Qi MPP sine wave charging circuit and wireless charger

Abstract

According to the Qi MPP sine wave charging circuit and the wireless charger, on the basis of an original MPP charging circuit, the sine wave shaping circuit is additionally arranged to improve the EMC performance, square wave charging is changed into sine wave charging, 128KHz frequency sine wave charging and 360KHz frequency sine wave charging are provided, the wireless charging EMC performance is improved, the high-frequency harmonic component is remarkably reduced, and the wireless charging efficiency is improved. And electromagnetic interference is reduced, so that the circuit better meets the EMC requirement of a vehicle factory. Moreover, the energy transmission efficiency of the sine wave signal is higher, the energy loss is reduced, and the overall performance of wireless charging is improved.

Description

Technical Field

[0001] The present application belongs to the field of wireless charging technology, and specifically relates to a Qi MPP sinusoidal wave charging circuit and a wireless charger. Background Art

[0002] Qi is the global wireless charging standard. MPP is another new wireless charging standard added after the Qi standard integrated Apple's Magsafe magnetic wireless charging. The full name of MPP is: Magnetic Power Profile.

[0003] MPP magnetic wireless charging utilizes magnetic attraction to bond the wireless charger and mobile device together. Typically, a magnetic attachment is installed between the wireless charger and the mobile device, magnetically attaching them together to achieve high magnetic coupling for wireless charging. Generally speaking, 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 MPP's hardware architecture is designed according to consumer-grade EMC requirements, it uses square-wave charging, resulting in strong EMC radiation. Consequently, the MPP's EMC performance fails to meet automotive standards. When tested using the RE of the automotive CISPR-25 CLASS4 EMC standard, EMC radiation from 0.1MHz to 400MHz exceeds the standard, failing to meet automotive EMC requirements. This is one of the reasons why the MPP cannot be properly installed in vehicles. Summary of the Invention

[0005] In response to the above-mentioned defects of the prior art, the present application provides a Qi MPP sinusoidal wave charging circuit and a wireless charger. By adding a sinusoidal wave shaping circuit to the original MPP charging circuit to improve the EMC performance, the square wave charging is changed to sinusoidal wave charging, and 128KHz frequency "sine wave" charging and 360KHz frequency "sine wave" charging are provided.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a Qi MPP sinusoidal wave charging circuit, the circuit comprising: a sinusoidal wave shaping circuit, one end of the sinusoidal wave shaping circuit being connected to a voltage control circuit via a full-bridge control circuit, and the other end being connected to a wireless charging terminal Ltx; The voltage control circuit is used to control the power output of wireless charging.

[0007] The full-bridge control circuit is used to realize wireless charging full-bridge MOSFET drive control.

[0008] Because square wave signals typically contain a large number of high-frequency harmonic components and 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. This significantly reduces the high-frequency harmonic components and electromagnetic interference, making the circuit more compliant with automakers' EMC requirements. Furthermore, the sine wave signal has higher energy transmission efficiency, reducing energy loss and improving the overall performance of wireless charging.

[0009] Preferably, the sine wave shaping circuit includes 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 to the full-bridge control circuit, and the other end is connected to the wireless charging terminal Ltx through the capacitor Ctx1; one end of the 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 respectively connected in parallel with the wireless charging terminal Ltx; one end of the capacitor C6 is connected to the inductor L1, and the other end is grounded; one end of the capacitor C7 is connected to the inductor L2, and the other end is grounded; the switch S3 is connected in series with the capacitor C4.

[0010] Preferably, when the circuit operates at a frequency of 128KHz, the switch S3 is closed, then the inductor L in the circuit = inductor L1 + inductor L2; the capacitor C in the circuit is the parallel capacitor of C4 and C5; capacitor C6 and capacitor C7 serve as sinusoidal wave filter capacitors during the dead zone of the full-bridge MOSFET; then the resonant frequency of the sinusoidal wave shaping circuit is the LC resonant frequency.

[0011] Preferably, when the circuit operates at a frequency of 360KHz, the switch S3 is turned off, then the inductor L in the circuit = inductor L1 + inductor L2; the capacitor C in the circuit = capacitor C5; capacitor C6 and capacitor C7 serve as sinusoidal wave filter capacitors during the dead zone of the full-bridge MOSFET; then the resonant frequency of the sinusoidal wave shaping circuit is the LC resonant frequency.

[0012] Preferably, the capacitor Ctx1 is connected in parallel with the capacitor Ctx2 and the capacitor Ctx3, the capacitor Ctx2 is connected in series with the switch S1, and the capacitor Ctx3 is connected in series with the switch S2.

[0013] Preferably, when the circuit operates at a frequency of 128 KHz and is charging normally, both the switch S1 and the switch S2 are closed.

[0014] Preferably, after the MPP mode handshake, the charging frequency needs to be switched from 128 kHz to 360 kHz, and at this time, the S1 switch and the S2 switch need to be in the disconnected state.

