NFC control power switch circuit and electronic equipment

Abstract

The invention provides an NFC control power switch circuit, which comprises an NFC antenna, a control chip and a power supply battery, and is characterized in that the control chip comprises an NFC power partition unit and a switch control unit; wherein when the NFC antenna senses that the external electronic equipment supporting the NFC function exists in a preset range, an induction voltage and an induction clock are generated; the NFC power supply partition unit is electrically connected to the NFC antenna, and is used for electrifying to work when receiving the induced voltage, and outputting a preset on-off control instruction to the on-off control unit when receiving an on-off command sent by an NFC card reader (PCD); the switch control unit is in a non-power-down power supply partition, is electrically connected to the NFC power supply partition unit, is also electrically connected between the power supply battery and the function unit, and is used for connecting or disconnecting the connection between the power supply battery and the function unit according to the preset switch control instruction. The NFC control power switch circuit has no dynamic power consumption during standby, only a small number of circuits have electric leakage, and the standby power consumption is reduced to the maximum extent.

Description

Technical Field

[0001] This invention relates to the field of electronic circuit technology, and in particular to an NFC control power switch circuit and electronic device. Background Technology

[0002] To improve user experience, wearable electronic devices are trending towards smaller and lighter sizes. This necessitates the use of very small batteries, such as button batteries. These batteries typically have low capacity, requiring extremely low standby power consumption. These electronic products often have requirements for water resistance and portability, necessitating wireless communication to control the power switch. Bluetooth technology is widely used in wireless communication, but Bluetooth communication requires periodically (the longest configurable period is generally 2 seconds) opening the receiving window during standby to check for valid data commands and send handshake signals. This periodic communication mechanism results in relatively high standby power consumption, with an average current generally exceeding 5 microamps. The annual standby power consumption would be 5 * 24 * 365 / 1000 = 43.8 mAh, which is unacceptable for applications aiming to use small button batteries with a capacity of less than 20 mAh.

[0003] With the advancement of technology, NFC (Near Field Communication) technology has gradually become an indispensable part of our daily lives, from mobile payments to access control and electronic tags. In NFC tag applications, batteries may not even be necessary; power is obtained on-site via an antenna during communication. However, currently, using NFC to control power switches generally requires a discrete NFC chip connected to a power control chip through a peripheral interface. This method requires the controlled chip's power supply, clock, and peripheral interface (such as I2C) to be active, resulting in high overall standby power consumption, typically at least several microamps of standby current. Summary of the Invention

[0004] The purpose of this invention is to provide an NFC control power switch circuit and electronic device that can solve the above-mentioned problems.

[0005] One aspect of this invention provides an NFC control power switch circuit, comprising: an NFC antenna, a control chip, and a power supply battery. The control chip includes an NFC power partitioning unit and a switch control unit. When the NFC antenna senses an external electronic device supporting NFC functionality within a preset range, it generates an induced voltage and an induced clock. The NFC power partitioning unit is electrically connected to the NFC antenna and is used to power on when receiving the induced voltage and to output a preset switch control command to the switch control unit when receiving a power-on / off command from a card reader (PCD). The switch control unit is electrically connected to the NFC power partitioning unit and also electrically connected between the power supply battery and a functional unit, and is used to connect or disconnect the connection between the power supply battery and the functional unit according to the preset switch control command.

[0006] Preferably, the NFC power partition unit is powered down when the external electronic device supporting NFC function exceeds the preset range.

[0007] Preferably, the NFC power partition unit includes a data terminal, an enable terminal, and a clock signal terminal. When the NFC power partition unit is powered on and receives a power-on / off command from the NFC reader (PCD): the data terminal outputs the preset power-on / off control command to the power-on / off control unit; the enable terminal outputs an NFC power-on reset signal to the power-on / off control unit; and the clock signal terminal outputs a clock signal to the power-on / off control unit.

