Wireless charging module and wireless charging apparatus

Abstract

The present application relates to a wireless charging module. In the wireless charging module, a low-frequency switching device is used to build a full-bridge switching circuit, common-mode inductors are electrically connected to two ends of a transmitting coil, capacitive filters are electrically connected to the two ends of the transmitting coil, and a radiation-shielding apparatus is arranged on a transmitting surface side of the transmitting coil, such that the wireless charging module using the low-frequency switching device can suppress conducted interference and also prevent radiated interference. While meeting the operating frequency requirements of a Qi2 charging standard and meeting EMC requirements, the wireless charging module can significantly reduce circuit configuration costs and meet the demands of users for a fast charging experience. Further provided in the present application is a wireless charging apparatus using the wireless charging module.

Description

A wireless charging module and a wireless charging device Technical Field

[0001] This application relates to the field of wireless charging, and in particular to a wireless charging module and a wireless charging device. Background Technology

[0002] Wireless charging technology is a technology that uses electromagnetic fields to transfer energy, allowing electronic devices to charge at distances of several centimeters or even more without a physical connection. Because it eliminates the need for cables, it avoids tangled and messy charging wires, resulting in cleaner designs and improved aesthetics in home and office environments. Furthermore, the elimination of plugging and unplugging reduces the risk of cable wear and damage, enhancing charging safety. Therefore, it offers advantages such as convenience, flexibility, durability, safety, and aesthetics. This technology has been widely applied in consumer electronics, medical devices, electric vehicles, and home furnishings, particularly in consumer electronics products such as smartphones, smartwatches, and headphones.

[0003] In 2023, the Wireless Power Consortium launched the updated wireless charging standard Qi2. This standard requires wireless chargers to operate at a frequency of 360kHz. Furthermore, it requires wireless chargers to not generate EMC (Electromagnetic Compatibility) issues during operation, and to be able to work normally without interfering with other devices in the vicinity, while also being unaffected by the surrounding electromagnetic environment. Summary of the Invention

[0004] Based on this, on the one hand, the purpose of this application is to provide a wireless charging module, comprising: a circuit board, wherein a transmitting circuit is disposed on the circuit board, the transmitting circuit including a power input terminal electrically connected to the power supply terminal of the circuit board, a full-bridge switching circuit electrically connected to the power input terminal, and an electromagnetic compatibility module electrically connected to the full-bridge switching circuit; a transmitting coil electrically connected to the electromagnetic compatibility module, the transmitting coil being electrically connected to the full-bridge switching circuit through the electromagnetic compatibility module; and a radiation shielding device connected to a ground terminal, the radiation shielding device being installed on the transmitting surface side of the transmitting coil.

[0005] Furthermore, the full-bridge switching circuit includes a first half-bridge and a second half-bridge, which are electrically connected to the power input terminal; the electromagnetic compatibility module includes a common-mode inductor and a capacitor filter; the common-mode inductor includes a first coil and a second coil, one end of the transmitting coil is electrically connected to the first half-bridge through the first coil, and the other end of the transmitting coil is electrically connected to the second half-bridge through the second coil; the capacitor filter includes a first filter capacitor and a second filter capacitor, the two ends of the transmitting coil are electrically connected to one end of the first filter capacitor and one end of the second filter capacitor, respectively, and the other ends of the first filter capacitor and the second filter capacitor are both grounded.

[0006] Furthermore, the first half-bridge includes a first switching device and a second switching device, and the second half-bridge includes a third switching device and a fourth switching device. The first, second, third, and fourth switching devices are N-type MOS transistors. One end of the first coil is electrically connected to the source of the first switching device and the drain of the second switching device, and the other end of the first coil is electrically connected to one end of the transmitting coil. One end of the second coil is electrically connected to the source of the third switching device and the drain of the fourth switching device, and the other end of the second coil is electrically connected to the other end of the transmitting coil.

[0007] Furthermore, the power input terminal includes a positive terminal and a negative terminal. The negative terminal is connected to the ground terminal. The drain of the first switching device and the drain of the third switching device are electrically connected to the positive terminal, and the source of the second switching device and the source of the fourth switching device are electrically connected to the negative terminal.

[0008] Furthermore, the switching frequencies of the first, second, third, and fourth switching devices are less than or equal to 1 MHz.

[0009] Furthermore, the transmitting circuit also includes a resonant capacitor, one end of the second coil is electrically connected to one end of the resonant capacitor, and the other end of the resonant capacitor is electrically connected to the source of the third switching device and the drain of the fourth switching device.

