Wireless charging device and foreign matter detection method, device, circuit and equipment thereof

Abstract

The application provides a wireless charging device and a foreign matter detection method, device, circuit and equipment thereof. The method comprises the following steps: applying a damping oscillation signal processing circuit to process a damping oscillation signal of a wireless power transmitter to be detected, so as to obtain a corresponding pulse signal; determining two target amplitudes of the damping oscillation signal and a target cycle number between the two target amplitudes according to the pulse signal; determining a current oscillation frequency and a current quality factor of the wireless power transmitter to be detected based on the two target amplitudes and the target cycle number; and determining whether there is foreign matter in the working range of the wireless power transmitter to be detected based on the current oscillation frequency, the current quality factor, a preset standard quality factor and a preset standard oscillation frequency. The application can output a pulse signal accurately reflecting the damping oscillation signal of the wireless power transmitter, so as to calculate the current quality factor and the current oscillation frequency of the wireless power transmitter based on the pulse signal, and realize more accurate foreign matter detection.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wireless charging, and particularly relates to a wireless charging device and a foreign matter detection method, device, circuit and equipment thereof. BACKGROUND

[0002] Wireless charge technology is a technology of charging a device without the aid of a wire and by using the principle of magnetic resonance. The technology is derived from wireless power transmission technology, and uses magnetic resonance to transmit electric charges in the air between a charger (a wireless power transmitter) and an electronic device, so that the coil and the capacitor of the charger form resonance between the charger and the device, and the technology realizes efficient transmission of electric energy.

[0003] In the alternating electromagnetic field formed by the coil and the capacitor, if there is metal foreign matter, eddy current effect will be generated, and a large amount of heat will be generated, which will cause the charging process to be abnormal, and even burn the electronic device being charged. Therefore, in the current wireless charging technology, the wireless power transmitter applies a foreign matter detection module. However, in the current foreign matter detection method, either a defective integrated method is used, or an expensive chip is applied, or a complex circuit needs to be built, and there is no unified, reliable and cost-effective detection method, which causes industry pain points. SUMMARY

[0004] The application provides a wireless charging device and a foreign matter detection method, device, circuit and equipment thereof. The circuit can output a pulse signal accurately reflecting a damping oscillation signal of a wireless power transmitter, so as to calculate a current quality factor and a current oscillation frequency of the wireless power transmitter based on the pulse signal, and realize more accurate foreign matter detection.

[0005] The first aspect of the application provides a damping oscillation signal processing circuit, which comprises at least one set of voltage dividing circuit and at least one set of pulse output circuit.

[0006] The voltage dividing circuit comprises a first resistor, a third resistor and a voltage dividing node. One end of the first resistor is connected to a second power supply voltage, and the other end is connected to the voltage dividing node. One end of the third resistor is connected to the damping oscillation signal, and the other end is connected to the voltage dividing node.

[0007] The pulse output circuit comprises a second resistor, a transistor and a pulse output node. One end of the second resistor is connected to a first power supply voltage, and the other end is connected to the pulse output node. The base of the transistor is connected to the voltage dividing node, and the collector and the emitter of the transistor are respectively connected to the pulse output node and a common terminal.

[0008] In some embodiments of the present application, a clamping circuit is further included, one end of the clamping circuit is connected to the common terminal, and the other end of the clamping circuit is connected to the voltage division node, and the clamping circuit is used to clamp the voltage at the voltage division node within a preset threshold.

[0009] In some embodiments of the present application, the clamping circuit includes a diode, a positive electrode of the diode is connected to the common terminal, and a negative electrode of the diode is connected to the voltage division node.

[0010] In some embodiments of the present application, the damped oscillation signal processing circuit includes two groups of voltage division circuits and two groups of pulse output circuits, and the two groups of voltage division circuits have different threshold voltages; the threshold voltages represent the amplitude of the damped oscillation signal when the triode is in the off state.

[0011] Embodiments of the second aspect of the present application provide a chip, which integrates the damped oscillation signal processing circuit of the first aspect.

