A method for detecting the temperature of a wireless charging device and a wireless charging coil

Abstract

An embodiment of the present application includes a wireless charging device, which relates to the field of wireless charging and includes a wireless charging circuit and a temperature detector; wherein, the wireless charging circuit is used to rectify the induced current generated by the wireless charging coil and output a DC charging current; the temperature detector is used to obtain a first voltage at both ends of the wireless charging coil, obtain a first current flowing through the wireless charging coil, and determine the temperature corresponding to the wireless charging coil according to the first voltage and the first current; wherein, the first voltage is a DC voltage or a low-frequency AC voltage, and the first current is a DC current or a low-frequency AC current; in this way, the temperature corresponding to the wireless charging coil can be directly calculated based on the inherent characteristics of the wireless charging coil, so that the temperature of the induction coil inside the terminal can be monitored more accurately and in a timely manner, improving the safety and reliability of the charging device.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of wireless charging, and in particular, to a temperature detection method for a wireless charging device and a wireless charging coil. Background Art

[0002] Wireless charging technology has been gradually popularized in terminal electronic products. Its working principle is that a transmitting coil is encapsulated in a wireless charger, and an alternating current with a certain frequency passes through the transmitting coil. The terminal includes a receiving coil inside. The receiving coil generates current through electromagnetic induction, and after rectifying the induced current, it is provided to the terminal device, thereby realizing the charging process of the terminal power supply. Therefore, wireless charging technology is a technology that provides the induced current generated by a wireless charging coil to the power supply device of the terminal to complete the charging of the power supply.

[0003] In order to achieve fast charging of the terminal, the charging power will be getting higher and higher, and it may reach more than 100w in the future. In high-power charging scenarios, the temperature of the receiving coil will be getting higher and higher. Since the charging coil is usually mounted on the battery area of the terminal, when the coil temperature is too high, there will be reliability risks and even damage to the terminal components. Therefore, accurately obtaining the temperature of the charging coil on the terminal side has become an important basis for designing the protection strategy of the terminal device. The existing temperature measurement method is: a thermistor is mounted around the wireless charging coil, and the negative temperature coefficient of the thermistor is used to calculate the temperature. Specifically, the thermistor senses the temperature change of the wireless charging coil through heat radiation or heat conduction, and calculates the current temperature by inversely calculating according to the change of the thermistor resistance value.

[0004] This method indirectly calculates the coil temperature by the change of the thermistor resistance value. In fact, due to the loss of temperature during the heat conduction process, the environment where the thermistor is located is not the same as the environment around the coil. Coupled with the interference of the operation of other components, the calculated temperature has a large difference from the actual temperature of the coil. At the same time, heat radiation or heat conduction requires transmission time, and this method of measuring temperature will cause a time delay in the calculated temperature and a poor temperature perception ability. Therefore, how to more accurately and efficiently monitor the temperature of the induction coil inside the terminal has become an urgent problem to be solved. Summary of the Invention

[0005] The embodiments of the present application provide a temperature detection method for a wireless charging device and a wireless charging coil, which is used to more accurately and timely monitor the temperature of the induction coil inside the terminal.

[0006] In the first aspect of the embodiments of the present application, a wireless charging device is provided, including: a wireless charging circuit and a temperature detector. Among them, the wireless charging circuit receives the induced current generated by the wireless charging coil, rectifies the induced current, and then outputs a DC charging current to charge the battery in the electronic device. The temperature detector calculates the corresponding temperature by obtaining the first voltage across the two ends of the wireless charging coil and the first current flowing through the wireless charging coil; therefore, the temperature detector is a circuit that realizes temperature detection by converting voltage and current to temperature, rather than a traditional temperature detector. It can be understood that the first voltage obtained by the temperature detector is a DC voltage or a low-frequency AC voltage, and the first current obtained is a DC current or a low-frequency AC current, so that the temperature corresponding to the wireless charging coil can be calculated according to the first voltage and the first current.

[0007] The wireless charging device provided by the embodiments of the present application can calculate the temperature corresponding to the wireless charging coil according to the first voltage across the two ends of the wireless charging coil and the first current flowing through the wireless charging coil obtained. In this way, the temperature corresponding to the wireless charging coil can be directly calculated according to the inherent characteristics of the wireless charging coil, and the real state of the wireless charging coil can be obtained more timely, so that the temperature of the induction coil inside the electronic device can be monitored more accurately and timely, so as to provide timely safety protection measures for it later, and improve the safety and reliability of the charging device.

