Charging circuit, chip and electronic equipment

Abstract

The invention relates to the technical field of wireless charging, in particular to a charging circuit, a chip and electronic equipment. The charging circuit acquires a voltage signal of a transmitting coil used for wireless charging in power supply equipment, and compares the acquired voltage signal with an analog reference signal to obtain a comparison signal. The charging circuit may then determine whether a metallic foreign matter is present within the magnetic field range of the transmit coil based on the pulse width of the comparison signal. In this way, the charging circuit can detect whether the metal foreign matter exists between the power supply equipment and the electric equipment or not without obtaining the power of the receiving coil in the electric equipment, and the metal foreign matter detection speed can be increased.

Description

Technical Field

[0001] The present application relates to the field of wireless charging technology, and in particular to a charging circuit, a chip and an electronic device. Background Art

[0002] Wireless charging refers to a charging method that uses electromagnetic fields to transfer energy between power supply equipment and power consumption equipment. When metal foreign objects enter the magnetic field generated by the transmitting coil of the power supply equipment and the receiving coil of the power consumption equipment, they will generate heat due to the eddy current effect. The heating of metal foreign objects will not only increase the transmission loss in the wireless charging circuit, but also cause serious safety hazards to the operation of the wireless charging circuit. Therefore, it is necessary to perform foreign object detection (FOD) on the wireless charging system.

[0003] At present, the power loss (PLOSS) detection method defined by the Qi standard (a wireless charging standard) is usually used to determine whether there is a metal foreign object between the power supply device and the power-consuming device. PLOSS detection detects the transmission power of the power supply device and the receiving power of the power-consuming device to obtain the power loss in the process of energy being transmitted from the power supply device to the power-consuming device, and determines the presence of foreign matter in the wireless charging circuit when the power loss exceeds a threshold. During the PLOSS detection process, the power-consuming device is required to first determine the receiving power of the power-consuming device and send the determined receiving power to the power supply device, and then the power supply device determines the power loss and whether there is a foreign object. In this way, the power supply device and the power-consuming device need to exchange data, which results in a long time and low efficiency in determining whether there is a foreign object in the wireless charging circuit through PLOSS detection. Summary of the invention

[0004] In view of this, the present application provides a charging circuit, a chip and an electronic device.

[0005] In a first aspect, the present application provides a charging circuit, including a control unit, a first inverter unit and a first sampling unit, wherein the control unit is connected to the first inverter unit and the first sampling unit; and the first inverter unit is used to output a first AC signal to the first wireless charging coil; the first sampling unit is used to collect a first voltage signal of the first wireless charging coil, compare the first voltage signal with a first analog reference signal to obtain a first comparison signal, and output the first comparison signal to the control unit; the control unit is used to send a first control signal to the first inverter unit, the first control signal is used to instruct the first inverter unit to convert the first DC signal received by the first inverter unit into a first AC signal, and the control unit is also used to determine whether there is a metal foreign object in the magnetic field range of the first wireless charging coil based on the first comparison signal.

[0006] In the above charging circuit, the control unit can collect the first voltage signal (e.g., coil voltage signal hereinafter) of the first wireless charging coil (e.g., the transmitting coil hereinafter) based on the first sampling unit, and obtain the first comparison signal after comparing the first voltage signal with the first analog reference signal to determine whether there is a metal foreign object within the magnetic field range of the first wireless charging coil. In this way, the control unit does not need to determine whether there is a metal foreign object within the magnetic field range of the first wireless charging coil by obtaining the power received by the receiving coil in the electrical device that is charged by receiving the electromagnetic field of the first wireless charging coil, which reduces the communication process between the control unit and the electrical device (e.g., the receiving chip in the electrical device), which is conducive to improving the speed at which the wireless charging circuit detects whether there is a metal foreign object within the magnetic field range of the first wireless charging coil.

[0007] In a possible implementation of the first aspect above, the control unit is further used to output a second control signal to the first inverter unit when it is determined that there is a metal foreign object within the magnetic field range of the first wireless charging coil, wherein the second control signal is used to instruct the first inverter unit to stop outputting the first AC signal to the first wireless charging coil.

[0008] In this implementation, the control unit may stop charging the electrical device through the first wireless charging coil when it is determined that there is a metal foreign object within the magnetic field range of the first wireless charging coil, thereby avoiding abnormalities in the charging circuit caused by the metal foreign object and avoiding safety hazards.

[0009] In a possible implementation of the first aspect, the charging circuit further includes a second inverter unit and a second sampling unit, wherein the control unit is connected to the second inverter unit and the second sampling unit; and the second inverter unit is used to output a second AC signal to the second wireless charging coil; the second sampling unit is used to collect a second voltage signal of the second wireless charging coil, compare the second voltage signal with a second analog reference signal to obtain a second comparison signal, and output the second comparison signal to the control unit; the control unit is used to send a third control signal to the second inverter unit, the third control signal is used to instruct the second inverter unit to convert the second DC signal received by the second inverter unit into a second AC signal, and the control unit is also used to determine whether there is a metal foreign object in the magnetic field range of the second wireless charging coil based on the second comparison signal.

[0010] In the method, the control unit can also determine whether there is a metal foreign object within the magnetic field range of the second wireless charging coil by acquiring a second voltage signal of the second wireless charging coil based on the second sampling unit, and obtaining a second comparison signal after comparing the second voltage signal with the second analog reference signal. In this way, the control unit does not need to determine whether there is a metal foreign object within the magnetic field range of the second wireless charging coil by obtaining the power received by the receiving coil in the electrical device that is charged by receiving the electromagnetic field of the second wireless charging coil, which reduces the communication process between the control unit and the electrical device (such as the receiving chip in the electrical device), and is conducive to improving the speed at which the wireless charging circuit detects whether there is a metal foreign object within the magnetic field range of the second wireless charging coil.

[0011] Furthermore, when the charging circuit charges different electrical devices through the first wireless charging coil and the second wireless charging coil, a control unit can detect whether there is a metal foreign object in the magnetic field range of the first wireless charging coil and whether there is a metal foreign object in the magnetic field range of the second wireless charging coil. Compared with the solution defined by the Qi standard that uses two transmitting chips to detect whether there is a metal foreign object in the magnetic field range of each corresponding wireless charging coil, the number of control units is reduced, which is conducive to reducing the cost of the charging circuit.

[0012] In a possible implementation of the first aspect above, the control unit is further used to output a fourth control signal to the second inverter unit when it is determined that there is a metal foreign object within the magnetic field range of the second wireless charging coil, and the fourth control signal is used to instruct the second inverter unit to stop outputting the second AC signal to the second wireless charging coil.

[0013] In this implementation, the control unit may stop charging the electrical device through the second wireless charging coil when it is determined that there is a metal foreign object within the magnetic field range of the second wireless charging coil, thereby avoiding abnormalities in the charging circuit caused by the metal foreign object and avoiding safety hazards.

[0014] In a possible implementation of the first aspect above, the first comparison signal is at a high level when the voltage value of the first voltage signal is greater than the voltage value of the first analog reference signal, and is at a low level when the voltage value of the first voltage signal is less than or equal to the voltage value of the first analog reference signal.

[0015] In a possible implementation of the first aspect above, the first sampling unit includes a first comparator and a first digital-to-analog converter, wherein the input end of the first digital-to-analog converter is connected to the first control unit, the output end of the first digital-to-analog converter is connected to the reference end of the first comparator, and the output end of the first comparator is connected to the first control unit; wherein the first digital-to-analog converter is used to receive a first digital reference signal corresponding to a first analog reference signal from the control unit, and output the first analog reference signal to the input end of the first comparator; and the first comparator is used to compare the first voltage signal received at the input end of the first comparator with the first analog reference signal, and output the first comparison signal to the first control unit.

