Wireless charging device and terminal device

Abstract

A wireless charging device and a terminal device, the wireless charging device (10) comprises a first receiving circuit (021) and a second receiving circuit (022); wherein: the first receiving circuit (021) comprises a parallel resonant circuit, the parallel resonant circuit is used for receiving a first electromagnetic induction signal from a transmitting circuit (01), forming a parallel resonant loop based on the first electromagnetic induction signal to trigger the transmitting circuit (01) to transmit a second electromagnetic induction signal; the second receiving circuit (022) is coupled with a load, and the second receiving circuit (022) is used for receiving the second electromagnetic induction signal from the transmitting circuit (01), generating electric energy based on the second electromagnetic induction signal and providing the electric energy to the load to charge the load, so that the wireless charging device (10) can stably charge the load.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of circuit, and particularly relate to a wireless charging device and a terminal device. BACKGROUND

[0002] With the development of electronic technology, the performance of mobile devices has been increasingly improved. More and more users like to use mobile devices to complete various things, which leads to high power consumption of mobile devices and requires timely charging. In order to improve the convenience of charging mobile devices, wireless charging technology applied to mobile devices has emerged and been widely used. When using wireless charging technology to charge mobile devices, the mobile devices can be directly placed on a charging base without connecting the mobile devices with a power adapter through a wire to complete charging.

[0003] In the conventional wireless charging technology, the electromagnetic coupling principle is usually used to complete the transfer of electric energy from a coil in a charging base to a coil in a mobile device to achieve charging of the mobile device. In order to complete the identification of the mobile device by the charging base to trigger the charging of the mobile device by the charging base, a capacitor is coupled across the coil in the mobile device to form a parallel resonant circuit with the coil. According to the Qi protocol proposed by the standard organization of low-frequency wireless power transmission (WPC, wireless power consortium), the resonant frequency of the above-mentioned parallel resonant circuit needs to be about 1MHz. When the charging base completes the identification of the mobile device to charge the mobile device, the parallel resonant circuit with the resonant frequency of about 1MHz can affect the stability of other components in the electric energy receiving circuit. Therefore, how to ensure the stability of the work of other components in the electric energy receiving circuit becomes a problem to be solved. SUMMARY

[0004] The wireless charging device and the terminal device provided by the present application can improve the stability of the wireless charging device.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] In a first aspect, the embodiments of the present application provide a wireless charging device, which comprises: a first receiving circuit and a second receiving circuit; wherein: the first receiving circuit comprises a parallel resonant circuit, the parallel resonant circuit is used to receive a first electromagnetic induction signal from a transmitting circuit, and a parallel resonant loop is formed based on the first electromagnetic induction signal to trigger the transmitting circuit to transmit a second electromagnetic induction signal; the second receiving circuit is coupled with a load, and the second receiving circuit is used to receive the second electromagnetic induction signal from the transmitting circuit, and electric energy is generated based on the second electromagnetic induction signal to provide the load to charge the load.

[0007] Here, the trigger of the transmitting circuit from transmitting the first electromagnetic induction signal to transmitting the second electromagnetic induction signal is implemented based on the Qi protocol proposed by the standard organization of low-frequency wireless power transmission (WPC, wireless power consortium). Specifically, based on the provisions in the Qi protocol, the resonance frequency of the parallel resonance circuit in the first receiving circuit is 1MHz, that is, the parallel resonance circuit with a resonance frequency of about 1MHz will form a parallel resonance loop based on the first electromagnetic induction signal, the induced current in the parallel resonance loop in turn affects the transmitting circuit, and after the effect is detected by the transmitting circuit, the transmitting circuit is triggered to transmit the second electromagnetic induction signal. The induced current in the parallel resonance circuit with other resonance frequencies far away from 1MHz affects the primary coil L1, which does not trigger the transmitting circuit 01 to transmit the second electromagnetic induction signal.

[0008] In a possible implementation, the second electromagnetic induction signal includes an alternating current, and a frequency range of the alternating current is 110KHz-205KHz.

[0009] The embodiments of the present application can avoid the generation of a parallel resonance loop on the transmission path of the receiving circuit for outputting power to the load, or set the resonance frequency of the parallel resonance generated on the transmission path of the receiving circuit for outputting power to the load to be far away from 1MHz, by setting the first receiving circuit and the second receiving circuit, that is, the part for responding to the transmitting circuit to be identified by the transmitting circuit, independent of the transmission path for transmitting power to the load. Therefore, the stability of the receiving circuit is improved.

[0010] In a possible implementation, the parallel resonance circuit includes a first primary coil and a first capacitor; and the first capacitor is coupled across the first primary coil.