[0008] Combined with the first aspect of the embodiments of the present application, in the first implementation manner of the first aspect of the embodiments of the present application: It can be understood that the temperature detector includes a detection module and a temperature operation module. The temperature operation module will determine the DC impedance of the wireless charging coil according to the first voltage and the first current, and then determine the temperature of the coil according to the change of its DC impedance, so as to accurately and timely monitor the temperature of the wireless charging coil. Optionally, the temperature operation module includes at least one of an analog circuit, a digital logic circuit, or a processor, wherein the processor can run software to execute the operation.

[0009] Combined with the first implementation manner of the first aspect of the embodiments of the present application, in the second implementation manner of the first aspect of the embodiments of the present application: For the material of the wireless charging coil, the DC impedance of the metal will change with the change of temperature, and the temperature coefficient of resistance is a physical quantity used to reflect the ability of the metal's DC impedance to change with temperature, that is, when the temperature of the metal changes by 1 degree Celsius, the relative change amount of the resistance value; in this way, the temperature detection module can determine the change of the DC impedance of the wireless charging coil in real time according to the first voltage and the first current, and then calculate the temperature change amount according to the change, so as to determine the corresponding temperature.

[0010] In this embodiment, the corresponding temperature can be determined directly according to the change in the DC impedance of the wireless charging coil, enabling more timely monitoring of the corresponding temperature. There is no need for other separate temperature detection devices to measure the temperature independently. Instead, only the voltage across the wireless charging coil and the current flowing through the wireless charging coil need to be measured, making the operation more convenient.

[0011] Combined with the first aspect to the second implementation manner of the first aspect of the embodiments of the present application, in the third implementation manner of the first aspect of the embodiments of the present application: The temperature detector may include a voltage detection module and a current detection module. Among them, the voltage detection module is used to measure the first voltage across the wireless charging coil; while the current detection module needs to provide a conduction loop for the wireless charging coil, generate the first current on the loop, and measure the first current at the same time. Through the first voltage measured by the voltage detection module and the first current measured by the current detection module, the corresponding DC impedance can be directly determined, providing conditions for calculating the temperature of the wireless charging coil.

[0012] Combined with the third implementation manner of the first aspect of the embodiments of the present application, in the fourth implementation manner of the first aspect of the embodiments of the present application: It can be understood that the wireless charging device further includes a capacitor. One end of the wireless charging coil is connected to the first input terminal of the wireless charging module through the capacitor, and the second end of the wireless charging coil is connected to the second input terminal of the wireless charging module.

[0013] Combined with the third implementation manner or the fourth implementation manner of the first aspect of the embodiments of the present application, in the fifth implementation manner of the first aspect of the embodiments of the present application: The current detection module in the wireless charging device may further include a DC power supply that directly provides direct current to the wireless charging coil to generate the first current flowing through the wireless charging coil.

[0014] Combined with the third implementation manner or the sixth implementation manner of the first aspect of the embodiments of the present application, in the seventh implementation manner of the first aspect of the embodiments of the present application: The wireless charging device further includes at least one inductor connected between the current detection module and the wireless charging coil. Its function is to block the high-frequency alternating current on the conduction loop, enabling the current detection module to detect the direct current or low-frequency alternating current flowing through the wireless charging coil, facilitating obtaining the DC impedance of the wireless charging coil.

[0015] Combined with the third implementation manner or the sixth implementation manner of the first aspect of the embodiments of the present application, in the seventh implementation manner of the first aspect of the embodiments of the present application: A filter is further included and connected to the voltage detection module. When the voltage detection module detects the voltage across the wireless charging coil, it is used to filter the voltage across the wireless charging coil, and then obtain the corresponding DC voltage or low-frequency alternating current voltage, thereby obtaining the DC impedance of the wireless charging coil.

[0016] Combined with the first to the seventh implementation manners of the first aspect of the embodiments of the present application, in the eighth implementation manner of the first aspect of the embodiments of the present application: The wireless charging device may include the wireless charging coil.