[0012] Embodiments of the third aspect of the present application provide a foreign object detection device for wireless charging, which includes:

[0013] The damped oscillation signal processing circuit of the first aspect is used to process the damped oscillation signal of a to-be-tested wireless power transmitter, to obtain a corresponding pulse signal.

[0014] A parameter calculation module is configured to determine a current oscillation frequency and a current quality factor of the to-be-tested wireless power transmitter according to the pulse signal.

[0015] A foreign object detection module is configured to determine whether there is a foreign object in the working range of the wireless power transmitter based on the current oscillation frequency, the current quality factor, and a preset standard quality factor and a preset standard oscillation frequency.

[0016] In some embodiments of the present application, a calibration module is further included, which is used to detect the actual voltage at the voltage division node of the damped oscillation signal processing circuit when the pulse signal generation logic changes, and calibrate the threshold voltage of the damped oscillation signal processing circuit based on the actual voltage.

[0017] Embodiments of the fourth aspect of the present application provide a wireless charging device, which includes a wireless power transmitter, and further includes the foreign object detection device for wireless charging of the third aspect.

[0018] Embodiments of the fifth aspect of the present application provide a wireless charging foreign object detection method, which includes:

[0019] The damped oscillation signal processing circuit of the first aspect is used to process the damped oscillation signal of a to-be-tested wireless power transmitter, to obtain a corresponding pulse signal.

[0020] determining two target amplitudes of the damped oscillation signal and a target period number between the two target amplitudes according to the pulse signal;

[0021] determining a current oscillation frequency and a current quality factor of the to-be-tested wireless power transmitter based on the two target amplitudes and the target period number;

[0022] determining whether there is a foreign object in an operating range of the to-be-tested wireless power transmitter based on the current oscillation frequency, the current quality factor, and a preset standard quality factor and a preset standard oscillation frequency.

[0023] In some embodiments of the present application, the determining the two target amplitudes of the damped oscillation signal and the target period number between the two target amplitudes according to the pulse signal comprises:

[0024] determining two target time instants according to a variation of the pulse signal, and a time difference between the two target time instants being the target period number;

[0025] determining that amplitudes corresponding to the two target time instants respectively are the two target amplitudes.

[0026] In some embodiments of the present application, the determining the two target time instants according to a variation of the pulse signal comprises:

[0027] determining a falling edge time instant and a rising edge time instant of each pulse signal generated by the damped oscillation signal according to the pulse signal;

[0028] determining that a middle time instant of generating an Mth pulse signal and a middle time instant of generating an Nth pulse signal respectively are the two target time instants based on the falling edge time instant and the rising edge time instant of the Mth pulse signal and the falling edge time instant and the rising edge time instant of the Nth pulse signal; the M and the N are two different natural numbers respectively.

[0029] In some embodiments of the present application, the determining the two target amplitudes of the damped oscillation signal and the target period number between the two target amplitudes according to the pulse signal comprises:

[0030] determining an initial amplitude of the damped oscillation signal as one of the target amplitudes and determining a threshold voltage of generating the pulse signal as the other target amplitude;

[0031] determining a number of pulse signals generated by the pulse signal as the target period number.

[0032] In some embodiments of the present application, the damping oscillation signal processing circuit comprises two sets of voltage dividing circuits and two sets of pulse output circuits, and the two sets of voltage dividing circuits have different threshold voltages.

[0033] The determining of the two target amplitudes of the damping oscillation signal and the target number of periods between the two target amplitudes according to the pulse signal comprises:

[0034] Determining the first pulse signal number and the second pulse signal number generated by the two threshold voltages respectively;

[0035] Determining the two threshold voltages as the two target amplitudes, and determining the difference between the first pulse signal number and the second pulse signal number as the target number of periods.

[0036] In some embodiments of the present application, further comprising:

[0037] Detecting the actual voltage of the voltage dividing node of the damping oscillation signal processing circuit when the pulse signal generation logic changes;

[0038] Calibrating the threshold voltage of the damping oscillation signal processing circuit based on the actual voltage.

[0039] The embodiment of the sixth aspect of the present application provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method of the fifth aspect when executing the computer program.