[0008] Preferably, the switch control unit includes: a first level conversion unit, electrically connected to the data terminal and enable terminal of the NFC power partition unit, used to convert the level of the preset switch control command according to the NFC power-on reset signal, and output a second switch control command; a second level conversion unit, electrically connected to the clock signal terminal and enable terminal of the NFC power partition unit, used to convert the clock signal transition signal or static level signal according to the NFC power-on reset signal as a conversion enable signal; and a register unit, including a clock signal terminal, an input terminal and an output terminal, wherein the clock signal terminal of the register unit is electrically connected to the second level conversion unit. A level conversion unit, with the input terminal of the register electrically connected to the first level conversion unit, is used to temporarily store and output the second switch control instruction; a logic control unit, electrically connected to the register unit, is used to receive the second switch control instruction and output a switch signal according to the second switch control instruction; a power switch, including a control terminal, a first terminal, and a second terminal, wherein the control terminal of the power switch is electrically connected to the logic control unit, the first terminal of the power switch is electrically connected to the power supply battery, and the second terminal of the power switch is electrically connected to the functional unit, and is used to turn on or off the connection between the power supply battery and the functional unit according to the switch signal.

[0009] Preferably, when the preset switch control command output by the data terminal is a power-off command, the NFC power-on reset signal is a high-level signal, the command converted by the first level conversion unit is a power-off control word, and the second level conversion unit converts it into a clock transition signal. When the preset switch control command output by the data terminal is a power-on command, the NFC power-on reset signal is a high-level signal, the command converted by the first level conversion unit is a power-on control word, and the second level conversion unit converts it into a clock transition signal.

[0010] Preferably, the preset switch control instruction is a 4-bit binary instruction; the first level conversion unit includes 4 conversion sub-units, each of which receives the 4-bit binary instruction and converts the level of the 4-bit binary instruction according to the NFC power-on reset signal to output the second switch control instruction.

[0011] Preferably, the register unit includes four register sub-units, the clock signal terminals of the four register sub-units are all electrically connected to the second level conversion unit, and the input terminals of the four register sub-units are electrically connected to the four conversion sub-units one-to-one to register and output the second switch control command.

[0012] Preferably, the logic control unit includes: an AND gate logic unit, including a first input terminal, a second input terminal, a third input terminal, a fourth input terminal, and an output terminal, wherein the first input terminal, the second input terminal, the third input terminal, and the fourth input terminal of the AND gate logic unit are electrically connected to the output terminals of the four register sub-units in a one-to-one correspondence, and the output terminal of the AND gate logic unit is electrically connected to the power switch; a first NOT gate logic unit, electrically connected between the second input terminal of the AND gate logic unit and the corresponding register sub-unit; and a second NOT gate logic unit, electrically connected between the fourth input terminal of the AND gate logic unit and the corresponding register sub-unit.

[0013] Preferably, the power switch is an NMOS transistor, the gate of the NMOS transistor is electrically connected to the output terminal of the AND gate logic unit, the drain of the NMOS transistor is electrically connected to the power supply battery, and the source of the NMOS transistor is electrically connected to the functional unit.

[0014] Another aspect of the present invention provides an electronic device including the NFC control power switch circuit described in any of the preceding claims.

[0015] Compared to existing technologies, the NFC control power switch circuit and electronic device proposed in this invention senses external electronic devices supporting NFC functionality through an NFC antenna. When such external electronic devices are sensed within a preset range, an induced voltage and an induced clock are generated, thereby powering on the NFC power partition unit. Upon receiving a power-on / off command from a card reader (PCD), the power switch unit outputs a pre-set switch control command to the switch control unit. The switch control unit then connects or disconnects the power supply battery and the functional unit according to the switch control command. Therefore, the NFC control power switch circuit has no dynamic power consumption in standby mode, with only a small amount of leakage current, minimizing standby power consumption to approximately 0.05 microamps. The annual standby power consumption is approximately 0.44 mAh. It is understood that standby current is strongly correlated with the leakage current of the selected process; applications sensitive to standby power consumption generally prioritize low-leakage processes. The 0.05 microamp leakage current data in this embodiment is based on a typical low-leakage process; an ultra-low leakage process could achieve even lower leakage current.

[0016] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 The schematic diagram illustrates a module diagram of an NFC control power switch circuit according to Embodiment 1 of the present invention.

[0019] Figure 2 The schematic diagram shows a circuit diagram of an NFC control power switch circuit 1 according to Embodiment 2 of the present invention.

[0020] Figure 3 This is a schematic diagram of the power-on / off process of the NFC control power switch circuit 1 according to Embodiment 2 of the present invention.

[0021] Figure 4 The schematic diagram illustrates the power-on timing of the NFC control power switch circuit according to Embodiment 2 of the present invention.

[0022] Figure 5 The diagram illustrates the power-off timing of the NFC control power switch circuit according to Embodiment 2 of the present invention.