[0017] The second aspect of the embodiments of the present application provides a method for detecting the temperature of a wireless charging coil, including: The process of wireless charging is that the wireless charging coil and an external coil generate an induced current through electromagnetic induction and magnetoelectric induction, and then the wireless charging circuit receives the induced current, rectifies the induced current, and outputs a direct current charging current to the power supply that needs to be charged; To measure the temperature of the wireless charging coil, first obtain the direct current voltage or low-frequency alternating current voltage at both ends of the wireless charging coil; Then obtain the direct current or low-frequency alternating current flowing through the wireless charging coil, and then determine the temperature corresponding to the wireless charging coil according to the obtained current and voltage.

[0018] When using this method to measure the temperature of the wireless charging coil, the system does not need to directly measure the temperature of the wireless charging coil, but calculates the corresponding temperature according to the current and voltage corresponding to the wireless charging coil. In this way, the corresponding temperature can be monitored more timely; Only by measuring the voltage at both ends of the wireless charging coil and the current flowing through the wireless charging coil to obtain the corresponding temperature, the operation is more convenient.

[0019] Combined with the second aspect of the embodiments of the present application, in the first implementation manner of the second aspect of the embodiments of the present application: Specifically, first determine the direct current impedance of the wireless charging coil according to the direct current voltage or low-frequency alternating current voltage at both ends of the wireless charging coil, and the direct current or low-frequency alternating current flowing through the wireless charging coil; Then determine the temperature according to the direct current impedance.

[0020] Due to the material of the wireless charging coil, usually the direct current impedance of metal will change with the change of temperature. Therefore, the change amount of temperature can be inversely calculated through the change of the direct current impedance corresponding to the wireless charging coil, so as to determine the temperature corresponding to the wireless charging coil. In this way, the real state of the wireless charging coil can be obtained more timely, and thus the temperature of the induction coil inside the terminal can be monitored more accurately and timely, so as to provide timely safety protection measures for it later and improve the safety and reliability of the charging device.

[0021] The third aspect of the embodiments of the present application provides an electronic device, including the wireless charging device described in the first aspect or any of its implementation manners, and a battery to be wirelessly charged.

[0022] Optionally, the electronic device is a terminal.

[0023] In the technical solution provided by the embodiment of the present application, the temperature detector first needs to obtain the first voltage across the wireless charging coil and the first current flowing through the wireless charging coil, and then calculate the temperature corresponding to the wireless charging coil according to the first current and the first voltage. In this way, the temperature corresponding to the wireless charging coil can be directly calculated based on the inherent characteristics of the wireless charging coil, and the true state of the wireless charging coil can be obtained more timely, so that the temperature of the induction coil inside the electronic device can be monitored more accurately and timely, so as to provide timely safety protection measures for it later and improve the safety and reliability of the charging device. Description of the Drawings

[0024] Figure 1 It is an impedance-temperature curve graph of a wireless charging coil provided by an embodiment of the present application;

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

[0026] Figure 3 It is a schematic structural diagram of another wireless charging device provided by an embodiment of the present application;

[0027] Figure 4 It is a schematic flow diagram of a temperature detection method for a wireless charging coil provided by an embodiment of the present application. Detailed Embodiment

[0028] The embodiment of the present application provides a temperature detection method for a wireless charging device and a wireless charging coil, which is used to more accurately and timely monitor the temperature of the induction coil inside the electronic device.

[0029] Wireless charging technology uses the principles of electromagnetic induction and magnetoelectric induction to charge. Its principle is similar to that of a transformer. There is a coil at each of the transmitting end and the receiving end. The transmitting end coil is connected to an AC power supply to generate an electromagnetic signal, and the receiving end coil induces the electromagnetic signal of the transmitting end to generate an induced current, and then rectifies the induced current to output a charging current, thus completing the charging process of the battery. As a technology that uses electromagnetic conversion to transmit energy, wireless charging technology will be limited by distance and conversion efficiency. Among them, the farther the distance of wireless power transmission, the greater the power loss, and it will cause higher energy consumption of the device; at the same time, the conversion efficiency of this technology is low, and its charging speed and charging efficiency are also relatively slow. In order to improve the charging speed of wireless charging, the future charging power will be higher and higher, and may reach more than 100w. In high-power charging scenarios, the temperature of the charging coil will remain at a relatively high level. Generally, an electronic device, such as a terminal as the receiving end, usually includes a charging coil mounted in the battery area and isolated by a protective film in the middle.