[0016] In this implementation, the first sampling unit collects the first voltage signal of the first wireless charging coil based on the first digital-to-analog converter and the first comparator, and inputs the first comparison signal after comparing the first voltage signal with the first analog reference signal to the control unit. Compared with the digital calculation method, determining the first comparison signal by analog method can increase the speed of the charging circuit acquiring the first voltage signal, which is conducive to further improving the speed of detecting whether there is a metal foreign body in the magnetic field range of the first wireless charging coil.

[0017] Optionally, the first digital-to-analog converter can adopt a digital-to-analog converter with higher precision (for example, higher resolution), which is beneficial to improve the accuracy of the first analog reference signal, thereby improving the accuracy of the first comparison signal, and further improving the accuracy of the control unit in determining whether there is a metal foreign object within the magnetic field range of the first wireless charging coil based on the first comparison signal.

[0018] In a possible implementation of the first aspect, the control unit is further configured to input a second digital reference signal to an input end of the first digital-to-analog converter when a pulse width of the first comparison signal is greater than the first pulse width, or when the pulse width of the first comparison signal is greater than the first pulse width for a first duration; the first digital-to-analog converter is further configured to output a third analog reference signal to a reference end of the first comparator when the second digital reference signal is received; the first comparator is further configured to output a third comparison signal to the first control unit after comparing a first voltage signal received at the input end of the first comparator with the third analog reference signal, wherein a pulse width of the third comparison signal is the same as the first pulse width, and the first pulse width is a pulse width of a fourth comparison signal obtained by comparing the third voltage signal of the first wireless charging coil with the first analog reference signal when there is no metal foreign matter within the magnetic field range of the first wireless charging coil; and the control unit determines, based on the first comparison signal, that there is a metal foreign matter within the magnetic field range of the first wireless charging coil, specifically: if a difference between a second voltage value corresponding to the second digital reference signal and a first voltage value corresponding to the first digital reference signal is greater than the first difference, the control unit determines that there is a metal foreign matter within the magnetic field range of the first wireless charging coil.

[0019] In this implementation, the control unit can determine whether there is a metal foreign object in the magnetic field range of the first wireless charging coil based on the relationship between the difference between the first voltage and the second voltage and the first difference only when the pulse width of the first comparison signal is greater than the first pulse width for a first time period. In this way, false detection due to signal fluctuations in the charging circuit can be avoided.

[0020] Optionally, in some implementations, the first pulse width may be an experimental value or an empirical value and may be pre-stored in the control unit or in a memory accessible to the control unit.

[0021] In a possible implementation of the first aspect above, the control unit determines that there is a metal foreign object within the magnetic field range of the first wireless charging coil based on the first comparison signal, specifically: if the pulse width of the first comparison signal is greater than the first pulse width, the control unit determines that there is a metal foreign object within the magnetic field range of the first wireless charging coil, wherein the first pulse width is the pulse width of the fourth comparison signal obtained by comparing the third voltage signal of the first wireless charging coil with the first analog reference signal when there is no metal foreign object within the magnetic field range of the first wireless charging coil.

[0022] In a possible implementation of the first aspect, the first sampling unit further includes a first resistance unit and a second resistance unit, and one end of the first resistance unit is connected to the first wireless charging coil, the other end of the first resistance unit is connected to one end of the second resistance unit and an input end of the first comparator, and the other end of the second resistance unit is grounded.

[0023] In a possible implementation of the first aspect, the control unit includes any one of the following control units: a central processing unit, a micro control unit, a digital signal processor, a field programmable logic gate array, and an application-specific integrated circuit.

[0024] In a second aspect, the present application provides a chip, which includes the charging circuit provided in the first aspect and any one of the various possible implementations of the first aspect.

[0025] In a third aspect, the present application provides an electronic device, which includes any one of the charging circuits provided in the first aspect and various possible implementations of the first aspect, or any one of the chips provided in the second aspect.

[0026] It should be understood that the beneficial effects of the second and third aspects mentioned above can be referred to the description of the first aspect mentioned above and will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 According to some embodiments of the present application, a schematic diagram of a scenario in which a wireless charging system performs foreign object detection is shown;

[0028] Figure 2 According to some embodiments of the present application, a schematic diagram of an equivalent model of a wireless charging system is shown;

[0029] Figure 3 According to some embodiments of the present application, a schematic diagram of a voltage signal in a transmitting coil is shown;

[0030] Figure 4 According to some embodiments of the present application, a schematic diagram of the structure of a charging circuit 10 is shown;

[0031] Figure 5 According to some embodiments of the present application, a specific structural schematic diagram of a charging circuit 10 is shown;

[0032] Figure 6 According to some embodiments of the present application, a schematic diagram of a comparison signal acquired by the sampling unit 14 is shown;

[0033] Figure 7 According to some embodiments of the present application, a schematic diagram of a comparison signal acquired by a sampling unit 14' is shown;

[0034] Figure 8 According to some embodiments of the present application, a schematic diagram of a wireless charging scenario is shown;

[0035] Fig. 9 According to some embodiments of the present application, a schematic diagram of the structure of a charging circuit 20 in a tablet computer 100 is shown;

[0036] Fig.10 According to some embodiments of the present application, a schematic diagram of a tablet computer 100 performing foreign body detection is shown;

[0037] Fig.11 According to some embodiments of the present application, a schematic diagram of the structure of a charging chip 200 is shown;

[0038] Fig.12 According to some embodiments of the present application, a schematic diagram of the structure of an electronic device 300 is shown;

[0039] Fig.13 According to some embodiments of the present application, a schematic structural diagram of an electronic device 400 is shown. DETAILED DESCRIPTION

[0040] Illustrative embodiments of the present application include, but are not limited to, charging circuits, chips, and electronic devices.

[0041] The technical solution of the present application is introduced below in conjunction with the accompanying drawings.

[0042] It can be understood that the power supply device in each embodiment of the present application refers to a device that can use its own battery or external DC signal as a power source to send a magnetic field to other devices through a coil. For example, the power supply device can be a wireless charging device (such as a wireless charger), a mobile phone, a tablet computer, an earphone box, etc. that can wirelessly charge other electronic devices.

[0043] It can be understood that the power-consuming device in each embodiment of the present application refers to a device that charges its own battery by coupling the magnetic field sent by other devices or equipment through a coil. For example, the power-consuming device may include but is not limited to mobile phones, tablet computers, wearable devices (such as headphones, smart watches, smart bracelets, etc.), and smart home devices (such as smart toothbrushes, etc.).

[0044] The technical solution of the present application is described below in conjunction with the accompanying drawings.

[0045] In some embodiments, the presence of foreign matter in the wireless charging circuit is determined based on PLOSS detection. During the PLOSS detection process, the power-consuming device needs to first determine the received power of the power-consuming device and send the determined received power to the power supply device, and then the power supply device determines the power loss and whether there is a foreign matter. In this way, the power supply device and the power-consuming device need to exchange data, resulting in a long time and low efficiency in determining whether there is a foreign matter in the wireless charging circuit through PLOSS detection.

[0046] Figure 1 According to some embodiments of the present application, a schematic diagram of a scenario in which a wireless charging system performs foreign object detection is shown.

[0047] refer to Figure 1 The scenario includes a power supply device 01 and a power consumption device 05. The power supply device 01 includes a power supply terminal 02, a transmitting chip 03 and a transmitting coil 04, and the power consumption device 05 includes a receiving coil 06, a receiving chip 07, a charger chip 08 and a battery 09.

[0048] The power supply terminal 02 is used to provide a DC signal to the transmitting chip 03. In some embodiments, the DC signal provided by the power supply terminal 02 to the transmitting chip 03 can be a DC signal outside the power supply device 01, or a DC signal provided by a battery inside the power supply device 01.

