Circuit structure, packaged chip, and electronic device

Abstract

The application discloses a circuit structure, a packaged chip and an electronic device, and relates to the technical field of circuits.The circuit structure comprises a signal isolation module, an impedance matching module, an NFC module, a radio frequency module, a SAR sensor and an antenna.The NFC module, the radio frequency module and the SAR sensor are all connected to the antenna through the signal isolation module.Under the condition that the NFC module, the radio frequency module and the SAR sensor do not interfere with each other, the NFC module can perform near field communication through the antenna, the radio frequency module can perform cellular communication through the antenna, and the SAR sensor can determine the distance between a human body and the antenna in the circuit structure through the antenna.In this way, the NFC module, the radio frequency module and the SAR sensor can share one antenna, and thus the demand of the application scene of the electronic device can be met.

Description

Technical Field

[0001] This application relates to the field of circuit technology, and in particular to a circuit structure, packaged chip, and electronic device. Background Technology

[0002] With the rapid development of electronic devices, such as mobile phones, tablets, and smartwatches, more and more functions are integrated. For example, current electronic devices integrate near field communication (NFC) functionality. To implement NFC functionality, electronic devices need to have an NFC antenna and an NFC module connected to that antenna.

[0003] In related technologies, electronic devices also include a specific absorption rate (SAR) antenna and a SAR sensor connected to the SAR antenna. The SAR sensor can determine the distance between a human body and the SAR antenna. When the electronic device is operating, it can reduce its electromagnetic radiation power when the distance between the human body and the SAR antenna is less than or equal to a preset distance, thereby reducing the impact of electromagnetic radiation on the human body. Based on the application scenarios of the electronic device, the NFC antenna and the SAR antenna may need to be located in the same position. That is, the NFC antenna and the SAR antenna need to be the same antenna.

[0004] Therefore, how to enable the NFC module and the SAR sensor to share a single antenna has become an urgent problem to be solved. Summary of the Invention

[0005] This application provides a circuit structure, a packaged chip, and an electronic device. When applied to an electronic device, this circuit structure allows the NFC module, SAR sensor, and radio frequency module to share a single antenna, thereby meeting the needs of various application scenarios of the electronic device. The technical solution is as follows:

[0006] Firstly, a circuit structure is provided. This circuit structure is applied to electronic devices. The circuit structure includes a signal isolation module, an impedance matching module, an NFC module, a radio frequency module, a SAR sensor, and an antenna.

[0007] The signal isolation module has a first terminal, a second terminal, a third terminal, and a fourth terminal. The first terminal of the signal isolation module is connected to the first terminal of the impedance matching module, and the second terminal of the impedance matching module is connected to the NFC module. The second terminal of the signal isolation module is connected to the radio frequency (RF) module. The third terminal of the signal isolation module is connected to the SAR sensor. The fourth terminal of the signal isolation module is connected to the feed point of the antenna. Thus, the NFC module can perform near-field communication via the antenna. During near-field communication via the antenna, the impedance matching module is used to match the internal impedance of the NFC module with the external impedance (i.e., the load impedance). The RF module can perform cellular communication via the antenna. The SAR sensor can determine the distance between a human body and the antenna in the circuit structure via the antenna. The signal isolation module is used to prevent interference between the NFC module, the RF module, and the SAR sensor.

[0008] In this embodiment, the circuit structure includes a signal isolation module, an impedance matching module, an NFC module, a radio frequency (RF) module, a SAR sensor, and an antenna. The NFC module, RF module, and SAR sensor are all connected to the antenna via the signal isolation module. Thus, without interference between the NFC module, RF module, and SAR sensor, the NFC module can perform near-field communication via the antenna; the RF module can perform cellular communication via the antenna; and the SAR sensor can determine the distance between a human body and the antenna in the circuit structure. In other words, the NFC module, RF module, and SAR sensor can share a single antenna, which meets the application requirements of electronic devices.

[0009] The circuit structure provided in the embodiments of this application will be explained in detail below from two possible solutions.

[0010] The first possible solution.

[0011] In some embodiments, the signal isolation module includes a first inductor, a first capacitor, and a second inductor. A first terminal of the first inductor is connected to a first terminal of the impedance matching module. A first plate of the first capacitor is connected to the radio frequency module. A first terminal of the second inductor is connected to the SAR sensor. The second terminals of the first inductor, the second plate of the first capacitor, and the second terminal of the second inductor are all connected to a feed point.

[0012] The impedance matching module includes a third capacitor, a fourth capacitor, a fifth capacitor, and a third inductor. The first plate of the third capacitor is connected to the first terminal of the signal isolation module, and its second plate is connected to ground. The first plate of the fourth capacitor is connected to the first terminal of the signal isolation module, and its second plate is connected to the first plate of the fifth capacitor and the first terminal of the third inductor. The second plate of the fifth capacitor is connected to ground. The second terminal of the third inductor is connected to the NFC module.

[0013] In some specific embodiments, the circuit structure should satisfy the following condition: the capacitance value at the feed point is less than or equal to a preset capacitance value. The preset capacitance value is the background capacitance threshold of the SAR sensor. The antenna, the first inductor, and the impedance matching module should satisfy the following condition: the external impedance of the NFC module is within a preset impedance range. The preset impedance range is the preset external impedance range of the NFC module. The preset external impedance range of the NFC module depends on the internal impedance of the NFC module. In this possible solution, the inductance value of the first inductor can be increased while the capacitance value of the impedance matching module is decreased, thus maintaining the external impedance of the NFC module unchanged while reducing the capacitance value at the feed point.

[0014] The second possible solution.

[0015] In some embodiments, the signal isolation module includes a first inductor, a first capacitor, a second inductor, and a second capacitor. A first terminal of the first inductor is connected to a first terminal of the impedance matching module. A first plate of the first capacitor is connected to the radio frequency module. A first terminal of the second inductor is connected to the SAR sensor. A second terminal of the second inductor is connected to the first plate of the second capacitor. The second terminal of the first inductor, the second plate of the first capacitor, and the second plate of the second capacitor are all connected to a feed point.

[0016] The impedance matching module includes a third capacitor, a fourth capacitor, a fifth capacitor, and a third inductor. The first plate of the third capacitor is connected to the first terminal of the signal isolation module, and its second plate is connected to ground. The first plate of the fourth capacitor is connected to the first terminal of the signal isolation module, and its second plate is connected to the first plate of the fifth capacitor and the first terminal of the third inductor. The second plate of the fifth capacitor is connected to ground. The second terminal of the third inductor is connected to the NFC module.

[0017] In some specific embodiments, the circuit structure should satisfy the following condition: the capacitance value at the connection between the SAR sensor and the first end of the second inductor is less than or equal to a preset capacitance value. The preset capacitance value is the background capacitance threshold of the SAR sensor. In some possible embodiments, the capacitance value of the second capacitor is greater than or equal to 100 picofarads, and less than or equal to 10 nF.

[0018] In some embodiments, the SAR sensor has a first preset capacitance range. The first preset capacitance range is used to determine whether the distance between the human body and the antenna in the circuit structure is less than or equal to a preset distance. The minimum value of the first preset capacitance range is... The maximum value of the first preset capacitance range is Among them, C Q C1 is the capacitance between the feed point and the ground wire, and C2 is the capacitance of the second capacitor. ΔC minΔC is the minimum value within the second preset capacitance range. max This is the maximum value within the second preset capacitance range. The second preset capacitance range is used to determine whether the distance between the human body and the antenna is less than or equal to a preset distance when the SAR sensor is only connected to the antenna.

[0019] In some embodiments, and The difference is greater than the minimum capacitance resolution of the SAR sensor, and It is greater than the minimum resolution of the SAR sensor's capacitance.

[0020] Secondly, a packaged chip is also provided. The packaged chip includes a signal isolation module, an impedance matching module, an NFC module, a radio frequency (RF) module, and a SAR sensor, all encapsulated within a packaged structure. Specifically, the first terminal of the signal isolation module is connected to the first terminal of the impedance matching module, and the second terminal of the impedance matching module is connected to the NFC module. The second terminal of the signal isolation module is connected to the RF module. The third terminal of the signal isolation module is connected to the SAR sensor. The fourth terminal of the signal isolation module is used to connect to the feed point of an antenna. The NFC module is used for near-field communication via the antenna. The RF module is used for cellular communication via the antenna. The SAR sensor is used to determine the distance between a human body and the antenna. The signal isolation module prevents interference between the NFC module, the RF module, and the SAR sensor. In other words, the signal isolation module, impedance matching module, NFC module, RF module, and SAR sensor in the above circuit structure can be packaged into a single chip. In some other embodiments, any one or more of the signal isolation module, impedance matching module, NFC module, RF module, and SAR sensor can also be packaged into a single chip.

[0021] Thirdly, an electronic device is also provided. The electronic device includes a circuit structure as described in any of the first aspects. Alternatively, the electronic device includes an antenna and a packaged chip as described in the second aspect.