[0030] During the charging process of an electronic device, the charging coil will generate a temperature rise, which will not only affect the charging coil itself, but also have an impact on the battery and other components. When the temperature of the charging coil is too high, reliability risks will occur, and even other components may be damaged. Therefore, it is necessary to obtain the temperature of the charging coil in real time and specify corresponding protection measures according to this temperature. Therefore, it has become an urgent problem to obtain the temperature of the charging coil on the receiving end side in a timely and accurate manner; the traditional technology of using a thermistor to measure the temperature of a wireless charging coil has many defects, which can be specifically referred to in the background technology introduction. In view of this, the embodiments of the present application mainly utilize the relationship between the resistivity of a metal and temperature to measure the temperature of a wireless charging coil.

[0031] The material of a wireless charging coil is usually a metal. The resistivity of a metal is a physical quantity used to represent the resistance characteristics of various substances. It reflects the property of a metal's hindrance to the flow of current. It is related to the type of metal and is also affected by temperature. The temperature coefficient of resistance represents the relative change in the resistance value of a metal when its temperature changes by 1 degree Celsius. That is, a DC or low-frequency current path can be set for the wireless charging coil, and the DC impedance of the wireless charging coil can be determined by measuring the voltage and current of the low-frequency path. Then, based on the temperature coefficient of resistance of the wireless charging coil, the change in DC impedance can be calculated, and the true temperature of the coil can be inversely calculated and provided to the charging system. In this way, parameters for reliability safety protection measures can be input, and the reliability protection accuracy of the system can be improved.

[0032] Exemplarily, the temperature coefficient of resistance of a wireless charging coil can be obtained in the following way. At a constant room temperature of 25°, the impedance value R0 of the wireless charging coil is obtained by the method of measuring current under pressure, and an impedance-temperature curve is plotted to obtain the temperature coefficient of resistance. Figure 1 An impedance-temperature curve graph of a wireless charging coil is provided, as Figure 1 shown. The material of this wireless charging coil is copper. First, the DC impedance of this wireless charging coil is measured in different temperature environments, and then the coordinates regarding impedance and temperature are determined. Then, curve fitting is performed on multiple points to obtain the temperature coefficient of resistance. It can be understood that in the Figure 1 shown impedance-temperature curve graph, it is a linear fitting, that is, the wireless charging coil has a stable temperature coefficient of resistance, which is the slope of this straight line. When the temperature coefficient of resistance of the wireless charging coil is obtained, its corresponding temperature can be inversely calculated.

[0033] Figure 2 The following is a schematic structural diagram of a wireless charging device provided by an embodiment of the present application. This wireless charging device is included in an electronic device, and the electronic device is taken as an example of a terminal for subsequent introduction. In addition to including the Figure 2 shown wireless charging device, this terminal also includes a battery, a screen, an antenna, a sensor, and other necessary functional circuits, which will not be elaborated in this embodiment. AsFigure 2 As shown, the wireless charging device can be the receiving device PRX; and the receiving device PRX includes a wireless charging coil L2, a wireless charging circuit, and a temperature detector. Among them, the temperature detector further includes a voltage measurement module, a current measurement module, and a temperature calculation module. The receiving device PTX receives the electromagnetic signal sent by the transmitting end PTX of the wireless charging, and the transmitting end PTX can generate a current in its internal transmitting coil to form the electromagnetic signal. Through the principle of electromagnetic induction, the receiving device PRX converts the electromagnetic signal into a charging signal, such as a current.

[0034] Among them, the first end (A4 end) of the wireless charging coil L2 is connected to one end of the wireless charging circuit through a capacitor C, and the second end (A3 end) of the wireless charging coil L2 is connected to the other end of the wireless charging circuit; the first end (A4 end) of the wireless charging coil L2 is connected to the A1 end of the voltage detection module in the temperature detector, and the second end (A3 end) of the wireless charging coil L2 is connected to the A1 end of the voltage detection module in the temperature detector; the first end (A4 end) of the wireless charging coil L2 is connected to the input end of the current detection module in the temperature detector through an inductor, and the other end of the current detection module is grounded; inside the temperature detector, the voltage detection module and the current detection module are respectively connected to the temperature calculation module to provide detection data for the temperature calculation module.