[0023] Explanation of key component symbols:

[0024] NFC control power switch circuit 1

[0025] External electronic devices 2

[0026] On-chip functional unit 31

[0027] External functional unit 32

[0028] Functional Unit 3

[0029] NFC Antenna 10

[0030] NFC power partition unit 20

[0031] Switch control unit 30

[0032] Control chip U1

[0033] Power supply battery 40

[0034] First level conversion unit 301

[0035] Second level conversion unit 302

[0036] Register unit 303

[0037] Logic control unit 304

[0038] Power switch 305

[0039] Data terminal D

[0040] Enable terminal EN

[0041] Clock signal terminal CK

[0042] Register subunit reg

[0043] Transformer subunit ls

[0044] AND gate logic unit A1

[0045] First NOT gate logic unit N1

[0046] The second NOT gate logic unit N2

[0047] NMOS transistor Q1 Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can be arranged and designed in various different configurations. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to make the disclosure of the present invention more thorough and complete. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0049] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0050] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set up," "connected," and "electrically connected" should be interpreted broadly. For example, they can refer to a direct connection or an indirect connection through an intermediate medium, or they can refer to the internal connection of two elements. It should be noted that when one element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intervening element present.

[0051] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0052] The terminology involved in this invention is explained as follows:

[0053] NFC (Near Field Communication) – The inventors discovered that to improve user experience, wearable electronic devices are trending towards miniaturization. This necessitates the use of very small batteries, such as button batteries. These batteries typically have low capacity, requiring extremely low standby power consumption. Such electronic products often require waterproofing and portability, necessitating wireless communication to control the power switch. Bluetooth technology is widely used in wireless communication, but it requires periodically opening the receiving window during standby (the longest configurable period is generally 2 seconds) to check for valid data commands and send handshake signals. This periodic communication mechanism results in relatively high standby power consumption, with an average current generally exceeding 5 microamps. The annual standby power consumption is 5 * 24 * 365 / 1000 = 43.8 mAh, which is unacceptable for applications aiming to use small button batteries (under 20 mAh).

[0054] The inventors have discovered that in NFC tag applications, batteries are not required; power is obtained on-site via an antenna during communication. However, currently, using NFC to control the power switch typically requires a discrete NFC chip connected to a power control chip through a peripheral interface. This method requires the controlled chip's power supply, clock, and peripheral interface (such as I2C) to be active, resulting in relatively high overall standby power consumption, typically at least several microamps, which fails to meet low-power requirements.

[0055] In view of this, embodiments of the present invention provide an NFC control power switch circuit and an electronic device, thereby solving the problem of high standby power consumption in electronic devices, which cannot meet the requirements for miniaturization and portability. Furthermore, the use of a multi-bit register combination to control the power switch increases anti-interference capability and reduces the possibility of abnormal power-on during standby.

[0056] Specifically:

[0057] A new NFC control power switch circuit is provided. This new NFC control power switch circuit senses external electronic devices that support NFC functionality through an NFC antenna. When the external electronic device is sensed within a preset range, an induced voltage and an induced clock are generated, thereby powering on the NFC power partition unit. Upon receiving a power-on / off command from a card reader (PCD), the circuit outputs a preset power-on control command to the power switch control unit. The power switch control unit then connects or disconnects the battery and functional unit according to the power switch control command. This results in zero dynamic power consumption and only a small amount of leakage current in the NFC control power switch circuit during standby, minimizing standby power consumption. The standby current can be reduced to approximately 0.05 microamps. Therefore, the annual standby power consumption is approximately 0.44 mAh.

