CN107947395B - Detection method for metal foreign matter and wireless charger - Google Patents
Detection method for metal foreign matter and wireless charger Download PDFInfo
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- CN107947395B CN107947395B CN201711107330.0A CN201711107330A CN107947395B CN 107947395 B CN107947395 B CN 107947395B CN 201711107330 A CN201711107330 A CN 201711107330A CN 107947395 B CN107947395 B CN 107947395B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
- H02J50/60—Circuit arrangements or systems for wireless supply or distribution of electric power responsive to the presence of foreign objects, e.g. detection of living beings
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Abstract
The invention provides a method for detecting a metal foreign body and a mobile terminal, wherein the method comprises the following steps: before the quality factor is measured, informing a receiving end of a charging circuit to disconnect the secondary coil and the rectifying circuit; measuring a quality factor of the charging circuit when a disconnection response to the connection sent by the receiving end is received; after the measurement is finished, informing the receiving end to close the connection of the secondary coil and the rectifying circuit; and determining whether metal foreign matters exist on the surface of the wireless charger according to the quality factor. The problems that metal foreign matter detection is inaccurate and detection difficulty is high due to the fact that the quality factor is inaccurate are solved, the measuring accuracy and the foreign matter detection accuracy of the quality factor are improved, and the detection difficulty is reduced.
Description
Technical Field
The invention relates to the technical field of wireless charging, in particular to a metal foreign matter detection method and a wireless charger.
Background
When the mobile terminal is wirelessly charged, if a metal foreign object exists in the wireless charger, an eddy current is generated in a changing magnetic field, so that the metal foreign object consumes magnetic field energy and generates heat, and finally, safety problems such as fire and the like are caused. Thus, before wireless charging, it is necessary to accurately detect whether a metallic foreign object exists in the wireless charger. If metallic foreign matter is found, the charging is stopped.
In the prior art, methods for detecting metal foreign matters comprise two schemes. The first scheme is that whether metal foreign matters exist or not is judged by calculating power loss of each coil in a charging circuit; the second scheme judges whether metal foreign matter exists or not by comparing the quality factor of the primary coil of the transmitting end with the set threshold value. And if the quality factor is smaller than the set threshold value, judging that the metal foreign matters exist.
However, for the first scheme, power loss on the inverter bridge of the transmitting end and other electrical components and transmitting coils cannot be directly measured, and the transmitting power of the transmitting end and the receiving power of the receiving end need to be measured in the same time window. For the second scheme, when the quality factor of the primary coil of the transmitting end is measured, the transmitting power of the primary transmitting coil is large, so that the rectifying circuit of the receiving end is activated to charge the filter capacitor at the rear end of the rectifying circuit, and the leakage current of the filter capacitor influences the measurement and calculation of the quality factor, so that the measurement is inaccurate, and the detection accuracy is further reduced.
Disclosure of Invention
The detection method of the metal foreign body and the wireless charger provided by the embodiment of the invention solve the problems of inaccurate detection of the foreign body and high detection difficulty caused by inaccurate measurement quality factor.
On one hand, the embodiment of the invention discloses a method for detecting metal foreign matters, which is applied to a wireless charger and comprises the following steps:
before the quality factor is measured, informing a receiving end of a charging circuit to disconnect the secondary coil and the rectifying circuit;
measuring a quality factor of the charging circuit when a disconnection response to the connection sent by the receiving end is received;
after the measurement is finished, informing the receiving end to close the connection of the secondary coil and the rectifying circuit;
and determining whether metal foreign matters exist on the surface of the wireless charger according to the quality factor.
On the other hand, the embodiment of the invention also discloses a wireless charger, which comprises:
the informing disconnection module is used for informing the receiving end of the charging circuit to disconnect the secondary coil and the rectifying circuit before measuring the quality factor;
the measuring module is used for measuring the quality factor of the charging circuit when receiving a disconnection response to the connection sent by the receiving end;
a notification closing module for notifying the receiving end to close the connection of the secondary coil and the rectifying circuit after the end of the measurement;
and the metal foreign matter determining module is used for determining whether metal foreign matters exist on the surface of the wireless charger according to the quality factor.
