CN117118097A

CN117118097A - Metal foreign matter detection circuit, method and related device

Info

Publication number: CN117118097A
Application number: CN202310261166.8A
Authority: CN
Inventors: 张安乐; 宋佳祥; 朱晓勇
Original assignee: Honor Device Co Ltd
Current assignee: Honor Device Co Ltd
Priority date: 2023-03-13
Filing date: 2023-03-13
Publication date: 2023-11-24

Abstract

The application provides a metal foreign matter detection circuit, a metal foreign matter detection method and a related device. The first end of the second coil is connected with a control circuit corresponding to the coil through a first switch circuit, and the second end of the second coil is directly connected with the control circuit. The first switch circuit is connected in parallel with the second switch circuit, and the second switch circuit comprises a first capacitor and a switch which are connected in series. The switching states of the first switch circuit and the second switch circuit are controlled to enable the second coil and the first capacitor to be connected in series to obtain an LC resonance circuit, the quality factor of the LC resonance circuit is obtained, and finally metal foreign matters in the position range of the second coil are detected according to the quality factor. According to the detection circuit, the second coil is used for assisting in detecting the metal foreign matters outside the first coil, so that the risk of overhigh temperature of the metal foreign matters caused by normal charging due to the fact that the metal foreign matters at the edge of the first coil are not detected is avoided, and the safety of a wireless charging process is improved.

Description

Metal foreign matter detection circuit, method and related device

Technical Field

The application relates to the technical field of wireless charging, in particular to a circuit, a method and a related device for detecting metal foreign matters.

Background

The wireless charging technology mainly adopts an electromagnetic induction principle, and realizes electric energy transmission by energy coupling through a coil. The wireless charger and the electronic equipment (i.e. mobile phone, bluetooth earphone, etc.) are respectively provided with coils. The wireless charger is internally provided with a transmitting coil, and the electronic equipment is internally provided with a receiving coil. The electronic equipment is placed on the wireless charger, after the wireless charger is powered on, alternating current on the transmitting coil generates a changing magnetic field, the receiving coil can sense the changing of the magnetic field to generate induction current, and then the induction current is converted into direct current to charge the mobile phone battery.

In the wireless charging process, if conductive objects such as metal (such as coins and keys) exist between the wireless charger and the electronic equipment, vortex current can be generated in the magnetic field, the joule effect of the vortex current can enable the metal objects to generate heat, if the heat cannot be released and is accumulated too high, the wireless charger and the electronic equipment can be damaged, and when serious, the battery of the electronic equipment can be overheated and exploded.

Disclosure of Invention

In view of this, the application provides a method and a related device for detecting metallic foreign matters so as to accurately detect metallic foreign matters, and the disclosed technical scheme is as follows:

In a first aspect, the present application provides a metal foreign matter detection circuit applied to an electronic device, the electronic device including a first coil and a second coil, the first coil being a wireless charging coil, the second coil being located at a periphery of the first coil, the metal foreign matter detection circuit including: the first end of the second coil is connected with the first end of the second coil control circuit through the first switch circuit, and the second end of the second coil is connected with the second end of the second coil control circuit; the second switching circuit is connected with the first switching circuit in parallel and comprises a first capacitor and a switch which are connected in series; the second coil control circuit obtains voltage peak value data of the LC resonance circuit in a discharging stage, and calculates a Q value of the LC resonance circuit according to the voltage peak value data, wherein the LC resonance circuit comprises a second coil and a first capacitor which are connected in series, and the Q value is used for detecting metal foreign matters in a position range of the second coil. According to the detection circuit, the second coil is used for assisting in detecting the metal foreign matters outside the first coil, so that the risk of overhigh temperature of the metal foreign matters caused by normal charging due to the fact that the metal foreign matters at the edge of the first coil are not detected is avoided, and the safety of a wireless charging process is improved.

In a possible implementation manner of the first aspect, the second coil is a near field communication NFC coil. Thus, the metal foreign matter detection accuracy can be improved without increasing the hardware cost.

In a possible implementation manner of the first aspect, the second switching circuit includes a first capacitor and a first switch; the first end of the first capacitor is connected with the first end of the second coil, the second end of the first capacitor is connected with the first end of the first switch, and the second end of the first switch is connected with the first end of the second coil control circuit; or, the first end of the first switch is connected with the first end of the second coil, the second end of the first switch is connected with the first end of the first capacitor, and the second end of the first capacitor is connected with the first end of the second coil control circuit.

In a possible implementation manner of the first aspect, the second switching circuit includes a first capacitor, a second switch and a third switch; the first end of the second switch is connected with the first end of the second coil, the second end of the second switch is connected with the first end of the first capacitor, the second end of the first capacitor is connected with the first end of the third switch, and the second end of the third switch is connected with the first end of the second coil control circuit. Like this, first electric capacity both ends all establish ties and have the switch, when electronic equipment utilized NFC coil to realize NFC communication function, second switch and third switch all break off to prevent the signal transmission of first electric capacity to NFC coil, avoided NFC coil to receive C2 interference.

In a possible implementation manner of the first aspect, the second coil control circuit controls the LC resonance circuit to charge and discharge, and triggers the peak detector to collect voltage peak data of the LC resonance circuit in a discharge phase. The scheme is applied to the scene that the second coil control circuit is provided with the corresponding peak detector, so that the second coil control circuit can directly trigger the peak detector to acquire voltage peak data in the charge-discharge process of the LC resonance circuit, thereby realizing rapid acquisition of required data and further improving the detection efficiency of the metal foreign matters.

In a possible implementation manner of the first aspect, the metal foreign object detection circuit includes a first coil control circuit connected to the first coil, the first coil control circuit controls the LC resonance circuit to charge and discharge, and triggers the peak detector to collect voltage peak data of the LC resonance circuit in a discharge phase.

In a possible implementation manner of the first aspect, the first coil control circuit is a wireless charging coil chip, and the second coil control circuit is an NFC chip.

In a possible implementation manner of the first aspect, the metal foreign object detection circuit includes a first coil control circuit connected with the first coil, and the first coil control circuit triggers the second coil control circuit to start.

In a possible implementation manner of the first aspect, the metal foreign object detection circuit includes a first coil control circuit connected to the first coil, the first coil control circuit controls the first switch circuit to be opened and the second switch circuit to be closed, so that the second coil and the first capacitor are connected in series to form an LC resonance circuit; or the second coil control circuit controls the first switch circuit to be opened and the second switch circuit to be closed, so that the second coil and the first capacitor are connected in series to form an LC resonance circuit.