[0010] Furthermore, the first coil and the second coil are symmetrically wound on a toroidal magnetic core.

[0011] Furthermore, the radiation shielding device includes a connector and an absorber; one end of the connector is connected to a grounding terminal, and the other end of the connector is connected to the absorber; the area of ​​the absorber can cover the emitting surface of the transmitting coil.

[0012] Furthermore, the absorbent includes a first absorbent portion and a second absorbent portion. The first absorbent portion is connected to one end of the connector. The second absorbent portion includes a plurality of absorbent strips that are parallel to each other and spaced apart. One end of each of the plurality of absorbent strips is connected to the first absorbent portion. The first absorbent portion is connected to one end of the connector.

[0013] Furthermore, the absorption strip is a parallel straight line segment, an arc-shaped line segment, or a wavy line segment.

[0014] On the other hand, this application also provides a wireless charging device, characterized in that it includes a housing, a mounting part, a wireless charging module, and a power supply terminal. The mounting part is disposed on the housing, and the wireless charging module is disposed on the mounting part. The wireless charging module includes a radiation shielding device, which is disposed on the charging area corresponding to the wireless charging module. The power supply terminal is disposed on the housing, and the wireless charging module is electrically connected to the power supply terminal. The radiation shielding device is connected to a ground terminal.

[0015] Compared to existing technologies, the wireless charging module and wireless charging device described in this application: by using low-frequency switching devices to build a full-bridge switching circuit, electrically connecting an electromagnetic compatibility module composed of a common-mode inductor and capacitor filter to both ends of the transmitting coil, and setting a radiation shielding device on the transmitting surface side of the transmitting coil, the wireless charging module using low-frequency switching devices can suppress both conducted interference and prevent radiated interference. This allows the wireless charging module to meet the operating frequency requirements of the Qi2 charging standard and comply with EMC requirements, while significantly reducing circuit setup costs and meeting users' requirements for a fast charging experience.

[0016] To better understand and implement this application, the following detailed description is provided in conjunction with the accompanying drawings. Attached Figure Description

[0017] Figure 1 is a schematic diagram of a wireless charging device provided in an embodiment of this application.

[0018] Figure 2 is a circuit diagram of a wireless charging module provided in an embodiment of this application.

[0019] Figure 3 is a schematic diagram showing the relative positions of the transmitting coil and the radiation shielding device provided in an embodiment of this application.

[0020] Figure 4 is a schematic diagram of the structure of a radiation shielding device provided in an embodiment of this application.

[0021] Figure 5 is a schematic diagram of the frequency-electric field strength test results without using the wireless charging module of this application.

[0022] Figure 6 is a schematic diagram of the frequency-electric field strength test results using the wireless charging module of this application.

[0023] Figure 7 is a schematic diagram of the structure of a wireless charging device provided in an embodiment of this application.

[0024] Figure 8 is a schematic diagram of the wireless charging device shown in Figure 7 after the casing has been removed.

[0025] Figure 9 is a schematic diagram showing the relative positions of the radiation absorption device and the wireless charging module shown in Figure 8. Embodiments of the present invention

[0026] The Qi2 charging standard requires wireless chargers to operate at a frequency of 360kHz. Taking wireless charging of a watch as an example, to achieve a fast charging power of 5W, the switching frequency of the switching devices (such as MOSFETs) must reach 1.78MHz to meet the operating frequency requirement and avoid EMC issues.

[0027] However, existing conventional MOSFETs have a switching frequency of less than 1MHz. If a wireless charger using this MOSFET outputs 5W of power, the MOSFET's switching speed cannot keep up. Its parasitic capacitance causes additional charging and discharging current during the switching process. When the frequency of this charging and discharging current forms a specific ratio with the frequency of the alternating current, high-frequency harmonics are generated. These high-frequency harmonics induce parasitic magnetic fields in the alternating magnetic field, leading to increased coil radiation and failure to meet the EMC safety requirements in the standards. To avoid EMC problems, wireless chargers using this MOSFET usually have to reduce the charging power, for example, to 2.5W to meet the above operating frequency requirements, resulting in reduced wireless charging efficiency and a poor user experience. If the wireless charger uses a MOSFET with a switching frequency higher than 1.78MHz, the cost is relatively high; for example, the cost of a gallium nitride MOSFET is several times that of a conventional MOSFET.