[0022] The technical effects achieved by the second and third aspects mentioned above are similar to those achieved by the corresponding technical means in the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the appearance of the first electronic device in the related technology;

[0024] Figure 2 This is a schematic diagram of the appearance of a second type of electronic device in the related technology;

[0025] Figure 3 It is the circuit structure diagram of the first electronic device in the related technology;

[0026] Figure 4 This is a schematic diagram of the structure of an electronic device in related technologies;

[0027] Figure 5 This is a circuit diagram of the second type of electronic device in the related technology;

[0028] Figure 6 This is a circuit diagram of the third type of electronic device in related technologies;

[0029] Figure 7 This is a schematic diagram of a circuit structure provided in an embodiment of this application;

[0030] Figure 8 This is a schematic diagram illustrating the working principle of a SAR sensor provided in an embodiment of this application;

[0031] Figure 9 This is an equivalent circuit diagram illustrating the working principle of a SAR sensor provided in an embodiment of this application;

[0032] Figure 10 This is a schematic diagram of the structure of a SAR sensor provided in an embodiment of this application;

[0033] Figure 11 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application;

[0034] Figure 12 This is a circuit diagram of the first circuit structure provided in the embodiments of this application;

[0035] Figure 13 This is a circuit diagram of the second circuit structure provided in the embodiments of this application;

[0036] Figure 14 This is an equivalent circuit diagram of the first NFC module, impedance matching module, first inductor, and antenna provided in the embodiments of this application;

[0037] Figure 15 yes Figure 14 The Smith chart of the equivalent circuit when the first electrical signal is input is shown.

[0038] Figure 16 This is an equivalent circuit diagram of the second type of NFC module, impedance matching module, first inductor, and antenna provided in the embodiments of this application;

[0039] Figure 17 yes Figure 16 The Smith chart of the equivalent circuit when the first electrical signal is input is shown.

[0040] Figure 18 This is a circuit diagram of the third circuit structure provided in the embodiments of this application;

[0041] Figure 19This is an equivalent circuit diagram of the circuit structure of the first SAR sensor provided in this application embodiment when it is in operation;

[0042] Figure 20 This is an equivalent circuit diagram of the circuit structure of the second SAR sensor provided in the embodiments of this application when it is in operation;

[0043] Figure 21 This is a circuit diagram of the fourth circuit structure provided in the embodiments of this application.

[0044] The meanings of the reference numerals in the related technologies are as follows: 10, electronic device; 112, NFC module; 114, NFC antenna; 122, SAR sensor; 124, SAR antenna; 132, radio frequency module; 134, radio frequency antenna;

[0045] The meanings of the reference numerals in the embodiments of this application are as follows:

[0046] 20. Circuit structure; 210. Signal isolation module; 220. Impedance matching module; 222. First impedance matching module; 224. Second impedance matching module; 230. NFC module; 240. Radio frequency module; 250. SAR sensor; 251. Multiplexing unit; 252. Shielded driving unit; 253. Capacitor voltage conversion unit; 254. Offset compensation unit; 255. Temperature sensing unit; 256. Computation unit; 257. Analog-to-digital conversion unit; 258. Processing unit; 260. Antenna; 30. Electronic equipment. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0048] It should be understood that "multiple" as mentioned in this application refers to two or more. In the description of this application, unless otherwise stated, " / " indicates "or," for example, A / B can mean A or B; "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist, for example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, to facilitate a clear description of the technical solutions of this application, the terms "first," "second," etc., are used to distinguish identical or similar items with essentially the same function and effect. Those skilled in the art will understand that the terms "first," "second," etc., do not limit the quantity or execution order, and that "first," "second," etc., do not necessarily imply differences.

[0049] Before providing a detailed explanation of the circuit structure provided in the embodiments of this application, the application scenarios and related technologies of the circuit structure will be explained first.

[0050] Electronic devices 10 include mobile phones, tablets, laptops, televisions, wearable devices, etc.; wearable devices include smart bracelets, wristbands, etc. Figure 1 and Figure 2 These are schematic diagrams of the appearance of two different electronic devices 10 in related technologies. Figure 1 The electronic device 10 shown is a mobile phone. Figure 2 The electronic device 10 shown is a tablet computer. With the rapid development of electronic devices 10, more and more functions are integrated into them. For example, electronic devices 10 can implement NFC functionality.

[0051] NFC, also known as Near Field Communication or Short Range Wireless Communication, refers to wireless communication with a distance of less than or equal to 10 cm. NFC uses electromagnetic coupling induction technology to provide short-range wireless connectivity, enabling bidirectional interactive communication between electronic device 10 and other electronic devices. Figure 3 This is a circuit structure diagram of an electronic device 10 in related technologies. For example... Figure 3 As shown, to implement NFC functionality, electronic device 10 needs to be equipped with an NFC antenna 114 and an NFC module 112 connected to the NFC antenna 114. The NFC module 112 is used for electromagnetic coupling induction with other electronic devices via the NFC antenna 114. Figure 4 This is a schematic diagram of the structure of an electronic device 10 in related technologies. For example... Figure 4 As shown, the NFC antenna 114 can be the top antenna among the frame antennas in the electronic device 10. A frame antenna refers to an antenna integrated with the frame of the electronic device 10. The top antenna among the frame antennas refers to the antenna located at the very top center of the frame antenna along the plane of the paper.

[0052] SAR value, also known as specific absorptivity or electromagnetic wave absorption ratio, refers to the energy absorbed by a unit mass of matter per unit time from the electromagnetic radiation emitted by a mobile terminal. SAR value is an important parameter for measuring the impact of electromagnetic radiation from electronic devices on the human body. The lower the SAR value, the less electromagnetic radiation energy is absorbed by the human body; the higher the SAR value, the more electromagnetic radiation energy is absorbed. Figure 5 This is a circuit diagram of another electronic device 10 in related technologies. For example... Figure 5As shown, in related technologies, the electronic device 10 also includes a SAR antenna 124 and a SAR sensor 122 connected to the SAR antenna 124. The SAR sensor 122 can determine whether a human body is close to the SAR antenna 124, that is, the SAR sensor 122 can determine the distance between the human body and the SAR antenna 124. When the electronic device 10 is working, it can reduce the electromagnetic radiation power of the electronic device 10 when the distance between the human body and the SAR antenna 124 is less than or equal to a preset distance, thereby reducing the SAR value and reducing the impact of electromagnetic radiation on the human body.

[0053] In related technologies, the electronic device 10 can also realize cellular communication functions. Cellular communication refers to mobile communication using cellular wireless networking, which can provide communication services such as voice, data, and video images through a cellular mobile communication network composed of base stations and electronic devices 10. Figure 6 This is a circuit structure diagram of another electronic device 10 in related technologies. For example... Figure 6 As shown, in related technologies, for cellular communication, the electronic device 10 also includes a radio frequency antenna 134 and a radio frequency module 132 connected to the radio frequency antenna 134. The radio frequency module 132 can transmit and receive cellular signals through the radio frequency antenna 134.

[0054] In related technologies, based on the application scenarios of the electronic device 10, the NFC antenna 114 and the SAR antenna 124 may need to be located in the same position. For example, both the NFC antenna 114 and the SAR antenna 124 may need to be the top antenna in the frame antenna of the electronic device 10. In this case, the NFC antenna 114 and the SAR antenna 124 need to be the same antenna. Therefore, how to make the NFC module 112 and the SAR sensor 122 share a single antenna becomes an urgent problem to be solved.

[0055] Therefore, this application provides a circuit structure, a packaged chip, and an electronic device. When this circuit structure is applied to an electronic device, the NFC module, SAR sensor, and radio frequency module can share a single antenna, thereby meeting the needs of the application scenarios of the electronic device.

[0056] The circuit structure provided in the embodiments of this application will be explained in detail below. In the embodiments of this application, the connection between two electrical structures (including electrical modules, electrical units, and electronic devices) is an electrical connection. Here, an electrical connection means that the two electrical structures can transmit electrical signals through the connection. In addition, the electrical connection between two electrical structures can be a direct connection through a wire or an indirect connection through other electrical structures.

[0057] Figure 7This is a schematic diagram of a circuit structure 20 provided in an embodiment of this application. This circuit structure 20 is applied to electronic devices. For example... Figure 7 As shown, the circuit structure 20 includes a signal isolation module 210, an impedance matching module 220, an NFC module 230, a radio frequency module 240, a SAR sensor 250, and an antenna 260.

[0058] The signal isolation module 210 has a first terminal a, a second terminal b, a third terminal c, and a fourth terminal d. The first terminal a, the second terminal b, and the third terminal c of the signal isolation module 210 can all transmit electrical signals to the fourth terminal d of the signal isolation module 210. Furthermore, when any one of the first terminal a, the second terminal b, or the third terminal c of the signal isolation module 210 transmits an electrical signal to the fourth terminal d of the signal isolation module 210, the electrical signal will not be transmitted to the other two of the first terminal a, the second terminal b, or the third terminal c.

