CN113068417B

CN113068417B - Wireless charging receiving end, electronic equipment and transmitting end

Info

Publication number: CN113068417B
Application number: CN201980006478.6A
Authority: CN
Inventors: 胡章荣; 魏巍; 衡草飞
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2019-10-28
Filing date: 2019-10-28
Publication date: 2023-08-22
Anticipated expiration: 2039-10-28
Also published as: WO2021081698A1; CN113068417A

Abstract

The application discloses a wireless charging receiving end, electronic equipment and a transmitting end. Each radio conversion device is used for converting an alternating magnetic field emitted by a wireless charging emitting end into voltage, and the converted voltage is used for forming output voltage; the switch module is coupled with at least two radio conversion devices for changing the connection between the radio conversion devices to change the output voltage. The connection means between the radio conversion devices include series, parallel, partial series, partial parallel or single radio conversion device operation. After the connection mode between the radio conversion devices is switched under the action of the switch module, the output voltage can be changed, and then the voltage reduction is realized. The application realizes the voltage reduction by changing the connection mode of the rectifier or the receiving coil, saves a primary voltage reduction module, thereby reducing the cost of the integrated circuit board, and the receiving end can also be used as a transmitting end for reverse charging.

Description

Wireless charging receiving end, electronic equipment and transmitting end

Technical Field

The present application relates to the field of wireless charging technologies, and in particular, to a wireless charging receiving terminal and an electronic device.

Background

Portable electronic devices have found widespread use in recent years. The traditional mode of charging the electronic equipment needs to frequently plug the power line, so that the device is easy to wear in the plug charging process, the safety is poor, and the attractiveness of the electronic equipment is also affected.

Wireless charging is a novel energy transmission mode. Compared with the traditional charging mode, the wireless charging can well solve the problems. Many electronic devices are now available that can support wireless charging, such as cell phones, smart watches, bluetooth headsets, electric toothbrushes, etc.

Because users have high requirements on the charging rate of electronic devices, the adoption of high-power wireless charging is becoming a mainstream trend. However, when high-power wireless charging is performed, the current rise can cause the increase of the heat consumption of the coil, the heating problem is more prominent, and the temperature protection mechanism of the wireless charging receiving end is easily triggered, so that the wireless charging efficiency is affected. In order to solve the heating problem of the receiving end during high-power wireless charging, an independent voltage reduction module can be arranged at the receiving end at present, the voltage reduction module reduces the voltage when the voltage output by the rectifier is higher, and then the battery is charged by using the reduced direct current. For example, to increase the heat dissipation capacity of the receiving end, the rectifier and the buck module need to be implemented on two different integrated circuit boards, respectively. The use of a buck module increases the hardware cost of the receiving end.

Disclosure of Invention

Based on the technical problems, the application provides a wireless charging receiving end and electronic equipment, which can reduce the voltage of the receiving end and simultaneously save the hardware cost.

The application provides a wireless charging receiving terminal, which mainly comprises: at least two radio conversion devices for generating an output voltage, wherein each radio conversion device is used for converting an alternating magnetic field emitted by a wireless charging transmitting end into a voltage, and the voltage is used for forming the output voltage; a switching module coupled to the at least two radio conversion devices for changing a connection of the at least two radio conversion devices to change the output voltage, the connection including series, parallel, partial series, partial parallel or operation of a single radio conversion device.

In the application, the output voltage can be changed, for example, increased or decreased, by changing the connection mode of at least two radio conversion devices, so that when the output voltage needs to be adjusted up or down, the output voltage is not needed to be adjusted up or down by using an extra voltage reduction module, thereby reducing the hardware cost. In addition, a plurality of connection modes can be established between the radio conversion devices, so that the range of the output voltage has a plurality of choices, and the radio conversion device can be suitable for actual requirements under a plurality of wireless charging scenes.

Alternatively, in the first aspect of the present application, each radio conversion device at the receiving end may include a receiving coil, and the switch module is configured to change a connection manner of at least two receiving coils in the at least two radio conversion devices, so that the at least two receiving coils operate in series, in parallel, in partial series or in partial parallel, or in a single receiving coil; the at least two receiving coils are used for converting an alternating magnetic field emitted by the wireless charging transmitting end into alternating voltage; the receiving end further comprises: and a rectifier for converting the alternating voltage into a direct voltage, the direct voltage being an output voltage. In the technical scheme, the output voltage can be changed by changing the connection mode between the receiving coils, so that the convenience of voltage reduction is improved, and the voltage reduction cost in the charging process of the receiving end is saved.

Optionally, in the first aspect of the present application, at least two radio conversion devices of the receiving end include: a first radio conversion device including a first coil and a second radio conversion device including a second coil; the switch module includes: a first switch, a second switch, and a third switch; the first end of the first coil and the second end of the second coil are respectively connected with a rectifier; the second end of the first coil is connected with the first end of the second coil through a first switch; the first end of the first coil is connected with the first end of the second coil through a second switch; the second end of the first coil is connected with the second end of the second coil through a third switch; the first end of the first coil and the first end of the second coil are homonymous ends.

Optionally, in the first aspect of the present application, the receiving end may further include: and the control module is used for controlling the switch module to change the series connection of the first coil and the second coil into parallel connection when the output voltage is larger than a preset voltage threshold value.

Optionally, in the first aspect of the present application, at least one of the first switch, the second switch, and the third switch includes: a switching element; a current zero-crossing detection circuit for generating a zero-crossing detection signal when a zero crossing of the current on the switching element is detected; and the driving circuit is used for driving the switching element under the control of the control module when receiving the zero-crossing detection signal from the current zero-crossing detection circuit. The switch described by the technical scheme controls the connection mode of at least two radio conversion devices, so that the safety and controllability of wireless charging are improved.

Alternatively, in the first aspect of the present application, the switching element includes a bidirectional metal-oxide-semiconductor field effect transistor. The bidirectional metal-oxide-semiconductor field effect transistor is used as a switching element to ensure the cut-off effect of current and promote the controllability of the connection mode of at least two radio devices.

Optionally, in the first aspect of the present application, the receiving end may further include: and a variable capacitor connected between the input terminal of the rectifier and at least one of the first terminal of the first coil and the second terminal of the second coil.

Optionally, in the first aspect of the present application, the control module may be further configured to increase the value of the variable capacitance when the control switch module changes the first coil and the second coil from serial to parallel. By changing the value of the variable capacitor, the resonant frequency of the wireless charging system can be kept stable before and after the connection mode between the coils is switched, so that the more stable wireless charging effect is improved.

Alternatively, in the second aspect of the present application, each radio conversion device may include: a receiving coil and a rectifier; the receiving coil is used for converting an alternating magnetic field emitted by the wireless charging transmitting end into alternating voltage; the rectifier is used for converting the alternating voltage output by the corresponding receiving coil into direct voltage, and the direct voltage is used for forming output voltage; the switching module is used for changing the connection mode of at least two rectifiers in at least two radio conversion devices so that the at least two rectifiers are connected in series, parallel, partially connected in series, partially connected in parallel or operated by a single rectifier. According to the technical scheme, the output voltage can be changed by changing the connection mode between the output ends of the at least two rectifiers, so that the convenience of voltage reduction is improved, and the voltage reduction cost in the charging process of the receiving end is saved.

Optionally, in a second aspect of the present application, the at least two radio conversion devices include: a third radio conversion device and a fourth radio conversion device, the third radio conversion device comprising a third coil and a first rectifier, the third coil being connected to an input of the first rectifier; the fourth radio conversion device includes a fourth coil and a second rectifier; the fourth coil is connected with the input end of the second rectifier; the switch module includes: a fifth switch, a sixth switch, and a seventh switch;

the second output end of the first rectifier is connected with the first output end of the second rectifier through a fifth switch; the first output end of the first rectifier is connected with the first output end of the second rectifier through a sixth switch; the second output terminal of the first rectifier is connected to the second output terminal of the second rectifier through a seventh switch.

Optionally, in the second aspect of the present application, the receiving end further includes: and the control module is used for controlling the switch module to change the series connection of the first rectifier and the second rectifier into the parallel connection when the output voltage is larger than a preset voltage threshold value. Through switching the first rectifier and the second rectifier from the series connection to the parallel connection, the output voltage can be reduced, the output voltage is prevented from continuously rising, and the problem that the temperature of the receiving end rises in the charging process is solved.

Optionally, in the above technical solution of the present application, the receiving end may further include: and the voltage detection circuit is used for detecting the value of the output voltage and sending the value of the output voltage to the control module.

Optionally, in the above technical solution of the present application, the receiving end further includes: and the charging management module is used for receiving the output voltage and charging the battery.

Optionally, the receiving end is further used as a transmitting end to perform reverse wireless charging for the battery of other wireless charging receiving ends.

Optionally, when the receiving end is used as a transmitting end to perform the reverse wireless charging, the at least two radio conversion devices are used for receiving an input voltage, and each radio conversion device is used for converting a voltage to be converted into an alternating magnetic field for wireless charging, wherein the voltage to be converted is formed by the input voltage;

the switching module is coupled to the at least two radio conversion devices for changing a connection of the at least two radio conversion devices to change the voltage to be converted, the connection including series, parallel, partial series, partial parallel, or a single radio conversion device.

In addition, the application also provides electronic equipment, which comprises the wireless charging receiving end provided in the technical scheme, and further comprises: a battery; and the receiving end is used for charging the battery.

