Qi MPP sine wave charging circuit and wireless charger

Abstract

The utility model provides a Qi MPP sine wave charging circuit and a wireless charger, the circuit comprises a sine wave shaping circuit, one end of the sine wave shaping circuit is connected to a voltage control circuit through a full bridge control circuit, and the other end of the sine wave shaping circuit is connected to a wireless charging end Ltx; wherein the sine wave shaping circuit comprises an inductor L1, an inductor L2, a capacitor C4, a switch S3, a capacitor C5, a capacitor C6 and a capacitor C7; one end of the inductor L1 is connected with the full-bridge control circuit, and the other end of the inductor L1 is connected to the wireless charging end Ltx through the capacitor Ctx1; one end of the inductor L2 is connected with the full-bridge control circuit, and the other end of the inductor L2 is connected to the wireless charging end Ltx; the capacitor C4 and the capacitor C5 are respectively connected in parallel with the wireless charging end Ltx; one end of the capacitor C6 is connected with the inductor L1 and the other end is grounded; one end of the capacitor C7 is connected with the inductor L2 and the other end is grounded; and the switch S3 is connected in series with the capacitor C4. The high-frequency harmonic component is obviously reduced, the electromagnetic interference is reduced, the energy loss is reduced, and the overall performance of wireless charging is improved.

Description

Technical Field

[0001] This application belongs to the field of wireless charging technology, specifically relating to a Qi MPP sine wave charging circuit and a wireless charger. Background Technology

[0002] Qi is the global wireless charging standard. MPP is another type of wireless charging standard added after the Qi standard integrates Apple's MagSafe magnetic attraction wireless charging. MPP stands for Magnetic Power Profile.

[0003] MPP (Magnetic Power Point) wireless charging is a wireless charging method that uses magnetic attraction to attach the wireless charger and the mobile device together. Typically, a magnetic attachment is installed between the wireless charger and the mobile device, using magnetic force to hold them together and achieve high magnetic coupling during wireless charging. Generally, MPP charging speeds are relatively stable and fast. Magnetic wireless charging is commonly used for mobile devices such as smartphones and smartwatches.

[0004] Because the hardware architecture of the MPP is designed according to consumer-grade EMC requirements, and because it uses square wave charging, resulting in strong EMC radiation, its EMC performance cannot meet automotive standards. When tested according to the automotive CISPR-25 CLASS4 EMC standard, EMC radiation in the 0.1MHz to 400MHz range exceeds the limit, failing to meet automotive EMC standards. This is one of the reasons why MPPs cannot be installed in vehicles. Utility Model Content

[0005] To address the shortcomings of the existing technology, this application provides a Qi MPP sine wave charging circuit and a wireless charger. By adding a sine wave shaping circuit to the original MPP charging circuit, the EMC performance is improved, and the square wave charging is changed to sine wave charging, providing 128KHz frequency "sine wave" charging and 360KHz frequency "sine wave" charging.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, this utility model provides a Qi MPP sine wave charging circuit, the circuit comprising: a sine wave shaping circuit, one end of which is connected to a voltage control circuit via a full-bridge control circuit, and the other end of which is connected to a wireless charging terminal Ltx;

[0008] The voltage control circuit is used to control the power output of wireless charging.

[0009] The full-bridge control circuit is used to implement full-bridge MOSFET drive control for wireless charging.

[0010] Since square wave signals typically contain numerous high-frequency harmonic components, they are prone to electromagnetic interference (EMI). This application uses a sine wave shaping circuit to transform the square wave into a sine wave, improving the EMC performance of wireless charging, significantly reducing high-frequency harmonic components, minimizing EMI, and making the circuit more compliant with automotive manufacturers' EMC requirements. Furthermore, sine wave signals have higher energy transmission efficiency, reducing energy loss and enhancing the overall performance of wireless charging.

[0011] Preferably, the sine wave shaping circuit includes inductor L1, inductor L2, capacitor C4, switch S3, capacitor C5, capacitor C6, and capacitor C7; one end of inductor L1 is connected to the full-bridge control circuit, and the other end is connected to the wireless charging terminal Ltx through capacitor Ctx1; one end of inductor L2 is connected to the full-bridge control circuit, and the other end is connected to the wireless charging terminal Ltx; capacitors C4 and C5 are connected in parallel with the wireless charging terminal Ltx; one end of capacitor C6 is connected to inductor L1, and the other end is grounded; one end of capacitor C7 is connected to inductor L2, and the other end is grounded; switch S3 is connected in series with capacitor C4.