[0058] Example 1

[0059] Figure 1 A schematic diagram of an NFC control power switch circuit 1 according to Embodiment 1 of the present invention is shown. The NFC control power switch circuit 1 is mainly used in wearable electronic devices. Figure 1 As shown, the NFC control power switch circuit 1 includes an NFC antenna 10, a control chip U1, and a power supply battery 40. The control chip U1 includes an NFC power partitioning unit 20 and a switch control unit 30. In this embodiment, when the NFC antenna 10 senses the presence of an external electronic device 2 supporting NFC function within a preset range, it generates an induced voltage and an induced clock. The NFC power partitioning unit 20 is electrically connected to the NFC antenna 10 and is used to power on when it receives the induced voltage generated by the NFC antenna 10, and to output a preset switch control command to the switch control unit 30 when it receives a power-on / off command from the card reader (PCD). Specifically, to meet the low power consumption requirement, the NFC power partitioning unit 20 only operates in passive mode, normally without power and not working. Only when an external electronic device 2 supporting NFC function, such as an NFC card reader or an NFC-enabled mobile phone, approaches the NFC antenna 10, the NFC antenna 10 generates an induced voltage, causing the NFC power partitioning unit 20 to power on. When the external electronic device 2 supporting NFC function is outside the preset range, the NFC antenna 10 no longer generates an induced voltage and an induced clock, and the NFC power partitioning unit 20 is powered off. Therefore, the NFC power partition unit 20 is powered on by sensing electrical energy through the NFC antenna 10 and does not need to obtain operating voltage from the power supply battery 40.

[0060] In this embodiment, the switch control unit 30 is electrically connected to the NFC power partition unit 20 and also electrically connected between the power supply battery 40 and the functional unit 3. It is used to connect or disconnect the connection between the power supply battery 40 and the functional unit 3 according to a preset switch control command. Specifically, the functional unit 3 may include only the on-chip functional unit 31, only the off-chip functional unit 32, or both, depending on the actual application requirements. The on-chip functional unit 31 is integrated into the control chip U1 and may be, but is not limited to, a high-precision analog-to-digital converter circuit. The off-chip functional unit 32 is not integrated into the control chip U1 and is a functional unit outside of the control chip U1; it may be, but is not limited to, a BLE (Bluetooth Low Energy) chip. The functional unit 3 can be determined according to the actual functions implemented by the electronic device and is not limited here. When the switch control unit 30 connects the power supply battery 40 and the functional unit 3, the power supply battery 40 supplies power to the functional unit 3 to enable it to operate normally. When the switch control unit 30 disconnects the power supply battery 40 from the functional unit 3, the power supply battery 40 stops supplying power to the functional unit 3. The switch control unit 30 can be understood as a non-power-loss power partition, and the functional unit 3 can be understood as a power-loss power partition.

[0061] In this embodiment, the NFC power partition unit 20 is powered on by the induced voltage of the NFC antenna 10. After receiving the power-on / off command sent by the card reader (PCD), the NFC power partition unit 20 outputs the switch control command to the switch control unit 30, thereby connecting or disconnecting the connection between the power supply battery 40 and the functional unit 3. There is no dynamic power consumption during standby, and only a small number of circuits have leakage current, thus minimizing standby power consumption.

[0062] Example 2

[0063] Figure 2 The schematic diagram illustrates the NFC control power switch circuit 1 according to Embodiment 2 of the present invention. In this embodiment, the connection relationship and working principle of the NFC antenna 10, NFC power partition unit 20, switch control unit 30 and power supply battery 40 are similar to those in Embodiment 1, and will not be repeated here.

[0064] In this embodiment, the NFC power partitioning unit 20 includes a data terminal D, an enable terminal EN, and a clock signal terminal CK. When the NFC power partitioning unit 20 is powered on and receives a power-on / off command from the card reader (PCD), the data terminal D outputs the preset power-on control instruction data to the power-on control unit 30. The enable terminal EN outputs the NFC power-on reset signal nfc_por_n to the power-on control unit 30. The clock signal terminal CK outputs the clock signal clk to the power-on control unit 30. When no power-on / off command is received from the NFC card reader (PCD), the data terminal D and the clock signal terminal CK remain at static levels, and the enable terminal EN generates a corresponding signal according to the NFC power-on status. When the NFC is powered off, the enable terminal EN is at a low level, and the outputs of the first level conversion unit and the second level conversion unit are both at the default static level, without any power-on / off control changes. Figure 3 , Figure 3 This is a schematic diagram of the power-on / off process of the NFC control power switch circuit 1 according to Embodiment 2 of the present invention. Figure 3 As shown, the power-on / off process of the NFC control power switch circuit 1 mainly includes the following steps: S31: NFC power-on, NFC power-on reset signal and working clock signal established; S32: Respond to NFC handshake command; S33: Respond to preset switch control command; S34: Execute switch control command; S35: NFC power-off. It should be understood that the above process is only a brief description of the basic NFC power-on / off process and is not intended to limit the order of execution steps. In practical applications, steps can be added or removed appropriately depending on the device type, such as including steps like responding to NFC security authentication.

