Wireless charging series resonant cavity, wireless charging method and device

Abstract

The present application discloses a wireless charging series resonant cavity, a wireless charging method, a wireless charging coil, and a device, which belong to the field of wireless charging. Among them, a wireless charging series resonant cavity includes a resonant unit, the resonant unit is connected to the bridge rectifier chip, the resonant unit includes at least two resonant cavities connected in series with each other, and at least two of the resonant cavities can be changably connected to the bridge rectifier chip to adapt to the needs of different power states. The present application also includes a wireless charging method, a wireless charging coil, and a wireless charging device; using the technical solution of the present application, when the current increases, the power consumption wasted by the inductor coil is reduced, the heating situation is improved, and the working efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the field of wireless charging, and in particular relates to a wireless charging series resonant cavity, a wireless charging method and a wireless charging device. Background Art

[0002] In high-current wireless charging resonant cavity circuit design, for the receiving chip IC to function properly, the resonant cavity (Ls & Cs) must typically receive a sufficiently high voltage during the digital ping phase. This means Ls must be sufficiently large. Currently, 8μH is a common choice for receiving coils in mobile phones. However, since the inductance value is proportional to the number of turns in the coil, the larger the Ls, the greater the parasitic series resistance of the coil. For example, the parasitic resistance of an 8μH coil is approximately 200mOhms.

[0003] When the current increases, since the parasitic resistance of the inductor Ls is 200m Ohms, while the resistance of the switching devices M1 to M4 is only 50m Ohms, the inductor will waste a lot of power and generate serious heat. Summary of the Invention

[0004] To address the deficiencies in the prior art, the present invention proposes a wireless charging series resonant cavity, a wireless charging method, a coil, and a device, which solve the problem that when the current increases, the inductive coil wastes a lot of power and generates heat.

[0005] A wireless charging series resonant cavity includes a resonant unit, which is connected to the bridge rectifier chip. The resonant unit includes at least two resonant cavities connected in series with each other. At least two of the resonant cavities can be variably connected to the bridge rectifier chip to adapt to the needs of different power states.

[0006] The resonant unit includes a first inductor (Ls1), a first capacitor (Cs1), a second inductor (Ls2), and a second capacitor (Cs2);

[0007] The first inductor (Ls1) and the second inductor are connected in series, and the first capacitor (Cs1) and the second capacitor (Cs2) are connected in series after the first inductor (Ls1), wherein the first capacitor (Cs1) and the second capacitor (Cs2) are connected in parallel;

[0008] A first switch is provided in series on the branch where the second capacitor (Cs2) is located;

[0009] comprising a second switch, one end of the second switch being connected between the first inductor (Ls1) and the second inductor (Ls2), and the other end being connected to the input end of the bridge rectifier chip;

[0010] It also includes a third switch, the second inductor (Ls2) is connected to the third switch, and the third switch is connected to the input end of the bridge rectifier chip.

[0011] The first capacitor Cs1 and the second capacitor Cs2 have the same capacitance value.

[0012] The first inductor Ls1 and the second inductor Ls2 have the same inductance value.

[0013] The second switch includes two back-to-back field effect transistors, a second transistor M8e and a third transistor M9e;

[0014] The gate of the second transistor (M8e) is connected to the gate of the third transistor (M9e) and is also connected to the first drive end (DRV_M8e) of the bridge rectifier chip. The source of the second transistor (M8e) is connected to the source of the third transistor (M9e). The drain of the second transistor (M8e) is connected between the first inductor (Ls1) and the second inductor (Ls2). The drain of the third transistor (M9e) is connected to the connection point ACN of the bridge rectifier chip.

[0015] The third switch includes two back-to-back field effect transistors, a fourth transistor M6e and a fifth transistor M7e;

[0016] The gate of the fourth transistor (M6e) is connected to the gate of the fifth transistor (M7e), and is also connected to the second drive end (DRV_M6e) of the bridge rectifier chip. The source of the fourth transistor (M6e) is connected to the source of the fifth transistor (M7e). The drain of the fourth transistor (M6e) is connected to one end of the second inductor (Ls2). The drain of the fifth transistor (M7e) is connected to the connection point ACN of the bridge rectifier chip.

