1 is maintained at no more than the first threshold value T1. The transmitting end control circuit 311 therefore believes that the charging of the NFC receiving end 320 has not reached the saturation state and continues to transmit the RF signal, so that the load is continuously powered.

[0056] Figure 6 is another exemplary circuit diagram of an NFC receiving end of an NFC device according to another embodiment of the present disclosure.

[0057] and Figure 5 compared to, Figure 6 The difference is that the voltage stabilizing circuit 325 can further include a three-terminal voltage regulator U1 to improve the accuracy of voltage stabilization and achieve smaller output ripple and noise. As shown in the figure, the input terminal IN of the three-terminal voltage regulator U1 is connected to the cathode of the voltage stabilizing diode Z1, the output terminal OUT is connected to the first resistor R1, and the ground terminal RNG is connected to the reference voltage V GND Since the three-terminal voltage regulator is a well-known device in the art, it will not be described in detail here.

[0058] also, Figure 6 The difference is that the NFC receiving terminal 320 can further include a first diode D1 and a first inductor L. The function of the first inductor L1 is to buffer the load current, so that the load current rises slowly, and the impact on the charging interface is reduced. At the same time, it can also reduce the voltage ripple to a certain extent. In addition, the presence of the first inductor L1 can also prevent the load supply voltage Vcc from being unstable due to the unstable transmission of the RF signal by the NFC transmitting terminal, and even cause the load to lose power for a short time. The first diode D1 can play a freewheeling role to consume the reverse induced electromotive force that may be generated by the first inductor L1.

[0059] It should be noted that Figure 5 and Figure 6 The circuit diagram shown is for example purposes only, and the present disclosure is not limited thereto. Figure 5 and Figure 6Other circuit configurations formed by the electronic components shown are also possible, as long as the above combination can be achieved. Figure 4 Describe the functionality.

[0060] The above describes the NFC devices 3 and 4 according to the embodiments of the present disclosure. NFC devices 3 and 4 can obtain power from their NFC transmitting ends to continuously power the load without configuring a rechargeable battery at their NFC receiving ends, avoiding the complex issues caused by considering the life and safety of rechargeable batteries, while avoiding the disposal of waste batteries and reducing the burden on the environment. In addition, since no rechargeable batteries are required, the NFC devices 3 and 4 are smaller in size and can be embedded in various devices (such as passive human-machine interfaces, passive temperature detection devices, passive actuators, passive sensors, etc.) for application in various scenarios, expanding the scope of application.

[0061] The following takes a human-machine interface device as an example to introduce an exemplary application of the NFC device 3 or 4 according to an embodiment of the present disclosure.

[0062] Figure 7 is an exemplary block diagram of a human-machine interface device according to an embodiment of the present disclosure.

[0063] Reference Figure 7 The human-machine interface device 7 includes an NFC device 710, a microprocessor 720, and a display screen 730. The microprocessor 720 and the display screen 730 can act as the front combination Figure 3 and Figure 4 The described load is connected to or integrated with the NFC receiving terminal of the NFC device 3 or 4. When the NFC transmitting terminal of the NFC device 710 is turned on and close to its NFC receiving terminal, the microprocessor 720 and the display screen 730 can be continuously powered to maintain their normal operation.

[0064] In contrast, since the microprocessor 720 and the display screen 730 have high power consumption, if the NFC device 2 according to the prior art is used, it is impossible to provide continuous power to them, and if the NFC device 1 according to the prior art is used, a rechargeable battery must be equipped. Therefore, the NFC device 3 or 4 according to the embodiment of the present disclosure has a wider application prospect than the NFC device 1 or 2 according to the prior art.

[0065] Those skilled in the art should understand that the above-mentioned specific embodiments are merely examples and not limitations, and various modifications, combinations, partial combinations and replacements may be made to the embodiments of the present disclosure according to design requirements and other factors. As long as they are within the scope of the attached claims or their equivalents, they belong to the scope of rights to be protected by the present disclosure.

Claims

1. An NFC device, comprising: NFC transmitter, including a transmitter control circuit and a transmitter antenna; as well as The NFC receiving end includes a receiving end control circuit, a receiving end antenna, a rectifier circuit, an energy storage capacitor and a voltage stabilizing circuit, wherein: The transmitting end control circuit transmits a radio frequency signal via the transmitting end antenna, The receiving end control circuit receives the radio frequency signal via the receiving end antenna and generates direct current based on the radio frequency signal. The rectifier circuit rectifies the radio frequency signal received by the receiving antenna. The energy storage capacitor is connected to the output end of the rectifier circuit to be charged, The voltage stabilizing circuit is connected in parallel with the energy storage capacitor to maintain the voltage across the energy storage capacitor at no more than a first threshold value. The receiving end control circuit senses the voltage value at both ends of the energy storage capacitor and sends the voltage value to the transmitting end control circuit, The transmitting end control circuit continues to transmit the radio frequency signal based on the voltage value being lower than a first threshold.

2. The NFC device according to claim 1, wherein: The NFC receiving end also includes a switch and a switch control circuit. The switch is connected between the output terminal of the rectifier circuit and the load, The switch control circuit is connected to the energy storage capacitor and the switch, and closes the switch when the voltage across the energy storage capacitor is higher than a second threshold, and opens the switch when the voltage across the energy storage capacitor is lower than the second threshold, and The first threshold is higher than the second threshold but lower than the voltage when the energy storage capacitor is charged to a saturation state.

3. The NFC device according to claim 2, wherein: The energy storage capacitor includes a first capacitor, a first end of the first capacitor is connected to the output end of the rectifier circuit, and a second end of the first capacitor is connected to a reference voltage.

4. The NFC device according to claim 3, wherein: The voltage stabilization circuit includes a voltage stabilization diode connected in parallel with the first capacitor.

5. The NFC device according to claim 3, wherein: The switch includes a first semiconductor switch, a first terminal of the first semiconductor switch is connected to the first terminal of the first capacitor, a second terminal of the first semiconductor switch is connected to the load, and a control terminal of the first semiconductor switch is connected to the switch control circuit.

6. The NFC device according to claim 5, wherein: The switch control circuit includes a first resistor, a second resistor and a second semiconductor switch. The first resistor and the second resistor are connected in series and then in parallel with the first capacitor. The first end of the second semiconductor switch is connected to the control end of the first semiconductor switch, the second end is connected to a reference voltage, and the control end is connected between the first resistor and the second resistor.

7. The NFC device according to claim 6, wherein: The NFC receiving end further includes a third resistor, and the third resistor is connected between the first end and the control end of the first semiconductor switch.

8. The NFC device according to claim 6, wherein: The NFC receiving end further includes a second capacitor, a first end of the second capacitor is connected to the second end of the first semiconductor switch, and a second end of the second capacitor is connected to the reference voltage.

9. The NFC device according to claim 4, wherein: The voltage stabilizing circuit also includes a three-terminal voltage stabilizer.

10. The NFC device according to claim 6, wherein: The NFC receiving end further includes a first inductor and a first diode, the first inductor is connected between the first semiconductor switch and the load, the cathode of the first diode is connected to the second end of the first semiconductor switch, and the anode of the first diode is connected to a reference voltage.

11. A human-machine interface device comprising the NFC device according to any one of the preceding claims 1 to 10.

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