In addition, the application also provides a wireless charging transmitting terminal, which comprises: at least two radio conversion means for receiving an input voltage, each of the radio conversion means for converting a voltage to be converted into an alternating magnetic field for wireless charging, the voltage to be converted being formed by the input voltage; a switching module coupled to the at least two radio conversion devices for changing a connection of the at least two radio conversion devices to change the voltage to be converted, the connection including serial, parallel, partial serial, partial parallel or single radio conversion device operation.

Compared with the prior art, the application has at least the following advantages: the wireless charging receiving end provided by the embodiment of the application comprises a switch module and at least two radio conversion devices. Each radio conversion device is used for converting an alternating magnetic field emitted by a wireless charging transmitting end into voltage; the voltage obtained by conversion of the radio conversion device is used for forming an output voltage; the switch module is coupled with at least two radio conversion devices for changing the connection between the radio conversion devices to change the output voltage. The connection means between the radio conversion devices include series, parallel, partial series, partial parallel or single radio conversion device operation. After the connection mode between the radio conversion devices is switched under the action of the switch module, the output voltage can be changed, and then the voltage reduction is realized. For example, switching at least two radio conversion devices in series to operate in partial series, parallel, partial parallel or a single radio conversion device causes the output voltage to decrease. As an example, the radio conversion device in the embodiment of the present application may include a receiving coil, so that the connection mode of the radio conversion device is changed, that is, the connection mode between the coils is changed; in addition, the radio conversion device may also comprise a receiving coil and a rectifier, so that the connection of the radio conversion device is changed, i.e. the connection between the rectifier outputs of different radio conversion devices is changed. According to the embodiment of the application, the voltage reduction is realized by changing the connection mode of the rectifier or the receiving coil, so that a primary voltage reduction module is saved, and the cost of the integrated circuit board can be reduced.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments described in the present application, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic diagram of a wireless charging scenario provided in an embodiment of the present application;

fig. 2 is a schematic diagram of a wireless charging scenario provided in an embodiment of the present application;

fig. 3 is a schematic structural diagram of a wireless charging receiving end according to an embodiment of the present application;

fig. 4 is a schematic diagram of a scenario in which the receiving end shown in fig. 3 is wirelessly charged;

FIG. 5 is a schematic diagram of a control module in the receiving end shown in FIG. 3;

FIG. 6 is a schematic diagram of another configuration of the control module in the receiving end shown in FIG. 3;

fig. 7 is a schematic diagram of a bidirectional MOS transistor according to an embodiment of the present application;

fig. 8 is a schematic diagram of a scenario in which a receiving end including three coils performs wireless charging according to an embodiment of the present application;

fig. 9 is a schematic structural diagram of another wireless charging receiving end according to an embodiment of the present application;

Fig. 10 is a schematic diagram of a scenario in which the receiving end shown in fig. 9 is wirelessly charged;

fig. 11 is a schematic diagram of a wireless charging scenario when each switch in the receiving end shown in fig. 9 is a MOS transistor;

fig. 12 is a schematic diagram of another scenario in which a receiving end is wirelessly charged;

fig. 13 is a schematic structural diagram of an electronic device according to an embodiment of the present application.

Detailed Description

For easy understanding, first, an application scenario of wireless charging of an electronic device is described. Referring to fig. 1, a schematic diagram of a wireless charging scenario according to an embodiment of the present application is shown. As shown in fig. 1, the wireless charging application scenario includes: adapter 101, wireless charging transmitting terminal 102, and wireless charging receiving terminal 103. As an example, the transmitting end 102 may be some device or component inside an electronic device with wireless charging capability. As an example, the electronic device with the wireless charging function may be a mobile phone, a tablet computer, a notebook computer, a wireless charging base, or the like, which has a wireless charging function to other devices. As an example, the receiving end 103 may be some device or component inside the electronic device that is wirelessly charged. As an example, the wirelessly charged electronic device may be a cell phone, tablet computer, notebook computer, bluetooth headset, smart watch, electric toothbrush, etc. The adapter 101 transmits the electric energy provided by the power supply to the transmitting end 102, and electromagnetic induction can be performed between the transmitting coil L1 of the transmitting end 102 and the receiving coil L2 of the receiving end 103, so that electric energy transmission is realized. The receiving coil L2 of the receiving end 103 is used for receiving the alternating magnetic field emitted by the transmitting coil L1 and converting the alternating magnetic field into alternating current. The receiving end 103 may be integrated with the battery Bat or may be detachably mounted.

As described above, when high-power wireless charging is performed, the heating problem of the receiving end is remarkable, which is not beneficial to efficient charging, but affects the wireless charging safety. If the receiving end adopts an extra depressurization module to realize depressurization, the hardware cost burden is increased for the receiving end, and meanwhile, a larger board-level area is required to be occupied. The embodiment of the application provides a technical scheme for solving the problems, and the output voltage is changed by changing the connection mode of at least two radio conversion devices in the receiving end, so that the voltage can be increased and the voltage can be reduced. Specifically, the application provides a wireless charging receiving terminal and electronic equipment. The following detailed description is made with reference to the embodiments and the accompanying drawings.

Example 1

Referring to fig. 2, a schematic diagram of a wireless charging scenario according to an embodiment of the present application is shown. As shown in fig. 2, in an embodiment of the present application, a receiving end of wireless charging includes: a radio conversion device 201 and a switching module 202. The number of radio conversion devices 201 in the receiving end is at least two (one in fig. 1 is merely an example). A control module 204 and a charge management module 205 may also be included in the scenario. Wherein the radio conversion device 201 is used for converting an alternating magnetic field emitted by a wireless charging transmitting terminal into a voltage. In practice, the radio conversion device 201 has a plurality of possible implementations. As a possible implementation, the radio conversion device 201 may comprise a receiving coil, whereby the radio conversion device 201 converts the alternating magnetic field into an alternating voltage. The ac voltage converted by all the radio conversion devices 201 working together in the present embodiment is used to form the output voltage Vout. As another possible implementation, the radio conversion device 201 may include a receiving coil and a rectifier, where the receiving coil is connected to an input terminal of the rectifier, and since the rectifier has an ability to convert ac power into dc power, the radio conversion device 201 converts dc voltage. The dc voltage converted by all the radio conversion devices 201 working together in this embodiment is used to form the output voltage Vout. In the embodiment of the present application, the output voltage Vout formed as described above is used for providing to the charge management module 205. The charge management module 205 receives the output voltage Vout and charges the battery.

In this embodiment, at least two radio conversion devices 201 of the receiving end can operate in a plurality of different connection modes. The connection modes of the radio conversion device 201 at least include the following: the series, parallel, partial series, partial parallel or single radio conversion device 201 operates.

Assuming that there are N radio conversion devices 201 in total (N is an integer greater than 1) at the receiving end, tandem means that there are N radio conversion devices 201 at the receiving end that operate in series; parallel means that the receiving end has N radio conversion devices 201 operating in parallel. When N is specifically an integer greater than 2, partial series connection means that the receiving end has M radio conversion devices 201 operating in series (M is an integer greater than 1 and less than N); partial parallel means that there are M radio conversion devices 201 at the receiving end operating in parallel.

The switch module 202 is coupled to at least two radio conversion devices 201 at the receiving end, and the switch module 202 has a function of changing the connection mode of the at least two radio conversion devices 201. Since the voltage converted by the operating radio conversion device 201 is used to form the output voltage Vout at the receiving end, when the connection of at least two radio conversion devices 201 is changed, the output voltage Vout is also changed.

In practice, the switch module 202 and the at least two radio conversion devices 201 may be directly coupled or indirectly coupled. In particular, the switch module 202 and the at least two radio conversion devices 201 may also establish an electrical connection, in particular, the electrical connection may be either a direct connection or an indirect connection. The manner in which the switch module 202 and the at least two radio conversion means 201 are interrelated is not limited here.

Generally, the term coupled may include both electrical and magnetic coupling. The terms coupled and connected in this embodiment are to be considered equivalent in terms of their specific electrical connection. The electrical connection includes interconnection of electrical signals by wires or by other devices, and the embodiment is not limited to a specific electrical connection manner.

In practical applications, the switch module 202 may have a plurality of possible implementations, and the switch module 202 may include a plurality of switches, where the specific form of the switches is not limited, and may be, for example, an independent switch or a composite switch.

It is assumed that the specifications of the receiving coils included in each radio conversion apparatus 201 are the same. As an example, the switching module 202 switches at least two radio conversion devices 201 in series to operate with a partial series, parallel, partial parallel or single radio conversion device 201, the output voltage Vout is reduced compared to before the switching of the connection mode. Conversely, when the switching module 202 switches at least two radio conversion devices 201 in the receiving end from a partially serial, parallel, partially parallel or single radio conversion device to operate all the radio conversion devices 201 in series, the output voltage Vout is increased compared to before the switching of the connection mode.

The control module 204 may be configured to control the switching module 202 to operate according to the output voltage Vout. For example, when the output voltage Vout is too large or too small, the control module 204 may send a corresponding control signal to the switch module 202 to change the connection manner between the radio conversion devices 201 at the receiving end through the action of the switch module 202. The above is the wireless charging receiving terminal provided by the embodiment of the application. Wherein each radio conversion device 201 is configured to convert an alternating magnetic field emitted from a transmitting terminal of wireless charging into a voltage, and the converted voltage is used to form an output voltage Vout by the radio conversion devices 201; the switching module 202 is coupled to the at least two radio conversion devices 201 for changing the connection of the at least two radio conversion devices 201 to change the output voltage Vout. When the connection mode of the radio conversion device 201 is switched under the action of the switch module 202, the output voltage Vout can be changed, so that the output voltage Vout can be reduced. The embodiment of the application realizes the voltage reduction by changing the connection mode of the rectifier or the receiving coil, so that a primary voltage reduction module is saved, the circuit structure is saved, the area and the cost of an integrated circuit board are reduced, and the application is especially suitable for electronic equipment with limited space like a mobile phone.