[0011] In a possible implementation, the second receiving circuit further includes a first series resonance circuit and a first rectifier bridge; the first series resonance circuit generates a first alternating current based on the second electromagnetic induction signal and provides the first alternating current to the first rectifier bridge; and the first rectifier bridge generates a first direct current based on the first alternating current and provides the first direct current to the load.

[0012] In a possible implementation, the first rectifier bridge includes a plurality of first transistors; the second receiving circuit further includes a driving circuit for driving the plurality of first transistors to be turned on or turned off; and the driving circuit and the plurality of first transistors are integrated on the same chip.

[0013] In a possible implementation, the first receiving circuit further includes a second series resonance circuit and a second rectifier bridge; the second series resonance circuit generates a second alternating current based on the second electromagnetic induction signal and provides the second alternating current to the second rectifier bridge; and the second rectifier bridge generates a second direct current based on the second alternating current to provide power to the chip.

[0014] By using the first receiving circuit to supply power to the secondary coil, the capability of supplying power to the chip can be enhanced, so that the second receiving circuit can stably supply power to the load.

[0015] In a possible implementation, the first series resonance circuit includes a second secondary coil and a second capacitor; one end of the second secondary coil is coupled to a first input end of the first rectifier bridge through the second capacitor; and the other end of the second secondary coil is coupled to a second input end of the first rectifier bridge.

[0016] In a possible implementation, the second receiving circuit further includes a third capacitor; one end of the third capacitor is coupled to one end of the second secondary coil through the second capacitor, and the other end of the third capacitor is coupled to the other end of the second secondary coil.

[0017] In a possible implementation, the second series resonance circuit includes the first secondary coil and a fourth capacitor; the fourth capacitor is coupled between one end of the first secondary coil and a first input end of the second rectifier bridge; and the other end of the first secondary coil is coupled to a second input end of the second rectifier bridge.

[0018] In a possible implementation, the wireless charging device further includes the transmitting circuit; and the transmitting circuit is configured to: transmit a first electromagnetic induction signal, and transmit a second electromagnetic induction signal when a change in the first electromagnetic induction signal is detected.

[0019] In a possible implementation, the transmitting circuit includes an inverter and a third series resonance circuit; the inverter is configured to convert a direct current input by a power supply into an alternating current and provide the alternating current to the third series resonance circuit; and the third series resonance circuit generates the first electromagnetic induction signal and the second electromagnetic induction signal based on the alternating current output by the inverter.

[0020] In a possible implementation, the third series resonance includes a primary coil and a fifth capacitor; one end of the primary coil is coupled to a first output end of the inverter through the fifth capacitor; and the other end of the primary coil is coupled to a second output end of the inverter.

[0021] In a second aspect, the embodiments of the present application provide a terminal device, which comprises the first receiving circuit and the second receiving circuit in the wireless charging device as described in the first aspect. In addition, the terminal device further comprises a load; the load is coupled with the output end of the second receiving circuit; and the second receiving circuit is configured to charge the load.

[0022] The load herein can include, but is not limited to, a battery, various processors or other types of devices for driving the terminal device to operate, such as a Graphics Processing Unit (GPU), a Central Processing Unit (CPU), an arithmetic accelerator or various digital circuits and analog circuits, etc.; and the load 40 can also be various integrated circuit chips, including but not limited to artificial intelligence chips, image processing chips, etc. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the description of the embodiments of the present application. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative labor on the basis of these drawings.

[0024] Figure 1 is a schematic diagram of an application scenario of the wireless charging device provided by the embodiments of the present application;

[0025] Figure 2 is a structural schematic diagram of the wireless charging device provided by the embodiments of the present application;

[0026] Figure 3 is a structural schematic diagram of the wireless charging device in the prior art;

[0027] Figure 4 is a structural schematic diagram of the second receiving device provided by the embodiments of the present application;

[0028] Figure 5 is another structural schematic diagram of the second receiving device provided by the embodiments of the present application;

[0029] Figure 6 is another structural schematic diagram of the first receiving device provided by the embodiments of the present application;

[0030] Figure 7 is a structural schematic diagram of the power transmitting device provided by the embodiments of the present application. DETAILED DESCRIPTION

[0031] With reference to the drawings and embodiments disclosed herein, it is understood that the drawings and embodiments are presented by way of example only and in no way limit the scope of this application. Numerous changes and modifications will become apparent to those skilled in the art once they learn of the basic inventive concepts disclosed herein.

