A wireless charging parallel resonant cavity, a wireless charging coil and a device

Abstract

The present application discloses a wireless charging parallel resonant cavity, a wireless charging method, a wireless charging coil and a device. A wireless charging parallel resonant cavity includes a resonant unit, and the resonant unit is connected to a bridge rectifier chip. The characteristics of the invention are as follows: the resonant unit includes at least two resonant cavities connected in parallel 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; a wireless charging method includes a first working state and a second working state. A wireless charging coil, two charging coils with equal inductance values, adopt a parallel winding method. A wireless charging device includes the wireless charging parallel resonant cavity. The present application reduces the overall parasitic resistance of the resonant unit, reduces the power consumption wasted by the inductor coil, thereby reducing the heat generation power and improving the actual charging efficiency.

Description

Technical Field

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

[0002] In wireless charging, in resonant cavity drive 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, the inductance value is proportional to the number of turns in the coil. A larger Ls increases 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 parallel 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 parallel resonant cavity includes a resonant unit connected to a bridge rectifier chip. The resonant unit includes at least two resonant cavities connected in parallel to 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] 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.

[0007] 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 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 cavity reduces the actual power used for charging. To this end, in high-power operation, another resonant cavity is incorporated 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.

[0008] There are two resonant cavities, including a first resonant cavity and a second resonant cavity connected in parallel with each other, the first resonant cavity includes a first inductor Ls1 and a first capacitor Cs1 connected in series with each other, and the second resonant cavity includes a second inductor Ls2 and a second capacitor Cs2 connected in series with each other, and both ends of the first resonant cavity and the second resonant cavity are connected to the input end of the bridge rectifier chip;

[0009] A first switch M5e is provided in series between the second capacitor and the bridge rectifier chip, and a second switch is provided in series between the second inductor and the bridge rectifier chip;

[0010] Wires are connected between the first inductor Ls1 and the first capacitor Cs1 , and between the second inductor Ls2 and the second capacitor Cs2 .

[0011] A first switch M5e is provided in series between the second capacitor and the bridge rectifier chip, and a second switch is provided in series between the second inductor and the bridge rectifier chip;

[0012] Wires are connected between the first inductor Ls1 and the first capacitor Cs1 , and between the second inductor L2 and the second capacitor Cs2 .

[0013] The first capacitor Cs1 and the second capacitor Cs2 have the same capacitance value.

[0014] The first inductor Ls1 and the second inductor Ls2 have the same inductance value.

[0015] The second switch includes two field effect transistors, a first transistor M6e and a second transistor M7e;

[0016] The gate of the first transistor M6e is connected to the gate of the second transistor M7e, and is also connected to the first driving terminal DRV_M6e of the bridge rectifier chip. The source of the first transistor M6e is connected to the source of the second transistor M7e. The drain of the first transistor M6e is connected to one end of the second inductor Ls2. The drain of the second transistor M7e is connected to one end of the first inductor Ls1.

[0017] The field effect transistor is a P-MOS.

[0018] A filter capacitor is connected in parallel with the first resonant cavity and the second resonant cavity.

[0019] A wireless charging method is implemented using the wireless charging parallel resonant cavity;

[0020] In the first working state, when the first switch and the second switch are both turned off, that is, the first switch M5e, the first transistor M6e and the second transistor M7e are all in the off state and connected to the first resonant cavity;

[0021] In the second working state, when the first switch and the second switch are both turned on, that is, the first switch M5e, the first transistor M6e and the second transistor M7e are all in the on state, connected to the first resonant cavity and the second resonant cavity.

[0022] A wireless charging coil, wherein the two charging coils with equal inductance values ​​are implemented using the following winding method: starting from the starting ends of the first inductance line and the second inductance line, the first inductance line and the second inductance line are wound in parallel until the ending ends of the first inductance line and the second inductance line.

[0023] A wireless charging device comprises the wireless charging parallel resonant cavity.