To facilitate understanding of various implementations of the receiving end provided in the above embodiments, the following description is provided in connection with various embodiments.

Example two

In the receiving end provided in this embodiment, the radio conversion device specifically includes a receiving coil, not including a rectifier, for converting an alternating magnetic field emitted from the wirelessly charged transmitting end into an alternating voltage. For the sake of clear understanding, the drawings relating to the present embodiment do not specifically depict the pattern of the radio conversion device, but rather the pattern of the receiving coil included in the radio conversion device.

Referring to fig. 3, the structure of a wireless charging receiving terminal according to an embodiment of the present application is shown. As shown in fig. 3, in the embodiment of the present application, the receiving end 30 for wireless charging includes: a receiving coil 301, a rectifier 302, a switching module 303, a control module 304 and a charge management module 305; wherein the number of receiving coils 301 corresponds to the number of radio conversion means in the receiving end 30. The receiving end 30 includes at least two receiving coils 301 therein. The number of the receiving coils 301 is not particularly limited in this embodiment, and may be 2 or more, for example, 3 or 4, and may be set according to actual needs.

Each receiving coil 301 is configured to convert an alternating magnetic field emitted by a transmitting coil L1 of a transmitting terminal of wireless charging into an alternating current and supply the alternating current to a rectifier 302; rectifier 302 converts the ac power to dc power for transmission to charge management module 305. The dc voltage converted by the rectifier 302 is provided as an output voltage Vout to the charge management module 305. To facilitate understanding of the function of the control module 304 of the receiving end 30 in this embodiment, the following description is made in connection with an example.

It is assumed that at least two radio conversion devices in the receiving end 30 include: a first radio conversion device and a second radio conversion device, wherein the first radio conversion device includes a receiving coil 301 called a first coil and the second radio conversion device includes a receiving coil 301 called a second coil.

The control module 304 is configured to switch the first coil and the second coil from serial connection to parallel connection by controlling the switch module 303 when the output voltage Vout provided by the rectifier 302 is greater than a preset voltage threshold. The inductance value of the first coil and the second coil after being connected in parallel is reduced because the inductance value of the two inductors after being connected in parallel is reduced, and the voltage of the first coil and the second coil after being connected in parallel is reduced because the voltage of the coils is in direct proportion to the inductance value of the coils. Therefore, when the connection mode of the first coil and the second coil is changed, the ac voltage supplied to the rectifier 302 by the first coil and the second coil in common decreases. It will be appreciated that as the ac voltage input to the rectifier 302 decreases, the dc voltage output by the rectifier 302, i.e., the output voltage Vout, also decreases. The preset voltage threshold may be set according to actual requirements, and specific values are not limited herein.

The charge management module 305 is configured to control the charging voltage and current according to the state of the battery Bat after receiving the output voltage Vout provided by the rectifier 302.

In this embodiment, the connection mode between the receiving coils 301 may be changed by the switching module 303, for example, from a series mode to a parallel mode, from a series mode to a partial series (for the case of more than two receiving coils 301), from a parallel mode to a partial parallel (for the case of more than two receiving coils 301), from a series mode to a single receiving coil 301 to operate, from a parallel mode to a series mode, and so on.

The wireless charging receiving terminal 30 provided in the above embodiments of the present application, the control module 304 of the receiving terminal 30 can switch the connection mode of the receiving coil 301 according to the output voltage of the rectifier 302. When the control module 304 determines that the output voltage Vout of the rectifier 302 is too large (e.g., greater than a preset voltage threshold), the control switch module 303 controls the on/off state of the switch to change from the series mode to the parallel mode. When the receiving coil 301 is changed from series to parallel, the output voltage Vout of the rectifier 302 is reduced compared with when the receiving coil 301 is connected in series, so that the rectifier 302 is effectively prevented from continuously outputting higher voltage at the same time, and the problems of overvoltage and excessive heat consumption are avoided. The receiving end 30 does not need to be provided with an additional voltage reducing module, so that the charging efficiency is not lost due to the voltage reducing module, and the rapid wireless charging is facilitated. In addition, the hardware cost and board area of the receiving end 30 are saved.

For the convenience of understanding the technical solution provided in this embodiment by those skilled in the art, the following description will take the receiving end 30 including two receiving coils as an example with reference to fig. 4. Fig. 4 is a schematic diagram of a scenario of wireless charging corresponding to the receiving end 30 shown in fig. 3.

As shown in fig. 4, the receiving end includes a first coil LW1 and a second coil LW2. Wherein, the first end and the second end of the first coil LW1 are A1 and A2, respectively, and the first end and the second end of the second coil LW2 are B1 and B2, respectively. A1 and B1 are the same name end, A2 and B2 are the same name end, A1 and B2 are the different name end, and A2 and B1 are the different name end. The switching module 303 includes: a first switch SW1, a second switch SW2 and a third switch SW3.

The second switch SW2 and the third switch SW3 may be implemented together by a composite switch, or may be implemented by two independent switches. In this embodiment, the second switch SW2 and the third switch SW3 can simultaneously perform the same action, for example, simultaneously turn on or simultaneously turn off, under the control of the control module 304, and in a specific implementation, the second switch SW2 and the third switch SW3 may be driven by the same pulse driving signal to drive their switch states.

The connection relationship of each of the receiving coils 301, each of the switches in the switching module 303, and the rectifier 302 is described below. The first terminal A1 of the first coil LW1 is connected to the positive input terminal AC1 of the rectifier 302, the second terminal A2 is connected to the first terminal B1 of the second coil LW2 through the first switch SW1, and the second terminal B2 of the second coil LW2 is connected to the negative input terminal AC2 of the rectifier 302. The first end A1 of the first coil LW1 is connected to the first end B1 of the second coil LW2 through the second switch SW 2; the second terminal A2 is connected to the second terminal B2 of the second coil LW2 through the third switch SW3.

When the second switch SW2 and the third switch SW3 shown in fig. 4 are both closed and the first switch SW1 is opened, the coil parallel mode corresponding to the receiving terminal 30; when the second switch SW2 and the third switch SW3 are both opened and the first switch SW1 is closed, the coil series mode corresponds to the receiving terminal 30.

The control module 304 of the receiving end 30 for wireless charging in this embodiment is configured to control the first switch SW1 to be closed, and control the second switch SW2 and the third switch SW3 to be opened, so that the second end A2 of the first coil LW1 is connected to the first end B1 of the second coil LW2 through the closed switch SW1, and the first coil LW1 and the second coil LW2 are connected in series; the control module 304 is further configured to control the first switch SW1 to be opened, the second switch SW2 to be closed, and the third switch SW3 to be closed, so that the same name ends of the two coils are connected, that is, the A1 is connected with the B1 and the A2 is connected with the B2, and the first coil LW1 and the second coil LW2 are connected in parallel.

As can be seen from the above description, during the wireless charging process, the inductance value of the receiving end also changes due to the change of the connection mode of the receiving coil. When the coils are switched from series connection to parallel connection, the inductance value of the receiving end is reduced; when the coils are switched from parallel to series, the inductance value of the receiving end increases. In order to ensure the working efficiency of wireless charging and avoid the fluctuation of the resonant frequency of the transmitting end and the receiving end due to the change of the inductance value of the receiving end, the receiving end 30 provided in the embodiment of the present application may further include a variable capacitor (not shown in fig. 3). In the embodiment of the present application, the variable capacitor may further include: the capacitance network with a variable capacitance, such as a switched capacitance network, may also include an adjustable capacitance, which is not limited in this embodiment. A specific implementation of the capacitive network is described below.

The receiving coil 301 of the receiving end 30 and the capacitor network are connected to form a resonant circuit. At the transmitting end, the transmitting coil and the capacitance of the transmitting end also form a resonant circuit. Electromagnetic induction of the transmitting end and the receiving end 30 is mainly performed through resonance circuits at both ends. The control module 304 of the receiving end 30 is further configured to control the capacitance value of the capacitor network to change when the inductance value of the receiving coil 301 is controlled to change, so that the resonant frequency of the resonant circuit of the receiving end 30 remains unchanged.

In practical applications, the resonant frequency of the resonant circuit of the receiving end 30 is inversely proportional to the product of the inductance value and the capacitance value. That is, the larger the product of the inductance value and the capacitance value, the smaller the resonance frequency; the smaller the product of the inductance value and the capacitance value, the larger the resonance frequency.

In this embodiment, in order to ensure the working efficiency of wireless charging, a specific implementation manner is to control the capacitance value of the capacitance network to change when the inductance value changes. For example, when the receiving coil 301 is switched from series to parallel, the inductance value of the receiving coil 301 becomes small, and at this time, the product of the inductance value and the capacitance value can be kept unchanged by increasing the capacitance value of the capacitance network, so that the resonance frequency is kept unchanged. When the receiving coil 301 is switched from parallel to series, the inductance value of the receiving coil 301 becomes large, and at this time, the product of the inductance value and the capacitance value can be kept unchanged by reducing the capacitance value of the capacitance network, thereby keeping the resonance frequency unchanged.

It should be noted that the variable capacitor may be disposed at various positions of the receiving end 30. For example:

(1) The variable capacitance is connected between the positive input of the rectifier 302 and the first end of the first coil;

(2) A variable capacitance is connected between the negative input terminal of the rectifier 302 and the second terminal of the second coil;

(3) The variable capacitance comprises two components, one of which is connected between the positive input of the rectifier 302 and the first end of the first coil and the other of which is connected between the negative input of the rectifier 302 and the second end of the second coil.