[0049] The transmitting chip 03 is used to convert the DC signal provided by the power supply end 02 into an AC signal, and transmit the AC signal to the transmitting coil 04 .

[0050] The transmitting coil 04 is used to transmit the AC signal from the transmitting chip 03 through the magnetic field.

[0051] The receiving coil 06 is used to couple the magnetic field sent by the transmitting coil 04 and convert the magnetic field into an AC signal.

[0052] The receiving chip 07 is used to rectify the AC signal coupled by the receiving coil 06 into a DC signal and transmit it to the charger chip 08 .

[0053] The charger chip 08 is used to charge the battery 09 based on the DC signal transmitted by the receiving chip 07 .

[0054] In some embodiments, the receiving chip 07 can detect the voltage and current of the receiving coil 06 to determine the power of the AC signal received by the power-consuming device 05 (i.e., the received power), and send the determined received power (or the voltage and current of the receiving coil) to the transmitting chip 03. Then, the transmitting chip 03 can determine the power loss between the power supply device 01 and the power-consuming device 05 (e.g., the difference between the received power and the transmitted power, and the ratio to the transmitted power) based on the received received power (or the voltage and current of the receiving coil) and the transmitted power of the transmitting coil 04 (e.g., it can be determined by the voltage of the transmitting coil 04 and the current of the transmitting coil 04), and when the power loss is greater than a threshold, it is determined that there is a metal foreign body between the power supply device 01 and the power-consuming device 05.

[0055] In the above process, the power-consuming device 05 needs to first determine the received power of the power-consuming device 05 (or the voltage and current of the receiving coil 06) and send the determined received power to the power supply device 01, and then the power supply device 01 determines the power loss and determines whether there is a metal foreign object based on the power loss. In this way, the power supply device 01 and the power-consuming device 05 need to exchange data, resulting in a long time and low efficiency in determining whether there is a metal foreign object in the wireless charging system through PLOSS detection.

[0056] Based on this, an embodiment of the present application provides a charging circuit, which is applied to a power supply device. The charging circuit can determine whether there is a metal foreign body between the power supply device and the power-consuming device based on the change of the voltage signal of the detecting transmitting coil. For ease of understanding, the principle of the technical solution provided by the embodiment of the present application is first introduced.

[0057] Since metal media have shielding properties against magnetic fields, when there are metal foreign objects in the magnetic field range generated by the transmitting coil of the power supply equipment and the receiving coil of the power consumption equipment, the equivalent model between the transmitting coil of the power supply equipment and the receiving coil of the power consumption equipment will change, and then parameters such as the voltage in the transmitting coil will change accordingly.

[0058] For example, Figure 2 According to some embodiments of the present application, a schematic diagram of an equivalent model of a wireless charging system is shown.

[0059] like Figure 2As shown, the transmitting circuit for wireless charging in the power supply device can be equivalent to a circuit including an AC power supply U1 (used to generate an AC signal obtained by inverting a DC signal by an inverter circuit in the transmitting chip), a resistor R1, a capacitor C1 and an inductor L1 (equivalent to a transmitting coil), wherein the positive electrode of the AC power supply U1 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to one end of the capacitor C1, the other end of the capacitor C1 is connected to one end of the inductor L1, and the other end of the inductor L1 is connected to the negative electrode of the AC power supply U1. The receiving circuit for wireless charging in the electric device can be equivalent to a circuit including an inductor L2, a capacitor C2, a resistor R2 and a resistor RL (equivalent to a load in the electric device), wherein one end of the inductor L2 is connected to one end of the capacitor C2, the other end of the capacitor C2 is connected to one end of the resistor R2, the other end of the resistor R2 is connected to one end of the resistor RL, and the other end of the resistor RL is connected to the other end of the inductor L2.

[0060] based on Figure 2 The equivalent model shown and Kirchhoff's voltage law can be used to obtain the phasor equation shown in formula (1):

[0061]

[0062] Among them, Z 11 is the self-impedance of the transmitting circuit, Z 12 is the mutual impedance of the transmitting circuit, Z 21 is the mutual impedance of the receiving circuit, Z 22 is the self-impedance of the receiving circuit, is the current in the transmitting coil (i.e., inductor L1), is the current in the receiving coil (i.e., inductor L2), is the voltage of the AC power source U1. And, Z 12 =Z 21 =jωM,j 2 =-1, ω is the voltage of AC power supply U1 angular frequency, M is the equivalent mutual inductance between the transmitting coil and the receiving coil.

[0063] By transforming formula (1), we can get the following formula (2):

[0064]

[0065] When the power supply device is charging the power consumption device, Z in formula (2) 11 , Z 22 is a fixed value, ω is a constant in a short period of time (for example, when the power supply device is charging the power device at a fixed power), and the equivalent mutual inductance M will increase with the increase of the magnetic flux in the area where the transmitting coil and the receiving coil are coupled. When the metal foreign body is in the area where the transmitting coil and the receiving coil are coupled, it will absorb the magnetic flux, resulting in a decrease in the magnetic flux in the area where the transmitting coil and the receiving coil are coupled, and a decrease in the equivalent mutual inductance M, thereby reducing the denominator in formula (2) and the current in the transmitting coil (i.e., inductance L1). Increase.

[0066] Since the voltage of inductor L1 is positively correlated with the current, when there is a metal foreign body in the area where the transmitting coil and the receiving coil are coupled, the voltage across the inductor L1 will increase. Figure 2 , when there is no metal foreign matter between inductor L1 and inductor L2, the voltage signal of inductor L1 measured by oscilloscope O1 ( Figure 2 The voltage signal at point A shown in the figure is waveform S10, and the peak-to-peak value of waveform S10 is 2V1; after inserting a metal foreign object between inductor L1 and inductor L2, the voltage signal of inductor L1 measured by oscilloscope O1 ( Figure 2 The voltage signal at point A shown in the figure is waveform S20, the peak-to-peak value of waveform S20 is 2V2, and V2>V1. That is to say, after a metal foreign object is inserted between the transmitting coil and the receiving coil, the voltage of the transmitting coil will increase, so it is possible to determine whether there is a metal foreign object between the power supply device and the power consumption device based on the voltage signal of the transmitting coil.

[0067] For example, reference Figure 3 The AC signal S0 is the voltage signal of the transmitting coil when there is no metal foreign matter between the power supply device and the power consumption device, and the AC signal S1 is the voltage signal of the transmitting coil when there is a metal foreign matter between the power supply device and the power consumption device. The periods of the AC signal S0 and the AC signal S1 are equal, and the amplitude of the AC signal S1 is greater than the amplitude of the AC signal S0.

[0068] If the AC signal S0 is compared with a certain analog reference signal V ref0 (Analog reference signal V ref0 The voltage value of the AC signal S0 is set to be smaller than the amplitude of the AC signal S0. The voltage value of the AC signal S0 is greater than the analog reference signal V ref0 The duration of the voltage value is d; since the periods of the AC signal S1 and the AC signal S0 are equal and the amplitude of the AC signal S1 is greater than the amplitude of the AC signal S0, the voltage value of the AC signal S1 is greater than the analog reference signal V in one period. ref0 The duration of the voltage value is D, and the voltage value of the AC signal S0 is greater than the analog reference signal V ref0The duration of the voltage value is d, and D is greater than d. Therefore, the charging circuit can collect the signal after the voltage signal of the transmitting coil (hereinafter referred to as the coil voltage signal) is compared with the analog reference signal (hereinafter referred to as the comparison signal, the comparison signal is high level when the voltage value of the coil voltage signal is greater than the voltage value of the analog reference signal, and is low level when the voltage value of the coil voltage signal is less than or equal to the voltage value of the analog reference signal), and judge whether there is a metal foreign body between the power supply device and the power consumption device based on the duration of the high level of each cycle in the comparison signal (hereinafter referred to as the pulse width) (for example, the charging circuit can determine that there is a metal foreign body between the power supply device and the power consumption device when the difference between the pulse width D of the comparison signal and the reference pulse width d is greater than a preset value).