[0059] Antenna 260 is used for receiving and transmitting radio electromagnetic waves. When antenna 260 is operating, it can convert radio electromagnetic waves into electrical signals, thereby achieving radio electromagnetic wave reception; it can also convert electrical signals into radio electromagnetic waves, thereby achieving radio electromagnetic wave transmission. Antenna 260 has a feed point, which refers to the connection point of antenna 260 for connecting to a feed line. In this embodiment, the feed point of antenna 260 is connected to the fourth terminal d of signal isolation module 210. Antenna 260 can be a frame antenna in an electronic device, or it can be any antenna in an electronic device other than a frame antenna.

[0060] Impedance matching module 220 has a first terminal e and a second terminal f. The first terminal e of impedance matching module 220 is connected to the first terminal a of signal isolation module 210, and the second terminal f of impedance matching module 220 is connected to NFC module 230. That is, NFC module 230 is connected to the first terminal a of signal isolation module 210 through impedance matching module 220. Here, impedance matching module 220 is used to match the internal impedance of NFC module 230 with its external impedance. The external impedance of NFC module 230 is also called load impedance. When the internal impedance and external impedance of NFC module 230 are matched, signal reflection generated when NFC module 230 inputs and outputs electrical signals can be suppressed, thereby maximizing the power of NFC module 230's input and output electrical signals. In this embodiment, NFC module 230 can be an NFC chip.

[0061] In other words, the NFC module 230 is connected to the antenna 260 through the second terminal f and the first terminal e of the impedance matching module 220, and the first terminal a and the fourth terminal d of the signal isolation module 210. For ease of description, in this embodiment, the electrical signal transmitted between the NFC module 230 and the antenna 260 during operation is referred to as the first electrical signal. Thus, when the NFC module 230 is operating, it can transmit the first electrical signal to the antenna 260 to generate an electromagnetic field, thereby enabling the NFC module 230 to perform electromagnetic coupling induction with other electronic devices through the electromagnetic field generated by the antenna 260, achieving near-field communication. It is understood that when the NFC module 230 transmits the first electrical signal between the antenna 260 and the antenna 260, the first electrical signal is not transmitted to the second terminal b and the third terminal c of the signal isolation module 210.

[0062] The radio frequency (RF) module 240 has a first terminal g. The first terminal g of the RF module 240 is connected to the second terminal b of the signal isolation module 210 for transmitting cellular signals. Cellular signals are a type of electrical signal. In some embodiments, the RF module 240 may also have a second terminal (not shown in the figure). The second terminal of the RF module 240 can be connected to the baseband subsystem in an electronic device. In some specific embodiments, the RF module 240 may include electronic devices such as switches, antenna tuners, amplifiers, mixers, local oscillators (LO), and filters. Amplifiers include power amplifiers (PA) and low noise amplifiers (LNA). The RF module 240 can be further divided into an RF receive path and an RF transmit path. The RF receive path operates in downlink mode, used to receive cellular signals, process the cellular signals (e.g., amplify, filter) to obtain baseband signals, and transmit them to the baseband subsystem. The radio frequency transmission channel operates in uplink mode to receive baseband signals from the baseband subsystem and process the baseband signals (such as amplification and filtering) to obtain cellular signals.

[0063] In other words, the first terminal g of the RF module 240 is connected to the antenna 260 through the second terminal b and the fourth terminal d of the signal isolation module 210. Thus, when the RF module 240 is working, it can transmit cellular signals to the antenna 260 and receive cellular signals transmitted by the antenna 260, thereby achieving cellular communication. Understandably, when the RF module 240 and the antenna 260 transmit cellular signals, the cellular signals will not be transmitted to the third terminal c of the signal isolation module 210, nor will they be transmitted to the NFC module 230 through the first terminal a of the signal isolation module 210.

[0064] SAR sensor 250 has a first terminal h. The first terminal h of SAR sensor 250 is connected to the third terminal c of signal isolation module 210. That is, the first terminal h of SAR sensor 250 is connected to antenna 260 through the third terminal c and the fourth terminal d of signal isolation module 210. Thus, when SAR sensor 250 is working, it can determine whether the distance between a human body and antenna 260 is less than or equal to a preset distance through antenna 260. In some embodiments, SAR sensor 250 may also have a second terminal (not shown in the figure). The second terminal of SAR sensor 250 can be connected to a system-on-chip (SOC) in an electronic device, so that when SAR sensor 250 determines that the distance between a human body and antenna 260 is less than or equal to the preset distance, that is, when it determines that the human body is close to antenna 260, it transmits a preset communication signal to SOC. SOC can reduce the electromagnetic radiation power of electronic device after receiving preset communication signal. It is understood that when SAR sensor 250 determines whether the distance between human body and antenna 260 is less than or equal to the preset distance through antenna 260, electrical signal transmission is required between SAR sensor 250 and antenna 260. For ease of description, in this embodiment, the electrical signal transmitted between the SAR sensor 250 and the antenna 260 during operation is referred to as the second electrical signal. When the second electrical signal is transmitted between the SAR sensor 250 and the antenna 260, it is not transmitted to the NFC module 230 through the first terminal a of the signal isolation module 210, nor is it transmitted to the radio frequency module 240 through the second terminal b of the signal isolation module 210. Thus, the signal isolation module 210 ensures that the NFC module 230, the radio frequency module 240, and the SAR sensor 250 do not interfere with each other during operation.

[0065] In this embodiment, the circuit structure 20 includes a signal isolation module 210, an impedance matching module 220, an NFC module 230, a radio frequency module 240, a SAR sensor 250, and an antenna 260. The NFC module 230, radio frequency module 240, and SAR sensor 250 are all connected to the antenna 260 via the signal isolation module 210. Thus, without interference between the NFC module 230, radio frequency module 240, and SAR sensor 250, the NFC module 230 can perform near-field communication via the antenna 260; the radio frequency module 240 can perform cellular communication via the antenna 260; and the SAR sensor 250 can determine whether the distance between a human body and the antenna 260 is less than or equal to a preset distance. In other words, the NFC module 230, radio frequency module 240, and SAR sensor 250 can share a single antenna 260, which meets the needs of various application scenarios for electronic devices.

[0066] It is understood that in some other embodiments of this application, the circuit structure 20 may not include any one of the NFC module 230, the radio frequency module 240, and the SAR sensor 250. When the circuit structure 20 does not include the NFC module 230, it may also not include the impedance matching module 220. For example, in some embodiments, the circuit structure 20 may only include the signal isolation module 210, the impedance matching module 220, the NFC module 230, the radio frequency module 240, and the antenna 260. In other embodiments, the circuit structure 20 may only include the signal isolation module 210, the radio frequency module 240, the SAR sensor 250, and the antenna 260, which will not be described in detail here.

[0067] The following explains the principle of SAR sensor 250 in "determining whether the distance between the human body and antenna 260 is less than or equal to a preset distance" and the structure of SAR sensor 250.

[0068] Figure 8 This is a schematic diagram illustrating the working principle of a SAR sensor 250 provided in an embodiment of this application. Figure 8 As shown, when the SAR sensor 250 needs to determine whether the distance between the human body and the antenna 260 is less than or equal to a preset distance through the antenna 260, the SAR sensor 250 can output a second electrical signal to the antenna 260. At this time, the antenna 260 can convert the received second electrical signal into radio electromagnetic waves and radiate them outward, thereby forming an outward radiating electromagnetic field. Figure 8 Figure (a) shows a schematic diagram of the electromagnetic field radiated outward by the antenna 260 when the distance between the human body and the antenna 260 is greater than a preset distance; Figure 8 Figure (b) shows a schematic diagram of the electromagnetic field radiated outward by antenna 260 when the distance between the human body and antenna 260 is less than or equal to a preset distance. (Comparison) Figure 8 As shown in Figures (a) and (b), since the human body is a conductor, when the human body approaches the antenna 260, i.e., when the distance between the human body and the antenna 260 is less than or equal to the preset distance, it will cause a change in the electromagnetic field radiated outward by the antenna 260. Generally, the preset distance can be set by those skilled in the art based on experience and requirements. The preset distance can be, for example, 10cm, 15cm, or 20cm, and is not limited here.

[0069] Figure 9 An equivalent circuit diagram illustrating the working principle of the SAR sensor 250 is shown. Among them, Figure 9 Figure (a) in the middle is Figure 8 The equivalent circuit of diagram (a) in the figure. Figure 9 Figure (b) is Figure 8 The equivalent circuit of diagram (b) in the diagram. See also... Figure 8 Figure (a) and Figure 9As shown in Figure (a), when the distance between the human body and antenna 260 is greater than a preset distance, only background capacitance CA exists between the first terminal h of SAR sensor 250 and ground wire GND. Background capacitance CA refers to the capacitance of the environment in which SAR sensor 250 is located when it is operating. The capacitance value of background capacitance CA does not change with the distance between the human body and antenna 260. In this case, the capacitance value of the first terminal h of SAR sensor 250 is the capacitance value of background capacitance CA. See also... Figure 8 Figure (b) in the middle and Figure 9 As shown in Figure (b), when the distance between the human body and antenna 260 is less than or equal to a preset distance, the influence of the human body on the electromagnetic field radiated outward by antenna 260 can be equivalent to a coupling capacitor CB connected in parallel with the background capacitor CA. In this case, compared to the case where the distance between the human body and antenna 260 is greater than the preset distance, the capacitance value of the first terminal h of SAR sensor 250 will inevitably change. Based on this, SAR sensor 250 can determine whether the distance between the human body and antenna 260 is less than or equal to the preset distance by detecting the capacitance value of its first terminal h. For example, a preset capacitance value range can be provided within SAR sensor 250. When the capacitance value of the first terminal h of SAR sensor 250 is within the preset capacitance value range, SAR sensor 250 determines that the distance between the human body and antenna 260 is less than or equal to the preset distance; conversely, when the capacitance value of the first terminal h of SAR sensor 250 is not within the preset capacitance value range, SAR sensor 250 determines that the distance between the human body and antenna 260 is greater than the preset distance.