[0028] To address the contradiction between meeting the operating frequency requirements of the Qi2 charging standard and complying with EMC requirements in existing technologies, which cannot simultaneously reduce costs and improve the user's wireless charging experience, this application proposes a wireless charging device. This device includes a wireless charging module that employs a full-bridge switching circuit composed of four low-frequency switching devices. A common-mode inductor and a grounded capacitor filter are connected to both ends of the transmitting coil, and a radiation shielding device is installed on the transmitting surface side of the transmitting coil. This solution addresses the problem of existing technologies being unable to simultaneously achieve cost reduction and improved user charging experience.

[0029] Please refer to Figure 1. An embodiment of this application proposes a wireless charging device 100, including a housing 1, and a wireless charging module 2, a signal module 6, and a control module 7 disposed within the housing 1. The wireless charging module 2 performs electromagnetic conversion and provides an alternating magnetic field. The signal module 6 is, for example, a charging protocol chip installed within the wireless charging device 100. The signal module 6 uses ASK modulation technology to achieve wireless communication between the wireless charging device 100 and the device to be charged. The control module 7 is, for example, an MCU chip installed within the wireless charging device 100. The control module 7 is electrically connected to both the wireless charging module 2 and the signal module 6. The control module 7 is used to control the driving of the transmitting coil 22 by the wireless charging module 2 according to the information transmitted by the signal module 6.

[0030] Please refer to Figures 2 and 3. The wireless charging module 2 of this embodiment includes a circuit board 20 (refer to Figure 8), a transmitting circuit 21 disposed on the circuit board 20, a transmitting coil 22 electrically connected to the transmitting circuit 21, and a radiation shielding device 4 connected to the ground terminal. The ground terminal in this application can be the ground terminal of the circuit board 20 in the wireless charging module 2, or it can be the housing 1 of the wireless charging device 100, as long as the grounding effect is achieved.

[0031] Referring to Figure 7, the housing 1 is provided with a charging part 12, which is positioned on the housing 1 corresponding to the transmitting coil 22. Preferably, the charging part 12 is circular. In order to fit more closely with the device to be charged and improve wireless charging efficiency, the charging part 12 has an arc-shaped recess 121 in the middle to fit the shape of the arc-shaped protrusion on the back of the device to be charged. The receiving coil of the device to be charged is usually disposed in the arc-shaped protrusion.

[0032] The transmitting coil 22 has a transmitting surface 221, and the radiation shielding device 4 is installed on the transmitting surface 221 of the transmitting coil 22. In this embodiment, the transmitting coil 22 is a circular sheet-like component formed by winding multiple strands of metal wire. The transmitting surface 221 is the surface of the transmitting coil 22 opposite to the receiving surface of the receiving coil of the device to be charged. The transmitting surface 221 is also the surface of the transmitting coil 22 facing the side where the charging part 12 is located. The transmitting surface 221 is located within the projection range of the circular area of ​​the charging part 12.

[0033] The wireless charging module 2 includes a power input terminal 23 disposed on the transmitting circuit 21, which is electrically connected to the power supply terminal of the circuit board 20. The transmitting circuit 21 includes a full-bridge switching circuit 211 and a resonant capacitor 212. The full-bridge switching circuit 211 is electrically connected to the transmitting coil 22. The full-bridge switching circuit 211 receives an external DC voltage signal through the power input terminal 23 and controls the switching devices to turn on and off according to the drive signal to output an alternating voltage signal of a specific frequency, thereby driving the transmitting coil 22 to work at the set resonant frequency, causing the inductor coil to generate an alternating magnetic field, thus realizing wireless energy transmission.

[0034] The wireless charging device 100 also includes an electromagnetic compatibility (EMC) module 3 disposed in the wireless charging module 2. The EMC module 3 is used to reduce the radiated interference of the wireless charging module 2 to EMC. Specifically, the EMC module 3 includes a common-mode inductor 31 and a capacitor filter 32. The common-mode inductor 31 is used to suppress the high-frequency harmonic voltage or high-frequency harmonic current generated by the full-bridge switching circuit 211 from being input to the transmitting coil 22. The capacitor filter 32 filters out common-mode noise. The EMC module 3, through the cooperation of its common-mode inductor 31 and capacitor filter 32, suppresses the conducted interference of high-frequency harmonics and reduces the radiated interference to EMC. One end of the resonant capacitor 212 is electrically connected to the EMC module 3, and the other end of the resonant capacitor 212 is electrically connected to the full-bridge switching circuit 211 to adjust the resonant frequency of the circuit.

