NFC function control module, NFC function module and electronic device

Abstract

A NFC function control module for controlling the function state of NFC module, comprising: control input module, switch module, ground port, NFC coil connection port; the control input module is used for electronic or mechanical input control state; the ground port is used for connecting power ground; the NFC coil connection port is used for connecting NFC coil; the opening state, through the control input module state, the switch module is in state A, the NFC coil connection port and the ground port are in low impedance state, and the NFC module enters the non-working state; the closing state, through the control input module state, the switch module is in state B, the NFC coil connection port and the ground port are in high impedance state, and the NFC module enters the working state.

Description

Technical Field

[0001] This application belongs to the field of electronic technology, specifically relating to an NFC function control module for controlling the functional state of an NFC module. Background Technology

[0002] With the widespread adoption of NFC, situations have arisen where it needs to be dynamically switched on and off, such as for security control, power-saving modes, or preventing unauthorized reading. For example, NFC can be turned off when a device enters sleep mode to save power; or NFC can be immediately disconnected after a payment is completed to prevent subsequent malicious reading.

[0003] Therefore, this application proposes an NFC switch scheme and circuit. Summary of the Invention

[0004] The technical problem this application aims to solve is the need to dynamically switch NFC functionality to prevent malicious reading. This application controls the NFC coil, changing its parameters such as resonant frequency and Q value, to prevent it from inductively coupling with the NFC coil on the other side. This prevents the transmission of data and energy via modulated radio frequency fields, thus achieving the purpose of controlling the NFC switch.

[0005] An NFC function control module for controlling the functional states of an NFC module includes: a control input module, a switch module, a ground port, and an NFC coil connection port. The control input module is used for electronic or mechanical input control. The ground port is used to connect to power ground. The NFC coil connection port is used to connect to an NFC coil. In the ON state, the switch module is in state A, and the NFC coil connection port and ground port are in a low-impedance state, so the NFC module is inoperable. In the OFF state, the switch module is in state B, and the NFC coil connection port and ground port are in a high-impedance state, so the NFC module is inoperable.

[0006] The switch module may include a mechanical-electronic switch; in the open state, state A is the connected state, the NFC coil connection port and the ground port are connected, and the NFC module enters an inoperable state; in the closed state, state B is the disconnected state, the NFC coil connection port and the ground port are not connected, and the NFC module enters an operational state.

[0007] It can also include resistor A and resistor B; resistor A is a high-impedance resistor; one end of resistor A is connected to the above-mentioned NFC coil electrical signal, and the other end of resistor A is connected to the above-mentioned ground port electrical signal; resistor B is a low-impedance resistor; resistor B is connected in series with the above-mentioned electromechanical switch; the series-connected resistor B and electromechanical switch are connected in parallel with the above-mentioned resistor A.

[0008] The switching module may include transistor Q2, MOSFET Q1, resistors R1, R2, R3, and R4; the control input module may include a control signal input port; the collector of transistor Q2 is electrically connected to the gate 1 of MOSFET Q1; the source 2 of MOSFET Q1 is electrically connected to power supply ground via resistor R4; the drain 3 of MOSFET Q1 is electrically connected to the NFC coil; the collector of transistor Q2 is electrically connected to the NFC coil via resistor R1; the emitter of transistor Q2 is electrically connected to power supply ground; the base of transistor Q2 is electrically connected to power supply ground via resistor R3; and the base of transistor Q2 is electrically connected to the control signal input port via resistor R2.

[0009] Alternatively, the aforementioned switch module may also include a mechanical-electronic switch S1; the collector of transistor Q2 is connected to the power supply ground signal through the aforementioned mechanical-electronic switch.

[0010] Alternatively, the aforementioned control signal input port can be electrically connected to one of the MCU's output control ports.

[0011] An NFC function module includes the aforementioned NFC function control module.

[0012] An electronic device includes the aforementioned NFC function control module.