In a second aspect, the present application further provides a metal foreign object detection circuit applied to an electronic device, where the electronic device includes a first coil and a second coil, the first coil is a wireless charging coil, the second coil is located at a periphery of the first coil, and the metal foreign object detection circuit includes: the first coil is connected with a first coil control circuit, and the first coil control circuit is used for controlling the working state of the first coil; the first end of the second coil is connected with the first end of the second coil control circuit through the third switch circuit, the second end of the second coil is connected with the second end of the second coil control circuit through the fourth switch circuit, and the second coil control circuit is used for controlling the working state of the second coil; the first end of the second coil is also connected with the first end of the first coil control circuit through a fifth switch circuit, the second end of the second coil is also connected with the second end of the first coil control circuit through a sixth switch circuit, and the fifth switch circuit comprises a first capacitor and a switch which are connected in series; the first coil control circuit acquires voltage peak value data of the LC resonance circuit in a discharging stage and a Q value obtained by calculation according to the voltage peak value data; the first coil control circuit detects a metallic foreign matter in a range of the second coil according to the Q value. According to the scheme, the metal foreign matters outside the WPC coil range can be accurately detected, the risk that the metal foreign matters at the edge of the WPC coil are not detected and the temperature of the metal foreign matters is too high due to normal charging is avoided, and finally the safety of a wireless charging process is improved. In addition, the RX chip calculates the Q value of the LC resonant circuit and detects the metal foreign matter according to the Q value, so that software (namely processing logic) and hardware of the NFC chip are not required to be modified, the cost of modifying the NFC chip is saved, and the cost of the whole metal foreign matter detection scheme is finally reduced.

In a possible implementation manner of the second aspect, the second coil is a near field communication NFC coil. Thus, the metal foreign matter detection accuracy can be improved without increasing the hardware cost.

In a possible implementation manner of the second aspect, the first coil control circuit controls the LC resonant circuit obtained by connecting the second coil in series with the first capacitor to charge and discharge, and triggers the peak detector to detect voltage peak data of the LC resonant circuit during a discharge phase of the LC resonant circuit.

In a possible implementation manner of the second aspect, the first coil control circuit controls the three switch circuits and the fourth switch circuit to be opened, and controls the fifth switch circuit and the sixth switch circuit to be closed, so that the second coil is connected in series with the first capacitor to obtain the LC resonance circuit.

In a possible implementation manner of the second aspect, the first coil control circuit is a wireless charging coil chip, and the second coil control circuit is an NFC chip.

In a third aspect, the present application also provides a method for detecting a metal foreign object, applied to an electronic device, the electronic device including the metal foreign object detection circuit of any one of the first aspects, the method including: controlling the switching state of a switching circuit connected with the second coil, so that the second coil is connected with the first capacitor in series to obtain an LC resonance circuit; controlling the LC resonance circuit to charge and discharging after the charge is completed; acquiring voltage peak value data of the LC resonance circuit in a discharge stage; and calculating the quality factor Q value of the LC resonant circuit according to the voltage peak value data, and detecting the metal foreign matters in the position range of the second coil according to the Q value.

In a fourth aspect, the application also provides a wireless charging system, which comprises a wireless charging base and electronic equipment; the wireless charging base comprises a first WPC coil and a first NFC coil, and the first NFC coil is positioned at the periphery of the first WPC coil; the electronic device comprises a second WPC coil and a second NFC coil, and the second NFC coil is positioned at the periphery of the second WPC coil; the wireless charging base controls the first NFC coil to emit a first NFC signal, and when the voltage value of the first NFC signal is detected to be lower than a normal voltage value, it is determined that metal foreign matters exist between the wireless charging base and the electronic equipment; or the electronic equipment controls the second NFC coil to emit a second NFC signal, and when the voltage value of the second NFC signal is detected to be lower than the normal voltage value, it is determined that the metal foreign matter exists between the electronic equipment and the wireless charging base. Therefore, the NFC coil can be arranged on the periphery of the WPC coil in the wireless charging base in the system, and the metal foreign matter at the edge of the WPC coil is detected through the NFC coil, so that the metal foreign matter detection accuracy of the wireless charging base is improved. In addition, the system can detect the metal foreign matters by utilizing the voltage change condition of NFC signals between the wireless charging base and the electronic equipment, an LC resonance circuit is not required to be formed by connecting the NFC coil and the capacitor in series, the hardware cost is reduced, meanwhile, the metal foreign matter detection accuracy is improved, and the safety of the wireless charging process is further improved.

In a fifth aspect, the present application also provides a wireless charging base, including the metal foreign matter detection circuit of any one of the first aspects.

In a sixth aspect, the present application also provides an electronic device including the metal foreign matter detection circuit of any one of the first aspects.

In a seventh aspect, the present application further provides a chip system, including: the system comprises at least one processor and an interface, wherein the interface is used for receiving code instructions and transmitting the code instructions to the at least one processor; the at least one processor executes code instructions to implement the metallic foreign object detection method of the third aspect.

In an eighth aspect, the present application also provides a computer-readable storage medium having instructions stored thereon that, when executed on an electronic device, cause the electronic device to perform the metal foreign object detection method as in the third aspect.

It should be appreciated that the description of technical features, aspects, benefits or similar language in the present application does not imply that all of the features and advantages may be realized with any single embodiment. Conversely, it should be understood that the description of features or advantages is intended to include, in at least one embodiment, the particular features, aspects, or advantages. Therefore, the description of technical features, technical solutions or advantageous effects in this specification does not necessarily refer to the same embodiment. Furthermore, the technical features, technical solutions and advantageous effects described in the present embodiment may also be combined in any appropriate manner. Those of skill in the art will appreciate that an embodiment may be implemented without one or more particular features, aspects, or benefits of a particular embodiment. In other embodiments, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are some embodiments of 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 system;

FIG. 2 is a schematic diagram of a coil position in the wireless charging system shown in FIG. 1;

FIG. 3 is a schematic diagram of a wireless charging base and a coil structure in an electronic device;

fig. 4 is a schematic diagram of an internal coil structure of an electronic device according to an embodiment of the present application;

fig. 5 is a schematic diagram of a coil structure of a wireless charging base according to an embodiment of the present application;

fig. 6 is a schematic diagram of a metal foreign matter detection circuit of an electronic device according to an embodiment of the present application;

FIG. 7 is a schematic circuit diagram of the metal foreign matter detection circuit shown in FIG. 6 in operation;

FIG. 8 is a flow chart of a method of detecting metallic foreign matter corresponding to the circuit shown in FIG. 6;

fig. 9 is a schematic diagram of another metal foreign matter detection circuit of the electronic device according to the embodiment of the application;

FIG. 10 is a flowchart of a method of detecting metallic foreign matter corresponding to the circuit shown in FIG. 9;

FIG. 11 is a schematic diagram of a metal foreign matter detection circuit of an electronic device according to an embodiment of the present application;

FIG. 12 is a schematic circuit diagram of the circuit of FIG. 11 in operation;

fig. 13 is a flowchart of a method of detecting metallic foreign matter corresponding to the circuit shown in fig. 11.

Detailed Description

The terms first, second, third and the like in the description and in the claims and in the drawings are used for distinguishing between different objects and not for limiting the specified order.

In embodiments of the application, words such as "exemplary" or "such as" are used to mean serving as an example, instance, or illustration. Any embodiment or design described herein as "exemplary" or "e.g." in an embodiment should not be taken as preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "such as" is intended to present related concepts in a concrete fashion.

As shown in fig. 1 and 2, taking an example that the electronic device is a mobile phone, the wireless charging system includes a wireless charging base 1 and a mobile phone 2.