An implementation of controlling the resonance frequency to be constant in the embodiment of the present application will be exemplarily described with reference to fig. 4. In fig. 4, the variable capacitance is connected in the above-described (1) th mode. In the wireless charging scenario shown in fig. 4, the capacitive network of the receiving end 30 includes: a first capacitor C1, a second capacitor C2, and a fourth switch SW4. The first end A1 of the first coil LW1 is connected to the positive input end AC1 of the rectifier 302 through the first capacitor C1; the second capacitor C2 and the fourth switch SW4 are connected in series and then connected to two ends of the first capacitor C1; the control module 304 is further configured to control the fourth switch SW4 to be closed when the first coil LW1 and the second coil LW2 are connected in parallel. When the fourth switch SW4 is turned on, the first capacitor C1 is connected in parallel with the second capacitor C2, and the capacitance value of the capacitor network is the capacitance value of the first capacitor C1 and the second capacitor C2 connected in parallel; when the fourth switch SW4 is turned off, the capacitance value of the capacitor network is the capacitance value of the first capacitor C1. The control module 304 controls the fourth switch SW4 to be turned on to increase the capacitance value of the capacitor network.

Assuming that the inductance values of the first coil LW1 and the second coil LW2 are both L, when the two coils are connected in series, the inductance value of the receiving coil 301 is 2L; when the two coils are connected in parallel, the inductance value of the receiving coil 301 is L/2. Assuming that the capacitance values of the first capacitor C1 and the second capacitor C2 are C, when the two coils LW1 and LW2 are connected in series, the capacitance value of the capacitor network is C/2; when the two coils are connected in parallel, the capacitance value of the capacitance network is 2C.

It can be seen that when the two coils LW1 and LW2 are connected in series, the product of the inductance value and the capacitance value is LC, and when the two coils are connected in parallel, the product of the inductance value and the capacitance value is still LC. I.e. the switching variation of the coil connection mode does not affect the resonance frequency of the resonance circuit. Therefore, the resonant frequency of the resonant circuit of the receiving end 30 remains unchanged in the wireless charging process, and the working efficiency of the receiving end 30 is also ensured.

In practical applications, the resonance frequency of the coils LW1 and LW2 when connected in series can be used as a resonance frequency reference value for subsequently adjusting the capacitance value of the capacitor network. That is, when the connection mode of the receiving coil 301 is changed during the wireless charging process, the capacitance value of the capacitor network is adjusted so that the resonant frequency of the resonant circuit is always kept unchanged by the resonant frequency reference value.

The following describes coil connection control and capacitor connection control of the wireless charging receiving terminal 30 in the whole wireless charging process. The receiving end shown in fig. 4 is still taken as an example in this example.

In this example, the Qi protocol standard is used for wireless charging of the receiving end 30. The standard has a strict definition on the shape and specification of the transmitting coil and also requires a coupling voltage for the receiving coil 301. The default coils LW1 and LW2 operate in a series mode in which both the inductance value of the receive coil 301 and the coil shape meet the certification requirements of the Qi protocol standard. The high power transmission is started only after the protocol handshake between the transmitting end and the receiving end 30 is completed, and then the control module 304 of the receiving end 30 controls the connection mode switching of the coil according to the output voltage Vout of the rectifier 302.

(1) The wireless charging receiving terminal 30 starts wireless charging. The initial charge phase default control module 304 controls the first switch SW1 to be closed, the second switch SW2 and the third switch SW3 to be opened, so that the coils LW1 and LW2 operate in series. The transmitting coil of the transmitting end outputs a default voltage, and the receiving coil 301 satisfies the authentication requirements of the Qi protocol standard, so the rectifier 302 of the receiving end 30 outputs a voltage conforming to the protocol prescribed value (for example, about 7V when the electronic device is a mobile phone). The output voltage may support the initiation of the receiver 30 protocol core. When the protocol kernel is started, the receiving end 30 can realize in-band communication with the wireless charging transmitting end through a carrier wave.

(2) After the receiving end 30 establishes in-band communication with the transmitting end, power handshaking is performed.

The receiving end 30 can identify the power level of the transmitting end through a power handshake. As an implementation, if the receiving end 30 recognizes that the transmitting end supports the base power level BPP protocol (Baseline Power Profile), which means that the transmission power between the transmitting end and the receiving end 30 is within 5W, the receiving end 30 does not need to request the transmitting end to boost; as another implementation, if the receiving end 30 recognizes that the transmitting end supports the extended power level EPP protocol (Extended Power Profile), which means that the transmission power between the transmitting end and the receiving end 30 may be between 5W and 15W, or that the transmitting end supports other proprietary protocols, the receiving end 30 may request the transmitting end to boost according to the protocol. After receiving the boosting request, the transmitting end starts boosting according to the request.

(3) As shown in fig. 4, the receiving end 30 may further include a voltage detection circuit 306. The voltage detection circuit 306 is configured to detect an output voltage Vout of the rectifier 302 of the receiving terminal 30, and send the output voltage Vout to the control module 304.

When Vout is greater than a first gear voltage (which may be configured as desired, for example, the electronic device is a cellular phone, and the first gear voltage may be 9V), the control module 304 controls to open the first switch SW1 and control to close the second switch SW2 and the third switch SW2 to switch the coil from the series mode to the parallel mode. At this time, the inductance value of the receiving coil 301 in common becomes 1/4 before switching. And, the control module 304 also controls the fourth switch SW4 to be turned on, so that the first capacitor C1 and the second capacitor C2 are connected in parallel, the capacitance value of the capacitor network in the resonant circuit is increased, and the resonant frequency is ensured to be basically unchanged before and after the coil connection mode is switched. Since the voltage coupled to the receiving coil 301 of the receiving terminal 30 is proportional to the square of the open side of the inductance value of the receiving coil 301 working together, the voltage coupled to the receiving terminal 30 becomes 1/2 of the original voltage after the receiving coil 301 is switched from the series mode to the parallel mode. It will be appreciated that the output voltage Vout of the rectifier 302 accordingly becomes around 1/2 of the previous.

(4) When the voltage detection circuit 306 detects that the output voltage Vout of the rectifier 302 is lower than a second gear voltage (the second gear voltage may be configured as required, and the second gear voltage is smaller than the first gear voltage, for example, the electronic device is a cellular phone, and the second gear voltage may be 4V), the control module 304 controls to open the second switch SW2 and the third switch SW3, and controls to close the first switch SW1. At this time, the receiving coil 301 of the receiving end 30 is switched from the parallel mode to the series mode. The inductance value of the receiving coil 301 becomes 4 times before the connection mode switching at this time. And, the control module 304 also controls the fourth switch SW4 to be turned off, so that only the first capacitor C1 in the capacitor network is turned on, thereby reducing the capacitance value of the capacitor network in the resonant circuit and maintaining the resonant frequency unchanged.

As can be seen from the above examples, the receiving end 30 in the present application can realize switching of the coil connection mode based on the output voltage Vout of the rectifier 302, so that in the high-voltage high-power wireless power transmission stage of the receiving end 30, voltage reduction can be realized by switching the coil into the parallel mode, so as to avoid continuous temperature rise of the receiving end 30, and meanwhile, compared with the arrangement of a special voltage reduction module, the one-stage voltage reduction loss is also saved. In the initial power-on (Ping) stage of the protocol or the low-voltage low-power wireless power transmission stage, coils are connected in series through control, so that the receiving end is ensured to meet the constraint of the Qi protocol.

The Ping degree of freedom refers to the coupling offset of the transmitting coil and the receiving coil allowed in the wireless charging process. If the receive and transmit coils are poorly coupled, the output voltage Vout of the rectifier 302 of the receive terminal 30 may be less than 7V, which can easily lead to a Qi protocol core that cannot start up properly. However, in the embodiment of the present application, the coils of the receiving end 30 in the Ping stage are connected in series, so as to increase the inductance of the receiving end 30 and increase the output voltage Vout of the rectifier 302. Therefore, when the coils of the receiving end 30 are connected in series, the Qi protocol core can be satisfied for power-up even if the coupling of the transmitting coil and the receiving coil is crossed. It can be seen that when the control module 304 of the receiving end 30 controls the coils to be connected in series, the Ping degree of freedom can be correspondingly improved to some extent. For example, the degree of freedom of Ping may be ±5mm in the past, and by adopting the technical scheme provided by the embodiment of the application, the coils of the receiving end 30 are controlled to be connected in series in the Ping stage, so that the degree of freedom of Ping is improved to ±10mm, that is, the coupling offset of ±5mm between the transmitting coil and the receiving coil can be tolerated in the past, and the coupling offset of ±10mm between the transmitting coil and the receiving coil can be tolerated nowadays.

The wireless charging receiving terminal provided in the above embodiment not only can be used as a forward wireless charging receiving terminal, but also can be used as a reverse wireless charging transmitting terminal. In the reverse wireless charging scenario, when each coil in the receiving coil 301 of the receiving end 30 is switched from serial to parallel, the charging power of the receiving end 30 to the opposite end can be doubled on the premise that the opposite end (the real wireless charging receiving end in this scenario) has the same heat dissipation condition. This is because the coupling voltage of the receiving terminal 30 becomes 1/2 before switching after the coil connection mode is switched. The coupling voltage of the opposite terminal before and after the switching of the coil connection mode of the receiving coil 301 is unchanged, that is, the charging power of the receiving terminal 30 to the opposite terminal is 2 times that before the switching.