[0013] One of the beneficial effects of the technical solution in this application is that by changing the resistance of the NFC coil to ground, the function of the NFC module can be changed without disconnecting the NFC coil, which is simple and efficient.

[0014] One of the beneficial effects of the technical solution in this application is that the NFC coil can be grounded directly through a mechanical switch, making the NFC module unable to receive or release electromagnetic signals.

[0015] One of the beneficial effects of the technical solution in this application is that by changing the parameters of the NFC coil, such as the resonant frequency and Q value, so that it cannot be inductively coupled with the NFC coil on the other side, it is impossible to transmit data and energy by modulating the radio frequency field, thereby achieving the purpose of controlling the NFC switch.

[0016] One of the beneficial effects of the technical solution in this application is that the NFC coil can be grounded directly through a mechanical switch and a low-impedance resistor, which protects the NFC module from damage caused by excessive current signal when the NFC module sends signals.

[0017] One of the beneficial effects of the technical solution in this application is that the NFC coil can be grounded through the low-impedance resistor directly via the electronic switch and the low-impedance resistor, so that the external electrical signal can control the module function and facilitate the control of the upper-layer program.

[0018] One of the beneficial effects of the technical solution in this application is that the NFC coil can be grounded through a low-impedance resistor by an electronic switch or a mechanical switch, so that external electrical signals can control the module function, which is convenient for upper-level program control. At the same time, the module function can also be controlled by an external mechanical switch, which is convenient for user operation. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the application scenario of Example 1; Figure 2 This is a schematic diagram of Example 2; Figure 3 This is a schematic diagram of Example 3; Figure 4 This is a schematic diagram of Example 4; Figure 5 This is a schematic diagram of Example 5. Detailed Implementation

[0020] The embodiments of this application will be further described in detail below with reference to the accompanying drawings.

[0021] It should be noted that the following description of preferred embodiments of this application does not constitute any limitation on this application. The description of preferred embodiments is merely an illustration of the general principles of this application. The embodiments described in this application are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the equipment or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first," "second," and technical features numbered with Arabic numerals 1, 2, 3, etc., and designations such as "A" and "B," are used for descriptive purposes only, for ease of explanation, and do not represent a temporal or spatial order; they should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first," "second," and numbered with Arabic numerals 1, 2, 3, etc., may explicitly or implicitly include one or more of that feature. In the description of this application, "several" means two or more, unless otherwise expressly and specifically defined.

[0023] like Figure 1 Example 1: Application scenario diagram.

[0024] As shown in the figure, the NFC function control module 0110 is used to control the functional state of the NFC module 0120, including: a control input module, which includes a control port 0113, a switch module, a ground port 0111, and an NFC coil connection port 0112; the control input module is used for electronic or mechanical input control state; the ground port is used to connect to the power ground; the NFC coil connection port 0112 is used to connect to the NFC coil 0121; in the on state, according to the control input module state, the switch module is in state A, the NFC coil connection port and the ground port are in a low impedance state, and the NFC module enters an inoperable state; in the off state, according to the control input module state, the switch module is in state B, the NFC coil connection port and the ground port are in a high impedance state, and the NFC module enters an operable state.

[0025] By changing the resistance of the NFC coil to ground, the function of the NFC module can be changed without disconnecting the NFC coil, which is simple and efficient.

[0026] like Figure 1 The schematic diagram of Embodiment 2 shows that the switch module includes a mechanical electronic switch 0210; in the on state, state A is the connected state, the NFC coil 0220 connection port and the ground port are in a connected state, and the NFC module enters an inoperable state; in the off state, state B is the disconnected state, the NFC coil connection port and the ground port are in a non-conductive state, and the NFC module 0230 enters an operable state.

[0027] By directly grounding the NFC coil through a mechanical switch, the NFC module can be prevented from receiving or releasing electromagnetic signals.