[0070] Based on the above working principle, the structure of the SAR sensor 250 can be as follows: Figure 10 As shown. See also Figure 10 The SAR sensor 250 includes a multiplexing unit 251, a shielding drive unit 252, a capacitor voltage conversion unit 253, an offset compensation unit 254, a temperature sensing unit 255, a computing unit 256, an analog-to-digital conversion unit 257, and a processing unit 258.

[0071] The multiplexing unit 251 has a first port 1, a second port 2, a third port 3, a fourth port 4, a fifth port 5, a sixth port 6, and a seventh port 7. The first port 1, second port 2, third port 3, fourth port 4, and fifth port 5 of the multiplexing unit 251 can all be connected to the antenna 260. "Connected to the antenna 260" here includes connection to the third terminal c of the signal isolation module 210, so as to connect to the antenna 260 through the third terminal c and the fourth terminal d of the signal isolation module 210. That is, the first port 1, second port 2, third port 3, fourth port 4, and fifth port 5 of the multiplexing unit 251 are all the first terminal h of the SAR sensor 250. In some other embodiments, the multiplexing unit 251 may also include only one or more of the first port 1, second port 2, third port 3, fourth port 4, and fifth port 5. The sixth port 6 of the multiplexing unit 251 is connected to the shielding drive unit 252, so that the shielding drive unit 252 can control and drive the shielding components in the multiplexing unit 251, thereby reducing radio frequency interference. The seventh port 7 of the multiplexing unit 251 is connected to the capacitor voltage conversion unit 253. Here, each of the first port 1, second port 2, third port 3, fourth port 4, and fifth port 5 of the multiplexing unit 251 can be connected to the seventh port 7 of the multiplexing unit 251.

[0072] Taking the connection of the first port 1 of multiplexing unit 251 to antenna 260 and the connection of the first port 1 of multiplexing unit 251 to the seventh port 7 as an example, when the first port 1 of multiplexing unit 251 and the seventh port 7 are connected, the capacitor-to-voltage conversion unit 253 can generate a first voltage signal according to the capacitance value of the first port 1 of multiplexing unit 251, and output the first voltage signal to the arithmetic unit 256. The first voltage signal is an analog electrical signal. During the process of capacitor-to-voltage conversion unit 253 generating the first voltage signal according to the capacitance value, offset compensation unit 254 can also detect and compensate for the offset of the first voltage signal generated by capacitor-to-voltage conversion unit 253, thereby ensuring the accuracy and stability of the first voltage signal output to arithmetic unit 256.

[0073] The temperature sensing unit 255 generates a second voltage signal based on the temperature of the environment where the SAR sensor 250 is located, and outputs the second voltage signal to the arithmetic unit 256. The second voltage signal is an analog electrical signal. The arithmetic unit 256 processes the first and second voltage signals. For example, the arithmetic unit 256 may include a programmable gain amplifier for linearly amplifying the first and second voltage signals. The arithmetic unit 256, the analog-to-digital converter 257, and the processing unit 258 are connected in sequence. The analog-to-digital converter 257 converts the analog electrical signal into a digital electrical signal. Thus, the processing unit 258 can determine the capacitance value of the first port 1 of the multiplexing unit 251 and the temperature of the environment where the SAR sensor 250 is located based on the received digital electrical signal.

[0074] It is understood that in some other embodiments, if the capacitor voltage conversion unit 253 only needs to be connected to one antenna 260, the SAR sensor 250 may not include the multiplexing unit 251 and the shielding drive unit 252. Additionally, the SAR sensor 250 may also not include the temperature sensing unit 255, etc., which will not be elaborated further.

[0075] Figure 11 This is a schematic diagram of the structure of an electronic device 30 provided in an embodiment of this application, which includes... Figure 10 The SAR sensor 250 is shown. Figure 11 In the illustrated electronic device 30, the processing unit 258 in the SAR sensor 250 is the microcontroller (MCU), i.e., a single-chip microcomputer, of the electronic device 30. For example... Figure 11 As shown, the analog-to-digital converter 257 can be connected to the MCU via an I2C (inter-integrated circuit) bus. The MCU can also be connected to an I2C chip, read-only memory (ROM), and random access memory (RAM) via the I2C bus. The RAM includes code RAM and data RAM. The I2C chip also has a first port 1, a second port 2, and a third port 3 for connecting to other electronic devices, which will not be described further.

[0076] The circuit structure 20 provided in the embodiments of this application will be explained in detail below from two possible solutions.

[0077] I. The first possible solution.

[0078] Figure 12 This is a circuit diagram of a circuit structure 20 provided in an embodiment of this application. For example... Figure 12As shown, in some embodiments, the signal isolation module 210 includes a first inductor L1, a first capacitor C1, and a second inductor L2.

[0079] The second terminal of the first inductor L1, the second plate of the first capacitor C1, and the second terminal of the second inductor L2 are all connected to the feed point of the antenna 260. That is, the second terminal of the first inductor L1, the second plate of the first capacitor C1, and the second terminal of the second inductor L2 are connected to the same node, which is the fourth terminal d of the signal isolation module 210, and this node is used to connect to the feed point of the antenna 260. In the following embodiments, for ease of description, the node connected to the second terminal of the first inductor L1, the second plate of the first capacitor C1, the second terminal of the second inductor L2, and the feed point of the antenna 260 is referred to as node Q.

[0080] The first terminal of the first inductor L1 is connected to the first terminal e of the impedance matching module 220. That is, the first terminal of the first inductor L1 is the first terminal a of the signal isolation module 210. Here, the first inductor L1 is used to block cellular signals, so that when the RF module 240 and the antenna 260 transmit cellular signals, the cellular signals will not be transmitted to the NFC module 230 through the first terminal a of the signal isolation module 210. Similarly, the first inductor L1 is also used to block the second electrical signal, so that the second electrical signal will not be transmitted to the NFC module 230 through the first terminal a of the signal isolation module 210.

[0081] The first plate of the first capacitor C1 is connected to the first terminal g of the RF module 240. That is, the first plate of the first capacitor C1 is also the second terminal b of the signal isolation module 210. Here, the first capacitor C1 is used to block the second electrical signal, so that when the SAR sensor 250 and the antenna 260 transmit the second electrical signal, the second electrical signal will not be transmitted to the RF module 240 through the second terminal b of the signal isolation module 210. Similarly, the first capacitor C1 is also used to block the first electrical signal, so that the first electrical signal will not be transmitted to the RF module 240 through the second terminal b of the signal isolation module 210.

[0082] The first terminal of the second inductor L2 is connected to the first terminal h of the SAR sensor 250. That is, the first terminal of the second inductor L2 is the third terminal c of the signal isolation module 210. Here, the second inductor L2 is used to block cellular signals, so that when the RF module 240 and the antenna 260 transmit cellular signals, the cellular signals will not be transmitted to the SAR sensor 250 through the third terminal c of the signal isolation module 210. Similarly, the second inductor L2 is also used to block the first electrical signal, so that the first electrical signal will not be transmitted to the SAR sensor 250 through the third terminal c of the signal isolation module 210.

[0083] It is understood that in other embodiments of this application, the first inductor L1, the first capacitor C1, and the second inductor L2 can all be replaced with other electrical units having the same signal blocking function. For example, the first inductor L1 can be replaced with a first isolation unit, which can be a high-order circuit formed by inductors and capacitors connected in series or in parallel, used to block cellular signals and the second electrical signal. The first capacitor C1 can be replaced with a second isolation unit, which can also be a high-order circuit formed by inductors and capacitors connected in series or in parallel, used to block the first electrical signal and the second electrical signal. The second inductor L2 can be replaced with a third isolation unit, which is used to block both cellular signals and the first electrical signal, and will not be described in detail here.

[0084] Still as Figure 12 As shown, in some embodiments, the impedance matching module 220 includes a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, and a third inductor L3.

[0085] The first plate of the third capacitor C3 is connected to the first terminal of the signal isolation module 210, and the first plate of the fourth capacitor C4 is also connected to the first terminal of the signal isolation module 210. That is, the first plates of the third capacitor C3 and the fourth capacitor C4 are connected together to form the first terminal e of the impedance matching module 220. The second plate of the third capacitor C3 is connected to ground GND. The second plate of the fourth capacitor C4 is connected to the first plate of the fifth capacitor C5 and the first terminal of the third inductor L3. The second plate of the fifth capacitor C5 is connected to ground GND. The second terminal of the third inductor L3 is connected to the NFC module 230. That is, the second terminal of the third inductor L3 is the second terminal f of the impedance matching module 220.