[0012] Preferably, when the circuit operates at a frequency of 128KHz, switch S3 is closed, then the inductance L in the circuit is equal to the sum of inductance L1 and inductance L2; the capacitor C in the circuit is C4 and C5 connected in parallel; capacitors C6 and C7 serve as sinusoidal filtering capacitors during the dead zone of the full-bridge MOSFET; and the resonant frequency of the sinusoidal shaping circuit is the LC resonant frequency.

[0013] Preferably, when the circuit operates at a frequency of 360KHz, switch S3 is turned off, then the inductance L in the circuit is equal to the sum of inductance L1 and inductance L2; the capacitor C in the circuit is equal to capacitor C5; capacitors C6 and C7 serve as sinusoidal filter capacitors during the dead zone of the full-bridge MOSFET; and the resonant frequency of the sinusoidal shaping circuit is the LC resonant frequency.

[0014] Preferably, capacitor Ctx1 is connected in parallel with capacitors Ctx2 and Ctx3, capacitor Ctx2 is connected in series with switch S1, and capacitor Ctx3 is connected in series with switch S2.

[0015] Preferably, when the circuit is operating at a frequency of 128KHz and charging normally, both switches S1 and S2 are closed.

[0016] Preferably, after the MPP mode handshake, the charging frequency needs to be switched from 128 kHz to 360 kHz, at which time the S1 switch and the S2 switch need to be in the off state.

[0017] Preferably, the full-bridge control circuit includes a first MOSFET, a second MOSFET, a third MOSFET, and a fourth MOSFET; and the first MOSFET and the second MOSFET are connected in series and then connected in parallel with the third MOSFET and the fourth MOSFET connected in series.

[0018] The inductor L1 is connected in parallel with the first MOSFET and the second MOSFET.

[0019] The inductor L2 is connected in parallel with the third MOSFET and the fourth MOSFET.

[0020] Secondly, this utility model also provides a wireless charger, which adopts the Qi MPP sine wave charging circuit as described in the first aspect.

[0021] Compared with the prior art, the advantages of this application are as follows:

[0022] This application provides a Qi MPP sine wave charging circuit and a wireless charger. By introducing a sine wave shaping circuit, the traditional square wave signal is converted into a sine wave signal, significantly improving the EMC performance of the wireless charging circuit. This application not only meets the stringent requirements of car manufacturers but also improves the efficiency and compatibility of wireless charging, showing broad application prospects. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a Qi MPP sine wave charging circuit in one embodiment.

[0024] Figure 2 This is a schematic diagram of a Qi MPP sinusoidal charging circuit operating at a frequency of 128KHz in one embodiment.

[0025] Figure 3 This is a schematic diagram of a Qi MPP sinusoidal charging circuit operating at a frequency of 360KHz in one embodiment. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions will be clearly and completely described below in conjunction with the embodiments of this application. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0027] In Embodiment 1, this utility model discloses a Qi MPP sine wave charging circuit. Qi is a wireless charging standard developed by the Wireless Power Consortium (WPC), widely used in consumer electronic devices such as mobile phones and tablets. The Qi MPP sine wave charging circuit described in this application supports multiple charging protocols. Through MPP support, it is compatible with devices from different brands, improving the user experience.

[0028] Specifically, such as Figure 1 As shown, the circuit includes: a sine wave shaping circuit, one end of which is connected to a voltage control circuit through a full-bridge control circuit, and the other end is connected to the wireless charging terminal Ltx;

[0029] The voltage control circuit is used to control the power output of wireless charging.

[0030] The full-bridge control circuit is used to drive and control the full-bridge MOSFETs for wireless charging. The full-bridge control circuit generates a square wave signal, which drives a sine wave shaping circuit through the MOSFET switches.

[0031] Since square wave signals typically contain numerous high-frequency harmonic components, they are prone to electromagnetic interference (EMI). This application uses a sine wave shaping circuit to transform the square wave into a sine wave, improving the EMC performance of wireless charging, significantly reducing high-frequency harmonic components, minimizing EMI, and making the circuit more compliant with automotive manufacturers' EMC requirements. Furthermore, sine wave signals have higher energy transmission efficiency, reducing energy loss and enhancing the overall performance of wireless charging.

