NFC energy capture and energy storage communication management circuit

Abstract

The utility model relates to an NFC (Near Field Communication) energy capture and energy storage communication management circuit, which aims at solving the technical problems that the rapid interactive connection between an NFC intelligent terminal and an NFC passive device of the existing similar product is relatively inconvenient, and the interaction can be successful after an interval time length. The circuit is characterized in that a radio frequency field energy external power supply Vout of an NFC communication circuit of the circuit is connected with a low-power-consumption MCU of an MCU control circuit, an NFC double-interface tag and a channel chip of the NFC communication circuit are in bidirectional connection with the low-power-consumption MCU of the MCU control circuit, and the low-power-consumption MCU of the MCU control circuit is respectively connected with a quick charging switch and a charging voltage detection of an NFC energy capture circuit. A voltage stabilizing circuit of the NFC energy capture circuit is connected with a driving circuit of the MCU control circuit, and a rectifying circuit of the NFC energy capture circuit is connected with a matching circuit of the NFC communication circuit, so that communication and energy capture functions are realized through the NFC antenna.

Description

Technical Field

[0001] This utility model relates to the field of wireless communication and wireless power supply, and is an NFC energy capture and energy storage communication management circuit. Background Technology

[0002] Currently, NFC (Near Field Communication) is a short-range, high-frequency wireless technology operating at 13.56MHz. It typically consists of a master device and a slave device. The master device has its own power supply, generates a radio frequency field, and initiates communication. The slave device does not have its own power supply; it obtains energy from the radio frequency field generated by the master device and converts it into electrical energy to meet its low-power operation and communication response requirements. Smartphones with built-in NFC functionality are playing an increasingly important role in daily life, with ubiquitous applications ranging from payments and simulating access cards to charging NFC wristbands and unlocking NFC passive electronic locks. These applications require higher energy levels in the radio frequency field and stronger energy capture capabilities from passive devices. For example, the Chinese patent document CN218563320U, with an authorization announcement date of March 3, 2023, and the utility model title "A Passive Electronic Lock Device for Bags Based on NFC," has been disclosed. NFC chip manufacturers (such as Shanghai Fudan Microelectronics Group Co., Ltd.) have developed products for similar applications, such as the FM11NT082 NFC dual-interface and channel chip, which enables contactless communication with a mobile app and, after authentication, can read and write the NFC chip's EEPROM. Simultaneously, it can interact with the device's (such as an electronic lock's) MCU via I2C, enabling communication between the mobile app and the device's MCU, and providing functions such as power supply and drive (e.g., locking and unlocking). To achieve these functions, channel mode switching of the FM11NT082 NFC chip is required. During application development, when encountering interactions between an NFC-enabled mobile phone and an NFC passive device, a time interval is required before successful interaction. Summary of the Invention

[0003] To overcome the aforementioned shortcomings, the purpose of this utility model is to provide an NFC energy capture and storage communication management circuit, thereby solving the technical problem that existing similar products' NFC smart terminals (NFC mobile phones or dedicated NFC master devices) have relatively inconvenient rapid interactive connections with NFC passive devices, requiring a time interval before successful interaction. This objective is achieved through the following technical solution.

[0004] An NFC energy capture and energy storage communication management circuit is disclosed. The circuit includes an NFC smart terminal and an NFC passive device. The NFC passive device includes an NFC communication circuit, an NFC energy capture circuit, an MCU control circuit, and an NFC antenna. The NFC communication circuit includes a matching circuit, an NFC dual-interface tag and channel chip, and an external power supply Vout for the NFC energy field. The NFC energy capture circuit includes a rectifier circuit, a voltage limiting protection circuit, a fast charging switch, a medium-speed charging current limiting resistor, an energy storage electrolytic capacitor, a charging voltage detection circuit, and a voltage regulator circuit. The MCU control circuit includes a low-power MCU, a driver circuit, functional modules, and status detection. The key structural design feature is that the external power supply Vout for the NFC communication circuit is connected to the NFC energy field. The low-power MCU of the U control circuit is connected to the NFC dual-interface tag and channel chip of the NFC communication circuit, which are bidirectionally connected to the low-power MCU of the MCU control circuit. The low-power MCU of the MCU control circuit is connected to the fast charging switch and charging voltage detection of the NFC energy capture circuit. The voltage regulator circuit of the NFC energy capture circuit is connected to the drive circuit of the MCU control circuit. The rectifier circuit of the NFC energy capture circuit is connected to the matching circuit of the NFC communication circuit. The rectifier circuit, voltage limiting protection circuit, fast charging switch, medium-speed charging current limiting resistor, and energy storage electrolytic capacitor of the NFC energy capture circuit constitute a rectification and energy storage management circuit. The NFC antenna is connected to the NFC communication circuit and the NFC energy capture circuit.