The wireless charging base 1 is internally provided with a wireless charging (WirelessPowerConsortium, WPC) coil 11, and a WPC coil in the wireless charging base 1 is a transmitting coil. The WPC coil 12 is arranged inside the mobile phone 2, and the WPC coil 12 is a receiving coil when the mobile phone is in a wireless forward charging state (i.e. the wireless charging base charges a battery in the mobile phone).

Fig. 3 shows a schematic diagram of a wireless charging base and a coil within an electronic device.

As shown in fig. 3 (1), the coil structure of the wireless charging base includes a magnetic plate 13 and a WPC coil 11. As shown in fig. 3 (2), the coil structure of the electronic device includes a WPC coil 12 and a magnetic plate 14.

Metallic foreign matter detection in wireless charging systems is mainly achieved by the change in quality factor (Q value) or power loss (P) of WPC coils _loss Power emitted by the wireless charging dock-power received by the electronic device).

For example, a preset threshold corresponding to the Q value is set. If the preset threshold corresponding to the Q value is too small, the foreign matter alarm is very easy to trigger by mistake, so that the charging is stopped, and the preset threshold cannot be too small in order to avoid the foreign matter alarm from being touched by mistake. However, when the metal object is located at the position shown as 15 in fig. 3 (1) and (2), the Q values of the WPC coil 11 of the wireless charging base and the WPC coil 12 of the electronic device are changed very little, the metal object cannot be detected by comparing the Q values with the corresponding preset threshold values, the charging system considers that no foreign matter exists and the charging is performed normally, and this may cause the temperature of the metal object to rise, further may cause damage to the wireless charging base and the electronic device, and may cause the battery in the electronic device to overheat and explode when serious. The same problem exists with detecting metallic foreign matter by power loss.

In order to solve the above technical problems, the present application provides a method for detecting a metal foreign object, which adds a coil (which may be referred to as an auxiliary detection coil) in an electronic device or a wireless charging base, and detects whether a metal foreign object exists between the wireless charging base and the electronic device by detecting a Q value of the auxiliary detection coil. Therefore, the detection accuracy of the metal foreign matters is improved, and the temperature rise of the metal foreign matters can be controlled, so that the safety risk is reduced. The application does not limit the type of auxiliary detection coil. For example, the auxiliary detection coil may be an electronic device or other existing coils in the wireless charging base, such as a near field communication (Near Field Communication, NFC) coil in the electronic device, which may improve the detection accuracy of the metallic foreign matter without increasing the hardware cost.

In some embodiments, the electronic device may be a cell phone, tablet, desktop, laptop, notebook, ultra mobile personal computer (Ultra-mobile Personal Computer, UMPC), handheld computer, netbook, personal digital assistant (Personal Digital Assistant, PDA), wearable electronic device, smart watch, or the like with wireless charging capability.

In an exemplary embodiment of the application, the electronic device may include a processor, a charge management module, a power management module, a battery, a wireless communication module, and the like. In addition, WPC coil and NFC coil are also arranged inside the electronic equipment. The wireless communication module in this embodiment may include a WPC chip and an NFC chip.

It is to be understood that the configuration illustrated in this embodiment does not constitute a specific limitation on the electronic apparatus. In other embodiments, the electronic device may include more or fewer components than shown, or certain components may be combined, or certain components may be split, or different arrangements of components. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

In the embodiment of the application, the WPC chip of the electronic equipment is used for communicating with the WPC chip in the wireless charging base and detecting whether metal foreign matters exist between the electronic equipment and the wireless charging base. In order to distinguish the WPC chip of the electronic device from the WPC chip of the wireless charging dock, the WPC chip of the electronic device is referred to herein as an RX (Receiver) chip and the WPC chip of the wireless charging dock is referred to herein as a TX (Transmitter) chip.

The electronic equipment can carry out wireless charging to the battery through the WPC chip and the wireless charging coil, and in the wireless charging process, whether metal foreign matters exist between the electronic equipment and the wireless charging base or not through the NFC chip and the NFC coil in an auxiliary mode.

The processor may include one or more processing units, and the different processing units may be separate devices or may be integrated in one or more processors. For example, in an embodiment of the application, the processor comprises an application processor (application processor, AP).

In an exemplary embodiment of the present application, the WPC chip and the NFC chip may implement indirect communication through the processor, for example, when the WPC chip sends data or instructions to the NFC chip, the WPC chip sends the data or instructions to the processor first, and then the processor forwards the data or instructions to the NFC chip. Similarly, when the NFC chip sends data or instructions to the WPC, the NFC chip sends the data or instructions to the processor, and then the processor forwards the data or instructions to the WPC chip.

In addition, an operating system is run on the components. For example, the number of the cells to be processed,operating System (OS)>Operating System (OS)>An operating system, etc. On the operating system, running applications such as settings, gallery, calendar, talk, map, etc. may be installed. In the embodiment of the application, a user can click the battery function item to enter the battery function page in the setting APP, and then the wireless charging switch is opened in the battery function page, so that the electronic equipment can be charged wirelessly.

The coil structure of the electronic device according to the embodiment of the present application will be described with reference to fig. 4 and 5.

In some examples, to meet NFC communication requirements (as NFC is commonly applied in the fields of mobile payment, smart entrance guards, bus cards, electronic tickets, smart tags, etc.), the electronic device is further provided with an NFC coil and an NFC chip.

In one example, as shown in fig. 4, an NFC coil 16 is disposed on the periphery of the WPC coil 12 for implementing the NFC functionality of the electronic device.

Aiming at the electronic equipment with the NFC coil arranged on the periphery of the WPC coil, the metal foreign body detection method can assist in detecting the metal foreign body by detecting the Q value of the NFC coil. For example, the Q value of the NFC coil may be calculated to detect whether there is a metal foreign object in the position range of the NFC coil, so as to improve the detection accuracy of the metal foreign object, and avoid the risk of excessive temperature of the metal foreign object caused by normal charging without detecting the metal foreign object.

In another example, at least two WPC coils may be disposed in the electronic device, and whether a metallic foreign object exists in a range where any WPC coil is located may be detected by detecting a Q value corresponding to the WPC coil. For example, one or more WPC coils may be added to the outer periphery of the original WPC coil 12. And judging whether the periphery of the original WPC coil has metal foreign matters or not by detecting the Q value corresponding to the added WPC coil.

In another exemplary embodiment of the present application, at least two coils may also be provided within the wireless charging base, for example, both coils may be WPC coils, or one may be WPC coils and the other may be NFC coils. In this way, the presence or absence of metallic foreign matter can be detected by the coil provided at the periphery.

Taking the wireless charging base with the WPC coil and the NFC coil as an example, as shown in fig. 5, other types of coils, such as the NFC coil 17, may be added on the periphery of the WPC coil 11 of the wireless charging base. Thus, the wireless charging base can determine whether or not the metallic foreign matter exists at the position indicated by 15 by detecting the change of the Q value of the NFC coil 17.

In some embodiments, in a scenario where the wireless charging base and the electronic device are both provided with NFC coils, the wireless charging base may determine whether the metallic foreign object exists by detecting a change (e.g., a voltage value change) of a communication signal (e.g., an NFC signal).