[0032] The terms "first", "second", and similar terms, as used herein do not denote any order, quantity, or importance, but rather are used to identify different components. Also, the terms "a" or "an", as used herein, do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items. The terms "connected" or "coupled", as used herein, are not limited to direct connections or couplings, but rather include indirect connections or couplings through one or more intermediaries.

[0033] In the present application, the words "example" and "exemplary" are used to mean serving as an example, instance, or illustration. Any implementation described herein as "example" or "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations. Rather, use of the terms "example" and "exemplary" is intended to present concepts in a concrete manner. In the description of embodiments of the present application, the term "plurality" is intended to mean two or more. For example, a plurality of crystals means two or more crystals.

[0034] Reference is made to Figure 1 which shows a schematic diagram of an application scenario of a wireless charging device 10 provided by the embodiments. The wireless charging device shown in the embodiments can be applied to a terminal device. The terminal device can include, but is not limited to, a mobile phone, a wearable device, an electric toothbrush, a tablet computer, and the like. As shown in Figure 1 The wireless charging device includes a transmitting circuit 01 and a receiving circuit 02. Generally, the receiving circuit 02 is arranged in the terminal device, and the transmitting circuit 01 is independent of the terminal device. The transmitting circuit 01 and the receiving circuit 02 in the wireless charging device can be independently produced and sold. For example, the transmitting circuit 01 and the voltage conversion circuit are arranged in the same product (for example, a wireless charging base) for sale, and the receiving circuit 02 is arranged in the terminal device for sale.

[0035] As shown in Figure 1As shown, the transmitting circuit 01 can be coupled to a power source 20. The power source 20 can be a voltage source that provides direct current (DC) power. In specific application scenarios, the power source 20 may include a home network and a voltage conversion circuit (e.g., a power adapter). The transmitting circuit 01 is coupled to the home network via the voltage conversion circuit. The voltage conversion circuit converts the AC power provided by the home network into DC power and then supplies it to the transmitting circuit 01, powering the transmitting circuit 01. Alternatively, the power source 20 may include a battery, which can also directly provide DC power to the transmitting circuit 01. Typically, the voltage supplied to the transmitting circuit 01 is adjustable from tens of volts to several tens of volts.

[0036] like Figure 1 The receiving circuit 02 shown includes a first receiving circuit 021 and a second receiving circuit 022. The output end of the second receiving circuit 022 is coupled to the load 40 to charge the load 40. The load 40 here may include but is not limited to: batteries, various processors or other types of devices that drive the operation of terminal equipment, such as a graphics processor (GPU), a central processing unit (CPU), an operation accelerator or various digital circuits and analog circuits, etc.; the load 40 can also be various integrated circuit chips, which include but are not limited to artificial intelligence chips, image processing chips, etc. It should be noted that the second receiving circuit 022 is usually not directly coupled to loads such as batteries, processors or chips, and is usually connected through Figure 1 The direct current-direct current (DC-DC) converter circuit 30 shown is coupled to a load 40. The DC-DC converter circuit 30 is configured to convert the voltage output by the second receiving circuit 022 into the voltage required for charging or operating the load 40, thereby powering the load 40. The DC-DC converter circuit 30 may include, but is not limited to, an inductive voltage conversion circuit such as a buck circuit, a boost circuit, or a boost-buck circuit. It may also include a capacitive voltage conversion circuit such as a switched capacitor circuit. The embodiments of the present application do not specifically limit the DC-DC converter circuit.

[0037] based on Figure 1 For the application scenarios shown, please refer to Figure 2 , Figure 2 A schematic diagram of the structure of a wireless charging device is shown. Figure 2As shown, the transmitting circuit 01 includes a primary coil L1, the first receiving circuit 021 includes a secondary coil L2, and the second receiving circuit 022 includes a secondary coil L3. The primary coil L1 is coupled with the secondary coil L2 and the secondary coil L3, respectively. In a first possible implementation, the secondary coil L2 and the secondary coil L3 are independent coils, respectively; in a second possible implementation, the secondary coil L2 and the secondary coil L3 can be two groups of coils formed by leading multiple taps from the same coil, which is not limited in the embodiments of the present application. The taps of the secondary coil L2 are connected in parallel with a capacitor C1. The capacitor C1 and the secondary coil L2 form a parallel resonant circuit. The transmitting circuit 01 inversely converts the direct current provided by the power supply 20 into alternating current and provides the alternating current to the primary coil L1. Based on the principle of electromagnetic coupling, the primary coil L1 transmits electric energy to the secondary coil L2 in the first receiving circuit 021 and the secondary coil L3 in the second receiving circuit 022. The specific circuit structure of the transmitting circuit 01 can refer to the description of the related embodiments shown in the drawings. Figure 7 The related description of the embodiments shown.