[0005] The external power supply Vout of the radio frequency field energy is set in the NFC dual-interface tag and channel chip. The NFC dual-interface tag and channel chip of the NFC communication circuit are connected to the matching circuit. The low-power MCU of the MCU control circuit is connected to the status detection and driving circuits respectively. The driving circuit is connected to the functional module. The fast charging switch, medium-speed charging current limiting resistor, charging voltage detection, and voltage regulation circuit of the NFC energy capture circuit are connected to the energy storage electrolytic capacitor. The fast charging switch and medium-speed charging current limiting resistor are connected to the rectifier circuit. The rectifier circuit is connected to the voltage limiting protection circuit.

[0006] Thus, the NFC passive device in this circuit interacts with the NFC smart terminal for energy and information via the radio frequency field. The NFC smart terminal is an NFC mobile phone or dedicated NFC master device that has its own power supply and provides the radio frequency energy field to initiate interactive communication. The NFC passive device is a passive device that captures electrical energy through the radio frequency field and does not have its own power supply. The NFC antenna is connected to the NFC communication circuit and the NFC energy capture circuit respectively, and realizes communication and energy capture functions through a single NFC antenna. The radio frequency field energy of the NFC communication circuit provides external power supply Vout to the low-power MCU of the MCU control circuit and the NFC dual-interface tag and channel chip through low-power fast external power supply. The NFC energy capture circuit manages the charging of the low-power MCU of the MCU control circuit, and drives the functional module when the charging voltage meets the voltage threshold of the drive circuit.

[0007] Preferably, the NFC communication circuit's NFC dual-interface tag and channel chip have a built-in radio frequency field energy harvesting function. In addition to powering the NFC dual-interface tag and channel chip for its own communication, excess energy is output through Vout to power the low-power MCU and the NFC dual-interface tag and channel chip. This eliminates the need for an NFC energy capture circuit, enabling rapid interaction with NFC smart terminals. Once the NFC smart terminal leaves the NFC passive device, the low-power MCU and the NFC dual-interface tag and channel chip are directly powered down. When they are brought close again, both are in their initial state and immediately begin interaction.

[0008] Preferably, the NFC energy capture circuit includes a rectifier circuit, a voltage limiting protection circuit, a medium-speed charging current limiting resistor, a fast charging switch, an energy storage electrolytic capacitor, a charging voltage detection circuit, and a voltage regulator circuit. When the NFC smart terminal approaches the NFC passive device, the energy storage electrolytic capacitor is charged at a medium speed through the medium-speed charging current limiting resistor without affecting the operation of the NFC communication circuit. When the low-power MCU of the MCU control circuit detects that the charging voltage is greater than a preset voltage threshold, it turns on the fast charging switch through charging management to enter the fast charging mode so that the energy storage electrolytic capacitor can be quickly charged. When the low-power MCU detects that the charging voltage meets the energy requirements of the functional module, it turns on the drive circuit to supply power and operate the functional module.