[0069] Based on the above method, the charging circuit can determine whether there is a metal foreign object between the power supply device and the power-consuming device by collecting the comparison signal of the coil voltage signal of the sending coil in the power supply device and comparing it with the analog reference signal. Compared with the detection method defined by the Qi standard, the charging circuit does not need to obtain the power of the receiving coil from the power-consuming device, which reduces the process of communicating with the power-consuming device, which is conducive to improving the speed of detecting foreign objects and improving detection efficiency.

[0070] For example, Figure 4 According to some embodiments of the present application, a schematic structural diagram of a charging circuit 10 is shown.

[0071] like Figure 4 As shown, the charging circuit 10 may include a control unit 11, an inverter unit 12, a codec unit 13, and a sampling unit 14. The control unit 11 is connected to the inverter unit 12, the codec unit 13, and the sampling unit 14, and the inverter unit 12, the codec unit, and the sampling unit 14 are connected to a transmitting coil 15 in a power supply device using the charging circuit 10.

[0072] The control unit 11 is used to output a control signal to the inverter unit 12 , where the control signal is used to control the inverter unit 12 to convert a DC signal into an AC signal and output the obtained AC signal to the transmitting coil 15 .

[0073] In some embodiments, the control unit 11 may be a system on chip (SoC) in a power supply device, such as a central processing unit (CPU). The control unit 11 may also be a microcontroller unit (MCU), a digital signal processor (DSP), a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), or other types of control units. The specific form of the control unit 11 is not limited in the embodiments of the present application.

[0074] In some embodiments, the control unit 11 is further configured to receive a comparison signal transmitted by the sampling unit 14, and determine whether there is a metal foreign object between the power supply device and the power consumption device based on the change in the pulse width of the comparison signal. For example, the control unit 11 can determine that there is a metal foreign object between the power supply device and the power consumption device when the difference between the pulse width of the comparison signal and the reference pulse width is greater than a preset value.

[0075] In some embodiments, the control unit 11 may be further configured to output a digital reference signal to the sampling unit 14 , so that the sampling unit 14 may compare the collected coil voltage signal with an analog reference signal corresponding to the digital reference signal to obtain a comparison signal.

[0076] It should be understood that the voltage value corresponding to the digital reference signal is the same as the voltage value of the corresponding analog reference signal.

[0077] In some embodiments, when the pulse width of the comparison signal received by the control unit 11 is greater than the reference pulse width (the digital reference signal output to the sampling unit 14 at this time is recorded as the digital reference signal VD 0 ), a digital reference signal with a different voltage value corresponding to the output of the sampling unit 14 can be sent to the sampling unit 14 until the pulse width of the comparison signal received by the control unit 11 is equal to the reference pulse width (the digital reference signal output to the sampling unit 14 at this time is recorded as the digital reference signal VD 1 Then, the control unit 11 can generate a digital reference signal VD 1 The voltage value minus the digital reference signal VD 0 When the voltage value difference (used to indicate the degree of difference between the pulse width of the comparison signal and the reference pulse width, the greater the difference between the pulse width of the comparison signal and the reference pulse width, the greater the difference) is greater than the preset difference, it is determined that there is a metal foreign body between the power supply device and the power-consuming device.

[0078] In some embodiments, the control unit 11 may also output a digital reference signal with a different voltage value to the sampling unit 14 only when the duration of the pulse width of the comparison signal being greater than the reference pulse width is greater than a preset duration. In this way, false detection can be avoided when the coil voltage signal fluctuates due to fluctuations in the charging circuit or the charging circuit actively adjusts the charging power, which is conducive to improving the accuracy of detection.

[0079] It should be understood that the control unit 11 outputs the aforementioned digital reference signal VD to the sampling unit. 1 After a preset time, the reference signal output to the sampling unit 14 can be restored to the digital reference signal VD 0 .

[0080] In some embodiments, the reference pulse width can be the difference between the coil voltage signal of the transmitting coil 15 and the digital reference signal VD when there is no metal foreign matter in the magnetic field of the transmitting coil 15. 0 The pulse width of the comparison signal obtained after comparison with the corresponding analog reference signal.

[0081] In some embodiments, the reference pulse width may be an experimental value or an empirical value.

[0082] In some embodiments, the reference pulse width may be different according to the charging state (e.g., output power, output voltage, etc.) of the charging circuit. That is, the storage unit (e.g., register) in the control unit 11 may store reference pulse widths corresponding to different output states, and obtain the corresponding reference pulse width from the storage unit based on the current charging state of the charging circuit, and then determine whether there is a metal foreign body between the power supply device and the power consumption device based on the obtained reference pulse width and the comparison signal.

[0083] In some embodiments, the digital reference signal VD 0 It may also be different according to the charging state of the charging circuit (eg, output power, output voltage, etc.) The control unit 11 may output different digital reference signals to the sampling unit 14 according to the charging state of the charging circuit.

[0084] In some embodiments, when the control unit 11 determines that there is a metal foreign object between the power supply device and the power-consuming device, it can stop charging the power-consuming device (for example, output a control signal to the inverter unit to stop outputting the AC signal) to avoid safety hazards or damage to the power supply device.

[0085] The inverter unit 12 is used to convert a DC signal input from a battery in the power supply device or from outside the power supply device into an AC signal according to a control signal of the control unit 11 , and output the AC signal to the transmitting coil 15 .

[0086] The transmitting coil 15 is used to transmit the AC signal input by the inverter unit 12 in the form of a magnetic field.

[0087] The sampling unit 14 is used to collect the coil voltage signal of the transmitting coil 15 , compare the collected coil voltage signal with the analog reference signal corresponding to the digital reference signal sent by the control unit 11 to obtain a comparison signal, and transmit the comparison signal to the control unit 11 .

[0088] In some embodiments, the sampling unit 14 may include a comparator, and the sampling unit 14 may input the coil voltage signal to the input terminal of the comparator, input the analog reference signal to the reference terminal of the comparator, and output the output result of the comparator as a comparison signal to the control unit 11. It should be understood that the comparator may output a high level when the voltage value of the coil voltage signal input to the input terminal is greater than the voltage value of the analog reference signal input to the reference terminal, and may output a low level when the voltage value of the coil voltage signal input to the input terminal is less than or equal to the voltage value of the analog reference signal input to the reference terminal.

[0089] In some embodiments, the control unit 11 may also directly output an analog reference signal corresponding to the digital reference signal to the sampling unit 14 , which is not limited here.

[0090] In some embodiments, the coil voltage signal of the transmitting coil 15 collected by the sampling unit 13 may be an actual voltage signal on the transmitting coil 15 , or may be a voltage signal obtained by dividing the actual voltage signal on the transmitting coil 15 , which is not limited here.

[0091] The codec unit 13 is used to communicate with the power-consuming device based on the communication method defined by the wireless charging protocol or standard (such as the Qi standard), for example, to obtain the charging parameters (such as power, voltage, current, etc.) required by the power-consuming device and to send the charging parameters (such as power, voltage, current, etc.) that the power supply device can provide to the power-consuming device.

[0092] In some embodiments, the codec unit 13 can be used for modulation and demodulation of signals, such as modulation and demodulation of signals in amplitude-shift keying (ASK) modulation format, frequency-shift keying (FSK) modulation format, and biphase mark code (BMC) format, so as to realize communication between the control unit 11 and the wireless charging chip (e.g., a receiving chip) in the power-consuming device.

[0093] The charging circuit 10 described above can detect metal foreign objects between the power supply device and the power-consuming device without detecting the power of the receiving coil in the power-consuming device, which is beneficial to improving the speed of detecting foreign objects and improving the detection efficiency.