[0035] It can be understood that the wireless charging coil L2 is used to receive the electromagnetic signal sent by the charging coil L1 in the transmitting device PTX and generate an induced current through the electromagnetic induction phenomenon; the capacitor C is used for energy storage and supplies power to the wireless charging circuit; and the wireless charging circuit is used to rectify the induced current generated by the wireless charging coil L2 and then output a direct current charging current to the battery of the terminal; the inductor is used to block the high-frequency alternating current flowing into the current detection module from the wireless charging coil L2; in the temperature detector, the current detection module is used to provide a direct current or low-frequency alternating current path for the wireless charging coil L2 and measure the direct current or low-frequency alternating current flowing through the wireless charging coil L2 on this path; and the voltage detection module in the temperature detector is used to detect the direct current voltage or low-frequency alternating current voltage across the wireless charging coil L2; the temperature calculation module in the temperature detector is used to receive the data provided by the voltage detection module and the current detection module and then calculate based on this data to determine the temperature corresponding to the wireless charging coil L2.

[0036] Exemplarily, the working process of the receiving device PRX can be: a high-frequency alternating current is passed through the charging coil L1 in the transmitting device PTX, electromagnetic induction and magnetoelectric induction phenomena occur with the wireless charging coil L2, the wireless charging coil L2 immediately generates an induced current, and the induced current is input to the wireless charging circuit through the capacitor C, and the wireless charging circuit rectifies it and provides a direct current charging current to the battery of the terminal.

[0037] Among them, the wireless charging circuit can be a rectifying circuit, whose function can be to convert the alternating current generated by the wireless charging coil into unidirectional pulsed direct current. The rectifying circuit is mainly composed of rectifying diodes and can include a half-wave rectifying circuit, a full-wave rectifying circuit or a bridge rectifying circuit, and the specific form is not limited.

[0038] When determining the temperature of the wireless charging coil L2, one end of the current detection device is connected to one end of the wireless charging coil L2 through an inductor, and the other end is grounded. In this way, when the current detection module is turned on, the current detection module provides a direct current or low-frequency alternating current path for the wireless charging coil L2, and extracts the direct current or low-frequency alternating current Is in the wireless charging circuit; among them, the path of Is is from the wireless charging circuit to the A3 end of the wireless charging coil L2, through the wireless charging coil L2 to the A4 end, and then flows into the current detection module through the inductor, and finally to the ground, forming a complete closed loop; the current detection module measures is to obtain the current value of the first current.

[0039] Then, the voltage detection module measures the first voltage across the wireless charging coil L2. It can be understood that the first voltage is also a direct current voltage or a low-frequency alternating current voltage and corresponds to the direct current or low-frequency alternating current. Exemplarily, the voltage detection module can be connected to the wireless charging coil L2 through a filter and then measure to obtain the voltage value of the first voltage.

[0040] After determining the current value of the first current and the voltage value of the first voltage, the voltage detection module and the current detection module transmit the data to the temperature calculation module; among them, the calculation module can include at least one of an analog circuit, a digital logic circuit or a processor. Among them, the processor can run software to perform the following calculations. The processor includes but is not limited to a central processing unit (CPU), a neural network processing unit (NPU), an application processor (AP), a modulation and demodulation processor, a graphics processing unit (GPU), a controller, a video codec, a digital signal processor (DSP) or a baseband processor.

[0041] Exemplarily, the temperature detection module first determines the DC impedance of the wireless charging coil L2 according to the current value of the first current and the voltage value of the first voltage. For example, it is calculated according to the formula R = V / I, where R is the DC impedance, V is the voltage value of the first voltage, and I is the current value of the first current.

[0042] After determining the DC impedance of the wireless charging coil L2, the temperature detection module can determine the corresponding temperature based on a stored impedance-temperature table. The impedance-temperature table is a table of DC impedance and temperature plotted based on the resistance temperature coefficient of the wireless charging coil L2. The temperature detection module can also directly calculate the temperature based on the resistance temperature coefficient η of the wireless charging coil L2. For example, the temperature can be inversely calculated using the formula R=R0*[1+η*(T-25)], where R is the measured current DC impedance, R0 is the DC impedance corresponding to the wireless charging coil L2 at 25 degrees, and T is the current temperature to be determined. It can be understood that the above formula can be used to obtain T=25+(R-R0) / (R0*η). That is, the DC impedance R of the wireless charging coil L2 determined by the temperature calculation module can be substituted into this formula to obtain the temperature corresponding to the wireless charging coil L2.