[0038] In a specific implementation, after the transmitting circuit 01 is connected to the power supply, it usually works in a first working mode, which is used to transmit a first electromagnetic signal to identify the receiving circuit. When the transmitting circuit 01 identifies the receiving circuit, it enters a second working mode, which is used to transmit a second electromagnetic signal to charge the load. By setting the first working mode and the second working mode, the transmitting circuit 01 can reduce the energy consumption and prolong the service life. In the first working mode, the transmitting circuit 01 can continuously or periodically generate a small-power alternating current on the primary coil L1, that is, an alternating current with a small current is generated on the primary coil L1. When the terminal device is set on the wireless charging base, based on electromagnetic induction, the electric energy on the primary coil L1 is transmitted to the secondary coil L2 in the first receiving circuit 021 and the secondary coil L3 in the second receiving circuit 022. Since the energy transmitted by the primary coil L1 to the secondary coil L2 and the secondary coil L3 is weak at this time, the voltage in the second receiving circuit cannot drive the transistors in the rectifier bridge of the second receiving circuit 022 to be turned on (the specific structure of the second receiving circuit 022 can refer to the description of the related embodiments shown in the drawings). Figure 4(related description of the embodiment shown), that is, a closed loop cannot be formed. After the secondary coil L2 obtains energy from the primary coil L1, an induced current is generated on the secondary coil L2. Since the capacitor C1 is connected in parallel at both ends of the secondary coil L2, that is, the secondary coil L2 and the capacitor C1 form a parallel resonant circuit, and current flows through the parallel resonant circuit. For the parallel resonant circuit, the induced current on the secondary coil L2 is higher than the total current input to the circuit, so that the current on the secondary coil L2 will in turn affect the current flowing through the primary coil L1, changing the original current amplitude on the primary coil L1. After the change in amplitude is detected by the transmitting circuit 01, the transmitting circuit 01 is triggered to switch from the first working state to the second working state. It should be noted that triggering the transmitting circuit 01 to switch from the first working state to the second working state is based on the Qi protocol launched by the standard organization for low-frequency wireless power transmission (WPC, wireless power consortium). Specifically, based on the provisions in the Qi protocol, in the following example Figure 2 In the illustrated first receiving circuit 021, the parallel resonant circuit formed by the secondary coil L2 and capacitor C1 has a resonant frequency of 1 MHz. This means that the induced current in the parallel resonant circuit with a resonant frequency of approximately 1 MHz adversely affects the primary coil L1. This effect is detected by the transmitting circuit 01, triggering the transmitting circuit 01 to enter the second operating mode. Induced currents in parallel resonant circuits with resonant frequencies far from 1 MHz adversely affect the primary coil L1 and do not trigger the transmitting circuit 01 to enter the second operating mode. Furthermore, the transition of the transmitting circuit 01 from the first operating state to the second operating state undergoes multiple processes, such as communication identification. For example, both the transmitting circuit 01 and the second receiving circuit 022 are equipped with a control circuit (or controller). To ensure that it is the receiving circuit 02, and not another object (such as a magnet), that changes the original current amplitude in the primary coil L1, the control circuit in the transmitting circuit 01, upon detecting the change in the original current amplitude in the primary coil L1, controls the transmitting circuit 01 to transmit an electromagnetic induction signal of a specific frequency based on the provisions of the Qi protocol. Upon detecting the electromagnetic induction signal of the specific frequency, the control circuit in the second receiving circuit 022 controls the second receiving circuit 022 to transmit an electromagnetic induction signal of a specific amplitude to the transmitting circuit 01 in response. After the transmitting circuit 01 and the second receiving circuit 022 complete power transmission preparations according to the protocol, they can enter the second operating state.

[0039] In a traditional power receiving circuit, a secondary coil Lb, a capacitor Ca and a capacitor Cb are usually set. The capacitor Cb is connected in parallel at both ends of the secondary coil Lb through the capacitor Ca, and a load is coupled at the output end of the power receiving circuit, such as Figure 3As shown. Furthermore, based on the provisions of the aforementioned Qi protocol, the parallel resonant frequency of the parallel resonant circuit formed by the secondary coil Lb and capacitor Cb is 1 MHz. After the primary coil La transfers electrical energy to the secondary coil Lb, the secondary coil Lb and capacitor Cb form a parallel resonant circuit. When the power transmission circuit operates in the first operating mode, this closed current loop is used to be recognized by the power transmission circuit; however, when the power transmission circuit operates in the second operating mode, current oscillations occur in the parallel resonant circuit formed by the secondary coil Lb and capacitor Cb, which has a resonant frequency of 1 MHz. Typically, the control circuit in the power receiving circuit controls the on and off of the transistors in the rectifier bridge by detecting the current in the power receiving circuit. The period and amplitude of the oscillating current generated at a parallel resonant frequency of 1 MHz can be easily misdetected by the control circuit, causing the transistors in the rectifier to turn on when they should not, or turn off when they should not, thereby affecting the stability of the rectifier.