[0040] The embodiment of the seventh aspect of the present application provides a computer readable storage medium having a computer program stored thereon, wherein the program is executed by a processor to implement the method of the fifth aspect.

[0041] The technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0042] The foreign object detection method provided in the embodiments of the present application can collect sufficient parameters based on the pulse signal output by the damping oscillation signal processing circuit, and can obtain more accurate and reliable oscillation frequency and quality factor according to the physical meaning of the LC oscillation circuit. Since the embodiment can measure the oscillation frequency f, it can satisfy the "foreign object detection mode based on the inherent frequency of the system" in the Qi protocol version 1.3, thereby increasing the applicability of the foreign object detection method. In addition, since the embodiment can measure the Q value and the oscillation frequency f of the system, it can determine whether there is a metal foreign object in the alternating electromagnetic field of the wireless power transmitter, whether there is a possible power receiver, whether there is a receiving device and a metal foreign object together, and even the degree of influence of the foreign object on the charging efficiency, thereby achieving more detailed foreign object determination. Attached Figure Description

[0043] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings.

[0044] In the attached diagram:

[0045] Figure 1 This illustration shows a damped oscillation signal generated by a second-order system constructed from the resonant capacitor and the transmitting coil of the wireless power transmitter in an embodiment of this application.

[0046] Figure 2 A schematic diagram of the damped oscillation signal processing circuit provided in an embodiment of this application is shown;

[0047] Figure 3 A flowchart illustrating the foreign object detection method for wireless charging provided in an embodiment of this application is shown.

[0048] Figure 4 This paper shows a schematic diagram of a second-order system structure constructed from the resonant capacitor and the transmitting coil of the wireless power transmitter under test in an embodiment of this application.

[0049] Figure 5 A schematic diagram of the damped oscillation curve under no-load conditions is shown in an embodiment of this application;

[0050] Figure 6 A schematic diagram of the damped oscillation curve with metallic foreign matter in an embodiment of this application is shown;

[0051] Figure 7 The damped oscillation curve after connecting to a wireless receiving device is shown in one embodiment of this application;

[0052] Figure 8 The pulse signal T_ output in the embodiment of this application is shown. OUT A schematic diagram showing the correspondence between the input damped oscillation signal T_IN and the voltage signal of the voltage divider node;

[0053] Figure 9 This paper illustrates the relationship between the pulse signal output by the damped oscillation signal processing circuit and the damped oscillation signal in an embodiment of this application.

[0054] Figure 10 A schematic diagram of the structure of a foreign object detection device for wireless charging according to an embodiment of this application is shown;

[0055] Figure 11A structural schematic diagram of a foreign matter detection device for wireless charging is shown;

[0056] Figure 12 A structural schematic diagram of an electronic device is shown.

[0057] Figure 13 A schematic diagram of a storage medium is shown. DETAILED DESCRIPTION

[0058] Exemplary embodiments of the present application will be described in detail with reference to the drawings. Although exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the scope of the application to those skilled in the art.

[0059] It should be noted that, unless otherwise specified, technical terms or scientific terms used in the present application should be understood as their common meanings to those skilled in the art to which the present application pertains.

[0060] When foreign matter detection is performed on a wireless charging device, an indirect foreign matter detection method of current voltage power monitoring can be used, or Q value detection, also known as quality factor detection, can be performed. The Q value is calculated before charging by measuring the Q value of the oscillation system of the wireless charging device to determine whether there is foreign matter. Q = 2π * stored energy / energy consumed by one oscillation. In the current technical solution, when the Q value is calculated, only the relationship between the amplitude change of the damped oscillation and time is measured, and the measurement of the oscillation frequency is ignored (or not collected due to technical conditions). However, for a wireless receiving device including an LC oscillation circuit, when there is a metal foreign matter, the metal foreign matter will change the frequency of the LC oscillation circuit after being connected to the wireless receiving device, which will in turn affect the change of the Q value. Therefore, calculating the Q value only by the relationship between the amplitude change of the damped oscillation and time may result in a large deviation in the calculation result, and thus it is not possible to accurately determine whether there is metal foreign matter.