[0043] It is understandable that since it is necessary to obtain the temperature of the charging coil in a timely manner and specify corresponding protection measures based on the temperature, for example, the system can set a detection cycle, detect and calculate the temperature of the wireless charging coil L2 once in each cycle, and provide timely and effective feedback on the temperature of the wireless charging coil L2.

[0044] In the technical solution provided in this embodiment, the temperature detector first needs to obtain a first voltage across the wireless charging coil and a first current flowing through the wireless charging coil, and then calculate the temperature corresponding to the wireless charging coil based on the first current and the first voltage. In this way, the corresponding temperature can be calculated directly based on the inherent characteristics of the wireless charging coil, and the true state of the wireless charging coil can be obtained more promptly, thereby enabling more accurate and timely monitoring of the temperature of the induction coil inside the terminal, so as to subsequently provide timely safety protection measures for it, thereby improving the safety and reliability of the charging device.

[0045] Figure 3 A schematic diagram of the structure of another wireless charging device provided in an embodiment of the present application is shown in FIG. Figure 3 As shown, similar to Figure 2 The wireless charging device also includes a receiving device PRX, which includes a wireless charging coil L2, a wireless charging circuit, and a temperature detector. The temperature detector also includes a voltage measurement module, a current measurement module, and a temperature calculation module. The current measurement module also includes a DC power supply.

[0046] Among them, the first end (A4 end) of the wireless charging coil L2 is connected to one end of the wireless charging circuit through the capacitor C, and the second end (A3 end) of the wireless charging coil L2 is connected to the other end of the wireless charging circuit. It can be understood that Figure 3 The wireless charging circuit is not shown in the figure, but its equivalent resistance R is given. LAlternatively, the first end (terminal A4) of the wireless charging coil L2 is connected to one end of the voltage detection module in the temperature detector through a filter, and the second end (terminal A3) of the wireless charging coil L2 is connected to the other end of the voltage detection module in the temperature detector through a filter; the first end (terminal A4) of the wireless charging coil L2 is connected to terminal A1 of the current detection module in the temperature detector through an inductor L3, and the second end (terminal A3) of the wireless charging coil L2 is connected to terminal A2 of the current detection module in the temperature detector through an inductor L4; inside the temperature detector, the voltage detection module and the current detection module are respectively connected to the temperature calculation module to provide detection data for the temperature calculation module.

[0047] It can be understood that the wireless charging coil L2 is used to receive the electromagnetic signal transmitted by the charging coil L1 in the transmitting device PTX and generate an induced current through the electromagnetic induction phenomenon; the capacitor C is used for energy storage and power supply to the wireless charging circuit; and the wireless charging circuit is used to rectify the induced current generated by the wireless charging coil L2 and then output a DC charging current to the battery of the terminal; the inductor is used to block the high-frequency alternating current on the current loop corresponding to the wireless charging coil L2 and the current detection module; the filter is used to filter the high-frequency alternating voltage across the wireless charging coil L2 to generate a DC voltage or a low-frequency alternating voltage; in the temperature detector, the current detection module is used to provide a DC or low-frequency alternating current path for the wireless charging coil L2 and measure the DC current or low-frequency alternating current flowing through the wireless charging coil L2 on this path; and the voltage detection module in the temperature detector is used to detect the DC voltage or low-frequency alternating voltage across the wireless charging coil L2; the temperature calculation module in the temperature detector is used to receive the data provided by the voltage detection module and the current detection module and then calculate based on this data to determine the temperature corresponding to the wireless charging coil L2.

[0048] Exemplarily, the working process of the receiving device PRX can be as follows: a high-frequency alternating current is passed through the charging coil L1 in the transmitting device PTX, electromagnetic induction and magnetoelectric induction phenomena occur with the wireless charging coil L2, and the wireless charging coil L2 immediately generates an induced current. The induced current is input to the wireless charging circuit through the capacitor C, and the wireless charging circuit rectifies it and provides a DC charging current to the power supply to be charged, such as the battery.