In practical applications, the control module 304 of the receiving end 30 includes a plurality of possible implementations. As an example, the first implementation implements the relevant functions of the control module 304 through an analog-to-digital converter and a controller; the second implementation implements the relevant functions of the control module 304 via a comparator. Two implementations of the control module 304 are described separately below.

The first implementation mode:

Referring to fig. 5, a schematic structural diagram of the control module 304 in the receiving end 30 according to the present embodiment is provided. As shown in fig. 5, in this embodiment, the control module 304 of the receiving end 30 includes: an analog-to-digital converter AD and a controller AP. The analog-to-digital converter AD is configured to convert the output voltage Vout detected by the voltage detection circuit 306 into a digital voltage, and send the digital voltage to the controller AP; the controller AP is configured to, when the digital voltage is determined to be greater than the preset voltage threshold, switch the receiving coil 301 from serial to parallel by controlling the switch module 303 to reduce the output voltage Vout of the rectifier 302.

In this implementation, the control module 304 controls the switching module 303 in a software manner based on the logic of the voltage comparison, thereby implementing switching of the connection mode of the receiving coil. In this implementation, the controller AP may also be configured to implement in-band communication or out-of-band communication with a controller at the transmitting end.

The second implementation mode:

referring to fig. 6, another schematic structural diagram of the control module 304 in the receiving end 30 according to the present embodiment is provided. As shown in fig. 6, in this embodiment, the control module 304 of the receiving end 30 includes: and a comparator 3041. The first input terminal v+ of the comparator 3041 is connected to the output voltage Vout of the rectifier 302, the second input terminal V-of the comparator 3041 is connected to the preset voltage threshold Vthr, and the output terminal Vo of the comparator 3041 is connected to the switching module 303. In this embodiment, the comparator 3041 may be a hysteresis comparator, and the preset voltage threshold includes a preset first voltage threshold Vthr1 corresponding to a rising edge and a preset second voltage threshold Vthr2 corresponding to a falling edge. Wherein the preset first voltage threshold Vthr1 is greater than the preset second voltage threshold Vthr2.

Specifically, when Vout is greater than Vthr1, the output Vo of the comparator 3041 is at a high level, which correspondingly controls the first switch SW1 of the switch module 303 to be opened, and controls the second switch SW2 and the third switch SW3 to be closed. Further, the receiving coil 301 is switched from series to parallel, and the output voltage Vout of the rectifier 302 is reduced. When Vout is less than Vthr2, the output Vo of the comparator 3041 is at low level, which correspondingly controls the first switch SW1 of the switch module 303 to be closed and controls the second switch SW2 and the third switch SW3 to be opened. Further, the receiving coil 301 is switched from parallel to series, and the output voltage Vout of the rectifier 302 is raised.

In this implementation, the control module 304 performs voltage comparison in a hardware manner by using the comparator 3041 and controls the switching module 303, thereby implementing switching of the connection mode of the receiving coil 301.

In the receiving end provided in the foregoing embodiment, at least one of the first switch SW1, the second switch SW2 and the third switch SW3 may include a switching element in the form of a bi-directional Metal-Oxide-semiconductor field effect transistor (MOSFET, abbreviated as MOS). In order to thoroughly prevent current from flowing when the switch is turned off, each switch in the receiving end in the embodiment may specifically use a bidirectional MOS transistor as a switching element. In practical application, the switching element for realizing the bidirectional current blocking function is not limited to a bidirectional MOS tube, and can be a thyristor or a relay.

For ease of understanding, the functional implementation of the bidirectional MOS transistor is described below in conjunction with fig. 7. Referring to fig. 7, a schematic diagram of a bidirectional MOS transistor according to the present embodiment is shown. As shown in fig. 7, each of the MOS transistors Q1 and Q2 in the bidirectional MOS transistor 700 includes an antiparallel diode. Because the diode has the characteristic of unidirectional conduction, no matter the current is positive or negative, the current cannot pass through the bidirectional MOS tube 700, so that the current is thoroughly blocked when the bidirectional MOS tube 700 is disconnected.

In the above embodiments, the switching modules are arranged at the input terminals of the rectifier, so that the current passing through each switch in the switching modules is an alternating current. In practical application, switching arc is generated when the alternating current is switched, and in order to reduce the influence, the embodiment of the application controls the switching action at the zero crossing time of the alternating current flowing through the switch, so that the switching arc is avoided when the switching action is performed.

For any switch of the receiving-end switch modules 303 provided in the second embodiment of the present application, the bidirectional MOS transistor 700 may be used as a switch element. The principle of the operation of the switch is described in detail below in connection with fig. 7. The switch shown in fig. 7 includes: a bidirectional MOS transistor 700 as a switching element, a current zero-crossing detection circuit 701, and a driving circuit 703. Fig. 7 illustrates only the bidirectional MOS transistor 700 as an exemplary form of switching element in the switch, and the actually employed switching element is not limited to the bidirectional MOS transistor. As shown in fig. 7, the zero-crossing detection signal and the switching signal transmitted by the control module 702 are used together as a condition for driving the switching element 700. The current zero-crossing detection circuit 701 is configured to implement current zero-crossing detection, and is configured to generate a zero-crossing detection signal when detecting a current zero crossing on the bidirectional MOS transistor 700. The control module 702 provides a switching signal. The driving circuit 703 is configured to drive the bidirectional MOS transistor under the control of the control module 702 when the zero-crossing detection signal is received from the current zero-crossing detection circuit 701.

The driving circuit 703 may be implemented by a two-input logic and gate. As an example, the logic and gate includes a first input terminal, a second input terminal, and an output terminal, the output terminal of the current zero crossing detection circuit 701 is connected to the first input terminal of the logic and gate, and the output terminal of the control module 702 is connected to the second input terminal of the logic and gate. The output end of the logic AND gate is connected with the control end of the MOS transistor Q1 and the control end of the MOS transistor Q2.

When the current flowing through the bidirectional MOS transistor 700 crosses zero and receives a switching signal indicating disconnection, the driving circuit 703 drives the bidirectional MOS transistor 700 to act. That is, when the zero-crossing detection signal and the switching signal are both effective signals, the driving circuit 703 controls the bidirectional MOS700 transistor to operate. When the judgment logic is implemented by a logical AND, for example, when the zero crossing detection signal is 1 and the switching signal is 1, an effective driving signal for controlling the bidirectional MOS transistor 700 is output, so that the bidirectional MOS transistor 700 operates. Through the mode, switching arc generated during switching action is effectively avoided, and charging safety is improved.

In the receiving end provided by the embodiment of the application, the number of the coils contained in the receiving coil is not limited to two, and when the number of the coils contained in the receiving coil is larger than two, the control module of the receiving end still controls the switch module to change the connection mode of the receiving coil by comparing the output voltage Vout of the rectifier with the preset voltage threshold.

The coil connection mode switching process of the receiving terminal will be described below taking an example in which the receiving terminal includes 3 receiving coils. Referring to fig. 8, a schematic diagram of a scenario in which a receiving end including three coils performs wireless charging is provided in an embodiment of the present application. As shown in fig. 8, the receiving end includes three receiving coils L81, L82, and L83. Wherein, the first end of the coil L81 is connected to the positive input AC1 of the rectifier 802, the second end of the coil L81 is connected to the first end of the coil L82 through the switch K1, the second end of the coil L82 is connected to the first end of the coil L83 through the switch K2, and the second end of the coil L83 is connected to the negative input AC2 of the rectifier 802.

In addition, the first end of the coil L81 is connected to the first end of the coil L82 through the switch K3, and is connected to the first end of the coil L83 through the switch K4; a second end of the coil L82 is connected with a second end of the coil L83 through a switch K5; a second end of the coil L81 is connected to a second end of the coil L83 via a switch K6.

The switches K1 and K2 may be realized by one composite switch or two independent switches. In this embodiment, the switches K1 and K2 can simultaneously perform the same action, for example, simultaneously close or simultaneously open under the control of a control module (not shown in fig. 8) at the receiving end, and in a specific implementation, the switches K1 and K2 may be driven by the same pulse driving signal to drive their switch states.

The switches K3, K4, K5 and K6 may be realized by one composite switch together or by four switches independent of each other. In this embodiment, the switches K3, K4, K5 and K6 can simultaneously perform the same action, for example, simultaneously close or simultaneously open under the control of a control module (not shown in fig. 8) at the receiving end, and in a specific implementation, the switches K3, K4, K5 and K6 may be driven by the same pulse driving signal to drive their switch states.

When the control module of the receiving end controls the switches K1 and K2 to be closed and controls the switches K3, K4, K5 and K6 to be opened, the three coils L81, L82 and L83 corresponding to the receiving end are started in series; when the control module of the receiving end controls the switches K1 and K2 to be opened and controls the switches K3, K4, K5 and K6 to be closed, the parallel mode of the three coils L81, L82 and L83 corresponding to the receiving end is started.

The control module may specifically utilize the voltage detection circuit 806 to detect the relative magnitudes of the output voltage Vout of the rectifier 802 and the preset first voltage threshold and the preset second voltage threshold, so as to control the switch. The preset first voltage threshold is larger than the preset second voltage threshold. When the output voltage Vout is greater than a preset first voltage threshold, the control module is configured to control the switches K1 and K2 to be opened and control the switches K3, K4, K5 and K6 to be closed, so that the three coils L81, L82 and L83 are connected in parallel; when the output voltage Vout is smaller than the preset second voltage threshold, the control module is configured to control the switches K1 and K2 to be closed and control the switches K3, K4, K5 and K6 to be opened, so that the three coils L81, L82 and L83 are connected in series again. The above handover control can avoid ping-pong handover.