In still another aspect, an embodiment of the present invention further discloses a wireless charger, which includes a processor, a memory, and a computer program stored on the memory and executable on the processor, and when the computer program is executed by the processor, the steps of the method for detecting a metal foreign object as described in any one of the above are implemented.
In a final aspect, the embodiment of the present invention further discloses a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the method for detecting a metallic foreign object as described in any one of the above are implemented.
In the embodiment of the invention, before the quality factor is measured, the receiving end of the charging circuit is informed to disconnect the secondary coil and the rectifying circuit; measuring a quality factor of the charging circuit when a disconnection response to the connection sent by the receiving end is received; after the measurement is finished, informing the receiving end to close the connection of the secondary coil and the rectifying circuit; and determining whether metal foreign matters exist on the surface of the wireless charger according to the quality factor. The method has the advantages of improving the measurement accuracy of the quality factor and the foreign matter detection accuracy and reducing the detection difficulty.
The foregoing description is only an overview of the technical solutions of the present invention, and the embodiments of the present invention are described below in order to make the technical means of the present invention more clearly understood and to make the above and other objects, features, and advantages of the present invention more clearly understandable.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments of the present invention will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without inventive labor.
FIG. 1 is a flow chart illustrating steps of a method for detecting metal foreign matter according to a first embodiment of the present invention;
FIG. 1A shows a block diagram of a system architecture of an embodiment of the invention;
fig. 1B is a block diagram of a circuit structure of a receiving end of a wireless charging system according to an embodiment of the present invention;
FIG. 1C shows a system flow diagram of an embodiment of the invention;
FIG. 1D is a diagram illustrating a resonance waveform emitted when detecting the presence of an object on the surface of an emitting end in an embodiment of the present invention;
FIG. 2 is a flow chart illustrating steps of a method for detecting metal foreign matter according to a second embodiment of the present invention;
FIG. 2A shows a circuit diagram for measuring the quality factor;
fig. 3 is a block diagram showing a wireless charger according to a third embodiment of the present invention;
fig. 4 shows a block diagram of a wireless charger in a fourth embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The following describes a method for detecting a metal foreign object and a wireless charger according to the present invention in detail by taking several specific embodiments.
Example one
Referring to fig. 1, a flowchart illustrating steps of a method for detecting a metal foreign object according to a first embodiment of the present invention may specifically include the following steps:
before the quality factor is measured, the receiving end of the charging circuit is informed to disconnect the secondary coil and the rectifying circuit, step 101.
The embodiment of the invention is suitable for the mobile terminal with the wireless charging function so as to ensure the safety of the charging process of the mobile terminal.
The wireless charging system comprises a transmitting end and a receiving end, wherein the transmitting end corresponds to the wireless charger, and the receiving end corresponds to a charging object, such as a mobile terminal like a mobile phone or a tablet computer. As shown in fig. 1A, the transmitting end includes: the device comprises a direct current input module, a full-bridge inversion module, a primary LC (inductance-capacitance) network module, an emission main control module, an emission end communication module and a quality factor measuring module, wherein the quality factor measuring module is a newly added module in the embodiment of the invention; the receiving end includes: the device comprises a secondary LCC (inductance-capacitance) network module, a receiving end communication module, a reverse bias voltage module, a receiving main control module, a full-bridge rectification and filtering module, a voltage reduction and stabilization module and a load module.
The direct current input module is used for inputting a direct current power supply.
The full-bridge inversion module is used for inverting an input direct-current power supply into alternating-current electric energy and transmitting the alternating-current electric energy through the primary coil.
The primary LC network module is a transmitting end LC resonance circuit and comprises a primary coil.