[0094] For example, Figure 5 According to some embodiments of the present application, a specific structural schematic diagram of a charging circuit 10 is shown.

[0095] like Figure 5 As shown, the charging circuit 10 may include a control unit 11, an inverter unit 12, a codec unit 13, and a sampling unit 14. The control unit 11 is connected to the inverter unit 12, the codec unit 13, and the sampling unit 14, and the inverter unit 12, the codec unit, and the sampling unit 14 are connected to a transmitting coil 15 in a power supply device using the charging circuit 10.

[0096] In some embodiments, reference Figure 5 The inverter unit 12 may include a metal-oxide semiconductor field effect transistor (MOSFET) control circuit (MOS control circuit for short) 121 and an inverter bridge 122 (also referred to as an inverter). The inverter bridge 122 may include a plurality of MOSFETs, and the MOS control circuit 121 may be used to output different control signals to the gates of the respective MOSFETs in the inverter bridge 122 according to the control signal input by the control unit 11 to control the conduction or disconnection of the respective MOSFETs, so that the inverter bridge 122 converts the DC signal into an AC signal.

[0097] In other embodiments, the inverter unit 12 may also be a circuit in other forms that can convert a DC signal input to the inverter unit 12 into an AC signal based on a received control signal, which is not limited here.

[0098] In some embodiments, reference Figure 5 The sampling unit 14 may include a comparator 141, a digital to analog converter (DAC) 142, a resistor 143 and a resistor 144. One end of the resistor 143 is connected to the transmitting coil 15 (eg Figure 2 A point as shown in the figure), the other end is connected to one end of the resistor 144 and the input end of the comparator 141, the other end of the resistor 144 is grounded, the reference end of the comparator 141 is connected to the output end of the DAC 142, the output end of the comparator 141 is connected to the control unit 11, and the input end of the DAC 142 is connected to the control unit 11.

[0099] The control unit 11 may input a digital reference signal to the input end of the DAC 142, and the DAC 142 may convert the digital reference signal inputted at the input end into a corresponding analog reference signal and output the analog reference signal to the reference end of the comparator 141. The comparator 141 may output a high level to the control unit 11 through the output end when the voltage value of the coil voltage signal received at the input end (e.g., the voltage divided signal of the voltage signal of the transmitting coil 15 by the resistor 143 and the resistor 144) is greater than the voltage value of the analog reference signal inputted at the reference end, and may output a low level to the control unit 11 through the output end when the voltage value of the coil voltage signal received at the input end (e.g., the voltage divided signal of the voltage signal of the transmitting coil 15 by the resistor 143 and the resistor 144) is less than or equal to the voltage value of the analog reference signal inputted at the reference end.

[0100] It should be understood that the digital reference signal received by the DAC can be a binary digital signal, and the DAC can convert the received binary digital signal into a corresponding analog signal based on the electrical characteristics of the DAC. For example, assuming that the DAC is 8 bits (i.e., the number of bits of the received binary digital signal is 8, and the decimal range represented is 0-255 (a total of 256 numbers)), the reference analog voltage of the DAC is 10V, and the digital reference signal received by the DAC is 01111000 (corresponding to decimal 120), then the voltage value of the analog reference signal output by the DAC is 120 / 255×10V=4.7V (the calculation method is only an example, different DACs can use different calculation methods, which are not limited here), and accordingly, the voltage value corresponding to the digital reference signal 01111000 is also 4.7V.

[0101] For example, Figure 6 According to some embodiments of the present application, a schematic diagram of a comparison signal acquired by the sampling unit 14 is shown.

[0102] refer to Figure 6 , the AC signal S0 is the voltage signal input to the input end of the comparator 141 (i.e., the coil voltage signal of the transmitting coil 15) when there is no metal foreign matter between the power supply device and the power consumption device, and the AC signal S1 is the coil voltage signal input to the input end of the comparator 141 (i.e., the coil voltage signal of the transmitting coil 15) when there is a metal foreign matter between the power supply device and the power consumption device, V ref0 is an analog reference signal input to the reference terminal of the comparator 141, the comparison signal S2 is a comparison signal (with a pulse width of d, i.e., a reference pulse width) output by the comparator 141 to the control unit 11 when the AC signal S0 is input to the input terminal of the comparator 141, the comparison signal S3 is a comparison signal (with a pulse width of D and D>d) output by the comparator 141 to the control unit 11 when the AC signal S1 is input to the input terminal of the comparator 141, and the periods (or frequencies) of the AC signal S0, the AC signal S1, the comparison signal S2, and the comparison signal S3 are the same.

[0103] The control unit 11 receives Figure 6 After comparing the analog reference signal S3, when the pulse width D of the comparison signal S3 is greater than the reference pulse width d (or the duration of the pulse width D being greater than the reference pulse width d is greater than the preset duration), the digital reference signal output to the input end of the DAC 142 is adjusted to a digital reference signal with a larger corresponding voltage value. ref1 When the control unit 11 receives the comparison signal, the pulse width is d, and the analog reference signal is V ref1 The corresponding digital reference signal is the digital reference signal VD ref1 , the control unit 11 can determine the digital reference signal VD ref1 The corresponding voltage value and the digital reference signal VD ref0 (The analog reference signal is V ref0 The difference between the voltage values ​​corresponding to the digital reference signal corresponding to the power supply device and the power consumption device is ΔV. Then, when ΔV is greater than the preset difference, the control unit 11 can determine that there is a metal foreign body between the power supply device and the power consumption device, and stop charging the power consumption device through the transmitting coil 15.

[0104] It should be understood that the voltage value corresponding to the digital reference signal can be determined according to the electrical characteristics of the DAC 142 and the binary number represented by the digital reference signal. For example, assuming that the DAC is 8 bits (i.e., the number of bits of the binary digital signal received by the DAC is 8, and the decimal range represented is 0-255), the reference analog voltage of the DAC is 10V, and the voltage value corresponding to the digital reference signal 01111000 (corresponding to decimal 120) is 120 / 255×10V=4.7V (the calculation method is only an example, and different DACs can use different calculation methods, which are not limited here).

[0105] In some embodiments, the resistor 143 and the resistor 144 may be replaced by a resistor unit obtained by connecting a plurality of resistors in series and / or in parallel, which is not limited herein.

[0106] It should be understood that the resistor 143 and the resistor 144 are used to divide the voltage signal on the transmitting coil 15 so that the collected coil voltage signal can match the output voltage of the DAC 142 and the comparator 141. In some embodiments, if the voltage signal on the transmitting coil 15 is low, the voltage signal on the transmitting coil 15 may not be divided, but the voltage signal of the transmitting coil 15 is directly input to the input end of the comparator 141.

[0107] For example, Figure 7 According to some embodiments of the present application, a schematic diagram of a comparison signal acquired by a sampling unit 14 ′ is shown.

[0108] refer to Figure 7 , the sampling unit 14' may include a comparator 141 and a DAC 142. The input end of the comparator 141 is connected to the transmitting coil 15, the reference end of the comparator 141 is connected to the output end of the DAC 142, the output end of the comparator 141 is connected to the control unit 11, and the input end of the DAC 142 is connected to the control unit 11. The control unit 11 may input a digital reference signal to the input end of the DAC 142, and the DAC 142 may convert the digital reference signal inputted at the input end into a corresponding analog reference signal and then output it to the reference end of the comparator 141. The comparator 141 may output a high level to the control unit 11 through the output end when the voltage value of the coil voltage signal received at the input end is greater than the voltage value of the analog reference signal inputted at the reference end, and may output a low level to the control unit 11 through the output end when the voltage value of the coil voltage signal received at the input end is less than or equal to the voltage value of the analog reference signal inputted at the reference end.