[0032] Preferably, the sine wave shaping circuit includes inductor L1, inductor L2, capacitor C4, switch S3, capacitor C5, capacitor C6, and capacitor C7. One end of inductor L1 is connected to the full-bridge control circuit, and the other end is connected to the wireless charging terminal Ltx through capacitor Ctx1. One end of inductor L2 is connected to the full-bridge control circuit, and the other end is connected to the wireless charging terminal Ltx. The wireless charging terminal Ltx transmits the sine wave signal to the receiving end through the wireless charging transmission coil. The receiving end is a device that receives the wireless charging signal, such as a mobile phone or tablet computer. Capacitors C4 and C5 are connected in parallel with the wireless charging terminal Ltx. One end of capacitor C6 is connected to inductor L1, and the other end is grounded. One end of capacitor C7 is connected to inductor L2, and the other end is grounded. Switch S3 is connected in series with capacitor C4. In the preferred embodiment of this application, the sine wave shaping circuit shapes the square wave signal into a sine wave signal through the combination of inductors L1 and L2 and capacitors C4, C5, C6, and C7, which significantly improves the EMC performance of wireless charging and increases energy transmission efficiency. The introduction of switch S3 provides dynamic tuning functionality, enabling the circuit to adapt to different charging needs.

[0033] like Figure 2 As shown, the circuit operates at a frequency of 128kHz, specifically as follows:

[0034] With switch S3 closed, inductors L1 and L2 and capacitors C4, C5, C6, and C7 form an LC resonant network, filtering and shaping the square wave signal into a sine wave signal. Therefore, the inductance L in the circuit equals the sum of inductance L1 and inductance L2; capacitor C is the parallel connection of C4 and C5; and capacitors C6 and C7 act as sine wave filtering capacitors during the dead time of the full-bridge MOSFETs. The resonant frequency of the sine wave shaping circuit is the LC resonant frequency. The shaped sine wave signal is transmitted to the receiver via the wireless charging terminal Ltx, achieving efficient energy transfer. Filtering high-frequency harmonics through the LC resonant network significantly reduces electromagnetic interference (EMI), ensuring the stability and safety of the charging process and meeting the EMC requirements of vehicle manufacturers and industry standards.

[0035] like Figure 3 As shown, the circuit operates at a frequency of 360kHz, specifically as follows:

[0036] When switch S3 is off, the inductance L in the circuit equals the sum of inductance L1 and inductance L2; the capacitance C equals the sum of capacitance C5; capacitances C6 and C7 act as sinusoidal filter capacitors during the dead time of the full-bridge MOSFET; and the series connection of inductors L1 and L2 and the parallel connection of capacitances C4 and C5 form an LC resonant circuit precisely matched to the 128kHz frequency. When switch S3 is closed, the resonant frequency of the circuit is determined by the LC resonant formula, ensuring efficient operation at 128kHz.

[0037] According to the LC resonance formula, the formula for calculating the resonant frequency is:

[0038] ;

[0039] Where f represents frequency, and the unit is Hertz (Hz).

[0040] L represents inductance, and the unit is Henry (H);

[0041] C represents capacitance, and the unit is farad (F).

[0042] Preferably, capacitor Ctx1 is connected in parallel with capacitors Ctx2 and Ctx3, capacitor Ctx2 is connected in series with switch S1, and capacitor Ctx3 is connected in series with switch S2.

[0043] Preferably, when the circuit is operating at a frequency of 128KHz and charging normally, both switches S1 and S2 are closed.

[0044] Preferably, after the MPP mode handshake, the charging frequency needs to be switched from 128 kHz to 360 kHz, at which time the S1 switch and the S2 switch need to be in the off state.

[0045] Preferably, the full-bridge control circuit includes a first MOSFET, a second MOSFET, a third MOSFET, and a fourth MOSFET; and the first MOSFET and the second MOSFET are connected in series and then connected in parallel with the third MOSFET and the fourth MOSFET connected in series.

[0046] The inductor L1 is connected in parallel with the first MOSFET and the second MOSFET.

[0047] The inductor L2 is connected in parallel with the third MOSFET and the fourth MOSFET.