For example, the electronic device controls its NFC coil to transmit an NFC signal, and the wireless charging base may detect a voltage value of the transmitted NFC signal, and if the voltage value of the transmitted NFC signal is smaller than a normal voltage value of the NFC signal, it is determined that there is a change in impedance between the two coils, and a metallic foreign object is present. If the voltage value of the transmitted NFC signal is equal to the normal voltage value, the impedance between the two coils is determined to be unchanged, and no metal foreign matter exists.

Similarly, the electronic device can also determine whether the metallic foreign matter exists by detecting the change of the voltage value of the NFC signal transmitted by the wireless charging base.

In another example, at least two WPC coils may be disposed in the wireless charging base, and whether a metal foreign object exists in a range where any WPC coil is located may be detected by detecting a Q value or a power loss corresponding to the WPC coil.

The following describes a metal foreign matter detection circuit for an electronic device according to an embodiment of the present application, taking an NFC coil as an example of an auxiliary detection coil.

1. NFC chip calculates Q value or detects metallic foreign matter

1. Two peak detectors are arranged in the metal foreign matter detection circuit, namely, an RX chip and an NFC chip are respectively provided with one peak detector

Fig. 6 is a schematic diagram of a metal foreign matter detection circuit in an electronic device according to an embodiment of the present application.

In an exemplary embodiment, a first end of the NFC coil is connected to one pin of the NFC chip through a first switching circuit, and a second end of the NFC coil is connected to another pin of the NFC chip. And a second switching circuit connected in parallel with the first switching circuit.

In an example, as shown in fig. 6, the first switching circuit includes a first switch SW1, the second switching circuit includes a capacitor C2 (i.e., a first capacitor), and the second switch SW2 and the third switch SW3 are connected in series. One end of the NFC coil is connected with one pin of the NFC chip through a first switch SW 1. The two ends of the capacitor C2 are respectively connected with a second switch SW2 and a third switch SW3 in series, and the second switch circuit is connected with the first switch circuit in parallel.

In the example shown in fig. 6, SW2 is connected in series between C2 and the NFC coil, and when the NFC coil performs NFC communication, SW2 is turned off, so that an electric signal of C2 can be prevented from being transmitted to the NFC coil, thereby avoiding interference of the NFC coil by C2.

In other embodiments, the second switching circuit may include a capacitor C2 and a switch connected in series with C2, for example, a switch may be connected in series to one end of the capacitor C2 connected to the NFC coil, such as SW2 shown in fig. 6. As another example, a switch may be connected in series to the end of the capacitor C2 connected to the NFC chip, such as SW3 shown in fig. 6.

In other embodiments of the application, the first and second switching circuits may also include a greater number of switches, which may be in series and/or parallel relationship, as the application is not limited in this regard.

In addition, one end of C2 is also connected with the input end of the first peak detector. The first peak detector is used for detecting voltage peak data (such as voltage peak, oscillation period number and the like) of an LC resonance circuit formed by connecting an NFC coil and C2 in series in a discharging stage and providing the voltage peak data to the NFC chip.

Referring again to fig. 6, one end of the WPC coil is connected to one end of the capacitor C1, the other end of the C1 is connected to one pin of the RX chip, and the other end of the WPC coil is connected to the other pin of the RX chip. One end of C1 is also connected with the input end of a second peak detector, and the second peak detector is used for collecting voltage peak value data of an LC resonance circuit formed by connecting the WPC coil and C1 in series in a discharging stage and providing the voltage peak value data to an RX chip.

In an example, the first peak detector may be integrated within the NFC chip or may be a device separate from the NFC chip. Likewise, the second peak detector may be integrated within the RX chip or may be a separate device from the RX chip.

In one example, SW1 may be a depletion NMOS transistor, defaults to a closed state. SW2 and SW3 may be enhanced NMOS transistors, default to an off state. Of course, in other embodiments, SW1 to SW3 may be other types of switching devices, and the present application is not limited to the types of switching devices of SW1 to SW 3. The switch states of SW1 to SW3 may be controlled by an RX chip or an NFC chip, which is not limited in the present application.

Fig. 7 is a circuit schematic diagram of the metal foreign matter detection circuit shown in fig. 6 in operation.

As shown in fig. 7, when the NFC coil is used for assisting in detecting a metallic foreign object, SW1 is opened, and SW2 and SW3 are closed, in which state the NFC coil and the capacitor C2 constitute an LC resonance circuit.

The NFC chip firstly controls the LC resonance circuit to charge, then controls the LC resonance circuit to discharge, and simultaneously triggers the first peak detector to collect voltage peak data of the LC resonance circuit in a discharge stage.

The first peak detector determines peak data (including voltage peak value and oscillation period number, for example) of the voltage signal in the LC resonance circuit through the collected voltage signal of the LC resonance circuit in the discharge stage, namely the voltage peak data, and sends the voltage peak data to the NFC chip. And the NFC chip calculates the Q value of the LC resonant circuit in the discharge stage based on the voltage peak data. And if the Q value is smaller than or equal to a preset threshold value, determining that the metal foreign matter exists at the position where the NFC coil is located. It can be seen that metallic foreign matter outside the position of the WPC coil can be detected by the NFC coil and the NFC chip.

In an example, the NFC chip may send a Q value to the RX chip, and the RX chip determines, according to the Q value, whether the metal foreign object exists at the location of the NFC coil.

In another example, after the NFC chip calculates the Q value, it may directly determine whether the metal foreign object exists at the position where the NFC coil is located according to the Q value, and send the detection result to the RX chip, where the RX chip executes corresponding processing logic according to the detection result.

The metal foreign matter detection circuit shown in fig. 6 is applicable to a wireless charging base, and is different in that the RX chip in the metal foreign matter detection circuit is to be replaced by a WPC chip on the wireless charging base side, that is, a TX chip, and the other contents are the same, and are not described herein again.

In other embodiments of the present application, when the electronic device determines that no metal foreign object exists in the position range of the NFC coil, the RX chip may further detect the metal foreign object in the position range of the WPC coil according to the Q value by further obtaining, by using the second peak detector, the Q value of the LC resonant circuit formed by the WPC coil in the discharging stage, and further detecting whether the metal foreign object exists in the position range of the WPC coil in the position range of the NFC coil.

Further, when the NFC coil is used for NFC communication, SW1 is closed, and SW2 and SW3 are open, i.e., the capacitor C2 is not connected to the line between the NFC coil and the NFC chip.

Next, a method for detecting a metal foreign object will be described with reference to a flowchart of a method for detecting a metal foreign object shown in fig. 8, and this embodiment is described by taking wireless forward charging of a mobile phone as an example, and the method is applied to a wireless charging system.

As shown in fig. 8, the metal foreign matter detection method to be applied to the electronic device side may include the steps of:

s100, starting an RX chip of the mobile phone.

After the mobile phone is started, the application processor can directly start the RX chip to supply power in the scene that the mobile phone needs to be charged wirelessly. For example, after an example, the application processor may directly activate the RX chip after the handset turns on the wireless charging switch.

S101, communication connection is established between the wireless charging base and the mobile phone.