[0009] This utility model features a reasonable circuit structure design, making it convenient for production and application. In particular, it facilitates rapid interactive connection between NFC smart terminals (NFC mobile phones or dedicated NFC master devices) and NFC passive devices, eliminating the need for time intervals before interaction. It is suitable for use as an NFC energy capture and energy storage communication management circuit, as well as for structural improvements to similar products. Attached Figure Description

[0010] Figure 1 This is a circuit principle framework diagram of the energy capture, storage, and communication management system of this utility model.

[0011] Figure 2 This is a schematic diagram of the single-antenna matching circuit of this utility model.

[0012] Figure 3 This is a schematic diagram of the NFC dual-interface tag and channel chip circuit of this utility model.

[0013] Figure 4 This is a schematic diagram of the rectifier energy storage management circuit of this utility model.

[0014] Figure 5 This is a schematic diagram of the charging voltage detection circuit of this utility model.

[0015] Figure 6 This is the schematic diagram of the voltage regulator circuit of this utility model.

[0016] Attached Figure Numbers and Names: 1. NFC Passive Device, 2. NFC Smart Terminal, 11. NFC Communication Circuit, 12. NFC Energy Harvesting Circuit, 13. MCU Control Circuit, 14. NFC Antenna, 111. Matching Circuit, 112. NFC Dual-Interface Tag and Channel Chip, 1121. RF Field Energy External Power Supply Vout, 121. Rectifier Circuit, 122. Voltage Limiting Protection Circuit, 123. Fast Charging Switch, 124. Medium-Speed ​​Charging Current Limiting Resistor, 125. Energy Storage Electrolytic Capacitor, 126. Charging Voltage Detection, 127. Voltage Regulator Circuit, 131. Low-Power MCU, 132. Driver Circuit, 133. Functional Module, 134. Status Detection. Implementation

[0017] The structure and use of this utility model will now be further described with reference to the accompanying drawings. Figures 1-6 The embodiment shown is an NFC energy capture and energy storage communication management circuit, which is particularly applicable to NFC passive devices such as NFC passive electronic locks.

[0018] like Figure 1 As shown, the circuit includes an NFC smart terminal 2 and an NFC passive device 1; the NFC passive device 1 includes an NFC communication circuit 11, an NFC energy harvesting circuit 12, an MCU control circuit 13, and an NFC antenna 14; the NFC communication circuit 11 includes a matching circuit 111, an NFC dual-interface tag and channel chip 112, and an external power supply Vout 1121 for the RF field energy; the NFC energy harvesting circuit 12 includes a rectifier circuit 121, a voltage limiting protection circuit 122, a fast charging switch 123, a medium-speed charging current limiting resistor 124, an energy storage electrolytic capacitor 125, a charging voltage detection 126, and a voltage regulator circuit 127; the MCU control circuit 13 includes a low-power MCU 131, a driver circuit 132, a functional module 133, and a status detection 134.

[0019] The aforementioned NFC antenna 14 is connected to the NFC communication circuit 11 and the NFC energy harvesting circuit 12 respectively, realizing communication and energy harvesting functions through a single NFC antenna; the RF field energy of the NFC communication circuit 11 is used to supply power Vout1121 to the low-power MCU131 of the MCU control circuit 13 and the NFC dual-interface tag and channel chip 112 in a low-power and fast manner; the NFC energy harvesting circuit 12 manages the charging through the low-power MCU131 of the MCU control circuit 13, and drives the functional module 133 when the charging voltage is detected to meet the voltage threshold of the drive circuit 132.

[0020] The aforementioned NFC energy capture circuit 12 includes a rectifier circuit 121, a voltage limiting protection circuit 122, a medium-speed charging current limiting resistor 124, a fast charging switch 123, an energy storage electrolytic capacitor 125, a charging voltage detection circuit 126, and a voltage regulator circuit 127. When the NFC smart terminal 2 approaches the NFC passive device 1, it performs medium-speed charging on the energy storage electrolytic capacitor 125 through the medium-speed charging current limiting resistor 124, without affecting the operation of the NFC communication circuit. The low-power MCU 131 of the MCU control circuit 13 detects the charging voltage through the charging voltage detection circuit 126. When the voltage exceeds the preset voltage threshold, the fast charging switch 123 is activated through the charging management to enter the fast charging mode, so that the energy storage electrolytic capacitor 125 can be quickly charged. The low-power MCU 131 detects that the charging voltage meets the energy required by the functional module 133, activates the drive circuit 132, supplies power and operates the functional module 133. The rectifier circuit 121, voltage limiting protection circuit 122, fast charging switch 123, medium-speed charging current limiting resistor 124, and energy storage electrolytic capacitor 125 of the above-mentioned NFC energy capture circuit constitute the rectification and energy storage management circuit.