[0028] A 13.56MHz NFC antenna can be viewed as a coupled coil. According to Ampere's law, when current flows through a conductor, a magnetic field is generated around the conductor, and the strength of this magnetic field is proportional to the number of turns and the area of ​​the coil. According to Faraday's law of electromagnetic induction, a time-varying magnetic field passing through a closed space will induce a voltage. Therefore, these two laws are applied to the NFC reader / writer and the NFC card, respectively. The reader / writer antenna generates a magnetic field that couples to the NFC card antenna, generating a voltage that powers the chip in the NFC card, thereby enabling energy and signal transmission.

[0029] Since NFC transmits electromagnetic signals and energy through near-field coupling between coils, by controlling the NFC coil and changing its parameters such as resonant frequency and Q value, it is impossible to make it inductively couple with the NFC coil on the other side. In this way, it is impossible to send data and energy by modulating the radio frequency field, thus achieving the purpose of controlling the NFC switch.

[0030] like Figure 3 The schematic diagram of Example 3 shows that it includes resistor A (0310) and resistor B (0320). Resistor A is a high-impedance resistor; one end of resistor A is connected to the NFC coil (0320) for electrical signal, and the other end of resistor A is connected to the ground port (0330) for electrical signal. Resistor B is a low-impedance resistor; resistor B is connected in series with the electromechanical switch (0340); the series-connected resistor B and electromechanical switch are connected in parallel with resistor A.

[0031] By directly connecting the NFC coil to ground via a mechanical switch and a low-impedance resistor, the current signal is protected from being too large and causing damage to the NFC module when it sends signals.

[0032] like Figure 4 The schematic diagram of Embodiment 4 is shown below. The switching module may include transistor Q2, MOSFET Q1, resistors R1, R2, R3, and R4; the control input module includes a control signal input port 0410; the collector of transistor Q2 is electrically connected to the gate 1 of MOSFET Q1; the source 2 of MOSFET Q1 is electrically connected to power ground through the aforementioned resistor R4; the drain 3 of MOSFET Q1 is electrically connected to the aforementioned NFC coil 0420; the collector of transistor Q2 is electrically connected to the aforementioned NFC coil through the aforementioned resistor R1; the emitter of transistor Q2 is electrically connected to power ground 0430; the base of transistor Q2 is electrically connected to power ground through the aforementioned resistor R3; and the base of transistor Q2 is electrically connected to the control signal input port 0410 through the aforementioned resistor R2.

[0033] By directly using an electronic switch and a low-impedance resistor, the NFC coil can be grounded through the low-impedance resistor, allowing external electrical signals to control the module's functions and facilitating upper-level program control.

[0034] When an external NFC sensor is present, an induced voltage is generated on the coil. The gate level of MOSFET Q1 is pulled high by the induced voltage through resistor R1, causing MOSFET Q1 to conduct. One end of the NFC coil is grounded through a small resistor R4, forming a low-impedance path. This forces the Q value of the coil to drop, significantly reducing the effective sensing range and suppressing magnetic field coupling, preventing the coil from effectively resonating with the external NFC coil. This method allows for a quick and physical deactivation of the NFC function without requiring manual control of the voltage generated by the NFC sensor, resulting in extremely low standby power consumption.

[0035] When the MCU pulls the base level of transistor Q2 high, turning Q2 on and pulling the gate level of MOSFET Q1 low to ground, MOSFET Q1 turns off. At this point, the low-impedance path between the NFC coil and ground disappears, restoring the circuit to a standard LC resonant circuit that can be formed with its matching capacitor. This allows for normal coupling with the coil of an external NFC device, enabling data exchange or power transfer. When data or power transfer ends or is interrupted, the MCU can either pull the base level of transistor Q2 low or cancel the control to pull the base of Q2 low through resistor R3, turning off transistor Q2 and returning the MOSFET to its off state controlled by the induced voltage.

[0036] like Figure 5 Schematic diagram of Example 5.