And a communication connection is established between the TX chip of the wireless charging base and the Rx chip in the mobile phone so as to facilitate communication between the wireless charging base and the mobile phone. For example, in one example, the Tx chip sends a Ping command to the Rx chip requesting to establish communication, and the Rx chip returns a signal strength packet (SignalStrength) (which may include information such as a supported power value) and identity information to the Tx chip after receiving the Ping command. The identity information is the identity information of the RX chip.

S102, the RX chip sends an NFC chip starting instruction to a processor in the mobile phone.

In this embodiment, after the mobile phone establishes communication connection with the wireless charging base, the NFC chip is started. For example, in one example, after the RX chip establishes a communication connection with the TX chip, an instruction to start the NFC chip is sent to a processor (e.g., an application processor).

Under the condition that the NFC coil is utilized to assist in detecting the metal foreign matters, the RX chip is started and then the NFC chip is triggered to start.

Under the condition that the mobile phone realizes the NFC function through the NFC chip and the NFC coil, the NFC chip is directly started by an application processor of the mobile phone. Also, in the case where the application processor directly starts up the NFC chip, the application processor does not start up the RX chip, in other words, the application processor directly starts up the NFC chip, or directly starts up the RX chip. The application processor does not directly start the NFC chip and the RX chip at the same time.

S103, the processor responds to the NFC chip starting instruction to trigger the NFC chip to start.

After the processor of the mobile phone receives the NFC chip starting instruction, the starting instruction can be sent to the NFC chip so as to start the NFC chip.

And S104, the RX chip controls the SW1 to be opened, and controls the SW2 and the SW3 to be closed, so that the NFC coil and the capacitor C2 are connected in series to obtain an LC resonance circuit.

In an example, after the RX chip sends an NFC chip start instruction to the application processor, SW1 in the circuit shown in fig. 10 is controlled to be opened, and SW2 and SW3 are controlled to be closed, and the NFC coil and the capacitor C2 are connected in series to form an LC resonant circuit.

The present application is not limited to the execution order of S102 and S104, and S102 may be executed first and then S104 may be executed, both steps may be executed simultaneously, or S104 may be executed first and then S102 may be executed.

In other embodiments, after the NFC chip is started, the switch states of SW1 to SW3 may be controlled by the NFC chip, and the controller of the switch states of SW1 to SW3 is not limited in the present application.

S105, the NFC chip controls the LC resonance circuit to charge, controls the LC resonance circuit to discharge after the charge is finished, and simultaneously triggers the first peak detector to detect voltage peak data in the discharge stage of the LC resonance circuit.

In this embodiment, the NFC chip controls the LC resonant circuit to charge first, and then discharges the LC resonant circuit after the charge is completed. For example, injecting a 3.3V voltage into the LC tank at time t0 charges the LC tank and then grounds the LC tank to discharge it.

Triggering a first peak detection while controlling the discharge of the LC resonance circuitThe detector collects the peak value of the voltage signal of the circuit according to a preset time interval (such as a period T). For example, t ₁ The voltage signal acquired at the moment is recorded as V (t) ₁ ) The voltage signal acquired at time tn is denoted as V (t _n )。

Further, a peak (voltage peak value) of the voltage signal is determined according to the collected voltage signal, and finally the period number N is obtained.

S106, the NFC chip receives voltage peak value data sent by the first peak value detector.

In one example, the voltage peak data may include a number of periods N of the voltage signal during a period of acquisition, and the respective voltage peaks V (t) _i )，1≤i≤n。

And S107, the NFC chip calculates the Q value of an LC resonance circuit formed by the NFC coil based on the voltage peak value data.

In one example, the Q value of the LC tank circuit may be calculated by the following formula:

in the above formula, N is the number of periods (from t ₁ To t _n The number of oscillation cycles of the LC resonant circuit included in the period of time), V (t ₁ ) To acquire the first voltage peak in the cycle, V (t _n ) For the last voltage peak in the acquisition period.

S108, the NFC chip sends the Q value to the processor.

S109, the processor sends the Q value to the RX chip.

Indirect communication between the NFC chip and the RX chip is achieved through S108 and S109.

S110, power transmission is carried out between the wireless charging base and the mobile phone.

The wireless charging base transmits electromagnetic wave energy through the WPC coil, the mobile phone receives the electromagnetic wave energy through the WPC coil and converts the electromagnetic wave energy into alternating current, and the mobile phone further converts the alternating current into direct current to charge a battery in the mobile phone.

S111, the RX chip judges whether the Q value is smaller than or equal to a preset threshold value, if yes, S112 is executed; if not, S113 is performed.

And after the RX chip detects the transmission power of the mobile phone and the wireless charging base, judging whether the Q value is smaller than or equal to a preset threshold value.

A higher Q value indicates a smaller rate of energy decay stored in the LC tank, and a lower Q value indicates a larger rate of energy decay in the LC tank.

The preset threshold value can be obtained according to the actual situation of the NFC coil, for example, NFC coils with different specifications can correspond to different preset threshold values.

For example, in one example, the preset threshold of the Q value is 60, and if the Q value of the LC resonant circuit is less than or equal to 60, it indicates that a metallic foreign object exists between the two. The absorption of electromagnetic wave energy by metallic foreign matter causes the energy attenuation of the LC resonant circuit to become fast and the Q value to decrease. Therefore, when the Q value is detected to be smaller than or equal to the preset threshold value, the existence of the metal foreign matters between the wireless charging base and the mobile phone is determined.

S112, the RX chip generates a foreign matter alarm signal and sends an end power transfer (End Power Transfer, EPT) signal to the wireless charging cradle informing it to end charging.

After the RX chip of the mobile phone detects the metal foreign matters, foreign matter alarm signals are generated, wherein the foreign matter alarm signals can be sound signals, light signals or graphic information displayed on a display interface of the mobile phone and are used for reminding a user of the existence of the foreign matters between the wireless charging base and the mobile phone.

At the same time, the handset sends an EPT signal to the wireless charging base. And the wireless charging base terminates the power transmission with the mobile phone after receiving the EPT signal.

And S113, the RX chip determines the charging power according to the Q value and selects the matched coil for charging.

For example, the Q value is in the range of 80 to 100, indicating that the mobile phone side coil is facing the center of the wireless charging base coil at this time, and the mobile phone can be charged at full power. Q value is in 60 ~ 80 within range, indicates that the coil of cell-phone side and wireless charging base's coil are not just right this moment, and the cell-phone can adopt partial power to charge.

In this embodiment, the NFC chip calculates the Q value of the LC resonant circuit according to the voltage peak value data of the LC resonant circuit acquired by the first peak detector in the discharge stage.

In addition, under the condition that the position range of the NFC coil is determined to be free of metal foreign matters (the position range of the NFC coil refers to the area covered by the NFC coil), the mobile phone can further detect whether the metal foreign matters exist in the position range of the WPC coil. Namely, the Q value of the LC resonant circuit formed by the WPC coil and the capacitor C1 in the discharging stage is detected, and whether the metal foreign matters exist is further judged according to the Q value, and the process is not repeated in the application.

S114, after the wireless charging base and the mobile phone are in communication connection, acquiring a Q value corresponding to a coil in the base, and judging whether the Q value is smaller than a preset threshold value; if yes, executing S115; if not, S113 is performed.