[0035] The power input terminal 23 provides power to the entire wireless charging module 2. The power input terminal 23 includes a positive terminal 231 and a negative terminal 232. The positive terminal 231 represents the positive terminal of the DC power supply and is used to connect to the positive terminal of the power supply terminal of the circuit board 20. The negative terminal 232 represents the negative terminal of the DC power supply and is used to connect to the negative terminal of the power supply terminal of the circuit board 20.

[0036] The full-bridge switching circuit 211 includes four switching devices, namely the first switching device 2111, the second switching device 2112, the third switching device 2113 and the fourth switching device 2114. The four switching devices are connected in a full-bridge configuration and alternately turn on and off to generate a high-frequency pulse width modulation signal.

[0037] In one embodiment of this invention, the first switching device 2111 and the second switching device 2112 are electrically connected to form a first half-bridge circuit; the third switching device 2113 and the fourth switching device 2114 are electrically connected to form a second half-bridge circuit. The first switching device 2111, the second switching device 2112, the third switching device 2113 and the fourth switching device 2114 are N-type MOSFETs, and preferably N-type MOSFETs with a switching frequency less than or equal to 1MHz. MOSFETs with a switching frequency less than or equal to 1MHz are low-frequency MOSFETs.

[0038] Specifically, the electrical connections of the first half-bridge circuit are as follows:

[0039] The drain of the first switching device 2111 is electrically connected to the positive terminal 231, its source is electrically connected to the drain of the second switching device 2112, and its gate is electrically connected to its drain; the source of the second switching device 2112 is electrically connected to the negative terminal 232, and its gate is electrically connected to its drain.

[0040] The electrical connections of the second half-bridge circuit are as follows:

[0041] The drain of the third switching device 2113 is electrically connected to the positive terminal 231, its source is electrically connected to the drain of the fourth switching device 2114, and its gate is electrically connected to its drain; the source of the fourth switching device 2114 is electrically connected to the negative terminal 232, and its gate is electrically connected to its drain.

[0042] The electromagnetic compatibility module 3 includes a common-mode inductor 31 and a capacitor filter 32. The common-mode inductor 31 includes a first coil 311 and a second coil 312. The first coil 311 and the second coil 312 are symmetrically wound on a toroidal magnetic core. The symmetrical winding of the coils can enhance the suppression of common-mode current and reduce the influence on differential-mode signals. In a specific implementation, one coil is connected between the transmitting coil 22 and the resonant capacitor 212, and the corresponding other coil is connected between the transmitting coil 22 and the full-bridge switching circuit 211.

[0043] In one embodiment of this invention, the electrical connections of the first coil 311 and the second coil 312 with the full-bridge switching circuit 211, the transmitting coil 22, and the resonant capacitor 212 are as follows:

[0044] One end of the first coil 311 is electrically connected to the source of the first switching device 2111 and the drain of the second switching device 2112, and the other end of the first coil 311 is electrically connected to one end of the transmitting coil 22; one end of the second coil 312 is electrically connected to the other end of the transmitting coil 22, and the other end of the second coil 312 is electrically connected to the resonant capacitor 212 and indirectly connected to the source of the third switching device 2113 and the drain of the fourth switching device 2114 through the resonant capacitor 212.

[0045] In another embodiment of this invention, the electrical connections of the first coil 311 and the second coil 312 with the full-bridge switching circuit 211, the transmitting coil 22, and the resonant capacitor 212 are as follows:

[0046] One end of the first coil 311 is electrically connected to the resonant capacitor 212 and indirectly connected to the source of the first switching device 2111 and the drain of the second switching device 2112 through the resonant capacitor 212. The other end of the first coil 311 is electrically connected to one end of the transmitting coil 22. One end of the second coil 312 is electrically connected to the other end of the transmitting coil 22, and the other end of the second coil 312 is electrically connected to the source of the third switching device 2113 and the drain of the fourth switching device 2114.

[0047] The capacitor filter 32 includes a first filter capacitor 321 and a second filter capacitor 322, which are connected in parallel across the two ends of the transmitting coil 22.