[0040] In the embodiment of the present application, by setting the first receiving circuit 021 and the second receiving circuit 022, that is, the parts used to respond to the transmitting circuit 01 so as to be recognized by the transmitting circuit 01, independently of the transmission path used to transmit electric energy to the load, it is possible to avoid the generation of a parallel resonant circuit on the transmission path for outputting electric energy to the load in the receiving circuit, or to set the resonant frequency of the parallel resonance generated on the transmission path for outputting electric energy to the load in the receiving circuit to be away from 1 MHz, thereby facilitating the improvement of the stability of the receiving circuit.

[0041] based on Figure 1 The application scenario shown, Figure 2 Please refer to the schematic diagram of the wireless charging device shown in the figure. Figure 4 , which shows a structural diagram of the receiving circuit 02 provided in an embodiment of the present application.

[0042] like Figure 4 As shown, the receiving circuit 02 includes a first receiving circuit 021 and a second receiving circuit 022. The first receiving circuit 021 includes a secondary coil L2 and a capacitor C1. The working principle of the first receiving circuit 021 is specifically referred to Figure 2 The relevant descriptions in the illustrated embodiment will not be repeated here. In addition to the secondary coil L3, the second receiving circuit 022 also includes a capacitor C2, a rectifier bridge Rec1 and a capacitor C3. The rectifier bridge Rec1 includes a first input terminal Va1, a second input terminal Va2 and an output terminal Vo1. Among them, the first tap of the secondary coil L3 is coupled to the first input terminal Va1 of the rectifier bridge Rec1 through the capacitor C2, and the second tap of the secondary coil L3 is coupled to the second input terminal Va2 of the rectifier bridge Rec1. The capacitor C3 is coupled between the output terminal Vo1 of the rectifier bridge Rec1 and the common ground Gnd. The output terminal Vo1 of the rectifier bridge is connected to the common ground Gnd. Figure 2The load coupling shown is used to output electrical energy to the load. In the second receiving circuit 022, as shown in Figure 2 The primary coil L1 shown transmits electrical energy to the secondary coil L3, and a periodic alternating current is generated on the secondary coil L3. The alternating current passes through the series resonant circuit composed of the secondary coil L3 and the capacitor C2, and is provided to the rectifier bridge Rec1. The rectifier bridge Rec1 converts the input alternating current into direct current after rectification, and provides the direct current to the output terminal Vo1. The current of the output terminal Vo1 is filtered by the capacitor C3 and transmitted to the DC-DC conversion circuit as shown in Figure 1 The DC-DC conversion circuit finally charges the load after DC-DC conversion.

[0043] In an embodiment of the present application, the bridge arm of the rectifier bridge Rec1 is composed of transistors, as shown in Figure 4 The rectifier bridge Rec1 includes transistors M1, M2, M3 and M4. The first pole of the transistor M1 and the first pole of the transistor M2 are coupled to the output terminal Vo1 of the rectifier bridge Rec1, the second pole of the transistor M1 and the first pole of the transistor M3 are coupled to the first input terminal Va1, the second pole of the transistor M2 and the first pole of the transistor M4 are coupled to the second input terminal Va2, and the second pole of the transistor M3 and the second pole of the transistor M4 are coupled to the common ground Gnd. In addition, the second receiving circuit 022 also includes a control circuit. The control circuit is used to control the conduction and disconnection of the transistors M1, M2, M3 and M4, so as to realize the rectification of the current input to the series resonant circuit composed of the secondary coil L3 and the capacitor C2. The transistors M1, M2, M3 and M4 can be NMOS field effect transistors or PMOS field effect transistors, and the embodiments of the present application do not limit them. When the above-mentioned transistors are field effect transistors, the above-mentioned first pole can be the source pole, and the second pole can be the drain pole; or the above-mentioned first pole can be the drain pole, and the second pole can be the source pole. In specific work, the control circuit can control the conduction of the transistors by detecting the voltage across the transistors, and control the disconnection of the transistors by detecting the zero-crossing current on the transistors. The transistor M1 is taken as an example for description. When the control circuit detects that the voltage of the second pole of the transistor M1 coupled to the first input terminal Va1 is higher than the voltage of the first pole coupled to the output terminal Vo1, the transistor M1 is controlled to be turned on; when the control circuit detects that the current on the transistor M1 is at the zero-crossing point (i.e. from positive to negative or from negative to positive), the transistor M1 can be controlled to be turned off. The control of the other transistors by the control circuit is referred to the control of the transistor M1, and will not be described herein. In addition, the control circuit can also be used for communication with the transmitting circuit 01 based on the Qi protocol.