[0024] Beneficial effects achieved by this application:

[0025] The present invention provides a resonant cavity driving circuit and method for wireless charging, which reduces the power consumption of the inductor coil when the current increases, improves the heating condition, and enhances working efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 : Schematic diagram of a wireless charging parallel resonant cavity according to an embodiment of the present invention;

[0027] Figure 2 : Schematic diagram of the winding of the inductor coil according to an embodiment of the present invention;

[0028] Figure 3 : Resonant cavity driving circuit in wireless charging in the prior art;

[0029] Among them, 1 is the starting end, 2 is the ending end of the second inductor line, and 3 is the ending end of the first inductor line. DETAILED DESCRIPTION

[0030] 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.

[0031] 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.

[0032] 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 3 As shown in FIG, a wireless charging resonant cavity driving circuit in the prior art is shown.

[0033] The present invention provides a wireless charging parallel 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.

[0034] A wireless charging parallel resonant cavity, including a resonant unit, such as Figure 1 As shown, the resonance unit is connected to the bridge rectifier chip, and the resonance unit includes at least two resonance cavities connected in parallel with each other. At least two of the resonance cavities can be changably connected to the bridge rectifier chip to adapt to the needs of different power states.

[0035] There are two resonant cavities, including a first resonant cavity and a second resonant cavity connected in parallel with each other, the first resonant cavity includes a first inductor Ls1 and a first capacitor Cs1 connected in series with each other, and the second resonant cavity includes a second inductor Ls2 and a second capacitor Cs2 connected in series with each other, and both ends of the first resonant cavity and the second resonant cavity are connected to the input end of the bridge rectifier chip;

[0036] A first switch M5e is provided in series between the second capacitor and the bridge rectifier chip, and a second switch is provided in series between the second inductor and the bridge rectifier chip;

[0037] Wires are connected between the first inductor Ls1 and the first capacitor Cs1 , and between the second inductor Ls2 and the second capacitor Cs2 .

[0038] The purpose of the wires: When two resonant cavities are connected in parallel, the inductance of L decreases and the value of C increases, ensuring stable resonant frequencies. In a preferred embodiment, the inductances of Ls1 and Ls2 are equal, and the capacitances of Cs1 and Cs2 are equal. This results in the inductance of the new resonant cavity being half the original value and the capacitance being doubled. The overall resonant frequency remains unchanged, ensuring that after the change, it matches the resonant cavity at the transmitter, ensuring maximum transmission efficiency.

[0039] A first switch M5e is provided in series between the second capacitor and the bridge rectifier chip, and a second switch is provided in series between the second inductor and the bridge rectifier chip;

[0040] Wires are connected between the first inductor Ls1 and the first capacitor Cs1 , and between the second inductor L2 and the second capacitor Cs2 .

[0041] The first capacitor Cs1 and the second capacitor Cs2 have the same capacitance value.

[0042] The first inductor Ls1 and the second inductor Ls2 have the same inductance value.

[0043] The second switch includes two field effect transistors, a first transistor M6e and a second transistor M7e;

[0044] The gate of the first transistor M6e is connected to the gate of the second transistor M7e, and is also connected to the first driving terminal DRV_M6e of the bridge rectifier chip. The source of the first transistor M6e is connected to the source of the second transistor M7e. The drain of the first transistor M6e is connected to one end of the second inductor Ls2. The drain of the second transistor M7e is connected to one end of the first inductor Ls1.

[0045] The field effect transistor is a P-MOS.

[0046] A filter capacitor is connected in parallel with the first resonant cavity and the second resonant cavity.