When the coils L81, L82, and L83 are switched from series to parallel, the inductance value of the receiving end decreases; when the coils L81, L82, and L83 are switched from parallel to series, the inductance value of the receiving end increases. In order to ensure that the working efficiency of wireless charging of the receiving end is not obviously reduced when the coil connection mode is changed, the embodiment of the application can also ensure the working efficiency of the receiving end by changing the capacitance value of the receiving end to keep the resonance frequency of the resonance circuit unchanged.

Specifically, the receiving end further comprises a capacitance network, and the capacitance network specifically comprises: a capacitor C81, a capacitor C82 and a switch K7, wherein a first end of the coil L81 is connected to the positive input AC1 of the rectifier 802 through the capacitor C81; the capacitor C82 and the switch K7 are connected in series and then connected to both ends of the capacitor C81. The control module of the receiving end is also used for controlling the switch K7 to be closed when the coils L81, L82 and L83 are connected in parallel, so that the capacitance value of the receiving end is increased; the control module is further used for controlling the switch K7 to be opened when the coils L81, L82 and L83 are connected in series, so that the capacitance value of the receiving end is reduced.

The product of the inductance value and the capacitance value is basically kept unchanged in the parallel mode and the series mode of the coil by changing the capacitance value of the capacitance network of the receiving end, so that the resonance frequency of the resonance circuit is kept unchanged. Not only the working efficiency of the receiving end is ensured, but also the stability and the reliability of the receiving end in the wireless charging process are improved.

It should be noted that, in the scenario shown in fig. 8, when the output voltage Vout of the rectifier 802 is greater than the preset first voltage threshold, the control module may be further configured to control each switching action, so that only two receiving coils in the receiving end operate in series, two coils operate in parallel, or a single receiving coil operates, thereby reducing the output voltage Vout of the rectifier 802.

In the scenario shown in fig. 8, as an example, when the output voltage Vout of the rectifier 802 is greater than a preset first voltage threshold, the control module sends a control signal to close the switches K6, K3 and K5, so that only the coils L81 and L82 operate in parallel; or the control module sends a control signal to enable the switches K1 and K5 to be closed, and only the coils L81 and L82 are connected in series to work; or the control module sends a control signal to close the switch K6, so that only the coil L81 works.

In practical applications, the receiving end for wireless charging provided in the above embodiment of the present application requires that each coil structure in the receiving coil be kept as symmetrical as possible so as to avoid unnecessary charging loss. Taking the receiving end shown in fig. 4 as an example, it is required that the shapes of the first coil LW1 and the second coil LW2 are the same, and the projection overlapping ratio on the electronic device corresponding to the battery Bat is larger than the preset ratio. As an example, the preset ratio is 95%, so that the overlapping ratio of the first coil LW1 and the second coil LW2 in the projection direction is ensured to be sufficiently high. In this embodiment, the projection overlapping ratio is not limited to a specific preset ratio, but may be other values, and of course, the projection overlapping ratio is 100% and the effect is best, but may be less than 100% due to requirements of a process and the like, and only needs to be greater than the preset ratio. Similarly, taking the receiving end shown in fig. 8 as an example, the coils L81, L82 and L83 are required to have the same shape, and the projection overlapping ratio on the electronic device corresponding to the battery Bat is larger than the preset ratio, so as to ensure that the overlapping ratio of the coils L81, L82 and L83 in the projection direction is sufficiently high.

In the foregoing embodiment, the control module at the receiving end controls the switch module to change the on/off state of the switch, and switches the connection mode of the receiving coil, so as to change the output voltage Vout of the rectifier. Based on the wireless charging receiving terminal provided by the foregoing embodiment, correspondingly, the application further provides another wireless charging receiving terminal. The receiving end changes the switching state of the switch by controlling the switch module so as to switch the connection mode of the output ends of at least two rectifiers, and changes the common output voltage Vout of the working rectifiers. The following detailed description is made with reference to the examples and the accompanying drawings.

Example III

In the receiving end provided in this embodiment, the radio conversion device specifically includes a receiving coil and a rectifier, where the receiving coil is used to convert an alternating magnetic field emitted by the wirelessly charged transmitting end into an alternating voltage, and the rectifier is used to convert the alternating voltage output by the corresponding receiving coil into a direct voltage. For the sake of clear understanding, the drawings relating to the present embodiment do not specifically depict the pattern of the radio conversion device, but specifically depict the pattern of the receiving coil and the rectifier included in the radio conversion device.

Referring to fig. 9, the structure of another wireless charging receiving terminal according to an embodiment of the present application is shown. Fig. 10 is a schematic diagram of a scenario in which the receiving end 90 shown in fig. 9 is wirelessly charged. As shown in fig. 9, in the embodiment of the present application, the receiving end 90 for wireless charging includes: a receiving coil 901, a rectifier 902, a switching module 903, a control module 904, and a charge management module 905; wherein the rectifier 902 is respectively connected with other modules; the control module 904 is connected to the switch module 903 and to the charge management module 905.

The number of receiving coils 901 in the receiving terminal 90 corresponds to the number of rectifiers 902. Only one set of receiving coils 901 and rectifiers 902 is illustrated in fig. 9, but in practice there are at least two sets of receiving coils 901 and rectifiers 902 in the receiving end 90. For other receiving coils 901 and rectifiers 902 not illustrated in fig. 9, the connection relationship with other respective modules is as shown in fig. 9.

The receiving coils 901 are in one-to-one correspondence with the rectifiers 902, and the receiving coils 901 are connected to the input ends of the corresponding rectifiers; a receiving coil 901, configured to convert the alternating magnetic field emitted by the transmitting coil L1 into alternating current and send the alternating current to a corresponding rectifier 902; a rectifier 902 for converting alternating current into direct current. The dc voltages respectively converted by the cooperating rectifiers 902 are used to form an output voltage Vout. The output voltage Vout is used to provide to the charge management module 905; the control module 904 is configured to, when the output voltage Vout is greater than a preset voltage threshold, switch the output terminal of each rectifier 902 from serial to partial serial, parallel, partial parallel or a single rectifier 902 to operate by controlling the switch module 903, so as to reduce the output voltage Vout common to the rectifiers 902 that operate after the connection mode is switched; the charging management module 905 is configured to receive the dc voltage Vout output by the front end (i.e. the co-operating rectifier 902) and charge the battery Bat.

It will be appreciated that when only a portion of the rectifiers 902 are operated in series, only a portion of the rectifiers 902 are operated in parallel, or only a single rectifier 902 is operated, the output voltage Vout common to the operated rectifiers 902 is reduced compared to when all the rectifiers 902 are operated in series.

In this embodiment, the switching of the connection mode of the output terminal of the rectifier 902 is controlled by the control module 904. Specifically, the control module 904 controls the open/close state of the switch in the switching module 903 according to the output voltage Vout common to the rectifiers 902. When the switching state of the switch in the switch module 903 changes, the connection mode of the output terminal of the rectifier can be switched due to the connection relationship between the switch and the output terminal of the rectifier 902.

The preset voltage threshold may be set according to actual requirements, and specific values are not limited herein. When the output voltage Vout of the co-operating rectifier 902 is greater than the preset voltage threshold, it indicates that the output voltage Vout of the co-operating rectifier 902 is too high, and the step-down is required to avoid the output voltage Vout from continuously increasing so that the receiving end 90 continuously increases in temperature and has excessive heat consumption. To this end, the control module 904 controls the switching of the switching module 903 to switch the output of the rectifier 902 from series to parallel operation, to partially parallel, to partially series, or to operate a single rectifier 902.

The wireless charging receiving terminal 90 provided in the above embodiments of the present application, the control module 904 of the receiving terminal 90 can switch the connection mode of the output terminal of the rectifier according to the output voltage Vout. When the output voltage Vout of the commonly operated rectifiers 902 is too large (for example, greater than a preset voltage threshold value), the switching states of the switches in the switch module are controlled to change, so that the output ends of the rectifiers are in parallel operation, in partial parallel connection, in partial series connection or in single rectifier operation, after the connection mode is changed, the output voltage Vout of the commonly operated rectifiers 902 is reduced compared with that of all the rectifiers in series connection, and therefore the continuously output of higher voltage by the rectifiers 902 is effectively prevented in the mean time, and the problems of overvoltage and excessive heat consumption are avoided. The receiving end 90 does not need to be provided with an additional voltage reducing module, so that the charging efficiency is not lost due to the voltage reducing module, and the wireless charging is facilitated to be performed more quickly. In addition, hardware cost and board area of the receiving end 90 are saved.

It is assumed that at least two radio conversion devices in the receiving end 90 include: a third radio conversion device and a fourth radio conversion device, wherein the receiving coil 901 included in the third radio conversion device is referred to as a third coil, and the rectifier 902 included in the third radio conversion device is referred to as a first rectifier; the fourth radio conversion device comprises a receiving coil 901 called fourth coil and a rectifier 902 called second rectifier.

The receiving coil 901 of the application scenario receiving terminal 90 shown in fig. 10 includes two coils. A specific implementation manner in which the control module 904 implements the switching of the coil series-parallel mode by controlling the switch module 903 is described below with reference to fig. 10. As shown in fig. 10, the receiving end includes a third coil LW3 and a fourth coil LW4, a first rectifier M1 and a second rectifier M2. Wherein the third coil LW3 corresponds to the first rectifier M1, and the fourth coil LW4 corresponds to the second rectifier M2. A third coil LW3 is connected to the input of the first rectifier M1, and a fourth coil LW4 is connected to the input of the second rectifier M2.

The control module 904 is configured to, when the output voltage Vout after the first rectifier M1 and the second rectifier M2 are connected in series is greater than a preset voltage threshold, change the output ends of the first rectifier M1 and the second rectifier M2 from the series to the parallel by controlling the switch module 903 so as to reduce the output voltage Vout common to the operating rectifiers.