After the wireless charging base and the mobile phone are in communication connection, when the mobile phone side executes the detection of the metal foreign matters, the wireless charging base side can also detect whether the metal foreign matters exist, the wireless charging base can utilize an LC resonance circuit formed by the WPC coil in the base and detect the Q value of the LC resonance circuit, finally the metal foreign matters are judged according to the Q value, and the process is the same as the process that the mobile phone detects the metal foreign matters through the WPC coil in the mobile phone, and the details are not repeated.

The wireless charging base may detect the Q value of the LC resonant circuit at the same time as the mobile phone, for example, after the mobile phone establishes communication connection with the wireless charging base. In addition, the timing of judging the metal foreign matter according to the Q value is the same as that of the mobile phone side, for example, the metal foreign matter is judged according to the Q value after the wireless charging base and the mobile phone perform power transmission.

S115, the wireless charging base alarms for foreign matters and finishes charging.

The foreign matter alarm mode of the wireless charging base is the same as that of the mobile phone side, and the wireless charging base is not repeated here.

It should be noted that, whether the mobile phone detects the metal foreign matter or the wireless charging base detects the metal foreign matter, a foreign matter alarm is generated and charging is terminated.

According to the metal foreign matter detection method provided by the embodiment, after the WPC chip (RX chip) on the mobile phone side is started, the NFC chip is triggered to start, and the NFC coil and the capacitor C2 are controlled to form an LC resonant circuit. And acquiring voltage peak value data of the LC resonant circuit in a discharge stage through a first peak value detector corresponding to the NFC chip, calculating a Q value by the NFC chip according to the voltage peak value data, and sending the Q value to the RX chip. And the RX chip detects whether metal foreign matters exist in the position range of the NFC coil according to the Q value. If the metal foreign matters exist, the RX chip sends out a foreign matter alarm signal, and meanwhile sends a charging termination instruction to the wireless charging base to terminate the wireless charging process. Therefore, the detection range of the metal foreign matters is enlarged, the risk that the metal foreign matters are too high due to normal charging caused by the fact that the metal foreign matters positioned at the edge of the WPC coil are not detected is avoided, and finally the safety of the wireless charging process is improved. In addition, the embodiment of the application can utilize the existing NFC coil of the electronic equipment to assist in detecting the metal foreign matters, and improve the detection accuracy of the metal foreign matters while not increasing the hardware cost.

In the embodiment shown in fig. 8, the NFC chip calculates a Q value according to the voltage peak value data collected by the first peak detector, and the RX chip further detects whether the metal foreign matter exists according to the Q value. In other embodiments of the present application, the NFC chip may calculate a Q value according to the voltage peak data, detect whether a metallic foreign object exists according to the Q value, and then send the detection result to the RX chip. The RX chip executes corresponding processing logic according to the received detection result, which is not described herein.

2. A peak detector is arranged in the metal foreign matter detection circuit

Fig. 9 is a schematic diagram of another metal foreign matter detection circuit of the electronic device according to the embodiment of the application. In this embodiment only one peak detector is provided, which is controlled by the RX chip. Furthermore, the peak detector may be integrated within the RX chip or independent of the RX chip and the NFC chip, respectively.

As shown in fig. 9, a first input terminal of the peak detector is connected to an LC resonance circuit obtained by connecting the NFC coil in series with the capacitor C2, and a second input terminal of the peak detector is connected to an LC resonance circuit obtained by connecting the WPC coil in series with the capacitor C1.

Similar to the foreign metal detection circuit shown in fig. 7, in the foreign metal detection circuit shown in fig. 10, SW1 to SW3 can be controlled by an NFC chip or an RX chip, and when SW1 is turned off and SW2 and SW3 are turned on, the NFC coil is connected in series with C2 to obtain an LC resonance circuit.

The NFC chip controls the charge and discharge process of the LC resonance circuit obtained by connecting the NFC coil and the C2 in series, and when the LC resonance circuit is controlled to start discharging, a signal triggering the acquisition of the peak detector is sent to the RX chip through the processor, so that the peak detector acquires the voltage peak data of the LC resonance circuit.

In an example, the peak detector detects voltage peak data of the LC resonant circuit and provides the voltage peak data to the NFC chip via the RX chip, and the NFC chip calculates a Q value according to the voltage peak data and determines whether the metal foreign object exists according to the Q value.

In another example, the peak detector detects voltage peak data of the LC resonant circuit and provides the voltage peak data to the RX chip, and the RX chip calculates a Q value from the voltage peak data and further determines whether the metallic foreign object is present according to the Q value.

Fig. 10 is a metal foreign matter detection flow chart of the metal foreign matter detection circuit shown in fig. 9, and as shown in fig. 10, the metal foreign matter detection method may include the steps of:

the implementation process of S201 to S204 is the same as the process of S101 to S104 in fig. 8, and will not be repeated here.

S205, the NFC chip controls the charge and discharge process of the LC resonance circuit, and when the LC resonance circuit starts to discharge, a voltage peak value acquisition instruction is sent to the processor.

S206, the processor sends a voltage acquisition instruction to the RX chip.

S207, the RX chip responds to the voltage peak value acquisition instruction and triggers the peak value detector to acquire voltage peak value data of the LC resonance circuit.

The step S205 to S207 of this embodiment realize that the peak detector is triggered to collect the voltage signal when the NFC chip controls the LC resonant circuit to start discharging.

In the metal foreign matter detection circuit shown in fig. 9, an NFC chip controls a charging and discharging process of an LC resonant circuit obtained by connecting an NFC coil and C2 in series, and an RX chip triggers a peak detector to collect voltage peak data. Therefore, in this embodiment, when the NFC chip controls the LC resonant circuit to start discharging, a voltage signal acquisition instruction is sent to the RX chip via the processor, and the RX chip triggers the peak detector to acquire the voltage signal of the LC resonant circuit.

S208, the peak detector sends the voltage peak data to the RX chip.

S209, power transmission is carried out between the wireless charging base and the mobile phone.

And S210, the RX chip calculates a Q value corresponding to the LC resonance circuit according to the voltage peak value data.

The process of calculating the Q value in S210 of this embodiment is the same as S107 in fig. 8, and will not be repeated here.

S211, the RX chip judges whether the Q value is smaller than or equal to a preset threshold value.

If the Q value is less than or equal to the preset threshold, S212 is performed. If the Q value is greater than the preset threshold, S214 is performed.

S212, the RX chip generates a foreign matter alarm signal.

S213, the RX chip sends an EPT packet to the wireless charging base to inform the wireless charging base of the end of charging.

And S214, the RX chip determines the charging power according to the Q value and selects the matched coil for charging.

In addition, under the condition that it is determined that no metal foreign matter exists in the position range of the NFC coil, the mobile phone will continue to detect whether the metal foreign matter exists in the position range of the WPC coil, and the detection process is the same as the corresponding process in the embodiment shown in fig. 8, which is not repeated here.

S215, after the wireless charging base and the mobile phone are in communication connection, acquiring a Q value corresponding to a coil in the base, and judging whether the Q value is smaller than a preset threshold value or not; if yes, executing S216; if not, S214 is performed.

S216, the wireless charging base alarms for foreign matters and finishes charging.