[0065] In this embodiment, the switch control unit 30 includes a first level conversion unit 301, a second level conversion unit 302, a register unit 303, a logic control unit 304, and a power switch 305. The first level conversion unit 301 is electrically connected to the data terminal D and the enable terminal EN of the NFC power partition unit 20, and is used to convert the level of the preset switch control command according to the NFC power-on reset signal nfc_por_n as a conversion enable function, and output a second control command. The second level conversion unit 302 is electrically connected to the clock signal terminal CK and the enable terminal EN of the NFC power partition unit 20, and is used to convert the level of the clock signal clk according to the NFC power-on reset signal nfc_por_n as a conversion enable function. The register unit 303 includes a clock signal terminal, an input terminal, and an output terminal. The clock signal terminal of the register unit 303 is electrically connected to the second level conversion unit 302, and the input terminal of the register unit 303 is electrically connected to the first level conversion unit 301, used to temporarily store and output the second control command. The logic control unit 304 is electrically connected to the register unit 303 and is used to receive the second control command and output a switch signal according to the second control command. The power switch 305 includes a control terminal, a first terminal, and a second terminal. The control terminal of the power switch 305 is electrically connected to the logic control unit 304, the first terminal of the power switch 305 is electrically connected to the power supply battery 40, and the second terminal of the power switch 305 is electrically connected to the functional unit 3, used to turn the connection between the power supply battery 40 and the functional unit 3 on or off according to the switch signal. It is understood that the above signals are only a brief description of the basic interface signals between the NFC circuit and the switch circuit. In practical applications, it is also necessary to consider that NFC uses antenna-sensing power, which may lead to unstable power supply, requiring additional fault-tolerant designs such as verification.

[0066] In this embodiment, when the NFC power partition unit starts working after power-on, it can determine whether the power switch 305 is in a connected or disconnected state after power-on based on the current instruction value of the register unit 303, and then output a preset switch control instruction to change the connected or disconnected state of the power switch 305. When the preset switch control instruction output by the data terminal D of the NFC power partition unit 20 is a power-off instruction, the reset signal nfc_por_n is high. The first level conversion unit 301 converts the preset power-off control instruction into a power-off control instruction level signal of the non-power-loss power partition where the switch control unit is located, and the second level conversion unit 302 converts the clock transition signal of the clock signal clk into a clock transition signal of the non-power-loss power partition where the switch control unit is located. When the preset switch control command output by data terminal D is a power-on command, the NFC power-on reset signal is a high-level signal. The first level conversion unit 301 converts the preset power-on control command into a power-on control command level signal for the non-power-loss power partition where the switch control unit is located. The second level conversion unit 302 converts the clock transition signal of the clock signal clk into a clock transition signal for the power partition where the switch control unit is located. The NFC power partition unit 20 is powered on or off according to the induced voltage of the NFC antenna 10, but the switch control unit 30 belongs to the non-power-loss power partition, that is, it is always powered as long as the power supply battery 40 is connected. In addition to converting different voltage signals, the first and second level conversions also have an isolation function to prevent the output signal of the power-loss power partition from being sent to the non-power-loss power partition and causing leakage. Furthermore, when the reset signal nfc_por_n is low, the outputs of the first and second level conversions remain at the default static level, and will not be falsely triggered to generate a power-on command. The NFC power-on reset signal nfc_por_n will also have a pull-down resistor added. When the NFC power partition is powered off, this signal will not be in a high-impedance state, but will remain at a low level.

[0067] Typically, a single register control instruction is sufficient to control the power switch 305 to turn on and off. However, in practical applications, electromagnetic interference, radiation, and ESD interference are unavoidable. To enhance protection against electromagnetic interference, radiation, and ESD interference, and to prevent the register value from being overturned by these abnormal factors during the shelf life, which could lead to the power switch being accidentally turned on and prematurely depleting the battery power, the register unit 303 in this embodiment includes four register subunits (reg). These subunits control the power switch 305 to turn on and off using a combination of four-bit control instructions to enhance anti-interference capabilities. Specifically, the preset switch control instruction is a four-bit binary instruction. The first level conversion unit 301 includes four conversion subunits (ls). Each of the four conversion subunits (ls) receives the four-bit binary instruction and converts the level of the four-bit binary instruction based on the NFC power-on reset signal nfc_por_n as the conversion enable function to output the second switch control instruction. The clock signal terminals of all four register subunits (reg) are electrically connected to the second level conversion unit 302 to receive the clock signal clk. The input terminals of the four register subunits (reg) are electrically connected one-to-one to the four conversion subunits (ls) to register and output the second switch control instruction. It is understood that this embodiment compromises on interference resistance and resource cost by selecting a combination of four registers. More register combinations could also be used to achieve higher interference resistance. It is understood that the combination of four registers is only one compromise in this embodiment; if stronger interference resistance is required, more register combinations could be selected, which would require a corresponding increase in resource cost.