[0061] In view of the above, there is no unified, reliable and cost-effective foreign matter detection method, and the embodiments of the present application provide a wireless charging device and a foreign matter detection method, device, damping oscillation signal processing circuit, electronic equipment and medium. The foreign matter detection method is based on the damping oscillation signal processing circuit, and the specific calculation and foreign matter analysis and detection steps can include but are not limited to: MCU, FPGA, digital logic unit and other processing modules with digital logic processing function. The damping oscillation signal processing circuit includes at least one set of voltage dividing circuit and at least one set of pulse output circuit; wherein the voltage dividing circuit includes a first resistor, a third resistor and a voltage dividing node, one end of the first resistor is connected to a second power supply voltage, and the other end is connected to the voltage dividing node; one end of the third resistor is connected to the damping oscillation signal, and the other end is connected to the voltage dividing node. The pulse output circuit includes a second resistor, a transistor and a pulse output node, one end of the second resistor is connected to a first power supply voltage, and the other end is connected to the pulse output node; the base of the transistor is connected to the voltage dividing node, and the collector and the emitter of the transistor are connected to the pulse output node and the common terminal respectively. The damping oscillation signal processing circuit can process the damping oscillation signal of the wireless power transmitter to be tested, and generate a corresponding pulse signal. By collecting and analyzing the pulse signal, the current oscillation frequency and quality factor of the wireless power transmitter to be tested can be determined, and then the calculated oscillation frequency and quality factor are compared with the preset oscillation frequency and quality factor, based on the principle of the wireless power transmitter and the physical properties of the metal, it can be determined whether there is foreign matter in the working range of the wireless power transmitter.

[0062] The embodiments of the present application construct a second-order system based on the resonance capacitor and the transmitting coil of the wireless power transmitter. After inputting a step signal to the system, as the response of the step signal, a damping oscillation signal as shown in Figure 1 can be generated at one end of the transmitting coil. When calculating Q value, the damping coefficient ζ of the damping oscillation signal can be referred to for calculating Q value. The specific calculation process is as follows:

[0063] Since the LC oscillation circuit is a second-order linear system, a differential equation can be established:

[0064]

[0065]

[0066] Wherein, R is the load of the second-order system, which can be but not limited to an electronic device capable of wireless charging; L is the inductance of the transmitting coil, in henry; C represents the capacitance value of the resonance capacitor, in farad; U C (t) represents the capacitance voltage of the resonance capacitor at time t, i(t) represents the current of the second-order system at time t, U in (t) represents the voltage of the second-order system at time t, that is, the amplitude of the damping oscillation signal.

[0067] Assuming the capacitor voltage as the output, the transfer function of the second-order system can be obtained by Laplace transform:

[0068]

[0069] And because of the resonance characteristics:

[0070]

[0071] The function of the typical second-order system is obtained:

[0072]

[0073]

[0074] Where ζ is the damping coefficient; ω0 is the resonance angular frequency of the damped oscillation signal; R is the load of the second-order system, which can be but is not limited to an electronic device capable of wireless charging; L is the inductance of the transmitting coil, in henry; and C represents the capacitance value of the resonance capacitor, in farad.

[0075] Comparing the above formula with the definition formula of Q value, we can arrange (at resonance):

[0076]

[0077] We get:

[0078]

[0079] Further, when calculating the Q value, we can first propose the 1→0 amplitude voltage decay curve of the damped oscillation signal:

[0080]

[0081] Take two points t0 and t1 on the curve:

[0082]

[0083] The calculation formula of the damping coefficient and the Q value is obtained:

[0084]

[0085]

[0086] If combined with the periodic characteristics of the sine curve, take the peak point U C (t) on the damped wave U C1 (t) and U C2 , and the time interval is t1-t0=nT, at this time:

[0087]

[0088]

[0089] Based on the principle of the wireless power transmitter and the physical properties of metal, it is known that, over time, within the alternating electromagnetic field of the wireless power transmitter, the Q value and the oscillation frequency f will change as follows:

[0090] If there is no metal device within the alternating electromagnetic field, the Q value is maximum, and the oscillation frequency is determined by the inherent oscillation frequency of the transmitter and remains unchanged.