[0049] When determining the temperature of the wireless charging coil L2, the current detection module includes a DC power supply, which can be a DC current source or a DC voltage source, and the specific form is not limited. Terminal A1 of the current detection module is connected to terminal A4 of the wireless charging coil L2 through the inductor L3, and terminal A2 of the current detection module is connected to terminal A3 of the wireless charging coil L2 through the inductor L4. In this way, when the current detection module is turned on, the current detection module does not need to extract current from the wireless charging circuit, but instead directly provides an independent DC or low-frequency AC path for the wireless charging coil L2. The DC power supply in the current detection module provides DC power for this path. The current Is can flow from terminal A1 of the current detection module through the inductor L3 to terminal A4 of the wireless charging coil L2, and then through terminal A3 of the wireless charging coil L2 through the inductor L4 to terminal A2 of the current detection module, forming a complete closed loop. The current detection module measures Is to obtain the current value of the first current.

[0050] Then, the voltage detection module measures the first voltage across the wireless charging coil L2. It will be understood that the first voltage is also a DC voltage or a low-frequency AC voltage, and corresponds to a DC current or a low-frequency AC current. Exemplarily, the first end (end A4) of the wireless charging coil L2 is connected to one end of the voltage detection module through a filter, and the second end (end A3) of the wireless charging coil L2 is connected to the other end of the voltage detection module through a filter to measure the voltage value of the first voltage.

[0051] The filter can be a filter circuit composed of capacitors and resistors, which can effectively filter out frequencies at or outside a specific frequency point. In this embodiment, the main function of the filter is to minimize the high-frequency AC voltage in the DC voltage, and its specific circuit form is not limited.

[0052] After determining the current value of the first current and the voltage value of the first voltage, the voltage detection module and the current detection module transmit the data to the temperature calculation module. For example, the temperature detection module first determines the DC impedance of the wireless charging coil L2 according to the current value of the first current and the voltage value of the first voltage, and then determines the temperature according to the DC impedance and the resistance temperature coefficient corresponding to the wireless charging coil. The specific method is the same as Figure 2 The manner of determining the temperature in the illustrated embodiment is similar and will not be described in detail here.

[0053] In the technical solution provided by this embodiment, the current detection module in the temperature detector directly provides an independent DC or low-frequency AC path for the wireless charging coil. By obtaining the first current on this path and the first voltage across the wireless charging coil corresponding to the first current, the temperature corresponding to the wireless charging coil is calculated. In this way, the temperature corresponding to the wireless charging coil can be directly calculated based on the inherent characteristics of the wireless charging coil, and the true state of the wireless charging coil can be obtained more timely. Thus, the temperature of the induction coil inside the terminal can be monitored more accurately and timely, so as to provide timely safety protection measures for it later and improve the safety and reliability of the charging device.

[0054] Figure 4 As shown in the flowchart of a method for detecting the temperature of a wireless charging coil provided by an embodiment of the present application, Figure 4 as shown, the method includes:

[0055] 401. Rectify the induced current generated by the wireless charging coil using a wireless charging circuit and output a DC charging current. Exemplarily, a high-frequency alternating current is passed through the wireless charging coil in the transmitting device, electromagnetic induction and magnetoelectric induction phenomena occur with the transmitting coil in the receiving device, an induced current is generated, and the induced current is input to the wireless charging circuit through a capacitor. The wireless charging circuit rectifies the induced current generated by the wireless charging coil in the receiving device and provides a DC charging current to the power supply to be charged, such as a battery.

[0056] 402. Obtain the first voltage across the wireless charging coil. Then, the receiving device provides a DC path or a low-frequency AC path for the wireless charging coil, and then obtains the DC voltage or low-frequency AC voltage across the wireless charging coil and measures it to obtain the voltage value of the first voltage.

[0057] 403. Obtain the first current flowing through the wireless charging coil. Then, obtain the corresponding DC current and low-frequency AC current flowing through the wireless charging coil. It can be understood that the DC current corresponds to the DC voltage, and the low-frequency AC current corresponds to the low-frequency AC voltage, so as to obtain the current value of the first current of the wireless charging coil.

[0058] 404. Determine the DC impedance of the wireless charging coil according to the first voltage and the first current. After determining the current value of the first current and the voltage value of the first voltage, it is necessary to calculate the DC impedance according to these values; Exemplarily, the receiving device first determines the DC impedance of the wireless charging coil according to the current value of the first current and the voltage value of the first voltage. For example, it is calculated according to the formula R = V / I, where R is the DC impedance, V is the voltage value of the first voltage, and I is the current value of the first current.