[0017] A filter capacitor (C3) is connected in parallel to the input end of the bridge rectifier chip.

[0018] A wireless charging method is implemented using the wireless charging series resonant cavity;

[0019] In the first working state, when the first switch and the second switch are both turned off and the third switch is turned on, that is, the first switch M5e, the second transistor M8e and the third transistor M9e are all in the off state, and the fourth transistor M6e and the fifth transistor M7e are in the on state, connected to the first resonant cavity;

[0020] In the second working state, when the first switch and the second switch are both turned on and the third switch is turned off, that is, the first switch M5e, the second transistor M8e and the third transistor M9e are all in the on state, and the fourth transistor M6e and the fifth transistor M7e are in the off state, the second resonant cavity is connected.

[0021] A wireless charging coil is provided, wherein an inductor wire is wound from a starting end to an ending end, and an intermediate lead is led out at a position midway between the ending end and the starting end. The portion between the starting end and the intermediate lead is the first inductor Ls1, and the portion between the intermediate lead and the ending end is the second inductor Ls2.

[0022] A wireless charging device comprises the wireless charging series resonant cavity.

[0023] Beneficial effects achieved by this application:

[0024] The present invention provides a wireless charging series resonant cavity, a wireless charging method, a coil, and a device. When the current increases, the power consumption wasted by the inductive coil is reduced, the heating condition is improved, and the working efficiency is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of a wireless charging series resonant cavity according to an embodiment of the present invention;

[0026] Figure 2 A schematic diagram of the winding of an inductor coil according to an embodiment of the present invention;

[0027] Figure 3 Resonant cavity driving circuit in wireless charging in the prior art. DETAILED DESCRIPTION

[0028] The present application will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present application.

[0029] Typically, for the receiver chip to function properly, the resonant cavity (Ls & Cs) must receive a sufficiently high voltage during the digital ping phase. This means Ls must be sufficiently large. Currently, 8μH is a common choice for receiver coils in mobile phones. However, the inductance value is proportional to the number of turns in the coil. A larger Ls value increases the parasitic series resistance of the coil. For example, the parasitic resistance of an 8μH coil is approximately 200mOhms.

[0030] At high current, the parasitic resistance of the inductor coil Ls is 200m Ohms, while that of M1 to M4 is only 50m Ohms. Therefore, the inductor coil will waste a lot of power and generate serious heat. Figure 3As shown in FIG, a wireless charging resonant cavity driving circuit in the prior art is shown.

[0031] The present invention provides a wireless charging series resonant cavity, a wireless charging method, a coil, and a device, which solve the problem that when the current increases, the inductive coil wastes a lot of power and generates heat.

[0032] A wireless charging series resonant cavity includes a resonant unit, which is connected to the bridge rectifier chip. The resonant unit includes at least two resonant cavities connected in series with each other. At least two of the resonant cavities can be variably connected to the bridge rectifier chip to adapt to the needs of different power states.

[0033] The resonant unit includes a first inductor (Ls1), a first capacitor (Cs1), a second inductor (Ls2), and a second capacitor (Cs2);

[0034] The first inductor (Ls1) and the second inductor are connected in series, and the first capacitor (Cs1) and the second capacitor (Cs2) are connected in series after the first inductor (Ls1), wherein the first capacitor (Cs1) and the second capacitor (Cs2) are connected in parallel;

[0035] A first switch is provided in series on the branch where the second capacitor (Cs2) is located;

[0036] comprising a second switch, one end of the second switch being connected between the first inductor (Ls1) and the second inductor (Ls2), and the other end being connected to the input end of the bridge rectifier chip;

[0037] It also includes a third switch, the second inductor (Ls2) is connected to the third switch, and the third switch is connected to the input end of the bridge rectifier chip.