[0021] like Figure 2 As shown, the matching circuit 111 of the NFC communication circuit 11 is a single-antenna matching circuit. The schematic diagram of the single-antenna matching circuit includes matching capacitors C1, C3, C4, C5, and C6. The connecting lines RF1 and RF2 of the single-antenna matching circuit are connected to the rectifier circuit 121 of the NFC energy harvesting circuit 12. The connecting lines LA and LB of the single-antenna matching circuit are connected to the NFC dual-interface tag and channel chip 112 of the NFC communication circuit 11.

[0022] like Figure 3As shown, the NFC communication circuit 11's NFC dual-interface tag and channel chip 112 includes an NFC dual-interface tag and channel chip U4, a capacitor C19 connected to the external power supply Vout for the RF field energy, and an I2C interface. The I2C interface includes I2C_IRQ pins, I2C_SDA pins, I2C_SCL pins, CSN pins, GND pins, VCC pins, Vout pins, LA pins, and LB pins. The NFC dual-interface tag and channel chip U4 can receive RF signals and energy, and communicate with NFC smart terminals. It can also communicate with a low-power MCU 131 through the I2C interface. When data is sent to the low-power MCU 131, the I2C_IRQ pin is used to interrupt and remind the low-power MCU 131 to actively initiate data reception. The capacitor C19 connected to the external power supply Vout for the RF field energy is generally a small capacitor of about 100nF to 1uF to ensure rapid power supply of Vout output energy without affecting the communication of the NFC tag.

[0023] like Figure 4 As shown, the rectifier and energy storage management circuit of the NFC energy capture circuit 12 includes a rectifier circuit 121, a voltage limiting protection circuit 122, a fast charging switch 123, a medium-speed charging current limiting resistor 124, an energy storage electrolytic capacitor 125, a charging voltage detection circuit 126, and a voltage regulator circuit 127. The rectifier circuit 121 is composed of D1, D2, D3, and D4, and the voltage limiting protection circuit 122 is composed of D5 and C8. D5 is a Zener diode with a voltage of approximately 16V. The fast charging switch 123... 3 consists of Q1, Q2, R3, and R4. BAT_CTRL is connected to the low-power MCU131 to control the on / off state of Q2 and Q1. When Q1 is on, fast charging is achieved. The medium-speed charging current-limiting resistor 124 consists of R1 and R2. R2 is a resistor of about 1K and R1 is a resistor of about 120 ohms. The energy storage electrolytic capacitor 125 is an electrolytic capacitor of about 1000uF / 25V. The value of this energy storage capacitor depends on the power required by the functional module 133.

[0024] like Figure 5 As shown, the charging voltage detection 126 includes voltage divider resistors R5 and R6. The low-power MCU 131 determines the charging voltage value of the energy storage electrolytic capacitor 125 by detecting the ADC value.

[0025] like Figure 6 As shown, the function of the voltage regulator circuit 127 is to reduce the voltage of the energy storage electrolytic capacitor 125 and then supply power to the drive circuit 132 and the functional module 133.

[0026] The above description is intended to illustrate the technical means of this utility model. The specific embodiments described are merely illustrative of the spirit of this utility model and are not intended to limit its technical scope. Any obvious improvements or substitutions made to this utility model by those skilled in the art in conjunction with existing common knowledge also fall within the protection scope of the claims of this utility model.