[0044] In a possible implementation, the structure of the second receiving circuit 022 can also be as shown in Figure 5 InFigure 5 In the embodiment, the second receiving circuit 022 comprises a secondary coil L3, a capacitor C2, a rectifier bridge Rec1 and a capacitor C3, the structures and connection relationships of the components are the same as those of the components in the second receiving circuit 022 shown in Figure 4 the second receiving circuit 022 shown in FIG. 2B, and details are referred to the related description of the second receiving circuit 022 shown in Figure 4 the second receiving circuit 022 shown in FIG. 2B, which will not be repeated here. Different from the second receiving circuit 022 shown in Figure 4 the second receiving circuit 022 shown in FIG. 2B, in the embodiment, the second receiving circuit 022 further comprises a capacitor C4. Figure 5 In the embodiment, the second receiving circuit 022 further comprises a capacitor C4. One end of the capacitor C4 is coupled to one of the taps of the secondary coil L3 through the capacitor C2, and the other end of the capacitor C4 is coupled to the other tap of the secondary coil L3. It should be noted that the resonance frequency of the parallel resonance circuit composed of the capacitor C4 and the secondary coil L3 is far away from 1 MHz, which can be much higher than 1 MHz or much lower than 1 MHz. For example, the resonance frequency of the parallel resonance circuit composed of the capacitor C4 and the secondary coil L3 can be 5 MHz. By setting the resonance frequency of the parallel resonance circuit composed of the secondary coil L3 and the capacitor C4 to be far away from 1 MHz, the period and amplitude of the oscillation current generated by the parallel resonance can be changed, so that the control circuit can avoid misjudging the signal as a signal for controlling the transistor in the rectifier bridge Rec1 to be turned on or turned off, and the stability of the receiving circuit can also be improved.

[0045] It should be noted that the transistors included in the rectifier bridge Rec1 shown in the embodiments of the present application and the control circuit for controlling the transistors to be turned on or turned off can be integrated in the same integrated chip.

[0046] Since the rectifier bridge Rec1 shown in Figure 4 and Figure 5 is composed of transistors, appropriate bias voltage needs to be provided by the power supply for the operation of each transistor, in addition, the driving circuit for driving the transistors to be turned on or turned off also needs to be powered by the power supply. In order to improve the utilization rate of the received electric energy by the receiving circuit, the first receiving circuit 021 can also supply power to the above integrated chip. Based on this, in a possible implementation manner, the structure of the first receiving circuit 021 is shown in Figure 6 FIG. 2A. In the embodiment, the first receiving circuit 021 further comprises a power supply circuit 023. Figure 6In the embodiment, the first receiving circuit 021 comprises the capacitor C5, the rectifier bridge Rec2 and the capacitor C6 in addition to the secondary coil L2 and the capacitor C1. One end of the capacitor C5 is coupled to one of the taps of the secondary coil L2, the other end of the capacitor C5 is coupled together with one end of the capacitor C1 and the first input terminal Va3 of the rectifier bridge Rec2, the second input terminal Va4 of the rectifier bridge Rec2 is coupled together with the other end of the capacitor C1 and the other tap of the secondary coil L2, the output terminal Vo2 of the rectifier bridge Rec2 is used to output electric energy, and the capacitor C6 is coupled between the output terminal Vo2 of the rectifier bridge Rec2 and the common ground Gnd. The capacitance of the capacitor C5 is greater than the capacitance of the capacitor C1, and in addition, the resonant frequency of the series resonant circuit composed of the secondary coil L2 and the capacitor C5 is 100 KHz. When the transmitting circuit 01 works in the first working mode, the primary coil L1 transmits energy to the secondary coil L2, and the current in the parallel resonant circuit composed of the secondary coil L2 and the capacitor C1 reversely affects the current in the primary coil L1, thereby triggering the transmitting circuit 01 to work in the second working mode. When the transmitting circuit 01 works in the second working mode, part of the energy transmitted by the transmitting circuit 01 is received by the secondary coil L2, and part of the energy is received by the secondary coil L3, and the secondary coil L2 and the secondary coil L3 respectively generate induced currents. The series resonant circuit composed of the secondary coil L3 and the capacitor C2 transmits the induced current on the secondary coil L3 to the rectifier bridge Rec1, and the rectifier bridge Rec1 converts alternating current into direct current and outputs to the load. The series resonant circuit composed of the secondary coil L2 and the capacitor C5 transmits the induced current on the secondary coil L2 to the rectifier bridge Rec2, and the rectifier bridge Rec2 converts alternating current into direct current to supply power to the above-mentioned integrated chip. In the embodiment, the bridge arm of the rectifier bridge Rec2 can be a diode, as shown in Figure 5 In other possible implementations, the bridge arm of the rectifier bridge Rec2 can also be a transistor, and at this time, the structure of the rectifier bridge Rec2 is the same as that of the rectifier bridge Rec1 as shown in Figure 4 This application will not be described in detail in the embodiment.