[0038] The first capacitor Cs1 and the second capacitor Cs2 have the same capacitance value.

[0039] The first inductor Ls1 and the second inductor Ls2 have the same inductance value.

[0040] The second switch includes two back-to-back field effect transistors, a second transistor M8e and a third transistor M9e;

[0041] The gate of the second transistor (M8e) is connected to the gate of the third transistor (M9e) and is also connected to the first drive end (DRV_M8e) of the bridge rectifier chip. The source of the second transistor (M8e) is connected to the source of the third transistor (M9e). The drain of the second transistor (M8e) is connected between the first inductor (Ls1) and the second inductor (Ls2). The drain of the third transistor (M9e) is connected to the connection point ACN of the bridge rectifier chip.

[0042] The third switch includes two back-to-back field effect transistors, a fourth transistor M6e and a fifth transistor M7e;

[0043] The gate of the fourth transistor (M6e) is connected to the gate of the fifth transistor (M7e) and is also connected to the second drive end (DRV_M6e) of the bridge rectifier chip. The source of the fourth transistor (M6e) is connected to the source of the fifth transistor (M7e). The drain of the fourth transistor (M6e) is connected to one end of the second inductor (Ls2). The drain of the fifth transistor (M7e) is connected to the connection point ACN of the bridge rectifier chip.

[0044] A filter capacitor (C3) is connected in parallel to the input end of the bridge rectifier chip.

[0045] A wireless charging method is implemented using the wireless charging series resonant cavity;

[0046] In the first working state, when the first switch and the second switch are both turned off and the third switch is turned on, that is, the first switch M5e, the second transistor M8e and the third transistor M9e are all in the off state, and the fourth transistor M6e and the fifth transistor M7e are in the on state, connected to the first resonant cavity;

[0047] There is no order relationship between the first working state and the second working state, and they are arranged according to actual needs. In the first working state, the device is in a low-power state and connected to the first resonant cavity. Due to the small current, it will not cause high heat;

[0048] In order to make the receiving coil easily driven by the wireless transmitting coil, Ls1 and Cs1 are 4μH and 300nH; Ls2 = Ls1, Cs2 = Cs1;

[0049] When the power is small, let:

[0050] DRV_M5e=V(ACP)

[0051] DRV_M6e=V(BSTN)

[0052] DRV_M8e=V(ACN)

[0053] When the first switch M5e, the second transistor M8e, and the third transistor M9e are all in the off state, and the fourth transistor M6e and the fifth transistor M7e are in the on state, the active combination of the resonant cavity driving circuit is (Ls1+Ls2), Cs1, and its resonant frequency is:

[0054]

[0055] Among them, fT1 The resonant frequency when the combination of the resonant cavity driving circuit is (Ls1+Ls2), Cs1, Ls1 is the inductance value of the first inductor Ls1, and Cs1 is the capacitance value of the first capacitor Cs1;

[0056] In the second working state, when the first switch and the second switch are both turned on and the third switch is turned off, that is, the first switch M5e, the second transistor M8e and the third transistor M9e are all in the on state, and the fourth transistor M6e and the fifth transistor M7e are in the off state, the second resonant cavity is connected.

[0057] In low-power operation, due to the low current, the heat generated by the resonant cavity is low, the temperature rise is not significant, and the impact on the operation of the semiconductor device is not significant.

[0058] In high-power operation, the current increases compared to low-power operation. In the aforementioned low-power state, if the resonant cavity does not change, the heat generated by the resonant cavity increases, causing the temperature to rise, affecting the normal operation of the semiconductor device. Since the total power transmitted from the transmitter to the receiver is constant, the increase in the heat generated by the resonant cavity reduces the actual power used for charging. To this end, in high-power operation, the second resonant cavity is connected by changing the connection relationship, reducing the parasitic resistance of the entire resonant unit, thereby reducing the heat generated and improving the actual charging efficiency.