[0086] In this possible solution, the circuit structure 20 should also satisfy the following condition 1: when the distance between the human body and the antenna 260 is greater than the preset distance, the capacitance value of the feed point of the antenna 260 is less than or equal to the preset capacitance value.

[0087] Specifically, as mentioned earlier, the principle by which the SAR sensor 250 "determines whether the distance between the human body and the antenna 260 is less than or equal to a preset distance through the antenna 260" is as follows: the SAR sensor 250 determines whether the distance between the human body and the antenna 260 is less than or equal to a preset distance by detecting the capacitance value of its first terminal h. The capacitor connected to the first terminal h of the SAR sensor 250 includes the background capacitance CA and the coupling capacitance CB. The background capacitance CA refers to the capacitance in the environment in which the SAR sensor 250 is located when it is operating. The capacitance value of the background capacitance CA does not change with the distance between the human body and the antenna 260. For example, the background capacitance CA includes the capacitor connected to the first terminal h of the SAR sensor 250, as well as parasitic capacitances in the circuit board on which the SAR sensor 250 is located. Figure 12 In the illustrated embodiment, the background capacitance CA includes a third capacitor C3, a fourth capacitor C4, and a fifth capacitor C5. The coupling capacitance CB refers to the capacitance generated when a human body approaches the antenna 260 during SAR sensor 250 operation. The capacitance value of the coupling capacitance CB changes with the distance between the human body and the antenna 260. Therefore, the capacitance value of the background capacitance CA has a significant impact on the capacitance value of the first terminal h of the SAR sensor 250, thus affecting the sensitivity of the SAR sensor 250 in detecting whether the distance between the human body and the antenna 260 is less than or equal to a preset distance. Generally, the SAR sensor 250 has a background capacitance threshold. The capacitance value of the background capacitance CA connected to the first terminal h of the SAR sensor 250 should be less than or equal to this background capacitance threshold. In this embodiment, the preset capacitance value refers to the background capacitance threshold of the SAR sensor 250.

[0088] exist Figure 12 In the illustrated embodiment, since only the second inductor L2 is connected between the first terminal h of the SAR sensor 250 and node Q, the capacitance value of the background capacitor CA connected to the first terminal h of the SAR sensor 250 is the capacitance value of node Q when the distance between the human body and the antenna 260 is greater than a preset distance. Since the feed point of the antenna 260 is connected to node Q, the capacitance value of the background capacitor CA connected to the first terminal h of the SAR sensor 250 is also the capacitance value of the feed point of the antenna 260 when the distance between the human body and the antenna 260 is greater than a preset distance. Therefore, in this possible solution, when the distance between the human body and the antenna 260 is greater than a preset distance, the capacitance value of the feed point of the antenna 260 should be less than or equal to the preset capacitance value.

[0089] Easy to understand, in Figure 12 In the embodiment shown, when the distance between the human body and the antenna 260 is greater than a preset distance, the capacitance value of the feed point of the antenna 260, that is, the capacitance value of node Q, is determined by the capacitance values ​​of the third capacitor C3, the fourth capacitor C4, and the fifth capacitor C5.

[0090] In this possible solution, the antenna 260, the first inductor L1, and the impedance matching module 220 should also satisfy the following condition 2: make the external impedance of the NFC module 230 within the preset impedance range.

[0091] Specifically, as mentioned earlier, the function of the impedance matching module 220 is to match the internal impedance of the NFC module 230 with its external impedance. Figure 12In the illustrated embodiment, the NFC module 230 is connected to the antenna 260 via the impedance matching module 220 and the first inductor L1. That is, the external impedance of the NFC module 230 is affected by the impedance of the impedance matching module 220, the impedance of the first inductor L1, and the impedance of the antenna 260.

[0092] The preset impedance range is the preset external impedance range of the NFC module 230. The preset external impedance range of the NFC module 230 depends on the internal impedance of the NFC module 230. When the external impedance of the NFC module 230 is within the preset impedance range, the internal impedance of the NFC module 230 can be matched with the external impedance. Based on this, in this possible solution, it is necessary to limit the antenna 260, the first inductor L1, and the impedance matching module 220 so that the external impedance of the NFC module 230 is within the preset impedance range.

[0093] Understandably, in this possible solution, Figure 12 The circuit structure 20 shown should simultaneously satisfy conditions 1 and 2 above. Condition 1 can be satisfied by changing the capacitance values ​​of the third capacitor C3, the fourth capacitor C4, and the fifth capacitor C5. However, changing these capacitance values ​​will inevitably change the impedance of the impedance matching module 220. Therefore, condition 2 can also be satisfied by further adjusting the inductance value of the first inductor L1. For example, the capacitance values ​​of the third capacitor C3, the fourth capacitor C4, and the fifth capacitor C5 in the impedance matching module 220 are generally in the nF (nanofa) range, resulting in a capacitance value in the feed point of the antenna 260 also being in the nF range when the distance between the human body and the antenna 260 is greater than a preset distance. While the preset capacitance values ​​vary depending on the SAR sensor 250, they are generally in the pF (picofa) range, such as 250pF, 300pF, 600pF, and 700pF. In this case, the capacitance value of the antenna 260 feed point can be reduced when the distance between the human body and the antenna 260 is greater than a preset distance by changing the capacitance value of the third capacitor C3, the fourth capacitor C4, and the fifth capacitor C5; and the internal impedance of the NFC module 230 can be matched with the external impedance by increasing the inductance value of the first inductor L1.

[0094] The following example, with a preset capacitance value of 700pF and a preset impedance range of 11Ω to 13Ω, will provide a detailed explanation of how circuit structure 20 can simultaneously satisfy conditions 1 and 2.

[0095] Figure 13 This is a circuit diagram of another circuit structure 20 provided in the embodiments of this application, compared to Figure 12 The circuit structure 20 shown is as follows. Figure 13 The circuit structure 20 shown does not include the second inductor L2 and the SAR sensor 250. Therefore, Figure 13 The circuit structure 20 shown only needs to satisfy condition 2 above, but does not need to satisfy condition 1 above.

[0096] exist Figure 13 In the circuit structure 20 shown, the capacitance of the first capacitor C1 is in the pF range, for example, between 10pF and 100pF. The inductance of the first inductor L1 is 47nH (nanohenries). The capacitance of the third capacitor C3 is 506pF. The capacitance of the fourth capacitor C4 is 566pF. The capacitance of the fifth capacitor C5 is 1522pF. The inductance of the third inductor L3 is 77nH. Figure 14 This is an equivalent circuit diagram of an NFC module 230, an impedance matching module 220, a first inductor L1, and an antenna 260 provided in an embodiment of this application. Figure 14 for Figure 13 The equivalent circuit diagram of the NFC module 230, impedance matching module 220, first inductor L1, and antenna 260 in the circuit structure 20 shown is illustrated. Figure 14 In this diagram, the first resistor R1 is the equivalent resistance to ground of the NFC module 230, and its value is 1Ω. The first equivalent inductance LA includes the first inductance L1 and the equivalent inductance of the antenna 260. The inductance value of the first equivalent inductance LA is equal to the sum of the inductance values ​​of the first inductance L1 and the equivalent inductance of the antenna 260. The equivalent inductance value of the antenna 260 is 103nH, therefore the inductance value of the first equivalent inductance LA is 150nH.

[0097] The frequency range of the first electrical signal is generally from 1 MHz (megahertz) to 20 MHz. Figure 15 yes Figure 14 The Smith chart shown is for the equivalent circuit with a first electrical signal input at a frequency of 13.56 MHz. According to... Figure 15 It can be seen that when the frequency of the first electrical signal is 13.56MHz, the impedance of the circuit formed by the antenna 260, the first inductor L1, and the impedance matching module 220 (i.e., the external impedance of the NFC module 230) is 11.997 - j0.029Ω. In other words, the external impedance of the NFC module 230 is approximately 12Ω. Therefore... Figure 13 The circuit structure 20 shown satisfies condition 2 above.

[0098] exist Figure 13 and Figure 14 In the illustrated embodiment, the relationship between the third capacitor C3, the fourth capacitor C4, and the fifth capacitor C5 is as follows: the fourth capacitor C4 and the fifth capacitor C5 are connected in series, and then connected in parallel with the third capacitor C3. Based on this, when the distance between the human body and the antenna 260 is greater than a preset distance, the capacitance value of node Q is:

[0099]

[0100] Among them, C Q C1 represents the capacitance value of node Q, in pF. C2 represents the capacitance value of the third capacitor C3, C4 represents the capacitance value of the fourth capacitor C4, and C5 represents the capacitance value of the fifth capacitor C5.

[0101] In other words, when the distance between the human body and the antenna 260 is greater than the preset distance, the capacitance value of the feed point of the antenna 260 is 918.573pF, which is greater than the preset capacitance value. In this case, the SAR sensor 250 cannot be directly connected to node Q through the second inductor L2.