[0047] In the conventional technology, the electric energy receiving circuit is only arranged in one secondary coil (for reference to Figure 3), if the above-mentioned integrated chip is arranged in the power receiving circuit, the integrated chip is usually powered by the energy obtained by the power receiving circuit itself, so that when the distance between the power receiving circuit and the power transmitting circuit is far or the placement position is too biased to cause weak electromagnetic induction, the current in the power transmitting circuit is weak and cannot drive the integrated chip to work. The embodiment of the present application can enhance the power supply capability of the above-mentioned integrated chip by using the first receiving circuit 021 to supply power to the above-mentioned integrated chip, so that the second receiving circuit 022 can stably supply power to the load. Further, in order to improve the power supply energy of the secondary coil L2 to the above-mentioned integrated chip, in one possible implementation, the number of turns of the secondary coil L2 is more than the number of turns of the secondary coil L3.

[0048] Based on Figure 1 the application scenario shown in Figure 7 , a structure diagram of the transmitting circuit 01 is shown. As shown in Figure 7 , the transmitting circuit 01 includes an inverter (IV) and a series resonance circuit. The inverter IV is composed of a plurality of transistors. Specifically, as shown in Figure 7 , the inverter includes a transistor M5, a transistor M6, a transistor M7 and a transistor M8. The first pole of the transistor M5 and the first pole of the transistor M6 are coupled to the positive input end V+ of the transmitting circuit 01, the second pole of the transistor M5 and the first pole of the transistor M7 are coupled to the first output end Vo3 of the inverter, and the second pole of the transistor M6 and the first pole of the transistor M8 are coupled to the second output end Vo4 of the inverter. The second pole of the transistor M7 and the second pole of the transistor M8 are coupled to the negative input end V- of the transmitting circuit 01. It should be noted that in some scenarios, the negative input end can be a common ground Gnd. As shown in Figure 7 , the series resonance circuit in the transmitting circuit 01 can include a capacitor C0 and a primary coil L1. One of the taps of the primary coil L1 is coupled to the first input end Vo3 of the inverter IV, and the other tap of the primary coil L1 is coupled to the second input end Vo4 of the inverter IV through the capacitor C0. In addition, as shown in Figure 7 , the transmitting circuit 01 further includes a control circuit, which is used to control the conduction or turn-off of each transistor forming the inverter IV, so as to control the size of the power output by the transmitting circuit 01, Figure 7 , the control circuit is not shown in the figure. In a specific implementation, the control circuit controls the size of the current in the series resonance circuit by controlling the switching frequency of each transistor and the duty cycle of each transistor. In addition, the control circuit can also trigger the conversion between the first working mode and the second working mode based on the Qi protocol by detecting the current change in the primary coil L1.

[0049] As shown in Figure 7As shown, when the transmitting circuit 01 works in the first working mode, the transistor M5 and the transistor M8 are turned on in the first time period, and the transistor M6 and the transistor M7 are turned on in the second time period, wherein the time length of the first time period and the time length of the second time period are both short, that is, the switching frequency of each transistor is high, so that the switching frequency of each transistor is far away from the resonance frequency of the series resonant circuit composed of the capacitor C0 and the primary coil L1. At this time, the current flowing through the primary coil L1 is small, that is, the electric energy output by the transmitting circuit 01 is small. When the control circuit in the transmitting circuit 01 detects that the current amplitude flowing through the primary coil L1 changes, the switching frequency of each transistor is adjusted, the duty cycle of each transistor is adjusted, so that the switching frequency of each transistor reaches the resonance frequency of the series resonant circuit composed of the capacitor C0 and the primary coil L1, the current flowing through the primary coil L1 is increased, and thus the electric energy output by the transmitting circuit 01 is increased.