[0109] In some embodiments, DAC 142 can sample a higher resolution DAC (for example, a DAC with a resolution of 8 bits, 12 bits, 16 bits, or 32 bits) to improve the accuracy of the analog reference signal input to the comparator 141, thereby improving the accuracy of the comparison signal output by the comparator 142, and further improving the accuracy of metal foreign matter detection performed by the control unit 11 based on the comparison signal.

[0110] In some embodiments, when the control unit 11 has the ability to output analog signals (for example, the control unit 11 includes a DAC), the sampling unit 14 / sampling unit 14' may not include the DAC 142, but the control unit 11 directly inputs the analog reference signal corresponding to the digital reference signal to the reference end of the comparator 141.

[0111] In some embodiments, the comparator 141 can sample a comparator with a lower propagation delay (the time interval from when the signal is input to the comparator for comparison to when the signal is output). In this way, the comparator 141 can output a corresponding comparison signal based on the change in the coil voltage signal detected on the transmitting coil 15 more quickly, so that the control unit 11 can detect the metal foreign body more promptly. In addition, the duration of the signal output by the comparator with a low propagation delay during the level change process is also shorter, so that the pulse width of the comparison signal is more accurate, which is conducive to improving the accuracy of the control unit 11 in detecting metal foreign bodies based on the comparison signal.

[0112] It should be understood that in other embodiments, the sampling unit 14 may include more or fewer modules, and may also use other circuits that can implement the aforementioned functions, which is not limited here.

[0113] In some embodiments, a power supply device may include multiple coils to facilitate charging of multiple electrical devices at the same time. Based on this, an embodiment of the present application also provides a charging circuit for use in a power supply device including N coils (N>1). The charging circuit includes: 1 control unit, N aforementioned inverter units, N aforementioned codec units, and N sampling units. Among them, the control unit is connected to each inverter unit, each codec unit, and each sampling unit, and the kth (k≤N) inverter unit, the kth codec unit, and the kth sampling unit are connected to the kth transmitting coil in the power supply device using the charging circuit.

[0114] It should be understood that the connection relationship between the control unit and the kth (k≤N) inverter unit, the kth codec unit, the kth sampling unit, and the kth transmitting coil, as well as the specific method for the control unit to determine whether there is a metal foreign body between the power supply device and the electrical equipment corresponding to the kth transmitting coil based on the comparison signal collected by the kth sampling unit can refer to the relevant description in the aforementioned charging circuit 10 and is not limited here.

[0115] Since currently a transmitting chip usually only supports foreign object detection for one coil, it means that a power supply device including N coils that can charge N electrical devices at the same time needs to use N transmitting chips, which increases the cost of the power supply device. However, in the charging circuit provided in the embodiment of the present application, only one control unit, and N aforementioned inverter units, N aforementioned codec units and N sampling units corresponding to the N coils are used to realize metal foreign object detection between the N coils and the corresponding electrical devices, which is conducive to cost saving.

[0116] For ease of description, the following takes a tablet computer 100 including two coils and capable of charging two devices (a keyboard 200 and a stylus pen 300) as an example to introduce the technical solution of the present application.

[0117] For example, Figure 8 According to some embodiments of the present application, a schematic diagram of a wireless charging scenario is shown. Fig. 9 According to some embodiments of the present application, a schematic diagram of the structure of a charging circuit 20 in a tablet computer 100 is shown.

[0118] refer to Figure 8 The tablet computer 100 includes a transmitting coil 101 and a transmitting coil 102. When the tablet computer 100 is placed on the keyboard 200 (as a power-consuming device), the tablet computer 100 can charge the keyboard 200 through the transmitting coil 101. When the stylus 300 (as a power-consuming device) is adsorbed onto the edge of the tablet computer 100 close to the coil 102, the tablet computer 100 can charge the stylus 300 through the coil 102.

[0119] refer to Fig. 9 The charging circuit 20 in the tablet computer 100 may include a control unit 109, an inverter unit 103, a codec unit 104, a sampling unit 105, an inverter unit 106, a codec unit 107, and a sampling unit 108. The control unit 109 is connected to the inverter unit 103, the codec unit 104, the sampling unit 105, the inverter unit 106, the codec unit 107, and the sampling unit 108 respectively; the inverter unit 103, the codec unit 104, and the sampling unit 105 are connected to the transmitting coil 101; the inverter unit 106, the codec unit 107, and the sampling unit 108 are connected to the transmitting coil 102.

[0120] The control unit 109 is used to output a control signal to the inverter unit 103, and the control signal is used to control the inverter unit 103 to convert the DC signal into an AC signal and output the obtained AC signal to the transmitting coil 101. The control unit 109 can also be used to output a control signal to the inverter unit 106, and the control signal is used to control the inverter unit 106 to convert the DC signal into an AC signal and output the obtained AC signal to the transmitting coil 102.

[0121] In some embodiments, the control unit 109 is further configured to receive the comparison signal transmitted by the sampling unit 105, and determine whether there is a metal foreign object between the tablet computer 100 and the power-consuming device (such as the aforementioned keyboard 200) charged by the coil 101 based on the change in the pulse width of the comparison signal. For example, the control unit 109 may determine that there is a metal foreign object between the tablet computer 100 and the keyboard 200 when the difference between the pulse width of the comparison signal and the reference pulse width is greater than a preset value.

[0122] In some embodiments, the control unit 109 is further configured to receive the comparison signal transmitted by the sampling unit 108, and determine whether there is a metal foreign object between the tablet computer 100 and the power-consuming device (such as the aforementioned stylus 300) charged by the coil 102 based on the change in the pulse width of the comparison signal. For example, the control unit 109 may determine that there is a metal foreign object between the tablet computer 100 and the stylus 300 when the difference between the pulse width of the comparison signal and the reference pulse width is greater than a preset value.

[0123] In some embodiments, the control unit 109 may be further configured to output a digital reference signal to the sampling unit 105 or the sampling unit 108 so that the sampling unit 105 or the sampling unit 108 may compare the collected coil voltage signal with an analog reference signal corresponding to the digital reference signal to obtain a comparison signal.

[0124] It should be understood that the digital reference signals output by the control unit 109 to the sampling unit 105 and the sampling unit 108 may be the same or different.

[0125] In some embodiments, when the pulse width of the comparison signal sent by the sampling unit 105 is greater than the reference pulse width (the digital reference signal output to the sampling unit 105 at this time is recorded as the digital reference signal VD 0 ), a digital reference signal with a larger corresponding voltage value can be output to the sampling unit 105 until the pulse width of the comparison signal sent by the sampling unit 105 received by the control unit 109 is equal to the reference pulse width (the digital reference signal output to the sampling unit 105 at this time is recorded as the digital reference signal VD 1 Then, the control unit 109 can generate a digital reference signal VD 1 The corresponding voltage value minus the digital reference signal VD 0 When the difference of the corresponding voltage values ​​is greater than the preset difference, it is determined that there is a metal foreign object between the tablet computer 100 and the keyboard 200 .

[0126] It should be understood that in other embodiments, the control unit 109 may output a digital reference signal with a correspondingly larger voltage value to the sampling unit 105 only when the duration of the pulse width of the comparison signal being greater than the reference pulse width is greater than the preset duration. In this way, false detection can be avoided when the coil voltage signal in the transmitting coil 101 fluctuates due to fluctuations in the charging circuit or the charging circuit actively adjusting the charging power, which is conducive to improving the accuracy of detection.

[0127] In some embodiments, when the pulse width of the comparison signal sent by the sampling unit 108 is greater than the reference pulse width (the digital reference signal output to the sampling unit 108 at this time is recorded as the digital reference signal VD 2 ), a digital reference signal with a larger corresponding voltage value can be output to the sampling unit 1085 until the pulse width of the comparison signal sent by the sampling unit 108 received by the control unit 109 is equal to the reference pulse width (the digital reference signal output to the sampling unit 108 at this time is recorded as the digital reference signal VD 3 Then, the control unit 109 can generate a digital reference signal VD 3 The corresponding voltage value minus the digital reference signal VD 2 When the difference of the corresponding voltage values ​​is greater than the preset difference, it is determined that there is a metal foreign object between the tablet computer 100 and the stylus pen 300 .