[0068] In this embodiment, the logic control unit 304 includes an AND gate logic unit A1, a first NOT gate logic unit N1, and a second NOT gate logic unit N2. The AND gate logic unit A1 includes a first input terminal, a second input terminal, a third input terminal, a fourth input terminal, and an output terminal. The first, second, third, and fourth input terminals of the AND gate logic unit A1 are electrically connected to the output terminals of four register subunits reg, and the output terminal of the AND gate logic unit A1 is electrically connected to a power switch 305. The first NOT gate logic unit N1 is electrically connected between the second input terminal of the AND gate logic unit A1 and the corresponding register subunit reg. The second NOT gate logic unit N2 is electrically connected between the fourth input terminal of the AND gate logic unit A1 and the corresponding register subunit reg.

[0069] In this embodiment, the power switch 305 is preferably an NMOS transistor Q1. The gate of the NMOS transistor Q1 is electrically connected to the output terminal of the AND gate logic unit A1, the drain of the NMOS transistor Q1 is electrically connected to the power supply battery 40, and the source of the NMOS transistor Q1 is electrically connected to the functional unit 3. When the output terminal of the gate logic unit A1 outputs a high level, the NMOS transistor Q1 is turned on; when the output terminal of the gate logic unit A1 outputs a low level, the NMOS transistor is turned off. In other embodiments of the present invention, the power switch 305 may also be a PMOS transistor or a bipolar transistor, etc., and is not limited thereto.

[0070] In this embodiment, the preset switch control commands are illustrated using binary power-on command 0101 and binary power-off command 0000 as examples. (See attached diagram.) Figure 4 and attached Figure 5 , attached Figure 4 This is a schematic diagram of the power-on timing of the NFC control power switch circuit 1 according to Embodiment 2 of the present invention. Figure 5 This is a schematic diagram of the power-on timing of the NFC control power switch circuit 1 according to Embodiment 2 of the present invention. When the binary values ​​of the output values ​​data_r[3], data_r[2], data_r[1], and data_r[0] of the 4-bit register subunit reg are 0101 from high to low, 0101 outputs a high-level switch signal after passing through the AND gate logic unit A1, the NMOS transistor Q1 is turned on, and the power supply battery 40 is connected to the functional unit 3. It can be understood that the power-on instruction is not limited to 0101, and the power-off instruction is not limited to 0000; other instructions can also be used. When other instructions are used, the switch control unit 30 makes adaptive adjustments accordingly.

[0071] Compared to existing technologies, the NFC control power switch circuit and electronic device proposed in this invention senses external electronic devices supporting NFC functionality through an NFC antenna. When such external electronic devices are sensed within a preset range, an induced voltage and an induced clock are generated, thereby powering on the NFC power partition unit to output a preset switch control command to the switch control unit. The switch control unit then connects or disconnects the power supply battery and functional units according to the switch control command. Therefore, the NFC control power switch circuit has no dynamic power consumption in standby mode, with only a small amount of leakage current, minimizing standby power consumption to approximately 0.05 microamps. The annual standby power consumption is approximately 0.44 mAh. Furthermore, the use of a multi-bit register combination to control the power switch increases anti-interference capabilities and reduces the possibility of abnormal power-on during standby. It is understood that standby current is strongly correlated with the leakage current of the selected process; generally, applications sensitive to standby power consumption will prioritize low-leakage processes. The 0.05 microamp leakage current data in this embodiment is based on a typical low-leakage process; an ultra-low leakage process could achieve even lower leakage current.