The Q value measuring module is used for measuring the voltage of the primary LC resonance circuit, comprises a sampling circuit, a differential amplifying circuit and a low-pass filter circuit, and finally enters the transmitting end main control module for processing.
The transmitting terminal main control module is used for detecting charging current, voltage, temperature, analog-to-digital conversion and an external circuit.
The communication module of the transmitting terminal is a modulation/demodulation circuit of the transmitting terminal, and the modulation mode of the signal transmitted by the transmitting terminal to the receiving terminal is FSK (Frequency Shift Keying).
The secondary LCC network module is an LCC resonant circuit of the receiving end and comprises a secondary coil.
The reverse bias voltage module consists of a Metal-Oxide semiconductor field Effect Transistor (MOSFET) switch circuit and has the characteristics of low impedance and quick response; and in the quality factor detection process, the connection state of the LCC circuit of the secondary coil and the rectifying circuit is controlled, and the switch is controlled by a main control module of the receiving end. It should be noted that the module is a newly added module in the embodiment of the present invention.
The full-bridge rectification is a rectification circuit which is used for converting alternating current received by the secondary LCC network module into direct current and consists of an MOSFET full-bridge circuit.
The filtering module is used for removing noise waves to enable direct current output to be smoother, and the filtering module is often composed of a large capacitor.
The voltage reduction and stabilization module consists of a power switch circuit and is used for reducing and stabilizing direct-current voltage to a load working range.
The load module comprises a mobile terminal and the like, such as a mobile phone.
The receiving main control module is used for controlling the communication module and the reverse bias voltage module. For example, the embodiment of the invention disconnects the connection between the secondary coil and the rectifying circuit by receiving the main control module.
The receiving end communication module is a Modulation and demodulation circuit of the receiving end, and the Modulation mode of the signal sent by the receiving end to the transmitting end is AM (Amplitude Modulation).
The embodiment of the invention is explained in detail based on the transmitting terminal.
Specifically, before the transmitting end measures the quality factor, the notification message is FSK modulated through the transmitting end communication module and is sent to the receiving main control module through the primary coil, so that the connection between the secondary coil of the receiving end and the rectifying circuit is disconnected until the quality factor measurement is finished.
And 102, measuring the quality factor of the charging circuit when receiving a disconnection response to the connection sent by the receiving end.
When the receiving end receives the notification message through the secondary coil, the notification message is demodulated through the communication module and then is sent to the receiving main control module. After the receiving main control module controls to disconnect the connection between the secondary coil and the rectifying circuit, the receiving end communication module sends a disconnection response to the transmitting main control module, so that the transmitting main control module informs the quality factor measuring module to start measurement.
The receiving main control module disconnects the connection between the secondary coil and the rectifying circuit by opening the switch. As shown in the circuit diagram of the wireless charging system in fig. 1B, a MOS (Metal-Oxide Semiconductor) switch K is a connection switch for connecting the secondary coil and the rectifying circuit. In addition, Lp is the inductance of the primary coil of the transmitting end, Ls is the inductance of the secondary coil of the receiving end, Cs and Cd are two capacitors of the resonant circuit respectively, Cf is the capacitor of the filter circuit, and R is the load.
It can be understood that the connection of the secondary coil and the rectifying circuit is always kept disconnected during the measurement of the quality factor.
The physical meaning of the figure of merit is Q2 pi (energy stored in the circuit/energy consumed per week). When measuring the quality factor of the transmitting end affected by the receiving end, the receiving end needs to be in an inactive state for more accurate measurement. In the energy transmission stage or the digital ping stage, the rectifier tube of the receiving end is conducted, then the filter circuit is charged, and at the moment, the energy of the transmitting end is transmitted to the receiving end, so that the measured quality factor of the transmitting end is inaccurate.