[0048] Specifically, one end of the first filter capacitor 321 is electrically connected to one end of the transmitting coil 22, and the other end of the first filter capacitor 321 is electrically connected to the negative terminal 232; one end of the second filter capacitor 322 is electrically connected to the other end of the transmitting coil 22, and the other end of the second filter capacitor 322 is electrically connected to the negative terminal 232. To obtain better filtering effect, the first filter capacitor 321 and the second filter capacitor 322 are grounded, such as by being electrically connected to the ground terminal of the circuit board 20.

[0049] The first half-bridge circuit and the second half-bridge circuit are electrically connected to the transmitting coil 22, the resonant capacitor 212, and the common-mode inductor 31 to form an H-type full-bridge connection. According to the drive signal, when the first switching device 2111 and the fourth switching device 2114 are turned on, the second switching device 2112 and the third switching device 2113 are turned off. The current flows from the DC power supply through the first switching device 2111 to the common-mode inductor 31, the transmitting coil 22, and the resonant capacitor 212, and then returns to the DC power supply through the fourth switching device 2114, forming a closed loop. At this time, the transmitting coil 22 generates a forward current. When the second switching device 2112 and the third switching device 2113 are turned on, the first switching device 2111 and the fourth switching device 2114 are turned off. The current flows from the DC power supply through the third switching device 2113 to the resonant capacitor 212, the transmitting coil 22, and the common-mode inductor 31, and then returns to the DC power supply through the second switching device 2112, forming a closed loop. At this time, the transmitting coil 22 generates a reverse current. The transmitting coil 22 alternately generates forward and reverse currents, thereby generating an alternating magnetic field and enabling wireless energy transmission.

[0050] Referring to Figure 3, the radiation shielding device 4 is installed on the emitting surface 221 side of the transmitting coil 22 and covers the emitting surface 221 of the transmitting coil 22. During wireless charging, the radiation shielding device 4 is located between the transmitting coil 22 and the receiving coil to absorb radiated energy, thereby reducing radiated interference to EMC.

[0051] Referring to Figure 4, the radiation shielding device 4 includes a connector 41 and an absorber 42. The connector 41 is a strip-shaped structure, with one end connected to the ground terminal of the circuit board 20 and the other end connected to the absorber 42. The absorber 42 includes a first absorber 421 and a second absorber 422. The first absorber 421 is a strip-shaped structure, and the second absorber 422 includes several parallel and spaced absorber strips 4221. One end of each absorber strip 4221 is connected to the first absorber 421, and the first absorber 421 is connected to one end of the connector 41. The absorber 42 can be circular or square. When the absorber 42 is circular, the first absorber 421 is an arc-shaped strip structure, with the absorber strips 4221 connected to the concave side of the arc-shaped strip, and one end of the connector 41 connected to the center of the convex side of the arc-shaped strip. It should be understood that the shape of the absorber 42 can be adjusted to other regular or irregular shapes according to product design requirements.

[0052] The radiation shielding device 4 is preferably in the form of an FPC (Flexible Printed Circuit). The FPC is preferably attached to the outer surface of the transmitting coil 22 (e.g., the emitting surface), but it can also be disposed on the inner wall or outer surface of the housing 1, or fixed within a cavity inside the housing 1. The radiation shielding device 4 can be located between the transmitting coil 22 and the receiving coil; this application does not impose any limitations. When the radiation shielding device covers the transmitting coil, under the influence of the parasitic magnetic field, the absorber generates a parasitic induced current. This parasitic induced current generates a negative magnetic field around the absorber, which cancels out the parasitic magnetic field. That is, the radiated energy generated by the parasitic magnetic field is converted into electrical energy in the absorber and absorbed, further reducing radiated interference to EMC. Therefore, for radiated energy that the electromagnetic compatibility module 3 fails to completely absorb, the radiation shielding device can further absorb it, and the two work together to achieve a better anti-interference effect. To prevent the current generated by the absorber from forming eddy currents and causing overheating, in some embodiments of this example, the other end of the connector 41 that is not connected to the absorber 42 is grounded to conduct away the parasitic induced current. Specifically, the grounding end connected to the connector 41 can be the grounding end of the circuit board 20 in the wireless charging module 2, or the housing 1 of the wireless charging device 100, or other components that can achieve the same grounding effect.

[0053] In order to improve the reliability of the radiation shielding device, in some embodiments of this example, the number of connectors 41 can be set to multiple as needed, and each connector 41 can be connected to several absorption strips 4221 at one end, and multiple connectors 41 are connected to the grounding end.