The implementation process of S211 to S216 in this embodiment is the same as that of S111 to S115 in fig. 8, and will not be repeated here.

According to the metal foreign matter detection method provided by the embodiment, the NFC chip is used for controlling the charging and discharging process of the LC resonant circuit, the RX chip is used for collecting voltage peak value data of the discharging stage of the LC resonant circuit and calculating to obtain the Q value, and whether the metal foreign matter exists is further judged according to the Q value. Therefore, the NFC chip does not need to be provided with a peak detector, and hardware cost is further reduced.

2. Calculating Q value by WPC chip (i.e. RX chip) of electronic device and judging whether metallic foreign matter exists or not according to Q value

In this embodiment, an RX chip controls a charging and discharging process of an LC resonant circuit formed by an NFC coil and a capacitor C2, calculates a Q value of the LC resonant circuit, and detects whether a metallic foreign object exists in a position range of the NFC coil.

In order to achieve the above purpose of calculating the Q value by the RX chip and judging whether the metal foreign object exists according to the Q value, the embodiment of the present application provides another metal foreign object detection circuit, in which one end of the NFC coil is connected to one pin of the NFC chip through the third switch circuit, and meanwhile, the end of the NFC coil is also connected to one pin of the RX chip through the fifth switch circuit. The other end of the NFC coil is connected with the other pin of the NFC chip through a fourth switching circuit, and meanwhile, the other end of the NFC coil is also connected with the other pin of the RX chip through a sixth switching circuit.

In an example, as shown in fig. 11, one end of the NFC coil is connected to one end of the SW11, the other end of the SW11 is connected to one pin of the NFC chip, meanwhile, this end of the NFC coil is also connected to one end of the SW13, the other end of the SW13 is connected to one end of the capacitor C2, and the other end of the C2 is connected to one pin (may be referred to as a first pin) of the RX chip. The other end of the NFC coil is connected with the other pin of the NFC coil through the SW 12. Meanwhile, this end of the NFC coil is also connected to another pin (which may be referred to as a second pin) of the RX chip through the SW 14.

In the example shown in fig. 11, the third switch circuit includes SW11, the fourth switch circuit includes SW12, the fifth switch circuit includes SW13 and a capacitor C2 connected in series, and the sixth switch circuit includes SW14.

Of course, in other embodiments, the third, fourth, fifth, and sixth switching circuits may further include two or more switches, which may be in series and/or parallel relationship, as the application is not limited in this regard.

Referring again to fig. 11, one end of the WPC coil is connected to the third pin of the RX chip after being connected in series with the capacitor C1, and the other end of the WPC coil is connected to the fourth pin of the RX chip.

An input end (which may be referred to as a first input end) of the peak detector is connected to a branch where the capacitor C2 is located, and is used for detecting a voltage peak of an LC resonant circuit formed by the NFC coil and the capacitor C2 in a discharge stage.

The other input end (which may be called a second input end) of the peak detector is connected to the branch where the capacitor C1 is located, and is used for detecting the voltage peak of the LC resonant circuit formed by the WPC coil and C1 in the discharge stage.

The peak detector may be integrated in the RX chip or may be a device independent of the RX chip, and the application is not limited to the package form of the peak detector.

In one example, SW11 and SW12 may be closed by default using depletion mode NMOS transistors. SW13 and SW14 may be off by default using enhanced NMOS transistors. The switching states of SW11 to SW14 can be controlled by the RX chip. Other types of switching devices may be used for SW11 to SW14, and the present application is not limited to the types of switching devices.

As shown in fig. 11, when SW11 and SW12 are closed, the NFC coil is connected with the NFC chip, and the NFC chip controls the NFC coil to send and receive instructions or data, so that the electronic device realizes the NFC communication function through the NFC coil and the NFC chip.

Fig. 12 is a circuit schematic diagram of the metal foreign matter detection circuit shown in fig. 11 in operation.

As shown in fig. 12, when SW11 and SW12 are off and SW13 and SW14 are on, the NFC coil is connected in series with a capacitor C2 to form an LC resonance circuit and connected to the RX chip. The RX chip controls the charge and discharge process of the LC resonance circuit, and triggers the peak detector to collect the voltage peak data of the LC resonance circuit when controlling the discharge of the LC resonance circuit. The RX chip further calculates to obtain the Q value of the LC resonant circuit according to the voltage peak value data, and finally judges whether the metal foreign matters exist according to the Q value.

The process of detecting the metallic foreign matter will be described in detail with reference to a flowchart of the metallic foreign matter detection method shown in fig. 13.

As shown in fig. 13, the metal foreign matter detection method may include the steps of:

s300, starting an RX chip of the mobile phone.

S301, communication connection is established between the wireless charging base and the mobile phone.

S302, the RX chip controls the SW11 and the SW12 to be opened, and the SW13 and the SW14 to be closed, so that the NFC coil and the capacitor C2 are connected in series to obtain an LC resonance circuit.

S303, the RX chip controls the charge and discharge process of the LC resonance circuit and triggers the peak detector to collect voltage peak data when discharge begins.

And S304, the RX chip calculates a Q value based on the voltage peak value data.

S307, the RX chip judges whether the Q value is smaller than or equal to a preset threshold value, if yes, S308 is executed; if not, S310 is performed.

S308, the RX chip generates a foreign matter alarm signal.

S309, the RX chip sends an EPT signal to the wireless charging base to end the charging.

And S310, the RX chip determines the charging power according to the Q value and selects the matched coil for charging.

In addition, when it is determined that the position range of the NFC coil does not have any metal foreign matter, the RX chip may continuously determine whether the position range of the WPC coil has any metal foreign matter, and the detection process is the same as the corresponding process in the embodiment shown in fig. 9, which is not described herein.

S311, after the wireless charging base and the mobile phone are in communication connection, acquiring a Q value corresponding to a coil in the base, and judging whether the Q value is smaller than a preset threshold value; if yes, executing S312; if not, S310 is performed.

S312, the wireless charging base alarms for foreign matters and finishes charging.

The implementation process of S311 to S3120 in this embodiment is the same as S114 to S115 in the embodiment shown in fig. 8, and will not be repeated here.

According to the metal foreign matter detection method provided by the embodiment, after the WPC chip (namely the RX chip) on the mobile phone side is started, the switch circuit is controlled to enable the NFC coil and the C2 to be connected in series to obtain the LC resonant circuit, the charging and discharging processes of the LC resonant circuit are controlled, and meanwhile the peak detector is triggered to collect voltage peak data of the LC resonant circuit in a discharging stage. The RX chip further calculates the Q value of the LC resonant circuit according to the voltage peak value data, and detects whether metal foreign matters exist in the position range of the NFC coil according to the Q value. Therefore, the scheme can accurately detect the metal foreign matters outside the WPC coil range, avoids the risk caused by overhigh temperature of the metal foreign matters due to normal charging caused by the fact that the metal foreign matters at the edge of the WPC coil are not detected, and finally improves the safety of the wireless charging process. In addition, the RX chip calculates the Q value of the LC resonant circuit and detects the metal foreign matter according to the Q value, so that software (namely processing logic) and hardware of the NFC chip are not required to be modified, the cost of modifying the NFC chip is saved, and the cost of the whole metal foreign matter detection scheme is finally reduced.