Specifically, the quality factor Q of the resonant circuit is WL/R1/WCR, where W is the frequency at which resonance is achieved, L is the inductance value of the resonant circuit, R is the capacitance value, C is the capacitance value, and the capacitance and the inductance are reciprocal. It should be noted that when the circuit reaches resonance, the circuit is impedance, and the inductor and the capacitor do not consume external power, but only mutually convert between the inductor and the capacitor.
A system flow corresponding to the embodiment of the present invention is shown in fig. 1C, in which:
standby Phase (Selection Phase): the transmitting end circuit is in a standby low power consumption state.
Simulation Ping phase (Analog Ping): and detecting whether an object exists on the surface of the primary coil of the transmitting terminal. If the object is detected, entering a quality factor measuring stage; otherwise, entering a standby stage.
Specifically, as shown in fig. 1D, the transmitting terminal periodically transmits a short pulse having a resonant frequency fod to act on the primary coil. Wherein the pulse time lasts todd. If there is no object on the surface of the primary coil of the transmitting end, the primary coil of the transmitting end generates a current Iod by transmitting a short pulse with a resonant frequency fod. The current detection circuit at the transmitting end measures the current of the primary coil within a specified time after the occurrence of the pulse. When the current Iodt of the primary coil is lower than Iod, the surface of the primary coil at the transmitting end is determined to have an object.
It should be noted that, when it is determined that an object exists on the surface of the primary coil at the transmitting end, step 101 is entered.
Quality factor measurement stage (Q-factor Measure): is performed before the digital Ping in order to avoid that the power transmitted during the digital Ping phase interferes with the quality factor measurement.
Digital Ping phase (Digital Ping): detecting whether a wireless receiver is present.
FOD (Foreign Object Detection) determination and Power Transfer Phase (FOD external Phase & Power Transfer Phase): including ID identification, configuration phase and FOD determination, calibration phase, and power transfer phase, among others.
And 103, after the measurement is finished, informing the receiving end to close the connection of the secondary coil and the rectifying circuit.
In practical applications, after the measurement is finished, the transmitting end sends a notification of closing the connection of the secondary coil and the rectifying circuit to the receiving end. Specifically, the notification message is FSK modulated by the transmitting terminal communication module and is sent to the receiving main control module through the primary coil, so that the connection between the secondary coil of the receiving terminal and the rectifying circuit is closed.
Specifically, the receiving main control module closes the connection between the secondary coil and the rectifying circuit by closing the switch. As shown in fig. 1B, the switch K is a connection switch that connects the secondary coil and the rectifier circuit.
And 104, determining whether metal foreign matters exist on the surface of the wireless charger according to the quality factor.
Specifically, when the quality factor is smaller than a set value, determining that a metal foreign body exists on the surface of the current transmitting end; and when the quality factor is larger than or equal to a set value, determining that no metal foreign matter exists on the surface of the current transmitting end.
After the metal foreign matter on the surface of the transmitting end is determined, the charging is stopped, and a user is prompted to perform safety check and treatment. Thereby ensuring the security of the mobile terminal.
In the embodiment of the invention, before the quality factor is measured, the receiving end of the charging circuit is informed to disconnect the secondary coil and the rectifying circuit; measuring a quality factor of the charging circuit when a disconnection response to the connection sent by the receiving end is received; after the measurement is finished, informing the receiving end to close the connection of the secondary coil and the rectifying circuit; and determining whether metal foreign matters exist on the surface of the wireless charger according to the quality factor. The method has the advantages of improving the measurement accuracy of the quality factor and the foreign matter detection accuracy and reducing the detection difficulty.
Example two
Referring to fig. 2, a flowchart illustrating steps of a method for detecting a metal foreign object according to a second embodiment of the present invention is shown, and the method may specifically include the following steps:
in step 201, before the quality factor is measured, a first private data packet containing measurement start information is sent to the receiving end of the charging circuit to inform the receiving end of disconnecting the secondary coil and the rectifying circuit.