[0102] In this scheme, by increasing the inductance value of the first inductor L1 and changing the capacitance values ​​of the third capacitor C3, the fourth capacitor C4, and the fifth capacitor C5, the capacitance value at the feed point of the antenna 260 is made less than the preset capacitance value when the distance between the human body and the antenna 260 is greater than a preset distance. In this way, the SAR sensor 250 can be connected to node Q through the second inductor L2, thereby obtaining... Figure 12 The circuit structure shown is 20.

[0103] Figure 12 The capacitance value of the first capacitor C1 in the circuit structure 20 shown is... Figure 13 The capacitance value of the first capacitor C1 in the circuit structure 20 shown is the same. Figure 12 In the circuit structure 20 shown, the inductance value of the first inductor L1 is 97nH, compared to Figure 13 The first inductor L1 has an inductance value increased by 50nH. The second inductor L2 has an inductance value of 82nH. The third capacitor C3 has a capacitance value of 364pF. The fourth capacitor C4 has a capacitance value of 407pF. The fifth capacitor C5 has a capacitance value of 1597pF. The third inductor L3 has an inductance value of 77nH. Figure 16 This is an equivalent circuit diagram of another NFC module 230, impedance matching module 220, first inductor L1, and antenna 260 provided in this application embodiment, and Figure 16 for Figure 12 The equivalent circuit diagram of the NFC module 230, impedance matching module 220, first inductor L1, and antenna 260 in the circuit structure 20 shown is illustrated. Figure 16In the diagram, the first resistor R1 is the equivalent resistance to ground of the NFC module 230, and its value is 1Ω. The second equivalent inductance LB includes the first inductance L1 and the equivalent inductance of the antenna 260. The inductance value of the second equivalent inductance LB is equal to the sum of the inductance values ​​of the first inductance L1 and the equivalent inductance of the antenna 260. The equivalent inductance value of the antenna 260 is 103nH, therefore the inductance value of the second equivalent inductance LB is 200nH.

[0104] Figure 17 yes Figure 16 The Smith chart shown is for the equivalent circuit with a first electrical signal input at a frequency of 13.56 MHz. According to... Figure 17 It can be seen that when the frequency of the first electrical signal is 13.56MHz, the impedance of the circuit formed by the antenna 260, the first inductor L1, and the impedance matching module 220 (i.e., the external impedance of the NFC module 230) is 11.991 + j0.135Ω. In other words, in this case, the external impedance of the NFC module 230 is still approximately 12Ω. Figure 12 The circuit structure 20 shown satisfies condition 2 above.

[0105] exist Figure 12 and Figure 16 In the embodiment shown, the capacitance value of node Q is:

[0106]

[0107] C Q The unit is pF. That is, when the distance between the human body and antenna 260 is greater than the preset distance, the capacitance value at the feed point of antenna 260 is 688.341 pF, which is less than the preset capacitance value. Therefore, the circuit structure 20 also satisfies condition 1 above.

[0108] Understandably, in this embodiment of the application, to increase the inductance value of the first inductor L1, the first inductor L1 can be replaced with an inductor with a larger inductance value. Alternatively, the first inductor L1 may also include several sub-inductors connected in series. To increase the inductance value of the first inductor L1, the number of sub-inductors connected in series in the first inductor L1 can be increased, or the sub-inductors can be replaced with inductors with a larger inductance value.

[0109] II. The second possible solution.

[0110] Figure 18 This is a circuit diagram of another circuit structure 20 provided in the embodiments of this application. For example... Figure 18 As shown, in some embodiments, the signal isolation module 210 includes a first inductor L1, a first capacitor C1, a second inductor L2, and a second capacitor C2. The circuit structure 20 in this embodiment is compared to... Figure 12The circuit structure 20 shown adds a second capacitor C2, and the second end of the second inductor L2 is connected to the feed point of the antenna 260 through the second capacitor C2.

[0111] Specifically, the second terminal of the first inductor L1, the second plate of the first capacitor C1, and the second plate of the second capacitor C2 are all connected to the feed point of the antenna 260. That is, the second terminal of the first inductor L1, the second plate of the first capacitor C1, and the second plate of the second capacitor C2 are connected to the same node, which is the fourth terminal d of the signal isolation module 210, and this node is used to connect to the feed point of the antenna 260. In the following embodiments, for ease of description, the node connecting the second terminal of the first inductor L1, the second plate of the first capacitor C1, the second plate of the second capacitor C2, and the feed point of the antenna 260 is still referred to as node Q.

[0112] The first terminal of the first inductor L1 is connected to the first terminal e of the impedance matching module 220. The first inductor L1 is used to block cellular signals and the second electrical signal. The first plate of the first capacitor C1 is connected to the first terminal g of the radio frequency module 240. The first capacitor C1 is used to block both the second and first electrical signals. The first terminal of the second inductor L2 is connected to the first terminal h of the SAR sensor 250. The second terminal of the second inductor L2 is connected to the first plate of the second capacitor C2. Here, the second inductor L2 and the second capacitor C2 are used to block both cellular signals and the first electrical signal.

[0113] In this embodiment, it is still as follows Figure 18 As shown, the impedance matching module 220 also includes a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, and a third inductor L3. In Figure 18 In the illustrated embodiment, the connection relationships of the electronic components (including the third capacitor C3, the fourth capacitor C4, the fifth capacitor C5, and the third inductor L3) in the impedance matching module 220 are compared to Figure 12 , Figure 13 Since no changes have been made, the connection relationships of the various electronic components will not be described again. It is easy to understand that in some other embodiments, the impedance matching module 220 may include more or fewer capacitors and inductors, and this application embodiment does not limit this.

[0114] In this possible solution, the circuit structure 20 should also satisfy the following condition 3: when the distance between the human body and the antenna 260 is greater than the preset distance, the capacitance value of the first end h of the SAR sensor 250 is less than or equal to the preset capacitance value.

[0115] Specifically, as mentioned above, the capacitor connected to the first terminal h of the SAR sensor 250 includes a background capacitor CA and a coupling capacitor CB. The smaller the value of the background capacitor CA, the better. In this embodiment, the value of the background capacitor CA should be less than or equal to a preset capacitance value. The preset capacitance value is the background capacitance threshold of the SAR sensor 250. That is, when the distance between the human body and the antenna 260 is greater than a preset distance, i.e., when there is no coupling capacitor CB, the capacitance value of the first terminal h of the SAR sensor 250 should be less than or equal to the preset capacitance value. In this embodiment, the first terminal h of the SAR sensor 250 can also be referred to as the connection point between the SAR sensor 250 and the first terminal of the second inductor L2. Therefore, condition 3 can also be expressed as: when the distance between the human body and the antenna 260 is greater than a preset distance, the capacitance value at the connection point between the SAR sensor 250 and the first terminal of the second inductor L2 is less than or equal to the preset capacitance value.

[0116] Easy to understand, in Figure 18 In the embodiment shown, when the distance between the human body and the antenna 260 is greater than a preset distance, the capacitance value of the first terminal h of the SAR sensor 250, that is, the capacitance value of the background capacitor CA connected to the first terminal h of the SAR sensor 250, is determined by the capacitance values ​​of the second capacitor C2, the third capacitor C3, the fourth capacitor C4, and the fifth capacitor C5.

[0117] In this possible solution, the antenna 260, the first inductor L1, and the impedance matching module 220 should also satisfy the above condition 2: make the external impedance of the NFC module 230 within the preset impedance range.

[0118] Understandably, in this possible solution, circuit structure 20 should simultaneously satisfy conditions 3 and 2. Specifically, while circuit structure 20 may satisfy condition 2, condition 3 can be achieved by adjusting the capacitance value of the second capacitor C2. For example, the capacitance values ​​of the third capacitor C3, fourth capacitor C4, and fifth capacitor C5 in the impedance matching module 220 are generally in the nF range. This results in the capacitance value at the first terminal h of the SAR sensor 250 also being in the nF range when the distance between the human body and the antenna 260 exceeds a preset distance. The preset capacitance values ​​are generally in the pF range, such as 250pF, 300pF, 600pF, and 700pF. In this case, the capacitance value at the first terminal h of the SAR sensor 250 can be reduced when the distance between the human body and the antenna 260 exceeds the preset distance by adjusting the capacitance value of the second capacitor C2.

[0119] The following example, with a preset capacitance value of 700pF and a preset impedance range of 11Ω to 13Ω, will provide a detailed explanation of how circuit structure 20 can simultaneously satisfy conditions 3 and 2.

[0120] Will Figure 18 The circuit structure 20 shown is... Figure 13 The circuit structure 20 shown is compared with that. Figure 13 The circuit structure 20 shown does not include the second inductor L2, the second capacitor C2, and the SAR sensor 250. Therefore, Figure 13 The circuit structure 20 shown only needs to satisfy condition 2 above, but does not need to satisfy condition 3 above.