The switch module 903 may specifically include: a fifth switch SW5, a sixth switch SW6 and a seventh switch SW7. The sixth switch SW6 and the seventh switch SW7 may be implemented by a single composite switch or by two independent switches. In this embodiment, the sixth switch SW6 and the seventh switch SW7 can simultaneously perform the same actions, for example, simultaneously turn on or simultaneously turn off, under the control of the control module 904, and in a specific implementation, the sixth switch SW6 and the seventh switch SW7 may be driven by the same pulse driving signal to drive their switch states.

The receiving end 90 further includes: a third capacitor C3 and a fourth capacitor C4. The third coil LW3 and the third capacitor C3 are connected in series and then connected to the input end of the first rectifier M1; the fourth coil LW4 and the fourth capacitor C4 are connected in series and then connected to the input terminal of the second rectifier M2.

The negative output end GND1 of the first rectifier M1 is connected with the positive output end Vout2 of the second rectifier M2 through a fifth switch SW 5; the positive output end Vout1 of the first rectifier M1 is connected with the positive output end Vout2 of the second rectifier M2 through a sixth switch SW 6; the negative output GND1 of the first rectifier M1 is connected to the negative output GND2 of the second rectifier M2 via a seventh switch SW 7.

The control module 904 is configured to control the fifth switch SW5 to be turned on and control the sixth switch SW6 and the seventh switch SW7 to be turned off, so that the negative output terminal GND1 of the first rectifier M1 and the positive output terminal Vout2 of the second rectifier M2 are connected in series; and is further configured to control the fifth switch SW5 to be opened, and control the sixth switch SW6 and the seventh switch SW7 to be closed, so that the positive output terminal Vout1 of the first rectifier M1 is connected to the positive output terminal Vout2 of the second rectifier M2, and the negative output terminal GND1 of the first rectifier M1 is connected to the negative output terminal GND2 of the second rectifier M2.

Since the fifth switch SW5, the sixth switch SW6 and the seventh switch SW7 are respectively located at the output ends of the rectifier M1 and/or the rectifier M2, the current passing through the fifth switch SW5, the sixth switch SW6 and the seventh switch SW7 is direct current. In this embodiment, the fifth switch SW5, the sixth switch SW6 and the seventh switch SW7 may be MOS transistors respectively. The specific implementation manner of driving the fifth switch SW5, the sixth switch SW6 and the seventh switch SW7 may refer to the previous description of fig. 7, and the specific details of the driving switch operation will not be repeated here.

Referring to fig. 11, the diagram is a schematic diagram of a wireless charging scenario when the fifth switch SW5, the sixth switch SW6 and the seventh switch SW7 are MOS transistors respectively. In addition, in the embodiment of the present application, the receiving end 90 may further include: a voltage detection circuit 906; the voltage detection circuit 906 is configured to detect an output voltage Vout of the rectifiers that work together, and send the output voltage Vout to the control module 904, so that the control module 904 controls the switching module 903.

In practical applications, the control module 904 of the receiving end 90 provided in this embodiment includes a plurality of possible implementations. The specific implementation manner is substantially the same as that of the control module 304 of the receiving end 30 in the foregoing embodiment, and it can be understood with reference to fig. 5 and 6, which are not repeated herein.

The receiving end 90 provided in this embodiment does not need to restrict strict symmetry between the coils of the receiving coil 901, and there is no special requirement for connection between the homonymous end and the heteronymous end. Taking fig. 11 as an example, if the third coil LW3 and the fourth coil LW4 are asymmetric, the coupling conditions of the two coils are different, and there is a difference in the voltages output from each. Reference herein to coils being asymmetric may refer to variations in the gauge of the coils. For this case, three different output voltages Vout can be generated in the receiving terminal by controlling the open and closed states of the fifth switch SW5, the sixth switch SW6 and the seventh switch SW 7.

(1) Output terminals of the first rectifier M1 and the second rectifier M2 are in series mode: the fifth switch SW5 is controlled to be turned on, and the sixth switch SW6 and the seventh switch SW7 are controlled to be turned off, so that the output voltage Vout is the sum of the voltages output by the first rectifier M1 and the second rectifier M2.

(2) The first rectifier M1 works alone: the seventh switch SW7 is controlled to be turned on, the fifth switch SW5 and the sixth switch SW6 are controlled to be turned off, and the output voltage Vout is the voltage output by the first rectifier M1.

(3) The second rectifier M2 works alone: the sixth switch SW6 is controlled to be turned on, the fifth switch SW5 and the seventh switch SW7 are controlled to be turned off, and the output voltage Vout is the voltage output by the second rectifier M2.

It will be appreciated that, because the third coil LW3 and the fourth coil LW4 are asymmetric, the voltage output from the first rectifier M1 in the above-described (2) th scenario is different from the voltage output from the second rectifier M2 in the above-described (3) th scenario. Assuming that one of the third coil LW3 and the fourth coil LW4 is a main coil and one is an auxiliary coil, the voltage output from the rectifier to which the main coil is connected is greater than the voltage output from the rectifier to which the auxiliary coil is connected.

When the third coil LW3 and the fourth coil LW4 are asymmetric, the connection mode of the output ends of the switching rectifiers is changed by the control module through corresponding actions of the control switch, or only a single rectifier is adopted to work, so that the commonly-working rectifiers output a plurality of different voltages from the above (1) to (3). The receiving terminal 90 may adjust the on/off state of the switch to achieve the step-down when the voltage output from the co-operating rectifiers is too high and needs to be stepped down, for example, from the connection mode in (1) to (2) or (3), or from the connection mode in (2) to (3) when the third coil LW3 is the main coil and the fourth coil LW4 is the auxiliary coil. Therefore, the wireless charging receiving terminal 90 provided in this embodiment can provide a voltage reduction effect with strong adaptability under the asymmetric coil condition.

When the receiving end comprises more than two coils, the control module can control the switching action in the switching module when the common output of the rectifiers needs to be reduced, so that the connection mode of the output ends of the rectifiers is switched from serial connection to partial serial connection, parallel connection, partial parallel connection or only one rectifier works.

For ease of understanding, a specific implementation of switching rectifier connection mode when the receiving end includes more than two radio conversion devices is described below in connection with fig. 12. As shown in fig. 12, the diagram is a schematic diagram of another scenario in which a receiving end performs wireless charging. In this scenario, the receiving end further includes a fifth radio conversion device, which specifically includes a fifth coil LW5 and a third rectifier M3, as compared to the receiving end shown in fig. 10. The fifth coil LW5 is connected in series with the fifth capacitor and then connected to the input terminal of the third rectifier M3.

The negative output end GND2 of the second rectifier M2 is connected with the positive output end Vout3 of the third rectifier M3 through an eighth switch SW 8; the negative output end GND2 of the second rectifier M2 is connected with the negative output end GND3 of the third rectifier M3 through a ninth switch SW 9; the positive output terminal GND1 of the first rectifier M1 is connected to the positive output terminal Vout3 of the third rectifier M3 through a tenth switch SW 10.

When the common output voltage Vout of the three rectifiers M1, M2 and M3 operating in series is too large (e.g. greater than a preset voltage threshold), the open/close state of each switch in fig. 12 may be changed under the control of a control module (not shown in fig. 12), so that the output terminals of the rectifiers operate in parallel, in partial series, or in a single rectifier.

For example, only the sixth switch SW6, the seventh switch SW7, the ninth switch SW9 and the tenth switch SW10 are controlled to be turned on to realize that the output terminals of the first rectifier M1, the second rectifier M2 and the third rectifier M3 are connected in parallel.

For example, only the sixth switch SW6, the seventh switch SW7 and the ninth switch SW9 are controlled to be closed, so as to realize that the output ends of the first rectifier M1 and the second rectifier M2 are connected in parallel; only the sixth switch SW6, the ninth switch SW9 and the tenth switch SW10 are controlled to be closed, so that the output ends of the second rectifier M2 and the third rectifier M3 are connected in parallel; only the seventh switch SW7 and the tenth switch SW10 are controlled to be closed to realize that the output terminals of the first rectifier M1 and the third rectifier M3 are connected in parallel.

For example, only the fifth switch SW5 and the ninth switch SW9 are controlled to be closed to realize that the output terminals of the first rectifier M1 and the second rectifier M2 are connected in series; only the sixth switch SW6 and the eighth switch SW8 are controlled to be closed to realize the series connection of the output terminals of the second rectifier M2 and the third rectifier M3.

For example, only the seventh switch SW7 is controlled to be closed to realize that the first rectifier M1 operates alone; only the sixth switch SW6 and the ninth switch SW9 are controlled to be closed to realize that the second rectifier M2 operates alone; only the tenth switch SW10 is controlled to be closed to realize that the third rectifier M3 operates alone.

Based on the wireless charging receiving terminal provided by the embodiment, correspondingly, the application further provides electronic equipment. Specific implementations of the electronic device are described below with reference to the embodiments and the accompanying drawings.

Example IV

Referring to fig. 13, the structure of an electronic device according to an embodiment of the present application is shown. The electronic device can be charged by wireless charging, and as an example, the electronic device may be a mobile phone, a tablet computer, a notebook computer, a bluetooth headset, a smart watch, an electric toothbrush, etc. As shown in fig. 13, the electronic device 140 includes at least: a wireless charging receiving terminal 1401, and a battery Bat.