[0048] Secondly, this utility model also provides a wireless charger, which adopts the Qi MPP sine wave charging circuit as described in the first aspect. Through a sine wave shaping circuit, the square wave signal is shaped into a sine wave signal, improving energy transmission efficiency. High-frequency harmonics are filtered out through an LC resonant network, improving EMC performance. Simultaneously, two operating frequencies are provided: 180kHz and 360kHz. When operating at these frequencies, the S3 switch is controlled by an MCU. The S3 switch switches a resonant capacitor C4. C6 and C7 are sine wave filtering capacitors during the dead time of the full-bridge MOSFET.

[0049] Although exemplary embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above exemplary embodiments are merely illustrative and are not intended to limit the scope of this application. Various changes and modifications can be made therein by those skilled in the art without departing from the scope and spirit of this application. All such changes and modifications are intended to be included within the scope of this application as claimed in the appended claims.

[0050] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0051] Although the description of this application has been given in conjunction with the specific embodiments described above, it will be apparent to those skilled in the art that many substitutions, modifications, and variations can be made based on the foregoing. Therefore, all such substitutions, modifications, and variations are included within the spirit and scope of the appended claims.

Claims

1. A Qi MPP sinusoidal wave charging circuit, characterized in that, The circuit includes: a sine wave shaping circuit, one end of which is connected to a voltage control circuit via a full-bridge control circuit, and the other end of which is connected to the wireless charging terminal Ltx; The sine wave shaping circuit includes inductor L1, inductor L2, capacitor C4, switch S3, capacitor C5, capacitor C6, and capacitor C7. One end of inductor L1 is connected to the full-bridge control circuit, and the other end is connected to the wireless charging terminal Ltx through capacitor Ctx1. One end of inductor L2 is connected to the full-bridge control circuit, and the other end is connected to the wireless charging terminal Ltx. Capacitors C4 and C5 are connected in parallel with the wireless charging terminal Ltx. One end of capacitor C6 is connected to inductor L1, and the other end is grounded. One end of capacitor C7 is connected to inductor L2, and the other end is grounded. Switch S3 is connected in series with capacitor C4.

2. The Qi MPP sine wave charging circuit according to claim 1, characterized in that, When the circuit operates at a frequency of 128KHz, with switch S3 closed, the inductance L in the circuit is equal to the sum of inductance L1 and inductance L2. The capacitor C in the circuit is a parallel connection of C4 and C5. Capacitors C6 and C7 serve as sinusoidal filtering capacitors during the dead zone of the full-bridge MOSFET. Therefore, the resonant frequency of the sinusoidal shaping circuit is the LC resonant frequency.

3. The Qi MPP sinusoidal charging circuit according to claim 1, characterized in that, When the circuit operates at a frequency of 360KHz, switch S3 is turned off. In this case, the inductance L = inductance L1 + inductance L2; the capacitance C = capacitance C5; and capacitances C6 and C7 serve as sinusoidal filtering capacitors during the dead time of the full-bridge MOSFET. Therefore, the resonant frequency of the sinusoidal shaping circuit is the LC resonant frequency.

4. A Qi MPP sinusoidal charging circuit according to any one of claims 1-3, characterized in that, The capacitor Ctx1 is connected in parallel with capacitors Ctx2 and Ctx3. The capacitor Ctx2 is connected in series with switch S1; the capacitor Ctx3 is connected in series with switch S2.

5. The Qi MPP sine wave charging circuit according to claim 4, characterized in that, When the circuit is operating at a frequency of 128KHz and charging normally, both switches S1 and S2 are closed.

6. The Qi MPP sine wave charging circuit according to claim 4, characterized in that, After the MPP mode handshake is completed, the charging frequency needs to be switched from 128 kHz to 360 kHz. At this time, the S1 switch and the S2 switch need to be in the off state.

7. The Qi MPP sine wave charging circuit according to claim 1, characterized in that, The full-bridge control circuit includes a first MOSFET, a second MOSFET, a third MOSFET, and a fourth MOSFET; and the first MOSFET and the second MOSFET are connected in series and then connected in parallel with the third MOSFET and the fourth MOSFET, which are connected in series.

8. The Qi MPP sine wave charging circuit according to claim 7, characterized in that, The inductor L1 is connected in parallel with the first MOSFET and the second MOSFET.

9. A Qi MPP sinusoidal charging circuit according to claim 8, characterized in that, The inductor L2 is connected in parallel with the third MOSFET and the fourth MOSFET.

10. A wireless charger, characterized in that, The wireless charger uses the QiMPP sine wave charging circuit as described in any one of claims 1-9.

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