[0050] The embodiments of the present application also provide a terminal device. The terminal device can be a portable computer (such as a mobile phone), a notebook computer, a wearable electronic device (such as a smart watch), a tablet computer, an augmented reality (AR) or virtual reality (VR) device, or an electric toothbrush, etc. Specifically, the terminal device shown in the present application includes a receiving circuit shown in any of the embodiments. Figure 1 、 Figure 2 、 Figure 4 、 Figure 5 or Figure 6 any embodiment.

[0051] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A wireless charging device, characterized in that: The wireless receiving circuit includes a first receiving circuit and a second receiving circuit; wherein: The first receiving circuit includes a parallel resonant circuit, the parallel resonant circuit being configured to receive a first electromagnetic induction signal from a wireless transmitting circuit, and to form a parallel resonant circuit based on the first electromagnetic induction signal, thereby generating an induced current in the parallel resonant circuit; the induced current being configured to instruct the wireless transmitting circuit to identify the wireless receiving circuit, thereby triggering the transmitting circuit to transmit a second electromagnetic induction signal; The second receiving circuit is coupled to a load, and is configured to receive the second electromagnetic induction signal from the wireless transmitting circuit, and generate electrical energy based on the second electromagnetic induction signal and provide the electrical energy to the load to charge the load.

2. The wireless charging device according to claim 1, wherein: The second receiving circuit includes a first series resonant circuit and a first rectifier bridge; The first series resonant circuit generates a first alternating current based on the second electromagnetic induction signal and provides the first alternating current to the first rectifier bridge; The first rectifier bridge generates a first direct current based on the first alternating current, and provides the first direct current to the load.

3. The wireless charging device according to claim 2, wherein: The first rectifier bridge includes a plurality of first transistors; The second receiving circuit further includes a driving circuit for driving the plurality of first transistors to be turned on or off; The driving circuit and the plurality of first transistors are integrated into the same chip.

4. The wireless charging device according to claim 3, wherein: The first receiving circuit further includes a second series resonant circuit and a second rectifier bridge; The second series resonant circuit generates a second alternating current based on the second electromagnetic induction signal and provides the second alternating current to the second rectifier bridge; The second rectifier bridge generates a second direct current based on the second alternating current to power the chip.

5. The wireless charging device according to claim 4, characterized in that: The parallel resonant circuit includes a first secondary coil and a first capacitor; The first capacitor is coupled to both ends of the first secondary coil.

6. The wireless charging device according to any one of claims 2 to 5, wherein: The first series resonant circuit includes a second secondary coil and a second capacitor; One end of the second secondary coil is coupled to the first input end of the first rectifier bridge through the second capacitor; The other end of the second secondary coil is coupled to the second input end of the first rectifier bridge.

7. The wireless charging device according to claim 6, wherein: The second receiving circuit further includes a third capacitor; One end of the third capacitor is coupled to one end of the second secondary coil through the second capacitor, and the other end of the third capacitor is coupled to the other end of the second secondary coil.

8. The wireless charging device according to claim 5, wherein: The second series resonant circuit includes the first secondary coil and a fourth capacitor; The fourth capacitor is coupled between one end of the first secondary coil and the first input end of the second rectifier bridge; The other end of the first secondary coil is coupled to the second input end of the second rectifier bridge.

9. The wireless charging device according to any one of claims 1-5, 7-8, characterized in that: The wireless charging device further includes the wireless transmitting circuit; The wireless transmitting circuit is configured to transmit the first electromagnetic induction signal, and transmit the second electromagnetic induction signal in response to detecting a change in the first electromagnetic induction signal.

10. The wireless charging device according to claim 9, characterized in that: The wireless transmission circuit includes an inverter and a third series resonant circuit; The inverter is used to convert the direct current input by the power supply into alternating current and provide it to the third series resonant circuit; The third series resonant circuit generates the first electromagnetic induction signal and the second electromagnetic induction signal based on the alternating current output by the inverter.

11. The wireless charging device according to claim 10, wherein: The third series resonance includes a primary coil and a fifth capacitor; One end of the primary coil is coupled to the first output end of the inverter through the fifth capacitor; The other end of the primary coil is coupled to the second output end of the inverter.

12. A terminal device, characterized in that: Comprising the wireless charging device and the load according to any one of claims 1 to 8; The load is coupled to the output end of the second receiving circuit in the wireless charging device; The second receiving circuit is used to charge the load.

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