[0128] In other embodiments, the control unit 109 may determine that there is a metal foreign body between the tablet computer 100 and the stylus 300 when the duration of the pulse width of the comparison signal being greater than the reference pulse width is greater than a preset duration. In this way, false detection can be avoided when the coil voltage signal in the transmitting coil 102 fluctuates due to fluctuations in the charging circuit or the charging circuit actively adjusting the charging power, which is conducive to improving the accuracy of detection.

[0129] In some implementations, the control unit 109 may restore the digital reference signal output to the sampling unit 105 or the sampling unit 108 to the digital reference signal VD after receiving the comparison signal having a pulse width equal to the reference pulse width for a preset duration. 2 .

[0130] The specific form of the control unit 109 can refer to the relevant description of the aforementioned control unit 11, which will not be repeated here.

[0131] The inverter unit 103 is used to convert a DC signal from a battery in the tablet computer 100 or an external input DC signal of the tablet computer 100 into an AC signal according to a control signal of the control unit 109 , and output the AC signal to the transmitting coil 101 .

[0132] It should be understood that the specific structure of the inverter unit 103 can refer to the relevant description of the inverter unit 12 mentioned above, and will not be repeated here.

[0133] The transmitting coil 101 is used to transmit the AC signal input by the inverter unit 103 in the form of a magnetic field.

[0134] The sampling unit 105 is used to collect the coil voltage signal of the transmitting coil 101 , compare the collected coil voltage signal with the digital reference signal to obtain a comparison signal, and transmit the comparison signal to the control unit 109 .

[0135] It should be understood that the specific structure of the sampling unit 105 can refer to the related description of the aforementioned sampling unit 14, and will not be repeated here.

[0136] The codec unit 104 is used to communicate with an electrical device (such as the keyboard 200) that is charged through the coil 101, for example, to obtain the charging parameters (such as power, voltage, current, etc.) required by the electrical device and to send the charging parameters (such as power, voltage, current, etc.) that the tablet computer 100 can provide to the electrical device.

[0137] The inverter unit 106 is used to convert a DC signal from a battery in the tablet computer 100 or an external input DC signal of the tablet computer 100 into an AC signal according to a control signal of the control unit 109 , and output the AC signal to the transmitting coil 102 .

[0138] It should be understood that the specific structure of the inverter unit 106 can refer to the relevant description of the inverter unit 12 mentioned above, and will not be repeated here.

[0139] The transmitting coil 102 is used to transmit the AC signal input by the inverter unit 106 in the form of a magnetic field.

[0140] The sampling unit 108 is used to collect the coil voltage signal of the transmitting coil 101 , compare the collected coil voltage signal with the analog reference signal to obtain a comparison signal, and transmit the comparison signal to the control unit 109 .

[0141] It should be understood that the specific structure of the sampling unit 108 can refer to the related description of the aforementioned sampling unit 14, and will not be repeated here.

[0142] The codec unit 107 is used to communicate with the electrical device (such as the stylus 300) charged through the coil 102, for example, to obtain the charging parameters (such as power, voltage, current, etc.) required by the electrical device and to send the charging parameters (such as power, voltage, current, etc.) that the tablet computer 100 can provide to the electrical device.

[0143] refer to Fig.10 , since currently one transmitting chip usually only supports foreign object detection for one coil, if the transmitting chip is used to detect whether there is a metal foreign object between the tablet computer 100 and the power-consuming device (keyboard 200 and stylus 300) based on the PLOSS detection method defined in the Qi standard, two transmitting chips need to be installed in the tablet computer 100. One of the two transmitting chips is used to charge the keyboard 200 using the transmitting coil 101, and detect whether there is a metal foreign object between the tablet computer 100 and the keyboard 200 based on the received power fed back by the keyboard 200 and the voltage / current in the transmitting coil 101; the other transmitting chip is used to charge the stylus 300 using the transmitting coil 102, and detect whether there is a metal foreign object between the tablet computer 100 and the stylus 300 based on the received power fed back by the stylus 300 and the voltage / current in the transmitting coil 102. In this way, the cost is increased and the speed at which the tablet computer 100 detects metal foreign objects is reduced.

[0144] Based on the charging circuit 20, the tablet computer 100 can charge two electrical devices (keyboard 200 and stylus 300) at the same time. Since the charging circuit 200 does not use a transmitting chip, but detects metal foreign objects between the electrical device and the tablet computer 100 through a control unit 109 and the inverter unit and sampling unit corresponding to the coil 101 and the coil 102 respectively, rather than using two transmitting chips, it is beneficial to reduce costs. In addition, during the process of detecting metal foreign objects, the tablet computer 100 does not need to obtain power from the electrical device, which is beneficial to improving the efficiency and speed of the tablet computer 100 in detecting metal foreign objects.

[0145] It should be understood that Fig. 9The structure of the charging circuit 20 shown is only an example. In other embodiments, the charging circuit 20 may also include more or fewer modules (such as a Q scanning circuit for detecting whether there is an electrical device close to the power supply device, etc.), and some modules may also be combined or split, which is not limited here.

[0146] An embodiment of the present application further provides a chip, which includes any one of the charging circuits provided in the aforementioned embodiments.

[0147] For example, Fig.11 According to some embodiments of the present application, a schematic structural diagram of a charging chip 200 is shown.

[0148] like Fig.11 As shown, the charging chip 200 includes a control unit, N (N is an integer greater than or equal to 1) inverter units, N codec units and N sampling units. The control unit is connected to each inverter unit, each codec unit and each sampling unit, and the kth (k≤N) inverter unit, the kth codec unit and the kth sampling unit are connected to the kth transmitting coil in the power supply device using the charging chip 200.

[0149] The control unit in the charging chip 200 can determine whether there is a metal foreign body between the electrical equipment corresponding to the kth transmitting coil based on the comparison signal output by the kth sampling unit. The connection relationship between the control unit in the charging chip 200 and the kth (k≤N) inverter unit, the kth codec unit, the kth sampling unit, and the kth transmitting coil in the power supply device using the charging chip 200, and the specific method in which the control unit determines whether there is a metal foreign body between the power supply device and the electrical equipment corresponding to the kth transmitting coil based on the comparison signal collected by the kth sampling unit can refer to the relevant description in the aforementioned charging circuit 10 and charging circuit 20, and is not limited here.

[0150] An embodiment of the present application also provides an electronic device, which may include the above chip.

[0151] For example, Fig.12 According to some embodiments of the present application, a schematic structural diagram of an electronic device 300 is shown.

[0152] like Fig.12 As shown, the electronic device 300 may include the above-mentioned charging chip 200 .

[0153] In some embodiments, the electronic device 300 may further include N transmitting coils connected to the charging chip 200 .

[0154] An embodiment of the present application also provides an electronic device, which may include any one of the charging circuits and transmitting coils provided in the aforementioned embodiments.

[0155] For example, Fig.13 According to some embodiments of the present application, a schematic structural diagram of an electronic device 400 is shown.

[0156] like Fig.13 As shown, the electronic device 400 includes a control unit, N (N is an integer greater than or equal to 1) inverter units, N codec units, N sampling units and N transmitting coils. The control unit is connected to each inverter unit, each codec unit, and each sampling unit, and the kth (k≤N) inverter unit, the kth codec unit, and the kth sampling unit are connected to the kth transmitting coil in the electronic device 400.