In the embodiment of the invention, the sending end informs the receiving end of the preparation of starting to measure the quality factor through a private data packet containing the measurement starting information, so that the receiving end disconnects the secondary coil from the rectifying circuit when receiving the information.
The specific content and form of the measurement start information may be set according to an actual application scenario, which is not limited in the embodiment of the present invention.
The circuit diagram for measuring the quality factor as shown in fig. 2A is composed of a sinusoidal ac voltage input Vs, a resistor R, a capacitor C, and a transmitting-side primary coil L. The series LC resonance circuit is voltage resonance, and the voltage difference between two ends of the inductor L or the capacitor C is equal to Q times of the external voltage Vs during resonance.
According to the embodiment of the invention, the quality factor is obtained through calculation by using the voltage V2 at two ends of the primary coil of the transmitting end and the voltage V1 input by the sine alternating voltage.
Specifically, the voltage V2 across the primary coil of the transmitting terminal, the voltage V1 of the sinusoidal alternating voltage input, may be measured by a voltmeter. The current passing through the primary coil of the transmitting terminal can be measured in other ways, and V1 and V2 can be calculated through a relation of voltage and current.
Specifically, the quality factor Q can be obtained by the following formula (1):
Q＝V2/V1 (1)
wherein, V1 is the voltage of sinusoidal AC voltage input, and V2 is the voltage across the primary coil of the transmitting terminal. It can be appreciated that since V1 is greater than V2, the quality factor Q is less than 1.
And 204, after the measurement is finished, sending a second private data packet containing measurement finishing information to the receiving end to inform the receiving end of closing the connection between the secondary coil and the rectifying circuit.
The embodiment of the invention informs the receiving end of the measurement through the private data packet containing the information of the measurement end, so that the receiving end closes the connection between the secondary coil and the rectifying circuit when receiving the information.
The specific content and form of the measurement end information may be set according to an actual application scenario, which is not limited in the embodiment of the present invention.
The embodiment of the invention accurately measures the quality factor through the handshake communication between the sending end and the receiving end.
Wherein, the reference quality factor is determined according to the intrinsic parameters of the receiving end and is a determined value.
Wherein the first threshold is larger when the reference quality factor is larger; conversely, the smaller the reference quality factor, the smaller the first threshold. The quantitative relationship between the first threshold and the parameter quality factor may be set according to an actual application scenario, which is not limited in the embodiment of the present invention.
And step 207, determining whether metal foreign matters exist on the surface of the wireless charger according to the first threshold and the quality factor.
Specifically, if the quality factor is smaller than a first threshold value, determining that a metal foreign matter exists on the surface of the current transmitting end; and if the quality factor is larger than or equal to the first threshold value, determining that no metal foreign matter exists on the surface of the current transmitting end.
In the embodiment of the invention, before the quality factor is measured, the receiving end of the charging circuit is informed to disconnect the secondary coil and the rectifying circuit; measuring a quality factor of the charging circuit when a disconnection response to the connection sent by the receiving end is received; after the measurement is finished, informing the receiving end to close the connection of the secondary coil and the rectifying circuit; and determining whether metal foreign matters exist on the surface of the wireless charger according to the quality factor. The method has the advantages of improving the measurement accuracy of the quality factor and the foreign matter detection accuracy and reducing the detection difficulty. In addition, the handshake communication between the receiving end and the transmitting end can be realized through the private data packet carrying the measurement starting information and the measurement ending information, and the connection state of the secondary coil and the rectifying circuit of the receiving end is informed mutually, so that the detection accuracy is further improved.
EXAMPLE III
Referring to fig. 3, a block diagram of a wireless charger according to a third embodiment of the present invention is shown.
The wireless charger 300 includes: a notification opening module 301, a measurement module 302, a notification closing module 303, and a metal foreign object determination module 304.
The functions of the modules and the interaction relationship between the modules are described in detail below.
A notification disconnection module 301 for notifying the receiving end of the charging circuit to disconnect the secondary coil and the rectifying circuit before measuring the quality factor.