[0059] As the charging current increases, Rx sends a predetermined instruction to Tx, causing Tx to increase the voltage of the transmitting coil. Rx is the wireless charging receiver. Tx is the wireless charging transmitter. At the same time, let:

[0060] DRV_M5e=V(BSTP)

[0061] DRV_M6e=V(ACN);

[0062] DRV_M8e=V(BSTN)

[0063] When the first switch M5e, the second transistor M8e, and the third transistor M9e are all in the on state, and the fourth transistor M6e and the fifth transistor M7e are in the off state, the active combination of the resonant cavity driving circuit is: Cs1, Cs2, and Ls1, so that the inductance value of the first inductor Ls1 is equal to the inductance value of the second inductor Ls2, and the capacitance value of the first capacitor Cs1 is equal to the capacitance value of the second capacitor Cs2, that is, Ls2 = Ls1, Cs2 = Cs1:

[0064] The total inductance and capacitance of the resonant cavity are:

[0065] Ls Total =Ls1

[0066] Cs Total =2·Cs1

[0067] Among them, Ls Total is the total inductance of the resonant cavity, Cs Total is the total capacitance of the resonant cavity;

[0068] Therefore, the resonant frequency of the resonant cavity remains unchanged:

[0069]

[0070] Among them, f T2 The resonant frequency when the resonant cavity driving circuit works is the combination of Cs1, Cs2 and Ls1. The first inductor Ls1 and the second inductor Ls2 are connected in series. The original 8μH inductor (i.e. Figure 2 The inductor Ls) in the circuit uses a center tap, and the number of winding turns is reduced by half, so that the series parasitic resistance of the coil becomes 1 / 2 of the original value. Under the premise that the resonant frequency of the resonant cavity remains unchanged, power consumption is saved and heat is reduced.

[0071] A wireless charging coil, such as Figure 2 As shown, the inductor wire is wound starting from the starting end until the ending end, and an intermediate lead is led out at the middle position between the ending end and the starting end. The part between the starting end and the intermediate lead is the first inductor Ls1, and the part between the intermediate lead and the ending end is the second inductor Ls2.

[0072] A wireless charging device comprises the wireless charging series resonant cavity.

[0073] A wireless charging series resonant cavity, the detailed connection relationship of which is as follows Figure 1 As shown, it includes: a first switch M5e, a fourth transistor M6e, a fifth transistor M7e, a second transistor M8e, a third transistor M9e, a first inductor Ls1, a second inductor Ls2, a first capacitor Cs1, and a second capacitor Cs2;

[0074] The source of the first switch M5e is connected to the connection point ACP of the bridge rectifier chip IC, the drain of the first switch M5e is connected to one end of the second capacitor Cs2, the other end of the second capacitor Cs2 is respectively connected to one end of the first capacitor Cs1 and one end of the first inductor Ls1, and the other end of the first capacitor Cs1 is connected to the connection point ACP of the bridge rectifier chip IC; the other end of the first inductor Ls1 is respectively connected to the drain of the second transistor M8e and one end of the second inductor Ls2; the source of the second transistor M8e is connected to the source of the third transistor M9e, and the drain of the third transistor M9e is connected to the connection point ACN of the bridge rectifier chip IC. The other end of the second inductor Ls2 is connected to the drain of the fourth transistor M6e, the source of the fourth transistor M6e is connected to the source of the fifth transistor M7e, and the drain of the fifth transistor M7e is connected to the connection point ACN of the bridge rectifier chip IC; the gate of the first switch M5e is connected to the drive signal terminal DRV_M5e of the bridge rectifier chip IC; the gate of the fourth transistor M6e is respectively connected to the gate of the fifth transistor M7e and the drive signal terminal DRV_M6e of the bridge rectifier chip IC; the gate of the second transistor M8e is respectively connected to the gate of the third transistor M9e and the drive signal terminal DRV_M8e of the bridge rectifier chip IC.