[0047] A wireless charging method is implemented using the wireless charging parallel resonant cavity;

[0048] In the first working state, when the first switch and the second switch are both turned off, that is, the first switch M5e, the first transistor M6e and the second transistor M7e are all in the off state and connected to the first resonant cavity;

[0049] 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 is connected to a resonant cavity. Due to the small current, it will not cause high heat;

[0050] In order to make the receiving coil easily driven by the wireless transmitting coil, Ls1 and Cs1 are 8μH and 300nH;

[0051] At low power: DRV_M5e=V(ACP), DRV_M6e=V(ACN), so that the combination of the resonant cavity is Ls1, Cs1, and the resonant frequency is:

[0052]

[0053] Among them, f T1 is the resonant frequency in the first working state, Ls1 is the inductance value of the first inductor Ls1, and Cs1 is the capacitance value of the first capacitor Cs1;

[0054] In the second working state, when the first switch and the second switch are both turned on, that is, the first switch M5e, the first transistor M6e and the second transistor M7e are all in the on state, connecting the first resonant cavity and the second resonant cavity;

[0055] 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.

[0056] 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 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 cavity reduces the actual power used for charging. To this end, in high-power operation, another resonant cavity is incorporated 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.

[0057] When the charging current increases, Rx sends a predetermined instruction to Tx, causing Tx to increase the voltage of the transmitting coil; at the same time:

[0058] DRV_M5e=BSTP;

[0059] DRV_M6e=BSTN.

[0060] Among them, DRV_M5e is the voltage of the drive signal terminal DRV_M5e of the bridge rectifier chip IC, DRV_M6e is the voltage of the drive signal terminal DRV_M6e of the bridge rectifier chip IC, BSTP is the voltage of the connection point BSTP of the bridge rectifier chip IC, and BSTN is the voltage of the connection point BSTN of the bridge rectifier chip.

[0061] External MOSFETs: M5e, M6e, and M7e are turned on simultaneously, with an on-resistance of 10mOhms. By properly designing Ls2 = Ls1 and Cs2 = Cs1, the inductance and capacitance of the resonant cavity are:

[0062]

[0063] Cs Total =2·Cs1

[0064] Therefore, the resonant frequency of the resonant cavity remains unchanged:

[0065]

[0066] Among them, Ls Total is the total inductance of the resonant cavity, Cs Total is the total capacitance of the resonant cavity.

[0067] However, the parallel connection of Ls1 and Ls2 reduces the series parasitic resistance of the coil to 1 / 2 of the original resistance, thus saving power consumption and reducing heat generation.

[0068] A wireless charging coil, such as Figure 2 As shown, the two charging coils with equal inductance values ​​are implemented using the following winding method: starting from the starting end 1, the first inductance line and the second inductance line are wound in parallel until the end end, and the end end should include the first inductance line end end 3 and the second inductance line end end 2. Then, the starting end 1 and the first inductance line end end 3 are the first inductance Ls1, and the starting end 1 and the second inductance line end end 2 are the second inductance Ls2.

[0069] A wireless charging device comprises the wireless charging parallel resonant cavity.

[0070] A wireless charging parallel resonant cavity, detailed connection relationship, such as Figure 1 As shown, it specifically includes: a first switch M5e, a first transistor M6e, a second transistor M7e, a first inductor Ls1, a second inductor Ls2, a first capacitor Cs1, and a second capacitor Cs2;

[0071] The first inductor Ls1 and the first capacitor Cs1 are connected in series to form a first resonant cavity, and the second inductor Ls2 and the second capacitor Cs2 are connected in series to form a second resonant cavity. The first resonant cavity and the second resonant cavity are connected in parallel and are both connected to a bridge rectifier chip.

[0072] The first switch M5e is located on the second capacitor Cs2 side of the second resonant cavity, and is respectively connected to the second capacitor Cs2 and the bridge rectifier chip. The first transistor M6e and the second transistor M7e are connected in series and are placed on the second inductor Ls2 side of the second resonant cavity, and are respectively connected to the second inductor Ls2 and the bridge rectifier chip. The connection point between the first inductor Ls1 and the first capacitor Cs1 is connected to the connection point between the second inductor Ls2 and the second capacitor Cs2.