A measuring module 302, configured to measure a quality factor of the charging circuit when receiving a disconnection response to the connection sent by the receiving end.
A notification closing module 303 configured to notify the receiving end to close the connection of the secondary coil and the rectifying circuit after the measurement is ended.
A metallic foreign object determination module 304, configured to determine whether a metallic foreign object exists on the surface of the wireless charger according to the quality factor.
In the embodiment of the invention, before the quality factor is measured, the receiving end of the charging circuit is informed to disconnect the secondary coil and the rectifying circuit; measuring a quality factor of the charging circuit when a disconnection response to the connection sent by the receiving end is received; after the measurement is finished, informing the receiving end to close the connection of the secondary coil and the rectifying circuit; and determining whether metal foreign matters exist on the surface of the wireless charger according to the quality factor. The method has the advantages of improving the measurement accuracy of the quality factor and the foreign matter detection accuracy and reducing the detection difficulty.
The third embodiment is a corresponding apparatus embodiment to the first embodiment, and details thereof are not repeated herein.
Example four
Referring to fig. 4, a block diagram of a wireless charger according to a fourth embodiment of the present invention is shown.
The wireless charger 400 includes: a notification opening module 401, a measurement module 402, a notification closing module 403, and a metal foreign object determination module 404.
The functions of the modules and the interaction relationship between the modules are described in detail below.
A notification disconnection module 401 for notifying the receiving end of the charging circuit to disconnect the secondary coil and the rectifying circuit before measuring the quality factor. Optionally, in an embodiment of the present invention, the disconnection notification module 401 includes:
the disconnection notifying submodule 4011 is configured to send a first private packet containing measurement start information to the receiving end of the charging circuit before the quality factor is measured, so as to notify the receiving end of disconnecting the secondary coil and the rectifying circuit.
A measuring module 402, configured to measure a quality factor of the charging circuit when receiving a disconnection response to the connection sent by the receiving end. Optionally, in an embodiment of the present invention, the measurement module 402 includes:
the voltage measurement submodule 4021 is configured to measure a voltage across the primary coil and a voltage of the sinusoidal ac voltage input based on a resonant circuit composed of the sinusoidal ac voltage input, a resistor, a capacitor, and a primary coil inductance of the wireless charger.
The quality factor determination sub-module 4022 is configured to determine the quality factor of the current charging system according to the voltage across the primary coil and the voltage of the sinusoidal ac voltage input.
A notification closing module 403 for notifying the receiving end to close the connection of the secondary coil and the rectifying circuit after the end of the measurement. Optionally, in an embodiment of the present invention, the notification closing module 403 includes:
a notification closing sub-module 4031, configured to send a second private data packet containing measurement end information to the receiving end, so as to notify the receiving end to close the connection between the secondary coil and the rectifying circuit.
A metallic foreign object determination module 404, configured to determine whether a metallic foreign object exists on the surface of the wireless charger according to the quality factor. Optionally, in an embodiment of the present invention, the metal foreign object determining module 404 includes:
the reference quality factor receiving sub-module 4041 is configured to receive the reference quality factor sent by the receiving end.
A first threshold determination sub-module 4042, configured to determine a first threshold according to the reference quality factor.
A metallic foreign object determination submodule 4043, configured to determine whether a metallic foreign object exists on the surface of the wireless charger according to the first threshold and the quality factor.
In the embodiment of the invention, before the quality factor is measured, the receiving end of the charging circuit is informed to disconnect the secondary coil and the rectifying circuit; measuring a quality factor of the charging circuit when a disconnection response to the connection sent by the receiving end is received; after the measurement is finished, informing the receiving end to close the connection of the secondary coil and the rectifying circuit; and determining whether metal foreign matters exist on the surface of the wireless charger according to the quality factor. The method has the advantages of improving the measurement accuracy of the quality factor and the foreign matter detection accuracy and reducing the detection difficulty. In addition, the handshake communication between the receiving end and the transmitting end can be realized through the private data packet carrying the measurement starting information and the measurement ending information, and the connection state of the secondary coil and the rectifying circuit of the receiving end is informed mutually, so that the detection accuracy is further improved.