[0075] The applicant of the present invention has made a detailed explanation and description of the implementation examples of the present invention in conjunction with the drawings in the specification. However, those skilled in the art should understand that the above implementation examples are only preferred implementation plans of the present invention, and the detailed description is only to help readers better understand the spirit of the present invention, and is not a limitation on the scope of protection of the present invention. On the contrary, any improvements or modifications based on the inventive spirit of the present invention should fall within the scope of protection of the present invention.

Claims

1. A wireless charging series resonant cavity, comprising a resonant unit connected to a bridge rectifier chip, characterized in that: The resonant unit includes two resonant cavities connected in series, and the two resonant cavities can be variably connected to the bridge rectifier chip to adapt to the needs of different power states; The resonant unit includes a first inductor (Ls1), a first capacitor (Cs1), a second inductor (Ls2), and a second capacitor (Cs2); One end of the first inductor (Ls1) is connected in series with the second inductor, and the other end of the first inductor (Ls1) is connected to one end of the first capacitor (Cs1) and one end of the second capacitor (Cs2), respectively, wherein the first capacitor (Cs1) and the second capacitor (Cs2) are connected in parallel; A first switch is provided in series on the branch where the second capacitor (Cs2) is located; the first switch is a first transistor (M5e), the gate of the first transistor (M5e) is connected to the driving end (DRV_M5e) of the bridge rectifier chip, the source of the first transistor (M5e) is connected to the other end of the first capacitor (Cs1) and the input end of the bridge rectifier chip, and the drain of the first transistor (M5e) is connected to the other end of the second capacitor (Cs2); comprising a second switch, wherein one end of the second switch is connected between the first inductor (Ls1) and the second inductor (Ls2), and the other end is connected to the input end of the bridge rectifier chip; It also includes a third switch, the second inductor (Ls2) is connected to the third switch, and the third switch is connected to the input end of the bridge rectifier chip; The first capacitor (Cs1) and the second capacitor (Cs2) have the same capacitance value; The first inductor (Ls1) and the second inductor (Ls2) have equal inductance values; The second switch includes two back-to-back field effect transistors, a second transistor (M8e) and a third transistor (M9e); The gate of the second transistor (M8e) is connected to the gate of the third transistor (M9e) and is also connected to the first drive terminal (DRV_M8e) of the bridge rectifier chip. The source of the second transistor (M8e) is connected to the source of the third transistor (M9e). The drain of the second transistor (M8e) is connected between the first inductor (Ls1) and the second inductor (Ls2). The drain of the third transistor (M9e) is connected to the input terminal of the bridge rectifier chip. The third switch includes two back-to-back field effect transistors, a fourth transistor (M6e) and a fifth transistor (M7e); The gate of the fourth transistor (M6e) is connected to the gate of the fifth transistor (M7e) and is also connected to the second drive terminal (DRV_M6e) of the bridge rectifier chip. The source of the fourth transistor (M6e) is connected to the source of the fifth transistor (M7e). The drain of the fourth transistor (M6e) is connected to one end of the second inductor (Ls2). The other end of the second inductor (Ls2) is connected to the drain of the second transistor (M8e). The drain of the fifth transistor (M7e) is connected to the input end of the bridge rectifier chip. A filter capacitor (C3) is connected in parallel to the input end of the bridge rectifier chip; In the first working state, when the first switch and the second switch are both turned off and the third switch is turned on, the first resonant cavity is connected; In the second working state, when the first switch and the second switch are both turned on and the third switch is turned off, the second resonant cavity is connected.

2. A wireless charging coil, applied to the wireless charging series resonant cavity as claimed in claim 1, characterized in that: Starting from the starting end, the inductor wire is wound until the ending end, and an intermediate lead is led out at a position halfway between the ending end and the starting end. The portion between the starting end and the intermediate lead is the first inductor (Ls1), and the portion between the intermediate lead and the ending end is the second inductor (Ls2).

3. A wireless charging device, characterized in that: The invention comprises the wireless charging series resonant cavity described in claim 1.

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