[0121] exist Figure 13 In the circuit structure 20 shown, the capacitance of the first capacitor C1 is in the pF range, for example, between 10pF and 100pF. The inductance of the first inductor L1 is 47nH. The capacitance of the third capacitor C3 is 506pF. The capacitance of the fourth capacitor C4 is 566pF. The capacitance of the fifth capacitor C5 is 1522pF. The inductance of the third inductor L3 is 77nH. The equivalent inductance of the antenna 260 is 103nH. Based on the... Figures 13 to 15 Analysis shows that in this case, the external impedance of the NFC module 230 is 11.997 - j0.029Ω, therefore Figure 13 The circuit structure 20 shown satisfies condition 2 above. The capacitance value of node Q is 918.573pF, which is greater than the preset capacitance value. In this case, if the SAR sensor 250 is directly connected to node Q through the second inductor L2, the capacitance value of the first terminal h of the SAR sensor 250 will be 918.573pF, which is greater than the preset capacitance value, when the distance between the human body and the antenna 260 is greater than the preset distance. Therefore, the SAR sensor 250 cannot be directly connected to node Q through the second inductor L2.

[0122] In this scheme, by connecting the second capacitor C2 in series between the second inductor L2 and node Q, without changing the inductance value of the first inductor L1, the capacitance value of the third capacitor C3, the capacitance value of the fourth capacitor C4, and the capacitance value of the fifth capacitor C5, the capacitance value of the first terminal h of the SAR sensor 250 can be reduced when the distance between the human body and the antenna 260 is greater than a preset distance, and the external impedance of the NFC module 230 will not be changed, that is, the circuit structure 20 will not be affected in satisfying condition 2.

[0123] For example, in Figure 18 In the circuit structure 20 shown, the capacitance of the second capacitor C2 can be 1000pF, and the inductance of the second inductor L2 is 82nH. The capacitance values ​​of the first capacitor C1, the first inductor L1, the third capacitor C3, the fourth capacitor C4, the fifth capacitor C5, the third inductor L3, and the inductance value of the equivalent inductance of the antenna 260 are relative to... Figure 13The circuit structure 20 shown remains unchanged. That is, the inductance of the first inductor L1 remains 47nH. The capacitance of the third capacitor C3 remains 506pF. The capacitance of the fourth capacitor C4 remains 566pF. The capacitance of the fifth capacitor C5 remains 1522pF. The inductance of the third inductor L3 remains 77nH. The equivalent inductance of the antenna 260 remains 103nH. In this case, the external impedance of the NFC module 230 remains 11.997 - j0.029Ω, therefore... Figure 18 The circuit structure 20 shown satisfies condition 2 above.

[0124] The second capacitor C2 and node Q are connected in series. Therefore, when the distance between the human body and antenna 260 is greater than a preset distance, the capacitance value at the first terminal h of the SAR sensor 250 is:

[0125]

[0126] Among them, C SAR C1 is the capacitance value of the first terminal h of the SAR sensor 250 when the distance between the human body and the antenna 260 is greater than a preset distance, in pF. C2 is the capacitance value of the second capacitor C2. That is, after connecting the second capacitor C2 in series between the second inductor L2 and node Q, the capacitance value of the first terminal h of the SAR sensor 250 when the distance between the human body and the antenna 260 is greater than the preset distance is 478.799 pF, which is less than the preset capacitance value. Therefore, the circuit structure 20 also satisfies the above condition 3.

[0127] Understandably, the capacitance value of the second capacitor C2 depends on the background capacitance threshold of the SAR sensor 250 and the capacitance value of node Q when the distance between the human body and the antenna 260 is greater than a preset distance. Therefore, the capacitance value of the second capacitor C2 can be set by those skilled in the art based on experience and requirements. Generally, the capacitance value of the second capacitor C2 is greater than or equal to 100 pF and less than or equal to 10 nF. For example, the capacitance value of the second capacitor C2 can be 100 pF, 500 pF, 1 nF, 5 nF, or 10 nF.

[0128] It should be noted that in this scheme, although adding a second capacitor C2 can... Figure 18 The circuit structure 20 shown satisfies condition 3 above, but compared to the case where the second capacitor C2 is not added, this will also reduce the capacitance value of the first end h of the SAR sensor 250 when the distance between the human body and the antenna 260 remains unchanged.

[0129] Figure 19 This is an equivalent circuit diagram of the circuit structure 20 of a SAR sensor 250 during operation, provided in an embodiment of this application, showing... Figure 18The circuit structure 20 shown is the equivalent circuit of the SAR sensor 250 when the distance between the human body and the antenna 260 is greater than a preset distance. For example... Figure 19 As shown, in this case, the capacitor connected to the first terminal h of the SAR sensor 250 includes the second capacitor C2 and the node capacitor CQ. The node capacitor CQ refers to the capacitance of node Q, which is the capacitance between the feed point of the antenna 260 and the ground line GND. In this case, the capacitance value of the first terminal h of the SAR sensor 250 is:

[0130]

[0131] Figure 20 This is an equivalent circuit diagram of the circuit structure 20 of another SAR sensor 250 provided in this application embodiment, which shows... Figure 18 The circuit structure 20 shown is the equivalent circuit of the SAR sensor 250 when the distance between the human body and the antenna 260 is a first distance, and the first distance is less than or equal to a preset distance. For example... Figure 20 As shown, in this case, the capacitor connected to the first terminal h of the SAR sensor 250 includes the second capacitor C2, the node capacitor CQ, and the coupling capacitor CB. The coupling capacitor CB refers to the capacitance formed by the coupling between the human body and the antenna 260 when the distance between them is the first distance. In this case, the capacitance value of the first terminal h of the SAR sensor 250 is:

[0132]

[0133] Among them, C SAR ′ represents the capacitance value of the first terminal h of the SAR sensor 250 when the distance between the human body and the antenna 260 is the first distance. ΔC represents the capacitance value of the coupling capacitor CB.

[0134] Therefore, it can be seen that for Figure 18 In the circuit structure 20 shown, before and after the distance between the human body and the antenna 260 reaches the first distance, the change in capacitance value at the first terminal h of the SAR sensor 250 is as follows:

[0135]

[0136] Generally, the capacitance of node Q is much larger than the capacitance of coupling capacitor CB. Therefore:

[0137]

[0138] Therefore, it can be seen that for Figure 18The circuit structure 20 shown, i.e., with the second capacitor C2 connected in series between the second inductor L2 and node Q, shows that before and after the distance between the human body and the antenna 260 reaches a first distance, the change in capacitance value at the first terminal h of the SAR sensor 250 is: Since ΔC is the capacitance value of the coupling capacitor CB, it can be known that after the second capacitor C2 is connected in series between the second inductor L2 and node Q, the rate of change of capacitance detected by the first terminal h of the SAR sensor 250 is the same as the original value. In this case, the threshold value of the preset capacitance range set in the SAR sensor 250 should also be changed back to the original value. This ensures that the SAR sensor 250 can detect whether the distance between the human body and the antenna 260 is less than or equal to the preset distance, thus guaranteeing the sensitivity of the SAR sensor 250 in detecting the approach of the human body.

[0139] Specifically, for example Figure 5 The circuit structure shown, where the first terminal h of the SAR sensor 250 is directly connected to the antenna 260, allows the SAR sensor 250 to have a second preset capacitance value range. The second preset capacitance value range is [ΔC]. min ΔC max ]. Wherein, ΔC min ΔC is the minimum value within the second preset capacitance range. max The capacitance value is the maximum value within the second preset capacitance value range. When the distance between the human body and the antenna 260 is less than or equal to the preset distance, the capacitance value of the first terminal h of the SAR sensor 250 is within the second preset capacitance value range; conversely, when the distance between the human body and the antenna 260 is greater than the preset distance, the capacitance value of the first terminal h of the SAR sensor 250 is not within the second preset capacitance value range. For example, when the distance between the human body and the antenna 260 is the first distance, the capacitance value of the first terminal h of the SAR sensor 250 is ΔC1. Wherein, the first distance is less than the preset distance, and ΔC1 is within [ΔC...]. min ΔC max Within [ΔC]. When the distance between the human body and antenna 260 is the second distance, the capacitance value of the first terminal h of SAR sensor 250 is ΔC2. Where the second distance is greater than a preset distance, and ΔC2 is not within [ΔC]. min ΔC max The situation where "the first end h of the SAR sensor 250 is directly connected to the antenna 260" can also be referred to as "the SAR sensor 250 is only connected to the antenna 260".

[0140] And for Figure 18 The circuit structure 20 shown, i.e., the circuit structure 20 including the second capacitor C2, is such that the rate of change of capacitance detected by the first terminal h of the SAR sensor 250 is the original... Therefore, when the distance between the human body and the antenna 260 is the first distance, the capacitance value of the first terminal h of the SAR sensor 250 is... When the distance between the human body and the antenna 260 is the second distance, the capacitance value of the first terminal h of the SAR sensor 250 is... In this case, to ensure that the SAR sensor 250 can correctly detect whether the distance between the human body and the antenna 260 is less than or equal to a preset distance, the minimum value of the preset capacitance range in the SAR sensor 250 should be [value missing]. The maximum value should be Here, the preset capacitance value range, i.e. This is called the first preset capacitance value range. In other words, Figure 18 In the circuit structure 20 shown, the SAR sensor 250 needs to determine whether the distance between the human body and the antenna 260 is less than or equal to a preset distance by using a first preset capacitance value range. When the capacitance value of the first terminal h of the SAR sensor 250 is within the first preset capacitance value range, the SAR sensor 250 determines that the distance between the human body and the antenna 260 is less than or equal to the preset distance; conversely, when the capacitance value of the first terminal h of the SAR sensor 250 is not within the first preset capacitance value range, the SAR sensor 250 determines that the distance between the human body and the antenna 260 is greater than the preset distance.