[0091] If there is only metal foreign matter (inductive load) within the alternating electromagnetic field, the Q value is greatly reduced, and the oscillation frequency remains unchanged.

[0092] If there is only a wireless power receiver (capacitive load) within the alternating electromagnetic field, the Q value will be slightly reduced, and the oscillation frequency will change (determined by the inherent frequency of the wireless power receiver).

[0093] After calculating the above Q value and the oscillation frequency f = 1 / T, the above process can be applied, that is, the Q value and the oscillation frequency f of the system can be obtained by continuous collection and calculation, and it can be further judged whether there is metal foreign matter within the alternating electromagnetic field of the wireless power transmitter, whether there is a possible power receiver, and even the degree of influence of the foreign matter on the charging efficiency.

[0094] However, the amplitude and oscillation period of the damped oscillation signal are often difficult to detect and inconvenient to obtain directly. The damped oscillation signal processing circuit provided in the embodiment is used to process the damped oscillation signal of the wireless power transmitter to be tested, generate a corresponding pulse signal, and obtain the amplitude and oscillation period of the damped oscillation signal by collecting and analyzing the pulse signal.

[0095] The embodiments of the present application will be described in detail below.

[0096] Embodiment One

[0097] Please refer to Figure 2 The structure diagram of the damped oscillation signal processing circuit provided in the embodiment of the present application is as follows Figure 2As shown, the circuit includes at least one voltage divider circuit and at least one pulse output circuit. The voltage divider circuit includes a first resistor R1, a third resistor R3, and a voltage divider node. One end of the first resistor R1 is connected to the second power supply voltage U2, and the other end is connected to the voltage divider node. One end of the third resistor R3 is connected to a damped oscillation signal, and the other end is connected to the voltage divider node. The pulse output circuit includes a second resistor R2, a transistor, and a pulse output node. One end of the second resistor R2 is connected to the first power supply voltage U1, and the other end is connected to the pulse output node. The base of the transistor is connected to the voltage divider node, and the collector and emitter of the transistor are connected to the pulse output node and a common terminal, respectively.

[0098] The voltage divider node can be any node between the first resistor R1 and the third resistor R3. This pulse output node is used to output a pulse signal, and the common terminal can be understood as the zero-point reference voltage of the entire circuit. The first power supply voltage U1 and the second power supply voltage U2 are both system operating voltages (which can be, but are not limited to, 3.3V, 5V, etc.).

[0099] It should be noted that the damped oscillation signal processing circuit can be an analog circuit (referring to a circuit used to transmit, transform, process, amplify, measure and display analog signals). Specifically, it can be integrated into a discrete chip as a hardware peripheral of the MCU. When the MCU has high integration capabilities, it can also be directly integrated into the MCU chip to save additional chips. This embodiment does not make specific limitations on this.

[0100] like Figure 2 As shown, the transistor can specifically be an NPN type. In this case, the base of the transistor is connected to the voltage divider node, the collector can be connected to the pulse output node, and the emitter is connected to the common terminal. Thus, only a small current is needed to turn on the transistor. After the transistor is turned on, when the selected second resistor is relatively large, the voltage division of the second resistor is equivalent to the first power supply voltage, causing the pulse output node to output a low level. When the transistor is turned off, no current flows through the second resistor, and the entire first power supply voltage can be output from the pulse output node, so the pulse output node can output a high level.

[0101] For example, in the above open-drain transistor circuit, the first power supply voltage U1 = 3.30V, the second resistor R2 = 10kΩ, and the base current I when the transistor is turned on... O When the current is 0.33mA, the cutoff voltage V OFF =0.63V.

[0102] When the voltage U at the voltage divider node T1 When it equals 3.3V, the output voltage U of the pulse output node OUT =0V, that is, output low level.

[0103] When the voltage U at the voltage divider nodeT1 When the output voltage U OUT of the pulse output node is equal to 0V, the output voltage U OFF of the pulse output node is equal to 3.3V, i.e. the output high level.