[0015] Preferably, the full-bridge control circuit includes a first MOS transistor, a second MOS transistor, a third MOS transistor and a fourth MOS transistor; and the first MOS transistor and the second MOS transistor are connected in series and then connected in parallel with the third MOS transistor and the fourth MOS transistor connected in series.

[0016] The inductor L1 is connected in parallel with the first MOS transistor and the second MOS transistor.

[0017] The inductor L2 is connected in parallel with the third MOS transistor and the fourth MOS transistor.

[0018] In a second aspect, the present invention further provides a wireless charger, which adopts the Qi MPP sinusoidal wave charging circuit as described in the first aspect.

[0019] Compared with the prior art, the present invention has the following advantages: This application provides a Qi MPP sinusoidal charging circuit and wireless charger. By introducing a sinusoidal wave shaping circuit, the traditional square wave signal is converted into a sinusoidal signal, significantly improving the EMC performance of the wireless charging circuit. This application not only meets the strict requirements of automakers, but also improves the efficiency and compatibility of wireless charging, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 FIG. 1 is a schematic diagram of a Qi MPP sinusoidal wave charging circuit in one embodiment.

[0021] Figure 2 FIG. 1 is a schematic diagram of a Qi MPP sinusoidal wave charging circuit when the circuit operates at a frequency of 128 kHz in one embodiment.

[0022] Figure 3 Schematic diagram of a Qi MPP sinusoidal charging circuit in an embodiment when the circuit operates at a frequency of 360KHz. DETAILED DESCRIPTION

[0023] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions will be clearly and completely described below in conjunction with the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0024] In Example 1, the present invention provides a Qi MPP sinusoidal charging circuit. Qi is a wireless charging standard developed by the Wireless Power Consortium (WPC) and widely used in consumer electronics devices such as mobile phones and tablets. The Qi MPP sinusoidal charging circuit described herein supports multiple charging protocols. Through MPP support, it is compatible with devices of different brands, improving the user experience.

[0025] Specifically, such as Figure 1As shown, the circuit includes: a sine wave shaping circuit, one end of the sine wave shaping circuit is connected to the voltage control circuit through a full-bridge control circuit, and the other end is connected to the wireless charging terminal Ltx; The voltage control circuit is used to control the power output of wireless charging.

[0026] The full-bridge control circuit is used to implement wireless charging full-bridge MOSFET drive control. The full-bridge control circuit generates a square wave signal, which drives the sine wave shaping circuit through the MOSFET switches.

[0027] Because square wave signals typically contain a large number of high-frequency harmonic components and 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. This significantly reduces the high-frequency harmonic components and electromagnetic interference, making the circuit more compliant with automakers' EMC requirements. Furthermore, the sine wave signal has higher energy transmission efficiency, reducing energy loss and improving the overall performance of wireless charging.

[0028] Preferably, the sine wave shaping circuit includes 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 to the full-bridge control circuit, and the other end is connected to the wireless charging terminal Ltx through the capacitor Ctx1; one end of the 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 terminal through the wireless charging transmission coil, and the receiving terminal receives the wireless charging signal of the device, such as a mobile phone, a tablet computer, etc. The capacitors C4 and C5 are respectively connected in parallel with the wireless charging terminal Ltx; one end of the capacitor C6 is connected to the inductor L1 and the other end is grounded; one end of the capacitor C7 is connected to the inductor L2 and the other end is grounded; the switch S3 is connected in series with the capacitor C4. In a preferred embodiment of the present application, the sine wave shaping circuit shapes the square wave signal into a sine wave signal through the combination of the inductors L1, L2 and the capacitors C4, C5, C6, and C7, significantly improving the EMC performance of wireless charging and improving the energy transmission efficiency. The introduction of switch S3 provides a dynamic tuning function, which enables the circuit to adapt to different charging requirements.

[0029] like Figure 2 As shown, when the circuit operates at a frequency of 128KHz, specifically: When switch S3 is 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 sinusoidal signal. In this circuit, inductor L = inductor L1 + inductor L2; capacitor C is the parallel combination of C4 and C5; capacitors C6 and C7 serve as sine wave filtering capacitors during the full-bridge MOSFET's operating dead band. The resonant frequency of the sinusoidal wave shaping circuit is the LC resonant frequency. The shaped sinusoidal signal is transmitted to the receiver via the wireless charging terminal Ltx, achieving efficient energy transfer. The LC resonant network filters high-frequency harmonics, significantly reducing electromagnetic interference (EMI). This ensures a stable and safe charging process, meeting EMC requirements of vehicle manufacturers and industry standards.