The fourth embodiment is a device embodiment corresponding to the second embodiment, and details can be found in reference to the second embodiment, which are not described herein again.
The embodiment of the present invention further provides a computer-readable storage medium, where a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the computer program implements each process of the above-mentioned method for detecting a metal foreign object, and can achieve the same technical effect, and in order to avoid repetition, the detailed description is omitted here. The computer-readable storage medium may be a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk.
It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
Through the above description of the embodiments, those skilled in the art will clearly understand that the method of the above embodiments can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware, but in many cases, the former is a better implementation manner. Based on such understanding, the technical solutions of the present invention may be embodied in the form of a software product, which is stored in a storage medium (such as ROM/RAM, magnetic disk, optical disk) and includes instructions for enabling a terminal (such as a mobile phone, a computer, a server, an air conditioner, or a network device) to execute the method according to the embodiments of the present invention.
While the present invention has been described with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, which are illustrative and not restrictive, and it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (10)
1. A detection method of metal foreign matters is applied to a wireless charger, and is characterized by comprising the following steps:
before the quality factor is measured, informing a receiving end of a charging circuit to disconnect the secondary coil and the rectifying circuit;
when a disconnection response to the connection sent by the receiving end is received, measuring a quality factor of a transmitting end of the charging circuit; the step of measuring the quality factor of the transmitting end is performed before a digital Ping phase of the wireless charger; the transmitting end comprises a primary coil, and when the connection between the secondary coil and the rectifying circuit is not disconnected, the power transmitted by the primary coil activates the rectifying circuit of the receiving end;
after the measurement is finished, informing the receiving end to close the connection of the secondary coil and the rectifying circuit;
and determining whether metal foreign matters exist on the surface of the wireless charger according to the quality factor.
2. The method of claim 1, wherein the step of notifying the receiving end of the charging circuit to disconnect the secondary coil from the rectifying circuit comprises:
and sending a first private data packet containing measurement start information to a receiving end of the charging circuit to inform the receiving end of disconnecting the secondary coil and the rectifying circuit.
3. The method of claim 1, wherein the step of informing the receiving end to close the connection of the secondary coil and the rectifying circuit comprises:
and sending a second private data packet containing measurement end information to the receiving end to inform the receiving end of closing the connection between the secondary coil and the rectifying circuit.
4. The method of claim 1, wherein the step of measuring the quality factor of the charging circuit comprises:
measuring a voltage across a primary coil of the wireless charger and a voltage of a sinusoidal alternating voltage input based on a resonant circuit consisting of the sinusoidal alternating voltage input, a resistor, a capacitor, and the primary coil;
and determining the quality factor of the current charging system according to the voltage at two ends of the primary coil and the voltage input by the sinusoidal alternating-current voltage.
5. The method of claim 1, wherein the step of determining whether metallic foreign objects are present on the surface of the wireless charger according to the quality factor comprises:
receiving a reference quality factor sent by a receiving end;
determining a first threshold value according to the reference quality factor;
and determining whether metal foreign matters exist on the surface of the wireless charger according to the first threshold and the quality factor.
6. A wireless charger, comprising:
the informing disconnection module is used for informing the receiving end of the charging circuit to disconnect the secondary coil and the rectifying circuit before measuring the quality factor;
the measuring module is used for measuring the quality factor of the transmitting end of the charging circuit when receiving the disconnection response of the receiving end to the connection; the measuring module measures a quality factor of the transmitting terminal before a digital Ping stage of the wireless charger; the transmitting end comprises a primary coil, and when the connection between the secondary coil and the rectifying circuit is not disconnected, the power transmitted by the primary coil activates the rectifying circuit of the receiving end;
a notification closing module for notifying the receiving end to close the connection of the secondary coil and the rectifying circuit after the end of the measurement;
and the metal foreign matter determining module is used for determining whether metal foreign matters exist on the surface of the wireless charger according to the quality factor.