[0073] In the first resonant cavity, one end of the first capacitor Cs1 is connected to the connection point ACP of the bridge rectifier chip, and the other end is respectively connected to one end of the first inductor Ls1 and the connection point between the second inductor Ls2 and the second capacitor Cs2; the other end of the first inductor Ls1 is connected to the connection point ACN of the bridge rectifier chip; the connection point ACN of the bridge rectifier chip is connected to the drain of the second transistor M7e, the source of the second transistor M7e is connected to the source of the first transistor M6e, and the gate of the second transistor M7e is respectively connected to the drain of the second transistor M7e and the source of the second transistor M6e. The first transistor M6e is connected to the gate of the first transistor M6e and the drive signal terminal DRV_M6e of the bridge rectifier chip. The drain of the first transistor M6e is connected to one end of the second inductor Ls2. The other end of the second inductor Ls2 is connected to one end of the second capacitor Cs2. The other end of the second capacitor Cs2 is connected to the drain of the first switch M5e. The source of the first switch M5e is connected to the connection point ACP of the bridge rectifier chip. The gate of the first switch M5e is connected to the drive signal terminal DRV_M5e of the bridge rectifier chip.

[0074] 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 parallel resonant cavity, comprising a resonant unit connected to a bridge rectifier chip, characterized in that: The resonant unit includes two resonant cavities connected in parallel with each other, and the two resonant cavities can be variably connected to the bridge rectifier chip to adapt to the needs of different power states; The two parallel resonant cavities include a first resonant cavity and a second resonant cavity connected in parallel, the first resonant cavity includes a first inductor (Ls1) and a first capacitor (Cs1) connected in series, the second resonant cavity includes a second inductor (Ls2) and a second capacitor (Cs2) connected in series, and both ends of the first resonant cavity and the second resonant cavity are connected to the input end of the bridge rectifier chip; A first switch (M5e) is provided in series between the second capacitor (Cs2) and the bridge rectifier chip, and a second switch is provided in series between the second inductor (Ls2) and the bridge rectifier chip; A wire is connected between the first inductor (Ls1) and the first capacitor (Cs1), and between the second inductor (Ls2) and the second capacitor (Cs2); 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 field effect transistors, a first transistor (M6e) and a second transistor (M7e); The gate of the first transistor (M6e) is connected to the gate of the second transistor (M7e) and is also connected to the first driving end (DRV_M6e) of the bridge rectifier chip, the source of the first transistor (M6e) is connected to the source of the second transistor (M7e), the drain of the first transistor (M6e) is connected to one end of the second inductor (Ls2), the other end of the second inductor (Ls2) is connected to one end of the second capacitor (Cs2), the other end of the second capacitor (Cs2) is connected to one end of the first switch, the other end of the first switch is connected to the input end of the bridge rectifier chip, the drain of the second transistor (M7e) is connected to one end of the first inductor (Ls1) and the input end of the bridge rectifier chip, the other end of the first inductor (Ls1) is connected to one end of the first capacitor (Cs1), and the other end of the first capacitor (Cs1) is connected to the input end of the bridge rectifier chip; The field effect transistor is a P-MOS; A filter capacitor is connected in parallel with the first resonant cavity and the second resonant cavity; In the first working state, when the first switch and the second switch are both turned off, the first resonant cavity is connected; In the second working state, when the first switch and the second switch are both turned on, the first resonant cavity and the second resonant cavity are connected.

2. A wireless charging coil, applied to the wireless charging parallel resonant cavity according to claim 1, characterized in that: Two charging coils with equal inductance values ​​are implemented using the following winding method: starting from the starting ends of the first inductance line and the second inductance line, the first inductance line and the second inductance line are wound in parallel until the ending ends of the first inductance line and the second inductance line, the starting end and the ending end of the first inductance line are the first inductance (Ls1), and the starting end and the ending end of the second inductance line are the second inductance (Ls2).

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

Images