[0141] For example, if the first terminal h of the SAR sensor 250 is directly connected to the antenna 260, the range of the second preset capacitance value set for the SAR sensor 250 is [55.5 × 10]. -6 The capacitance between the feed point (node ​​Q) of antenna 260 and ground GND is 2nF, and the capacitance of the second capacitor C2 is 600pF. Therefore, the range of the first preset capacitance value should be [4.58 × 10⁻⁶ pF, 8.2pF]. -6 pF, 0.677pF).

[0142] It is readily understood that in this embodiment, and The difference should be greater than the minimum capacitance resolution of the SAR sensor 250; and, It should also be greater than the minimum capacitance resolution of the SAR sensor 250. The minimum capacitance resolution of the SAR sensor 250 refers to the smallest change in capacitance that the SAR sensor 250 can detect when it is operating. In other words, it should be:

[0143]

[0144] Where ΔF is the minimum capacitance resolution of the SAR sensor 250.

[0145] It is understood that in this embodiment, the circuit structure 20 may also include both of the above-mentioned possible solutions. In this case, on the one hand, there is a second capacitor C2 between the second inductor L2 and node Q. On the other hand, the capacitance value of the feed point of the antenna 260 when the distance between the human body and the antenna 260 is greater than a preset distance can be reduced by increasing the inductance value of the first inductor L1 and changing the capacitance values ​​of the third capacitor C3, the fourth capacitor C4, and the fifth capacitor C5, thereby reducing the capacitance value of the background capacitance CA of the SAR sensor 250.

[0146] exist Figure 12 , Figure 13 , Figure 18 In the circuit structure 20 shown, all NFC modules 230 are single-ended devices. That is, each NFC module 230 is connected to the feed point (i.e., node Q) of the antenna 260 only through an impedance matching module 220 and a first inductor L1. Figure 21 This is a circuit diagram of another circuit structure 20 provided in the embodiments of this application. For example... Figure 21 As shown, in some other embodiments, the NFC module 230 can also be a two-terminal device. In this case, the circuit structure 20 may include two impedance matching modules 220 (i.e., a first impedance matching module 222 and a second impedance matching module 224) and two first inductors L1 (i.e., inductors L11 and L12). The first terminal j of the NFC module 230 is connected to the feed point of the antenna 260 through the first impedance matching module 222 and the inductor L11; the second terminal k of the NFC module 230 is connected to the feed point of the antenna 260 through the second impedance matching module 224 and the inductor L12. The first impedance matching module 222 includes capacitors C31, C41, and C51, and inductor L31; the second impedance matching module 224 includes capacitors C32, C42, and C52, and inductor L32. The structure of the first impedance matching module 222 is exactly the same as that of the second impedance matching module 224, and will not be described in detail here.

[0147] In the circuit structure 20 provided in this application embodiment, any one or more electrical structures can be packaged within the packaging structure to form a packaged chip. That is, any one or more of the signal isolation module 210, impedance matching module 220, NFC module 230, radio frequency module 240, SAR sensor 250, and antenna 260 can be packaged into a single chip.

[0148] This application embodiment also provides a packaged chip. The packaged chip includes a signal isolation module 210, an impedance matching module 220, an NFC module 230, a radio frequency module 240, and a SAR sensor 250, all encapsulated within a packaged structure. The first terminal of the signal isolation module 210 is connected to the first terminal of the impedance matching module 220, and the second terminal of the impedance matching module 220 is connected to the NFC module 230. The second terminal of the signal isolation module 210 is connected to the radio frequency module 240. The third terminal of the signal isolation module 210 is connected to the SAR sensor 250. The fourth terminal of the signal isolation module 210 is used to connect to the feed point of the antenna 260. The NFC module 230 is used for near-field communication via the antenna 260. The radio frequency module 240 is used for cellular communication via the antenna 260. The SAR sensor 250 is used to determine that the distance between a human body and the antenna 260 is less than or equal to a preset distance. The signal isolation module 210 is used to prevent interference between the NFC module 230, the radio frequency module 240, and the SAR sensor 250. In other words, the electrical structures in the circuit structure 20 above, except for the antenna 260, can be packaged into a chip.

[0149] This application also provides an electronic device. The electronic device includes the circuit structure 20 or packaged chip as described in any of the above embodiments.

[0150] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A circuit structure, characterized by, The circuit structure comprises a signal isolation module, an impedance matching module, an NFC module, a radio frequency module, a SAR sensor and an antenna. The first end of the signal isolation module is connected with the first end of the impedance matching module, and the second end of the impedance matching module is connected with the NFC module. The signal isolation module is used for making the NFC module, the radio frequency module and the SAR sensor not interfere with each other.

2. The circuit structure of claim 1, wherein, The signal isolation module comprises a first inductor, a first capacitor and a second inductor. The first end of the first inductor is connected with the first end of the impedance matching module. The second end of the first inductor, the second pole plate of the first capacitor and the second end of the second inductor are connected with the feed point.

3. The circuit structure of claim 2, wherein, The capacitance value of the feed point is less than or equal to a preset capacitance value, and the preset capacitance value is a background capacitance threshold value of the SAR sensor.

4. The circuit structure of claim 3, wherein, The antenna, the first inductor and the impedance matching module satisfy the following condition: the external impedance of the NFC module is in a preset impedance range, and the preset impedance range is a preset external impedance range of the NFC module.

5. A circuit arrangement as claimed in any one of claims 2 to 4, characterized in that The signal isolation module further comprises a second capacitor. The first pole plate of the second capacitor is connected with the second end of the second inductor, and the second pole plate of the second capacitor is connected with the feed point.

6. The circuit structure of claim 5, wherein, The capacitance value at the connection between the SAR sensor and the first end of the second inductor is less than or equal to a preset capacitance value, and the preset capacitance value is a background capacitance threshold value of the SAR sensor.

7. The circuit structure of claim 6, wherein, The capacitance value of the second capacitor is greater than or equal to 100 pF, and the capacitance value of the second capacitor is less than or equal to 10 nF.

8. The circuit structure as described in claim 6 or 7, characterized in that, The SAR sensor has a first preset capacitance value range, the first preset capacitance value range is used to determine that the distance between the human body and the antenna in the circuit structure is less than or equal to a preset distance; the minimum value of the first preset capacitance value range is The maximum value of the first preset capacitance value range is wherein C Q is a capacitance value between the feeding point and the ground, C2 is a capacitance value of the second capacitor; ΔC min is a minimum value of a second preset capacitance value range, ΔC max is a maximum value of the second preset capacitance value range, the second preset capacitance value range being used to determine that the distance between the human body and the antenna is less than or equal to the preset distance when the SAR sensor is connected with only the antenna.

9. The circuit structure of claim 8, wherein, a difference between the voltage of the SAR sensor and the voltage of the reference voltage source is greater than a capacitance minimum resolution of the SAR sensor, and a difference between the voltage of the SAR sensor and the voltage of the reference voltage source is greater than a capacitance minimum resolution of the SAR sensor, and a difference between the voltage of the SAR sensor and the voltage of the reference voltage source is greater than a capacitance minimum resolution of the SAR sensor, and 10. The circuit structure according to any one of claims 1 to 9, characterized in that, The impedance matching module comprises a third capacitor, a fourth capacitor, a fifth capacitor and a third inductor. The first pole plate of the third capacitor is connected with the first end of the signal isolation module, and the second pole plate of the third capacitor is connected with a ground wire.

11. A packaged chip, comprising: The first end of the third inductor is connected with the fifth capacitor and the second pole plate of the fourth capacitor. The package chip comprises a signal isolation module, an impedance matching module, an NFC module, a radio frequency module and a SAR sensor. The first end of the signal isolation module is connected with the first end of the impedance matching module, the second end of the impedance matching module is connected with the NFC module; the second end of the signal isolation module is connected with the radio frequency module; the third end of the signal isolation module is connected with the S AR sensor; and the fourth end of the signal isolation module is used for connecting with the feed point of the antenna. The NFC module is used for carrying out near field communication through the antenna; the radio frequency module is used for carrying out cellular communication through the antenna; the S AR sensor is used for determining the distance between the human body and the antenna through the antenna; and the signal isolation module is used for making the NFC module, the radio frequency module and the S AR sensor not interfere with each other.

12. An electronic device, comprising: The electronic device comprises the circuit structure according to any one of claims 1 to 10; or the electronic device comprises an antenna and the packaging chip according to claim 11.

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