[0054] To avoid changes in the magnetic field caused by sudden changes in current, in some embodiments of this example, the connector 41 is preferably of uniform thickness with a width ranging from 0.5mm to 8.0mm. When the width of the connector 41 is less than 0.5mm, the efficiency of conducting induced current will decrease, while when the width of the connector 41 is greater than 8.0mm, the connector 41 will occupy more internal space. Moreover, for the weak induced current generated by the absorber 42, conducting these induced currents does not require an excessively large connector 41, and an excessively large connector 41 will increase production costs. The width of the connector 41 is preferably 4.0mm, which can balance the efficiency of conducting induced current with the economy of product manufacturing. It should be understood that the width of the connector 41 can also be set to different specifications such as 1.0mm and 2.0mm according to product design requirements. Furthermore, the width of the absorption strips 4221 is consistent, ranging from 0.1mm to 0.5mm. When the width of the absorption strip 4221 is less than 0.1mm, the area of ​​the absorption strip 4221 is too small, and the effect of absorbing radiation in the alternating magnetic field is reduced. When the width of the absorption strip 4221 is greater than 0.5mm, the eddy current phenomenon generated by itself will lead to an increase in heat generation. The width of the absorption strip 4221 is preferably 0.2mm, which can balance the effect of absorbing radiation while reducing heat generation.

[0055] To avoid short circuits and eddy currents caused by small spacing between several absorption sections, in some embodiments of this example, the spacing between two adjacent absorption strips 4221 is in the range of 0.1mm-0.5mm, preferably 0.2mm.

[0056] To avoid mutual interference between the magnetic fields generated by two adjacent absorption strips 4221, in some embodiments of this example, the width and spacing of two adjacent absorption strips 4221 are equal.

[0057] Since the parasitic magnetic field is generated by high-frequency harmonics, even if the connector 41 conducts away the parasitic induced current, the absorber 42 itself will still generate a certain eddy current phenomenon (i.e., each absorber strip 4221 will generate eddy current). To further prevent the formation of eddy currents and the resulting heat generation, in some embodiments, to control the volume of the absorber 42, the shielding coverage area of ​​the absorber 42 is matched with the area of ​​the transmitting coil 22. Preferably, the area of ​​the absorber 42 is greater than or equal to the area of ​​the transmitting coil 22, so as to balance the radiation absorption effect and prevent heat generation. Taking a wireless charging device for watches as an example, the diameter of the transmitting coil in the current wireless charger for watches is 24mm, so the diameter of the absorber 42 is set at 24mm~26mm, that is, the diameter of the absorber 42 is greater than or equal to the diameter of the transmitting coil. The corresponding diameter of the radiation shielding device is 25mm~28mm. The diameter of the radiation shielding device is slightly larger than the diameter of the absorber 42 because an insulating film layer needs to be set on the outer edge of the absorber 42.

[0058] Since the parasitic magnetic field is generated by high-frequency harmonics, if the absorber 42 has high conductivity, it will act as a conductor for the parasitic magnetic field and as an insulator for the alternating magnetic field. Therefore, in some embodiments, the absorber 42 is made of a material with extremely high conductivity to achieve the effect of not affecting the passage of the alternating magnetic field and not affecting wireless charging. For example, metals such as copper, gold, silver, and aluminum are used to make the absorber 42 and the connector 41.

[0059] To reduce losses, in some embodiments, the absorbent strip 4221 is preferably set as a parallel straight line segment; the shape of the absorbent strip 4221 may also be a non-straight line segment, such as an arc segment or a wavy segment, but the spacing between each two adjacent absorbent strips 4221 is uniform and equal.

[0060] Please refer to Figures 5 and 6. Figure 5 shows the frequency-electric field strength test results using a low-frequency MOSFET without a common-mode inductor, capacitor filter, or radiation shielding. As shown in Figure 5, the electric field strength at points 3 and 4 near 300MHz exceeds the set standard value. Figure 6 shows the frequency-electric field strength test results using a low-frequency MOSFET with a common-mode inductor, capacitor filter, and radiation shielding. As shown in Figure 5, the electric field strength at any operating frequency does not exceed the standard value. The test results corresponding to Figure 5 are shown in Table 1.

[0061] Table 1

[0062]

[0063] Therefore, it can be seen that the wireless charging device in this embodiment, although using low-cost low-frequency MOSFETs as switching devices, can still meet the operating frequency requirements of the Qi2 charging standard and comply with EMC requirements while satisfying users' requirements for fast charging experience.