[0157] It should be understood that the connection relationship between the control unit in the charging chip 200 and the kth (k≤N) inverter unit, the kth codec unit, the kth sampling unit, and the kth transmitting coil, as well as the specific method in which the control unit determines whether there is a metal foreign body between the power supply device and the electrical equipment corresponding to the kth transmitting coil based on the comparison signal collected by the kth sampling unit can refer to the relevant description in the aforementioned charging circuit 10 and charging circuit 20, and is not limited here.

[0158] It should be understood that in the embodiments of the present application, "or" describes the association relationship of associated objects, indicating that two relationships may exist. For example, A or B can represent: A exists alone, and B exists alone, where A and B can be singular or plural.

[0159] It should be understood that the term "connection" involved in the embodiments of the present application describes the connection relationship between two objects and can represent two connection relationships. For example, the connection between A and B can represent two situations: A is directly connected to B, and A is connected through C and B.

[0160] It should be understood that in the embodiments of the present application, "for example", "in some embodiments", "in another embodiment", "in another embodiment", "exemplarily" and the like are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "example" in the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of the word example is intended to present concepts in a concrete way.

[0161] It should be understood that the words "first", "second" and the like involved in the embodiments of the present application are only used for the purpose of distinguishing descriptions, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying order. The words "equal to" involved in the embodiments of the present application can be used in conjunction with "greater than", and are applicable to the technical solutions adopted when "greater than" is used, and can also be used in conjunction with "less than", and are applicable to the technical solutions adopted when "less than" is used. It should be noted that when "equal to" is used in conjunction with "greater than", it cannot be used in conjunction with "less than"; when "equal to" is used in conjunction with "less than", it cannot be used in conjunction with "greater than".

[0162] In the accompanying drawings, some structural or method features may be shown in a specific arrangement and / or order. However, it should be understood that such a specific arrangement and / or order may not be required. Instead, in some embodiments, these features may be arranged in a manner and / or order different from that shown in the illustrative drawings. In addition, the inclusion of structural or method features in a particular figure does not mean that such features are required in all embodiments, and in some embodiments, these features may not be included or may be combined with other features.

[0163] It should be understood that in the examples and descriptions of this patent, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that a process, method, article, or device that includes a series of elements includes not only those elements, but also other elements that are not explicitly listed, or also includes elements that are inherent to such process, method, article, or device. In the absence of further restrictions, an element defined by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article, or device that includes the element.

Claims

1. A charging circuit, characterized in that: The invention comprises a control unit, a first inverter unit and a first sampling unit, wherein the control unit is connected to the first inverter unit and the first sampling unit; and The first inverter unit is used to output a first AC signal to the first wireless charging coil; The first sampling unit is used to collect a first voltage signal of the first wireless charging coil, compare the first voltage signal with a first analog reference signal to obtain a first comparison signal, and output the first comparison signal to the control unit; The control unit is used to send a first control signal to the first inverter unit, wherein the first control signal is used to instruct the first inverter unit to convert a first DC signal received by the first inverter unit into the first AC signal, and The control unit is further configured to determine whether there is a metal foreign object within the magnetic field range of the first wireless charging coil based on the first comparison signal.

2. The circuit according to claim 1, characterized in that The control unit is further configured to output a second control signal to the first inverter unit when it is determined that there is a metal foreign object within the magnetic field range of the first wireless charging coil, wherein the second control signal is configured to instruct the first inverter unit to stop outputting the first AC signal to the first wireless charging coil.

3. The circuit according to claim 1, characterized in that The charging circuit further includes a second inverter unit and a second sampling unit, wherein the control unit is connected to the second inverter unit and the second sampling unit; and, The second inverter unit is used to output a second AC signal to the second wireless charging coil; The second sampling unit is used to collect a second voltage signal of the second wireless charging coil, compare the second voltage signal with a second analog reference signal to obtain a second comparison signal, and output the second comparison signal to the control unit; The control unit is used to send a third control signal to the second inverter unit, wherein the third control signal is used to instruct the second inverter unit to convert the second DC signal received by the second inverter unit into the second AC signal, and The control unit is further configured to determine whether there is a metal foreign object within the magnetic field range of the second wireless charging coil based on the second comparison signal.

4. The circuit according to claim 3, characterized in that The control unit is further configured to output a fourth control signal to the second inverter unit when it is determined that there is a metal foreign object within the magnetic field range of the second wireless charging coil, wherein the fourth control signal is configured to instruct the second inverter unit to stop outputting the second AC signal to the second wireless charging coil.

5. The circuit according to any one of claims 1 to 4, characterized in that The first comparison signal is at a high level when the voltage value of the first voltage signal is greater than the voltage value of the first analog reference signal, and is at a low level when the voltage value of the first voltage signal is less than or equal to the voltage value of the first analog reference signal.

6. The circuit according to claim 5, characterized in that The first sampling unit includes a first comparator and a first digital-to-analog converter, wherein the input end of the first digital-to-analog converter is connected to the first control unit, the output end of the first digital-to-analog converter is connected to the reference end of the first comparator, and the output end of the first comparator is connected to the first control unit; in, The first digital-to-analog converter is used to receive a first digital reference signal corresponding to the first analog reference signal from the control unit, and output the first analog reference signal to the reference terminal of the first comparator; The first comparator is used for comparing the first voltage signal received at the input end of the first comparator with the first analog reference signal, and then outputting the first comparison signal to the first control unit.

7. The circuit according to claim 6, characterized in that The control unit is further configured to input a second digital reference signal to an input terminal of the first digital-to-analog converter when a pulse width of the first comparison signal is greater than the first pulse width, or when the pulse width of the first comparison signal is greater than the first pulse width for a first duration; the first digital-to-analog converter is further configured to output a third analog reference signal to a reference terminal of the first comparator when the second digital reference signal is received; the first comparator is further configured to output a third comparison signal to the first control unit after comparing the first voltage signal received at the input terminal of the first comparator with the third analog reference signal, wherein the pulse width of the third comparison signal is the same as the first pulse width, and the first pulse width is the pulse width of a fourth comparison signal obtained by comparing the third voltage signal of the first wireless charging coil with the first analog reference signal when there is no metal foreign matter within a preset magnetic field range of the first wireless charging coil; Furthermore, the control unit determines, based on the first comparison signal, that there is a metal foreign object within the magnetic field range of the first wireless charging coil, specifically: If a difference between a second voltage value corresponding to the second digital reference signal and a first voltage value corresponding to the first digital reference signal is greater than a first difference, the control unit determines that a metal foreign object exists within the magnetic field range of the first wireless charging coil.

8. The circuit according to claim 5 or 6, characterized in that: The control unit determines, based on the first comparison signal, that there is a metal foreign object within the magnetic field range of the first wireless charging coil, specifically: If the pulse width of the first comparison signal is greater than the first pulse width, the control unit determines that there is a metal foreign object within the magnetic field range of the first wireless charging coil, wherein the first pulse width is the pulse width of a fourth comparison signal obtained by comparing the third voltage signal of the first wireless charging coil with the first analog reference signal when there is no metal foreign object within the magnetic field range of the first wireless charging coil.

9. The circuit according to claim 6, characterized in that The first sampling unit also includes a first resistance unit and a second resistance unit, and one end of the first resistance unit is connected to the first wireless charging coil, the other end of the first resistance unit is connected to one end of the second resistance unit and the input end of the first comparator, and the other end of the second resistance unit is grounded.

10. The circuit according to claim 1, characterized in that The control unit includes any one of the following control units: a central processing unit, a micro control unit, a digital signal processor, a field programmable logic gate array, and a dedicated integrated circuit.

11. A chip, characterized in that: The chip includes the charging circuit according to any one of claims 1 to 10.

12. An electronic device, characterized in that: The electronic device comprises the charging circuit according to any one of claims 1 to 10, or the chip according to claim 11.

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