[0104] Suppose the boundary voltage of the logic change (the output voltage changes from low level to high level, or from high level to low level) is the above-mentioned cut-off voltage V T1 .

[0105] Then the logic of the output of the triode management (the relationship between U OUT and U T1 ) is:

[0106]

[0107] Since U OFF <V BE , the overcurrent I IN of the base and the emitter is equal to 0, according to the equal current through the first resistor R1 and the third resistor R3, the following formula can be obtained (wherein U2 is the second power voltage connected to the first resistor):

[0108]

[0109] Then the following can be obtained:

[0110]

[0111] Therefore, the amplitude voltage U TH of the damped oscillation signal input by the system is equal to the logic threshold V TH , which can also be called the threshold voltage of the circuit (the relationship between U IN and U T1 ):

[0112]

[0113] Further, the relationship between the output pulse signal T OUT (voltage value U OUT ), the input damped oscillation signal T IN (voltage value U IN ) and the logic threshold V TH is as follows:

[0114]

[0115] At the same time, it can also be found that R1 and R3 constitute a linear resistance network, and the circuit conforms to the voltage superposition principle, so that the test point T1 and the input signal T IN present a linear function relationship, and by calculating the selected R1 and R3, the logic threshold V TH, further adjust the threshold voltage of the circuit, namely U OUT When the threshold value changes, the input damped oscillation signal T IN The voltage value of the damped oscillation signal T IN .

[0116] It should be noted that Figure 2 The connection mode of the triode is NPN type, but the type of the triode is not limited in the embodiment, which can also be PNP type, as long as the current outflow end is connected to the common end, the current inflow end is connected to the first power supply voltage, and the triode can realize the functions of cutoff and amplification.

[0117] The damped oscillation signal processing circuit provided by the embodiment is simple in structure and does not need integrated circuit devices such as operational amplifiers and comparators, but can accurately obtain the corresponding pulse signal of the damped oscillation signal, and then accurately calculate the target amplitude and target oscillation period of the damped oscillation signal, so as to determine the current oscillation frequency and quality factor of the to-be-measured wireless power transmitter, and then compare the calculated oscillation frequency and quality factor with the preset oscillation frequency and quality factor, based on the principle of the wireless power transmitter and the physical properties of the metal, whether there is a foreign object in the working range of the wireless power transmitter can be determined.

[0118] In some embodiments, the damped oscillation signal processing circuit further comprises a clamping circuit, one end of the clamping circuit being connected to the common end and the other end being connected to the voltage division node, the clamping circuit being used to clamp the voltage of the voltage division node within a preset threshold value, so as to prevent the triode from being damaged due to the too large negative voltage amplitude of the base connection.

[0119] The preset threshold value can be set according to the voltage resistance characteristics of the triode, so as to better protect the triode.

[0120] Specifically, the clamping circuit comprises a diode, the anode of the diode being connected to the common end and the cathode of the diode being connected to the voltage division node. By using the characteristics of forward conduction and reverse cutoff of the diode, the diode can be reversely connected to the voltage division node T1, so as to clamp the voltage of T1 within the preset threshold value, and the triode can be protected.

[0121] Further, the damped oscillation signal processing circuit comprises two groups of voltage division circuits and two groups of pulse output circuits, and the two groups of voltage division circuits have different threshold voltages. The threshold voltage represents the amplitude of the damped oscillation signal when the triode is in the cutoff voltage state. In this way, two pulse signals with different amplitudes can be obtained based on the input damped oscillation signal.

[0122] Embodiment two

[0123] Based on the same concept as the damped oscillation signal processing circuit described above, this embodiment also provides a chip that integrates a damped oscillation signal processing circuit as described in any of the above embodiments.

[0124] Specifically, the chip can be a dedicated chip that includes the aforementioned discrete components, or it can be an integrated MCU chip, as long as it can achieve the function of the circuit and output the pulse signal corresponding to the damped oscillation signal.

[0125] The chip provided in this embodiment is based on the same concept as the damped oscillation signal processing circuit described above. Therefore, it can at least achieve the beneficial effects that the damped oscillation signal processing circuit can achieve. Furthermore, any implementation of the damped oscillation signal processing circuit can be applied to the chip provided in this embodiment, and will not be described in detail here.