[0064] Please refer to Figures 7 to 9. One embodiment of this application provides a wireless charging device 100, including a housing 1, a mounting portion 11, a wireless charging module 2, and a power supply terminal 5. The mounting portion 11 is disposed on the housing 1, and the wireless charging module 2 is disposed within the mounting portion 11. The wireless charging module 2 includes a radiation shielding device 4, which is disposed on the corresponding charging area of ​​the wireless charging module 2. The power supply terminal 5 is disposed on the housing 1 or the mounting portion 11, and the wireless charging module 2 is electrically connected to the power supply terminal 5. The radiation shielding device 4 is connected to the ground terminal of the wireless charging module 2. By providing the mounting portion 11 on the housing 1, the wireless charging module 2 and its radiation shielding device 4 can be supported and protected.

[0065] Please refer to Figures 7 and 8. The mounting part 11 is provided with a mounting groove 111, in which the wireless charging module 2 and the radiation shielding device 4 are located. The opening of the mounting groove 111 faces the charging part 12 of the housing 1, so that when the wireless charging module 2 is installed in the mounting groove 111, the charging surface 221 of the wireless charging module 2 can be aligned with the position of the charging part 12. This avoids the misalignment of the transmitting coil 22 of the wireless charging module 2 with the receiving coil of the device to be charged, which would reduce the wireless charging efficiency or even prevent charging. Moreover, the radiation shielding device 4 located between the charging surface 221 and the charging part 12 can also better absorb radiation energy.

[0066] In one embodiment of this invention, the mounting part 11 is integrally formed with the housing 1 to improve the overall structural strength of the wireless charging device 100. In another embodiment of this invention, the mounting part 11 is detachably connected to the housing 1 to facilitate the assembly of the wireless charging module 2 and the radiation shielding device 4 during the manufacturing process.

[0067] The wireless charging module 2 includes a circuit board 20 and a transmitting coil 22 disposed on the mounting part 11, and a transmitting circuit 21, a signal module 6 and a control module 7 disposed on the circuit board 20 and electrically connected to the transmitting coil 22.

[0068] Please refer to Figure 9. In one embodiment of this example, the transmitting coil is configured as a ring winding structure and is installed in a module housing 24. The module housing 24 is preferably a circular housing. The module housing 24 is installed in the mounting groove 111 and covers the transmitting coil 22, specifically covering the transmitting surface 221 of the transmitting coil 22. The module housing 24 provides physical protection and stability for the transmitting coil.

[0069] The radiation shielding device 4 can be installed on the outer surface of the module housing 24 facing the charging section 12 to facilitate installation and replacement; alternatively, the radiation shielding device 4 can be installed inside the module housing 24 and cover the emitting surface 221 of the transmitting coil 22 to improve product integration and facilitate modular design. The radiation shielding device 4 can be installed, for example, by adhesive bonding. It is worth noting that the module housing 24 can also serve as the grounding terminal of the radiation shielding device 4.

[0070] Please refer to Figures 2 and 8. The power input terminal 23 is electrically connected to the power supply terminal 5 to provide power to the entire transmitting circuit 21. The positive terminal 231 and the negative terminal 232 of the power input terminal 23 are used to be electrically connected to the positive and negative terminals of the power supply terminal 5, respectively.

[0071] Please refer to Figures 8 and 9. In one embodiment of this example, the mounting groove 111 is located in the middle of the mounting part 11. Along the length of the mounting part 11, the circuit board 20 is fixed to one side of the mounting groove 111. The wireless charging module 2 is arranged parallel to the circuit board 20, and the power supply end 5 is installed on the side of the circuit board 20 away from the mounting groove 111. This arrangement can significantly reduce the overall thickness of the wireless charging device 100 and improve the portability of the wireless charging device 100.

[0072] The power supply terminal 5 can be an electrical connector (such as a USB Type-C connector) directly mounted on the circuit board 20, or a charging cable electrically connected to the circuit board 20; the power supply terminal 5 can also be a charging pin mounted on the housing 1, which is used to connect to an external AC power socket. In this case, the charging pin converts the external AC power into DC power that can be used by the wireless charging module 2 through the AC to DC conversion module and DC to DC conversion module provided in the wireless charging device 100.