[0030] like Figure 3 As shown, when the circuit operates at a frequency of 360KHz, specifically: When switch S3 is off, the circuit's inductor L = inductor L1 + inductor L2; the circuit's capacitor C = capacitor C5; capacitors C6 and C7 serve as sine wave filter capacitors during the full-bridge MOSFET's operating dead zone. The series connection of inductors L1 and L2 and the parallel connection of capacitors C4 and C5 form an LC resonant circuit precisely matching the 128 kHz frequency. When switch S3 is closed, the circuit's resonant frequency is determined by the LC resonance formula, ensuring efficient operation at 128 kHz.

[0031] According to the LC resonance formula, the calculation formula for the resonant frequency is: ; Where f represents frequency, the unit is Hertz (Hz); L represents inductance, the unit is Henry (H); C represents capacitance, the unit is Farad (F); Preferably, the capacitor Ctx1 is connected in parallel with the capacitor Ctx2 and the capacitor Ctx3, the capacitor Ctx2 is connected in series with the switch S1, and the capacitor Ctx3 is connected in series with the switch S2.

[0032] Preferably, when the circuit operates at a frequency of 128 KHz and is charging normally, both the switch S1 and the switch S2 are closed.

[0033] Preferably, after the MPP mode handshake, the charging frequency needs to be switched from 128 kHz to 360 kHz, and at this time, the S1 switch and the S2 switch need to be in the disconnected state.

[0034] Preferably, the full-bridge control circuit includes a first MOS transistor, a second MOS transistor, a third MOS transistor and a fourth MOS transistor; and the first MOS transistor and the second MOS transistor are connected in series and then connected in parallel with the third MOS transistor and the fourth MOS transistor connected in series.

[0035] The inductor L1 is connected in parallel with the first MOS transistor and the second MOS transistor.

[0036] The inductor L2 is connected in parallel with the third MOS transistor and the fourth MOS transistor.

[0037] In a second aspect, the present invention further provides a wireless charger, which uses the Qi MPP sinusoidal charging circuit described in the first aspect. A sine wave shaping circuit shapes a square wave signal into a sinusoidal signal, improving energy transmission efficiency. The LC resonant network filters out high-frequency harmonics, improving EMC performance. Two operating frequencies are also provided. When operating at 180 kHz and 360 kHz, the S3 switch needs to be controlled by an MCU. This is achieved by switching a resonant capacitor C4. C6 and C7 are sinusoidal filter capacitors during the dead zone of the full-bridge MOSFET.

[0038] Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely illustrative and are not intended to limit the scope of the present application. Various changes and modifications may be made therein by those skilled in the art without departing from the scope and spirit of the present application. All such changes and modifications are intended to be included within the scope of the present application as required by the appended claims.

[0039] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0040] Although the present application is described in conjunction with the above specific embodiments, it is obvious that those skilled in the art can make many substitutions, modifications and variations based on the above content. 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 is connected to a wireless charging terminal Ltx; Among them, the sine wave shaping circuit includes 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 to the full-bridge control circuit, and the other end is connected to the wireless charging terminal Ltx through the capacitor Ctx1; one end of the 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 respectively connected in parallel with the wireless charging terminal Ltx; one end of the capacitor C6 is connected to the inductor L1, and the other end is grounded; one end of the capacitor C7 is connected to the inductor L2, and the other end is grounded; the switch S3 is connected in series with the capacitor C4.

2. A Qi MPP sinusoidal wave charging circuit according to claim 1, characterized in that: When the circuit operates at a frequency of 128 kHz and switch S3 is closed, the inductor L in the circuit is equal to the inductor L1 + the inductor L2; the capacitor C in the circuit is the parallel combination of capacitors C4 and C5; capacitors C6 and C7 serve as sine wave filter capacitors during the dead zone of the full-bridge MOSFET; and the resonant frequency of the sine wave shaping circuit is the LC resonant frequency.

3. The Qi MPP sinusoidal wave charging circuit according to claim 1, characterized in that: When the circuit operates at a frequency of 360 kHz and the switch S3 is turned off, the inductor L in the circuit = the inductor L1 + the inductor L2; the capacitor C in the circuit = the capacitor C5; the capacitors C6 and C7 serve as sine wave filter capacitors during the dead zone of the full-bridge MOSFET; and the resonant frequency of the sine wave shaping circuit is the LC resonant frequency.

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

5. A Qi MPP sinusoidal wave charging circuit according to claim 4, characterized in that: When the circuit operates at a frequency of 128 kHz and is charging normally, both switch S1 and switch S2 are closed.

6. The Qi MPP sinusoidal wave charging circuit according to claim 4, characterized in that: After the MPP mode handshake, the charging frequency needs to be switched from 128 kHz to 360 kHz, and the S1 and S2 switches need to be in the disconnected state.

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

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

9. The Qi MPP sinusoidal wave charging circuit according to claim 7, characterized in that: The inductor L2 is connected in parallel with the third MOS transistor and the fourth MOS transistor.

10. A wireless charger, characterized in that: The wireless charger adopts the QiMPP sinusoidal wave charging circuit as described in any one of claims 1-8.

Images