[0059] 405. Determine the temperature based on the DC impedance. After determining the DC impedance of the wireless charging coil, the receiving device can determine the corresponding temperature according to the stored impedance-temperature correspondence table, where the impedance-temperature correspondence table is a correspondence table of DC impedance and temperature drawn based on the temperature coefficient of resistance of the wireless charging coil; it can also directly perform temperature calculation according to the temperature coefficient of resistance η of the wireless charging coil. For example, the temperature can be calculated inversely using the formula R = R0 * [1 + η * (T - 25)], where R is the currently measured DC impedance, R0 is the DC impedance corresponding to the wireless charging coil at 25 degrees, and T is the currently to-be-determined temperature value; it can be understood that according to the above formula, T = 25 + (R - R0) / (R0 * η) can be obtained, that is, according to this formula, the DC impedance R of the wireless charging coil determined by the temperature calculation module can be substituted to obtain the corresponding temperature of the wireless charging coil.

[0060] The embodiment of the present application further provides an electronic device, including Figure 3 or Figure 4 the wireless charging device shown in any one of the embodiments, and a battery to be wirelessly charged. Optionally, the electronic device is a terminal.

[0061] The above has introduced in detail the wireless charging device and the temperature detection method of the wireless charging coil provided by the embodiments of the present application. Specific examples are used herein to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A wireless charging device, characterized in that, Comprising: A wireless charging circuit for rectifying the induced current generated by a wireless charging coil and outputting a DC charging current; A temperature detector for obtaining a first voltage across the two ends of the wireless charging coil, obtaining a first current flowing through the wireless charging coil, and determining the temperature corresponding to the wireless charging coil according to the first voltage and the first current; wherein, the first voltage is a DC voltage or a low-frequency AC voltage, the first current is a DC current or a low-frequency AC current, and the first voltage and the first current are inherent characteristics of the wireless charging coil; The temperature detector includes a current detection module; The current detection module is used to provide a DC or low-frequency AC path for the wireless charging coil, generate and measure the first current; The temperature detector further includes a temperature calculation module; The temperature calculation module is used to determine the DC impedance of the wireless charging coil according to the first voltage and the first current; and determine the temperature according to the DC impedance.

2. The device according to claim 1, characterized in that, The temperature detection module is specifically used for: determining the temperature according to the relationship between the DC impedance and the resistance temperature coefficient of the wireless charging coil.

3. The device according to claim 1, characterized in that, The temperature detector further includes: A voltage detection module for measuring the first voltage.

4. The device according to claim 3, characterized in that, It further includes a capacitor; the first end of the two ends is connected to the first input end of the wireless charging circuit through the capacitor, and the second end of the two ends is connected to the second input end of the wireless charging circuit.

5. The device according to claim 3 or 4, characterized in that, The current detection module further includes: a current source for generating the first current.

6. The device according to any one of claims 1 to 4, characterized in that, It further includes an inductor connected to the current detection module for blocking the high-frequency AC current flowing from the wireless charging coil into the current detection module.

7. The device according to claim 3 or 4, characterized in that, It further includes a filter connected to the voltage detection module for filtering the voltage across the two ends to obtain the first voltage.

8. The device according to any one of claims 1 to 4, characterized in that, It further includes the wireless charging coil.

9. A temperature detection method for a wireless charging coil, characterized in that, The method includes: Rectifying the induced current generated by the wireless charging coil by using the wireless charging circuit and outputting a DC charging current; Obtaining a first voltage across the two ends of the wireless charging coil, where the first voltage is a DC voltage or a low-frequency AC voltage; Obtaining a first current flowing through the wireless charging coil by using the current detection module in the temperature detector, where the first current is a DC current or a low-frequency AC current, the current detection module is used to provide a DC or low-frequency AC path for the wireless charging coil, generate and measure the first current, and the first voltage and the first current are inherent characteristics of the wireless charging coil; Determining the temperature corresponding to the wireless charging coil according to the first voltage and the first current; The determining the temperature corresponding to the wireless charging coil according to the first voltage and the first current includes: Determining the DC impedance of the wireless charging coil according to the first voltage and the first current; Determining the temperature according to the DC impedance.

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