7. The wireless charger of claim 6, wherein the notification disconnection module comprises:
and the disconnection notifying submodule is used for sending a first private data packet containing measurement starting information to the receiving end of the charging circuit before the quality factor is measured so as to notify the receiving end of disconnecting the secondary coil and the rectifying circuit.
8. The wireless charger of claim 6, wherein the notification closing module comprises:
and the notification closing submodule is used for sending a second private data packet containing measurement ending information to the receiving end so as to notify the receiving end to close the connection between the secondary coil and the rectifying circuit.
9. The wireless charger of claim 6, wherein the measurement module comprises:
a voltage measurement submodule for measuring a voltage across a primary coil of the wireless charger and a voltage of the sinusoidal alternating voltage input based on a resonant circuit composed of the sinusoidal alternating voltage input, a resistor, a capacitor, and the primary coil;
and the quality factor determining submodule is used for determining the quality factor of the current charging system according to the voltage at two ends of the primary coil and the voltage input by the sinusoidal alternating-current voltage.
10. The wireless charger according to claim 6, wherein the metallic foreign object determination module includes:
the reference quality factor receiving submodule is used for receiving the reference quality factor sent by the receiving end;
a first threshold determination submodule for determining a first threshold value from the reference figure of merit;
and the metal foreign matter determining submodule is used for determining whether metal foreign matter exists on the surface of the wireless charger according to the first threshold and the quality factor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN110945745B (en) * | 2018-07-19 | 2023-09-01 | 联发科技（新加坡）私人有限公司 | Foreign object detection in a wireless power transfer system |
| WO2020015746A1 (en) | 2018-07-19 | 2020-01-23 | Mediatek Singapore Pte. Ltd. | Detecting foreign objects in wireless power transfer systems |
| CN108923552A (en) * | 2018-07-27 | 2018-11-30 | 浙江泰米电子科技有限公司 | A kind of wireless charging foreign bodies detection circuit and method |
| CN109143383A (en) * | 2018-09-11 | 2019-01-04 | 上海楚山电子科技有限公司 | A kind of metallic foreign body recognition methods based on wireless charging technology |
| CN110165726B (en) * | 2019-04-28 | 2022-04-15 | 南京睿赫电子有限公司 | Wireless charging device and charging method |
| CN110146927B (en) | 2019-05-16 | 2022-02-15 | 京东方科技集团股份有限公司 | Charging system, foreign matter detection method and component, and charging control method and device |
| CN112630540B (en) * | 2019-09-24 | 2022-07-19 | 华润微集成电路(无锡)有限公司 | Inductance quality factor measuring method, corresponding measuring circuit and application thereof |
| CN111211598B (en) * | 2020-02-12 | 2022-11-22 | 华为数字能源技术有限公司 | Wireless charging circuit, wireless charging method, wireless charging equipment and wireless charging system |
| CN111208357B (en) * | 2020-02-17 | 2020-12-08 | 珠海智融科技有限公司 | Q value detection circuit and working method thereof |
| CN113972728A (en) * | 2020-07-21 | 2022-01-25 | 北京小米移动软件有限公司 | Wireless charging method, device, terminal and storage medium |
| CN113972703B (en) * | 2020-07-21 | 2024-07-09 | 北京小米移动软件有限公司 | Wireless charging method, device, terminal and storage medium |
| CN112701808B (en) * | 2020-12-21 | 2023-06-09 | 歌尔股份有限公司 | Foreign matter detection circuit, wireless charging system and foreign matter detection method |
| CN112737148B (en) * | 2020-12-23 | 2023-07-14 | 歌尔股份有限公司 | Foreign matter detection circuit, wireless charging system and foreign matter detection method |
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