[0073] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the embodiments of this application. The singular forms “a,” “the,” and “the” used in the embodiments and claims of this application are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that, unless otherwise stated, “a plurality” and “several” refer to two or more; “and / or” refers to and includes any or all possible combinations of one or more associated listed items; “first,” “second,” “third,” etc., are used only to distinguish and not to describe a particular order or sequence, nor should they be construed as indicating or implying relative importance. When the above description relates to drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. In the description of this application, those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0074] The embodiments described above are merely examples of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and this application also intends to include these modifications and variations.

Claims

1. A wireless charging module, characterized in that, include: A circuit board, wherein a transmitting circuit is provided on the circuit board, the transmitting circuit includes a power input terminal electrically connected to the power supply terminal of the circuit board, a full-bridge switching circuit electrically connected to the power input terminal, and an electromagnetic compatibility module electrically connected to the full-bridge switching circuit; The transmitting coil is electrically connected to the electromagnetic compatibility module, and the transmitting coil is electrically connected to the full-bridge switching circuit through the electromagnetic compatibility module. A radiation shielding device is connected to a grounding terminal and is installed on the emitting surface side of the transmitting coil.

2. The wireless charging module according to claim 1, characterized in that: The full-bridge switching circuit includes a first half-bridge and a second half-bridge, and the first half-bridge and the second half-bridge are electrically connected to the power input terminal. The electromagnetic compatibility module includes a common-mode inductor and a capacitor filter; The common-mode inductor includes a first coil and a second coil. One end of the transmitting coil is electrically connected to the first half-bridge through the first coil, and the other end of the transmitting coil is electrically connected to the second half-bridge through the second coil. The capacitor filter includes a first filter capacitor and a second filter capacitor. The two ends of the transmitting coil are electrically connected to one end of the first filter capacitor and one end of the second filter capacitor, respectively. The other ends of the first filter capacitor and the second filter capacitor are both grounded.

3. The wireless charging module according to claim 2, characterized in that: The first half-bridge includes a first switching device and a second switching device, and the second half-bridge includes a third switching device and a fourth switching device. The first switching device, the second switching device, the third switching device and the fourth switching device are N-type MOSFETs. One end of the first coil is electrically connected to the source of the first switching device and the drain of the second switching device, and the other end of the first coil is electrically connected to one end of the transmitting coil; one end of the second coil is electrically connected to the source of the third switching device and the drain of the fourth switching device, and the other end of the second coil is electrically connected to the other end of the transmitting coil.

4. The wireless charging module according to claim 3, characterized in that: The power input terminal includes a positive terminal and a negative terminal. The negative terminal is connected to the ground terminal. The drain of the first switching device and the drain of the third switching device are electrically connected to the positive terminal, and the source of the second switching device and the source of the fourth switching device are electrically connected to the negative terminal.

5. The wireless charging module according to claim 3, characterized in that: The switching frequencies of the first, second, third, and fourth switching devices are less than or equal to 1 MHz.

6. The wireless charging module according to claim 3, characterized in that: The transmitting circuit also includes a resonant capacitor, one end of the second coil is electrically connected to one end of the resonant capacitor, and the other end of the resonant capacitor is electrically connected to the source of the third switching device and the drain of the fourth switching device.

7. The wireless charging module according to claim 2, characterized in that: The first and second coils are symmetrically wound on a toroidal magnetic core.

8. The wireless charging module according to any one of claims 1-7, characterized in that: The radiation shielding device includes a connector and an absorber; one end of the connector is connected to a grounding terminal, and the other end of the connector is connected to the absorber; the area of ​​the absorber can cover the emitting surface of the transmitting coil.

9. The wireless charging module according to claim 8, characterized in that: The absorbent includes a first absorbent portion and a second absorbent portion. The first absorbent portion is connected to one end of the connector. The second absorbent portion includes a plurality of absorbent strips that are parallel to each other and spaced apart. One end of each of the plurality of absorbent strips is connected to the first absorbent portion. The first absorbent portion is connected to one end of the connector.

10. The wireless charging module according to claim 9, characterized in that: The absorption strip is a parallel straight line segment, an arc-shaped line segment, or a wavy line segment.

11. A wireless charging device, characterized in that, It includes a housing, a mounting part, a wireless charging module, and a power supply terminal. The mounting part is disposed on the housing, and the wireless charging module is disposed on the mounting part. The wireless charging module includes a radiation shielding device, which is disposed on the charging area corresponding to the wireless charging module. The power supply terminal is disposed on the housing, the wireless charging module is electrically connected to the power supply terminal, and the radiation shielding device is connected to the ground terminal.

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