In the electronic device 140 provided in this embodiment, the receiving terminal 1401 that is wirelessly charged may be any one of the receiving terminals provided in the foregoing embodiment. The receiving end provided in the foregoing embodiment includes a switch module and at least two radio conversion devices. Each radio conversion device is used for converting an alternating magnetic field emitted by a wireless charging transmitting end into voltage; the voltage converted by the radio conversion means is used to form an output voltage. The switch module is coupled to the at least two radio conversion devices for changing the connection of the at least two radio conversion devices to change the output voltage. The connection means between the radio conversion devices include series, parallel, partial series, partial parallel or single radio conversion device operation. When the connection mode of the radio conversion device is switched under the action of the switch module, the output voltage can be changed, and then the voltage reduction is realized. For example, switching at least two radio conversion devices in series to operate in partial series, parallel, partial parallel or a single radio conversion device may step down the output voltage. Therefore, when the output voltage is overlarge, even the problems of overheat and heat consumption of electronic equipment, influence on wireless charging efficiency or damage to a circuit due to overvoltage and the like are possibly caused, the voltage reduction can be effectively realized by changing the connection mode of the radio conversion device, so that the problems are avoided.

Compared with the method for realizing the voltage reduction of the receiving end by adopting the voltage reduction module, in the electronic equipment 140 provided by the embodiment of the application, the receiving end 1401 can realize the voltage reduction in time by changing the connection mode of the radio conversion device, so that the first-stage voltage reduction module is saved, the loss of the charging efficiency is reduced, and the heat consumption of the system is effectively reduced in a high-power wireless charging scene, thereby improving the experience of a user on wireless charging of the electronic equipment 140. In addition, the receiving end saves hardware cost and board-level area, and has obvious advantages.

It should be understood that in the present application, "at least one (item)" means one or more, and "a plurality" means two or more. "and/or" for describing the association relationship of the association object, the representation may have three relationships, for example, "a and/or B" may represent: only a, only B and both a and B are present, wherein a, B may be singular or plural. The character "/" generally indicates that the context-dependent object is an "or" relationship. "at least one of" or the like means any combination of these items, including any combination of single item(s) or plural items(s). For example, at least one (one) of a, b or c may represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", wherein a, b, c may be single or plural.

The above description is only of the preferred embodiment of the present application, and is not intended to limit the present application in any way. While the application has been described with reference to preferred embodiments, it is not intended to be limiting. Many possible variations and modifications of the disclosed technology can be made by anyone skilled in the art without departing from the scope of the application, or it is intended to be modified to be equivalent to the equivalent embodiments of the application. Therefore, any simple modification, equivalent variation and modification of the above embodiments according to the technical substance of the present application still fall within the scope of the technical solution of the present application.

Claims

1. A receiving terminal for wireless charging, comprising:

at least two radio conversion devices for generating an output voltage, wherein each radio conversion device is used for converting an alternating magnetic field emitted by a wireless charging transmitting end into a voltage, and the voltage is used for forming the output voltage;

a switching module coupled to the at least two radio conversion devices for changing a connection of the at least two radio conversion devices to change the output voltage, the connection including serial, parallel, partial serial, partial parallel, or single radio conversion device operation;

The receiving end further includes: a variable capacitance; when the switch module changes the connection mode of the at least two radio conversion devices, the capacitance value of the variable capacitor is adjusted according to the change of the connection mode of the at least two radio conversion devices.

2. The receiving end according to claim 1, wherein each radio conversion device comprises a receiving coil, and the switch module is configured to change a connection manner of at least two receiving coils in the at least two radio conversion devices, so that the at least two receiving coils are connected in series, in parallel, in partial series or in partial parallel, or a single receiving coil works;

the at least two receiving coils are used for converting alternating magnetic fields emitted by the wireless charging emitting end into alternating voltage;

the receiving end further comprises: and the rectifier is used for converting the alternating voltage into direct voltage, and the direct voltage is used as the output voltage.

3. The receiving end according to claim 2, wherein the at least two radio conversion means comprise: a first radio conversion device including a first coil and a second radio conversion device including a second coil;

The switch module includes: a first switch, a second switch, and a third switch;

the first end of the first coil and the second end of the second coil are respectively connected with the rectifier;

the second end of the first coil is connected with the first end of the second coil through the first switch;

the first end of the first coil is connected with the first end of the second coil through the second switch;

the second end of the first coil is connected with the second end of the second coil through the third switch;

the first end of the first coil and the first end of the second coil are the same name ends.

4. A receiving end according to claim 3, further comprising: and the control module is used for controlling the switch module to change the first coil and the second coil from serial connection to parallel connection when the output voltage is larger than a preset voltage threshold value.

5. The receiver of claim 4, wherein at least one of the first switch, the second switch, and the third switch comprises:

a switching element;

a current zero-crossing detection circuit for generating a zero-crossing detection signal when a zero crossing of a current on the switching element is detected;

And the driving circuit is used for driving the switching element under the control of the control module when the zero-crossing detection signal is received from the current zero-crossing detection circuit.

6. The receiver of claim 5, wherein the switching element comprises a bi-directional metal-oxide-semiconductor field effect transistor.

7. The receiver of any of claims 4-6, wherein the variable capacitance is connected between the input of the rectifier and at least one of the first terminal of the first coil and the second terminal of the second coil.

8. The receiver of claim 7, wherein the control module is further configured to increase the value of the variable capacitance when controlling the switching module to change the first coil and the second coil from serial to parallel.

9. The receiving end according to any one of claims 4-6, further comprising: and the voltage detection circuit is used for detecting the value of the output voltage and sending the value of the output voltage to the control module.

10. The receiving end according to any one of claims 1-6, further comprising: and the charging management module is used for receiving the output voltage and charging the battery.

11. The receiver according to any one of claims 1-6, wherein the receiver further performs reverse wireless charging as a transmitting end for a battery of other wireless charging receiver.

12. The receiving terminal according to claim 11, wherein when the receiving terminal performs the reverse wireless charging as a transmitting terminal, the at least two radio converting means for receiving an input voltage, each of the radio converting means for converting a voltage to be converted into an alternating magnetic field for wireless charging, the voltage to be converted being formed by the input voltage;

the switching module is coupled to the at least two radio conversion devices and is used for changing the connection mode of the at least two radio conversion devices to change the voltage to be converted, wherein the connection mode comprises serial connection, parallel connection, partial serial connection, partial parallel connection or single radio conversion device operation.

13. A receiving terminal for wireless charging, comprising:

each radio conversion device includes: a receiving coil and a rectifier;

the receiving coil is used for converting an alternating magnetic field emitted by the wireless charging transmitting end into alternating voltage;

the rectifier is used for converting the alternating voltage output by the corresponding receiving coil into direct voltage, and the direct voltage is used for forming the output voltage;

the switch module is used for changing the connection mode of at least two rectifiers in the at least two radio conversion devices so as to enable the at least two rectifiers to be connected in series, in parallel, in part in series, in part in parallel or operate by a single rectifier.

14. The receiving end according to claim 13, wherein the at least two radio conversion means comprise: a third radio conversion device and a fourth radio conversion device, the third radio conversion device comprising a third coil and a first rectifier, the third coil being connected to an input of the first rectifier; the fourth radio conversion device includes a fourth coil and a second rectifier; the fourth coil is connected with the input end of the second rectifier;

The switch module includes: a fifth switch, a sixth switch, and a seventh switch;

the second output end of the first rectifier is connected with the first output end of the second rectifier through the fifth switch;

the first output end of the first rectifier is connected with the first output end of the second rectifier through the sixth switch;

the second output end of the first rectifier is connected with the second output end of the second rectifier through the seventh switch.

15. The receiving end of claim 14, further comprising: and the control module is used for controlling the switch module to change the first rectifier and the second rectifier from serial connection to parallel connection when the output voltage is larger than a preset voltage threshold value.

16. The receiving end of claim 15, further comprising: and the voltage detection circuit is used for detecting the value of the output voltage and sending the value of the output voltage to the control module.

17. The receiving end according to any one of claims 13-16, further comprising: and the charging management module is used for receiving the output voltage and charging the battery.

18. The receiver according to any one of claims 13-16, wherein the receiver further performs reverse wireless charging as a transmitter for a battery of other wireless charging receivers.

19. The receiving terminal according to claim 18, wherein when the receiving terminal performs the reverse wireless charging as a transmitting terminal, the at least two radio converting means for receiving an input voltage, each of the radio converting means for converting a voltage to be converted into an alternating magnetic field for wireless charging, the voltage to be converted being formed by the input voltage;

20. An electronic device comprising the wireless charging receiver of any one of claims 1-12, or 13-19, further comprising: a battery;

the receiving terminal is used for charging the battery.

21. A transmitting terminal for wireless charging, comprising:

at least two radio conversion means for receiving an input voltage, each of the radio conversion means for converting a voltage to be converted into an alternating magnetic field for wireless charging, the voltage to be converted being formed by the input voltage;

A switching module coupled to the at least two radio conversion devices for changing a connection of the at least two radio conversion devices to change the voltage to be converted, the connection including serial, parallel, partial serial, partial parallel, or single radio conversion device operation;

the transmitting end further comprises: a variable capacitance;

when the switch module changes the connection mode of the at least two radio conversion devices, the capacitance value of the variable capacitor is adjusted according to the change of the connection mode of the at least two radio conversion devices.

22. A transmitting terminal for wireless charging, comprising:

Each radio conversion device includes: a coil and a rectifier;

the coil is used for converting the voltage to be converted into an alternating magnetic field for wireless charging;

the rectifier is used for converting the input voltage from direct current voltage to alternating current voltage, the alternating current voltage is connected to the coil, and an alternating magnetic field is emitted through the coil;