[0072] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An NFC control power switch circuit, characterized in that, It includes an NFC antenna, a control chip, and a power supply battery. The control chip includes an NFC power partitioning unit and a switch control unit. When the NFC antenna senses the presence of an external electronic device supporting NFC within a preset range, it generates an induced voltage and an induced clock. The NFC power partition unit is electrically connected to the NFC antenna and is used to power on when receiving the induced voltage, and to output a preset switch control command to the switch control unit when receiving a power-on / off command from the NFC reader (PCD). The switch control unit is located in the non-power-loss power partition, electrically connected to the NFC power partition unit, and also electrically connected between the power supply battery and the functional unit, for turning on or off the connection between the power supply battery and the functional unit according to the preset switch control command.

2. The NFC control power switch circuit according to claim 1, characterized in that, When the external electronic device supporting NFC function exceeds the preset range, the NFC power partition unit is powered down.

3. The NFC control power switch circuit according to claim 1, characterized in that, The NFC power partition unit includes a data terminal, an enable terminal, and a clock signal terminal. When the NFC power partition unit is powered on and receives a power-on / off command from the card reader (PCD): The data terminal outputs the preset switch control command to the switch control unit; The enable terminal outputs an NFC power-on reset signal to the switch control unit; The clock signal terminal outputs a clock signal to the switch control unit.

4. The NFC control power switch circuit according to claim 3, characterized in that, The switch control unit includes: The first level conversion unit is electrically connected to the data terminal and the enable terminal of the NFC power partition unit. It is used to convert the level of the preset switch control command according to the NFC power-on reset signal as the conversion enable signal, and output the second switch control command. The second level conversion unit is electrically connected to the clock signal terminal and the enable terminal of the NFC power partition unit, and is used to convert the clock signal's transition signal or static level according to the NFC power-on reset signal as the conversion enable signal; The register unit includes a clock signal terminal, an input terminal, and an output terminal. The clock signal terminal of the register unit is electrically connected to the second level conversion unit, and the input terminal of the register is electrically connected to the first level conversion unit. It is used to temporarily store and output the second switch control instruction. A logic control unit, electrically connected to the output of the register unit, is used to receive the second switch control command and output a switch signal according to the second switch control command; A power switch includes a control terminal, a first terminal, and a second terminal. The control terminal of the power switch is electrically connected to the logic control unit, the first terminal of the power switch is electrically connected to the power supply battery, and the second terminal of the power switch is electrically connected to the functional unit. The power switch is used to turn the connection between the power supply battery and the functional unit on or off according to the switch signal.

5. The NFC control power switch circuit according to claim 4, characterized in that: When the preset switch control command output by the data terminal is a power-off command, the NFC power-on reset signal is a high-level signal, the command converted by the first level conversion unit is a power-off control word, and the second level conversion unit converts a clock transition signal. When the preset switch control command output by the data terminal is a power-on command, the NFC power-on reset signal is a high-level signal, the command converted by the first level conversion unit is a power-on control word, and the second level conversion unit converts a clock transition signal.

6. The NFC control power switch circuit according to claim 5, characterized in that: The preset switch control command is a 4-bit binary command; The first level conversion unit includes four conversion sub-units, each of which receives the four-bit binary instruction and converts the level of the four-bit binary instruction according to the NFC power-on reset signal to output the second switch control instruction.

7. The NFC control power switch circuit according to claim 6, characterized in that: The register unit includes four register sub-units. The clock signal terminals of the four register sub-units are all electrically connected to the second level conversion unit. The input terminals of the four register sub-units are electrically connected to the four conversion sub-units in a one-to-one correspondence to store and output the second switch control command.

8. The NFC control power switch circuit according to claim 7, characterized in that, The logic control unit includes: An AND gate logic unit includes a first input terminal, a second input terminal, a third input terminal, a fourth input terminal, and an output terminal. The first input terminal, the second input terminal, the third input terminal, and the fourth input terminal of the AND gate logic unit are electrically connected to the output terminals of the four register subunits in a one-to-one correspondence. The output terminal of the AND gate logic unit is electrically connected to the power switch. The first NOT gate logic unit is electrically connected between the second input terminal of the AND gate logic unit and the corresponding register subunit; The second NOT gate logic unit is electrically connected between the fourth input terminal of the AND gate logic unit and the corresponding register subunit.

9. The NFC control power switch circuit according to claim 8, characterized in that, The power switch is an NMOS transistor, the gate of which is electrically connected to the output of the AND gate logic unit, the drain of which is electrically connected to the power supply battery, and the source of which is electrically connected to the functional unit.

10. An electronic device, characterized in that, Includes the NFC control power switch circuit as described in any one of claims 1-9.

Images