Claims

1. An NFC energy capture and energy storage communication management circuit, comprising an NFC smart terminal and an NFC passive device; the NFC passive device comprising an NFC communication circuit, an NFC energy capture circuit, an MCU control circuit, and an NFC antenna; the NFC communication circuit comprising a matching circuit, an NFC dual-interface tag and channel chip, and an external power supply Vout for radio frequency field energy; the NFC energy capture circuit comprising a rectifier circuit, a voltage limiting protection circuit, a fast charging switch, a medium-speed charging current limiting resistor, an energy storage electrolytic capacitor, a charging voltage detection circuit, and a voltage regulator circuit; the MCU control circuit comprising a low-power MCU, a drive circuit, functional modules, and status detection; characterized in that... The NFC communication circuit's radio frequency field energy supply Vout is connected to the low-power MCU of the MCU control circuit. The NFC dual-interface tag and channel chip of the NFC communication circuit are bidirectionally connected to the low-power MCU of the MCU control circuit. The low-power MCU of the MCU control circuit is connected to the fast charging switch and charging voltage detection of the NFC energy capture circuit. The voltage regulator circuit of the NFC energy capture circuit is connected to the drive circuit of the MCU control circuit. The rectifier circuit of the NFC energy capture circuit is connected to the matching circuit of the NFC communication circuit. The rectifier circuit, voltage limiting protection circuit, fast charging switch, medium-speed charging current limiting resistor, and energy storage electrolytic capacitor of the NFC energy capture circuit constitute a rectification and energy storage management circuit. The NFC antenna is connected to both the NFC communication circuit and the NFC energy capture circuit.

2. The NFC energy capture and energy storage communication management circuit according to claim 1, characterized in that... The external power supply Vout of the radio frequency field energy is set in the NFC dual-interface tag and channel chip. The NFC dual-interface tag and channel chip of the NFC communication circuit are connected to the matching circuit. The low-power MCU of the MCU control circuit is connected to the status detection and driving circuits respectively. The driving circuit is connected to the functional module. The fast charging switch, medium-speed charging current limiting resistor, charging voltage detection, and voltage regulation circuit of the NFC energy capture circuit are connected to the energy storage electrolytic capacitor. The fast charging switch and medium-speed charging current limiting resistor are connected to the rectifier circuit. The rectifier circuit is connected to the voltage limiting protection circuit.

3. The NFC energy capture and energy storage communication management circuit according to claim 2, characterized in that... The matching circuit of the NFC communication circuit is a single-antenna matching circuit, which includes matching capacitors C1, C3, C4, C5, and C6. The single-antenna matching circuit connection lines RF1 and RF2 are connected to the rectifier circuit of the NFC energy harvesting circuit. The single-antenna matching circuit connection lines LA and LB are connected to the NFC dual-interface tag and channel chip of the NFC communication circuit.

4. The NFC energy capture and energy storage communication management circuit according to claim 2, characterized in that... The NFC communication circuit includes an NFC dual-interface tag and channel chip U4, a capacitor C19 connected to the external power supply Vout of the radio frequency field, and an I2C interface. The I2C interface includes I2C_IRQ pin, I2C_SDA pin, I2C_SCL pin, CSN pin, GND pin, VCC pin, Vout pin, LA pin, and LB pin.

5. The NFC energy capture and energy storage communication management circuit according to claim 2, characterized in that... The rectifier circuit of the NFC energy capture circuit consists of D1, D2, D3, and D4; the voltage limiting protection circuit consists of D5 and C8; D5 is a Zener diode with a voltage of approximately 16V; the fast charging switch consists of Q1, Q2, R3, and R4; the medium-speed charging current limiting resistor consists of R1 and R2; R2 is a resistor with a voltage of approximately 1K; R1 is a resistor with a voltage of approximately 120 ohms; and the energy storage electrolytic capacitor is an electrolytic capacitor with a voltage of approximately 1000uF / 25V.

6. The NFC energy capture and energy storage communication management circuit according to claim 2, characterized in that... The charging voltage detection of the NFC energy capture circuit includes voltage divider resistors R5 and R6.

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