The foregoing is merely illustrative of specific embodiments of the present application, and the scope of the present application is not limited thereto, but any changes or substitutions within the technical scope of the present application should be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. The utility model provides a metal foreign matter detection circuit, its characterized in that is applied to electronic equipment, electronic equipment includes first coil and second coil, first coil is wireless charging coil, the second coil is located the periphery of first coil, metal foreign matter detection circuit includes:

the first end of the second coil is connected with the first end of the second coil control circuit through the first switch circuit, and the second end of the second coil is connected with the second end of the second coil control circuit;

the second switching circuit is connected with the first switching circuit in parallel, and comprises a first capacitor and a switch which are connected in series;

the second coil control circuit obtains voltage peak value data of the LC resonance circuit in a discharging stage, and calculates a quality factor Q value of the LC resonance circuit according to the voltage peak value data, wherein the LC resonance circuit comprises the second coil and the first capacitor which are connected in series, and the Q value is used for detecting metal foreign matters in a position range of the second coil.

2. The metallic foreign object detection circuit of claim 1, wherein the second coil is a near field communication NFC coil.

3. The metal foreign matter detection circuit according to claim 1 or 2, wherein the second switch circuit includes the first capacitor and a first switch;

the first end of the first capacitor is connected with the first end of the second coil, the second end of the first capacitor is connected with the first end of the first switch, and the second end of the first switch is connected with the first end of the second coil control circuit;

or, the first end of the first switch is connected with the first end of the second coil, the second end of the first switch is connected with the first end of the first capacitor, and the second end of the first capacitor is connected with the first end of the second coil control circuit.

4. The metal foreign matter detection circuit according to claim 1 or 2, wherein the second switching circuit includes the first capacitor, a second switch, and a third switch;

the first end of the second switch is connected with the first end of the second coil, the second end of the second switch is connected with the first end of the first capacitor, the second end of the first capacitor is connected with the first end of the third switch, and the second end of the third switch is connected with the first end of the second coil control circuit.

5. The foreign metal detection circuit of any of claims 1-4, wherein the second coil control circuit controls the LC tank circuit to charge and discharge and triggers a peak detector to collect voltage peak data of the LC tank circuit during a discharge phase.

6. The foreign metal detection circuit of any of claims 1-4, wherein the foreign metal detection circuit includes a first coil control circuit coupled to the first coil, the first coil control circuit controlling the LC tank circuit to charge and discharge and triggering a peak detector to collect peak voltage data of the LC tank circuit during a discharge phase.

7. The foreign metal detection circuit of claim 6, wherein the first coil control circuit is a wireless charging coil chip and the second coil control circuit is an NFC chip.

8. The metallic foreign object detection circuit of any of claims 1-7, wherein the metallic foreign object detection circuit includes a first coil control circuit coupled to the first coil, the first coil control circuit triggering activation of the second coil control circuit.

9. The metal foreign object detection circuit of any one of claims 1-6, wherein the metal foreign object detection circuit includes a first coil control circuit connected to the first coil, the first coil control circuit controlling the first switch circuit to open and the second switch circuit to close such that the second coil and the first capacitor are connected in series to form an LC resonant circuit;

or the second coil control circuit controls the first switch circuit to be opened and the second switch circuit to be closed, so that the second coil and the first capacitor are connected in series to form an LC resonance circuit.

10. The utility model provides a metal foreign matter detection circuit, its characterized in that is applied to electronic equipment, electronic equipment includes first coil and second coil, first coil is wireless charging coil, the second coil is located the periphery of first coil, metal foreign matter detection circuit includes:

the first coil is connected with a first coil control circuit, and the first coil control circuit is used for controlling the working state of the first coil;

the first end of the second coil is connected with the first end of the second coil control circuit through a third switch circuit, the second end of the second coil is connected with the second end of the second coil control circuit through a fourth switch circuit, and the second coil control circuit is used for controlling the working state of the second coil;

The first end of the second coil is also connected with the first end of the first coil control circuit through a fifth switch circuit, the second end of the second coil is also connected with the second end of the first coil control circuit through a sixth switch circuit, and the fifth switch circuit comprises a first capacitor and a switch which are connected in series;

the first coil control circuit obtains voltage peak value data of the LC resonance circuit in a discharging stage and a quality factor Q value calculated according to the voltage peak value data;

the first coil control circuit detects metal foreign matters in the range of the second coil according to the Q value.

11. The metallic foreign object detection circuit of claim 10, wherein the second coil is a near field communication NFC coil.

12. The metal foreign object detection circuit according to claim 10 or 11, wherein the first coil control circuit controls the LC resonance circuit obtained by connecting the second coil in series with the first capacitor to charge and discharge, and triggers a peak detector to detect voltage peak data of the LC resonance circuit during a discharge phase of the LC resonance circuit.

13. The foreign metal detection circuit of any of claims 10-12, wherein the first coil control circuit controls the three switch circuits and the fourth switch circuit to open, and controls the fifth switch circuit and the sixth switch circuit to close such that the second coil is connected in series with the first capacitor to provide an LC resonant circuit.

14. The metallic foreign object detection circuit of any of claims 10-13, wherein the first coil control circuit is a wireless charging coil chip and the second coil control circuit is an NFC chip.

15. A metal foreign matter detection method, characterized by being applied to an electronic device including the metal foreign matter detection circuit according to any one of claims 1 to 14, the method comprising:

controlling the switching state of a switching circuit connected with the second coil, so that the second coil is connected with the first capacitor in series to obtain an LC resonance circuit;

controlling the LC resonance circuit to charge and discharging after the charge is completed;

acquiring voltage peak value data of the LC resonance circuit in a discharge stage;

and calculating the quality factor Q value of the LC resonant circuit according to the voltage peak value data, and detecting the metal foreign matters in the position range of the second coil according to the Q value.

16. A wireless charging system is characterized by comprising a wireless charging base and electronic equipment;

the wireless charging base comprises a first wireless charging WPC coil and a first near field communication NFC coil, and the first NFC coil is located at the periphery of the first WPC coil;

The electronic device comprises a second WPC coil and a second NFC coil, wherein the second NFC coil is positioned at the periphery of the second WPC coil;

the wireless charging base controls the first NFC coil to emit a first NFC signal, and when the voltage value of the first NFC signal is detected to be lower than a normal voltage value, it is determined that a metal foreign object exists between the wireless charging base and the electronic equipment;

or the electronic equipment controls the second NFC coil to emit a second NFC signal, and when the voltage value of the second NFC signal is detected to be lower than a normal voltage value, it is determined that a metal foreign object exists between the electronic equipment and the wireless charging base.

17. A wireless charging dock comprising the metal foreign detection circuit of any one of claims 1-14.

18. An electronic device comprising the metal foreign matter detection circuit of any one of claims 1 to 14.

19. A chip system, comprising: at least one processor and an interface for receiving code instructions and transmitting to the at least one processor; the at least one processor executes the code instructions to implement the metallic foreign object detection method of claim 15.

20. A computer-readable storage medium having instructions stored thereon that, when executed on an electronic device, cause the electronic device to perform the metal foreign object detection method of claim 15.