[0037] Based on Example 4, the switching module may further include a mechanical-electronic switch S1; the collector of transistor Q2 is connected to the power supply ground signal through the aforementioned mechanical-electronic switch.

[0038] The NFC coil can be grounded through a low-impedance resistor via an electronic or mechanical switch, allowing external electrical signals to control the module's functions, facilitating upper-level program control. At the same time, the module's functions can also be controlled via an external mechanical switch, making it convenient for user operation.

[0039] Adding a physical button S1 allows the NFC to be turned on normally by manually pressing the button, which pulls the base level of the MOSFET low. This application scenario can be used for some low-power solutions that draw power from the NFC, such as electronic paper phone cases, etc.

[0040] Pressing the button enables the NFC to function normally for a short period of time. During this time, the NFC draws power to the MCU in the circuit. The MCU can then control transistor Q2 to keep the NFC functioning normally until it needs to be turned off, thus achieving the shutdown effect.

[0041] Alternatively, the aforementioned control signal input port can be electrically connected to one of the MCU's output control ports.

[0042] An NFC function module includes the aforementioned NFC function control module. An electronic device includes the aforementioned NFC function control module.

[0043] As shown in the accompanying drawings, the above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of the application specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. An NFC function control module, used to control the functional state of an NFC module. Its features are, Includes: control input module, switch module, grounding port, and NFC coil connection port; The control input module is used for electronic or mechanical input control status; The grounding port is used to connect to the power supply ground; The NFC coil connection port is used to connect an NFC coil; When the switch module is in the power-on state, the switch module is in state A, the NFC coil connection port and the ground port are in a low impedance state, and the NFC module enters an inoperable state. When the switch module is in the off state, the switch module is in state B by controlling the input module state. The NFC coil connection port and the ground port are in a high impedance state, and the NFC module enters the working state.

2. The NFC function control module according to claim 1, characterized in that, The switching module includes a mechanical-electronic switch; In the ON state, state A is the ON state, the NFC coil connection port and the ground port are in a connected state, and the NFC module enters an inoperable state. In the off state, state B is the disconnected state, the NFC coil connection port and the ground port are in a non-conductive state, and the NFC module enters the working state.

3. The NFC function control module according to claim 2, characterized in that, It also includes resistor A and resistor B; Resistor A is a high-impedance resistor; one end of resistor A is connected to the NFC coil electrical signal, and the other end of resistor A is connected to the ground port electrical signal. Resistor B is a low-impedance resistor; resistor B is connected in series with the electromechanical switch; the series-connected resistor B, electromechanical switch, and resistor A are connected in parallel.

4. The NFC function control module according to claim 1, characterized in that, The switching module includes transistor Q2, MOSFET Q1, resistors R1, R2, R3, and R4; The control input module includes a control signal input port; The collector of transistor Q2 is connected to the gate of MOSFET Q1 by an electrical signal (1); The source (2) of the MOSFET Q1 is connected to the power supply ground signal through the electron R4; The drain (3) of the MOSFET Q1 is connected to the NFC coil electrical signal; The collector of transistor Q2 is connected to the NFC coil via the electron R1; The emitter of transistor Q2 is connected to the power supply ground signal; The base of transistor Q2 is connected to the power supply ground signal through the electron R3; The base of transistor Q2 is electrically connected to the control signal input port through the electronic R2.

5. The NFC function control module according to claim 4, characterized in that, The switching module also includes a mechanical-electronic switch S1; The collector of transistor Q2 is connected to the power supply ground signal through the electromechanical switch.

6. The NFC function control module according to claim 4, characterized in that, The control signal input port is electrically connected to one of the output control ports of the MCU.

7. An NFC functional module, characterized in that, Includes the NFC function control module as described in any one of claims 1 to 6.

8. An electronic device, characterized in that, Includes the NFC function control module as described in any one of claims 1 to 6.

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