[0126] Example 3

[0127] Based on the same concept as the damped oscillation signal processing circuit described above, this embodiment also provides a wireless charging foreign object detection method, such as... Figure 3 As shown, the method includes the following steps:

[0128] Step S1: Apply the damped oscillation signal processing circuit described above to process the damped oscillation signal of the wireless power transmitter under test to obtain the corresponding pulse signal.

[0129] like Figure 4 The diagram shows a second-order system structure constructed from the resonant capacitor and transmitting coil of the wireless power transmitter under test in this embodiment. The damped oscillation signal generated by this second-order system during operation can be collected at the TEST point shown in the diagram. Where L is the transmitting coil, C is the resonant capacitor, and SW1 and SW2 are the power supply voltages of the LC oscillation circuit, respectively. Based on this system, the generation process of the damped oscillation signal is as follows:

[0130] 1) In the initial equilibrium state, both SW1 and SW2 output 0V.

[0131] 2) SW1 outputs 1V and SW2 outputs 0V to charge the LC (at this time, a damped oscillation from 0 to 1 will be generated).

[0132] 3) Wait 1ms for the LC to finish charging and reach equilibrium (at this point there is no oscillation);

[0133] 4) Both SW1 and SW2 output 0V, discharging the LC (at this time, a damped oscillation of 1→0 will be generated).

[0134] The “1V” output by SW1 mentioned above is the amplitude of the step signal. In wireless charging systems, the voltage can typically be selected from 1V to 9V.

[0135] It can be understood that the stored energy of the LC circuit of the wireless power transmitter is relatively fixed. Then the attenuation conditions in different cases are as shown in Figures 5-7 , in which the horizontal coordinate is time in microseconds and the vertical coordinate is voltage value in volts. Figure 5 is a damping oscillation curve when the load is empty, at which time only the bus resistance of the loop consumes energy, and the oscillation amplitude decays relatively slowly. Figure 6 is a damping oscillation curve after the wireless receiving device is connected, the receiving end induces current, which increases a path of consumption, and the oscillation amplitude decays relatively faster, and the system resonance frequency changes. Figure 7 is a damping oscillation curve after the metal foreign matter is connected, when the metal foreign matter exists, the foreign matter induces current, and because there is no capacitor in the loop and the resistance is small, the oscillation amplitude decays very fast.

[0136] Based on the structure and principle of the damping oscillation signal processing circuit provided in the above embodiment one, in this embodiment, the relationship between the logic threshold V TH and the cutoff voltage V OFF is as follows:

[0137]

[0138] It can be calculated that the relationship among the output pulse signal T OUT (voltage value U OUT ), the input damping oscillation signal T_IN (voltage value U IN ), and the logic threshold V TH is as follows:

[0139]

[0140] It can be obtained through experiments that the corresponding relationship among the output pulse signal T OUT (voltage value U OUT ), the input damping oscillation signal T_IN (voltage value U IN ), and the voltage signal of the voltage dividing node is as shown in Figure 8 .

[0141] In step S2, two target amplitudes of the damping oscillation signal and a target period number between the two target amplitudes are determined according to the pulse signal.

[0142] The target amplitude can be the amplitude corresponding to any two time points in the damping oscillation signal decay process, as long as the target period number between the two time points can be determined. The target period number can be an integer or can not be an integer, which is not specifically limited in this embodiment. In order to facilitate calculation and collection, the amplitude corresponding to the peak time of the damping oscillation signal can be selected as the target amplitude in this embodiment.

[0143] In some embodiments, step S2 can include the following processing: determining two target instants according to the change edges of the pulse signal, and the time difference between the two target instants is the target period number; and determining the amplitudes corresponding to the two target instants as the two target amplitudes.

[0144] In the embodiment, the MCU or other digital logic unit can be combined with a clock to record the change edges of the pulse signal output by the damped oscillation signal processing circuit. The instant of the first falling edge is recorded as t F1 , the instant of the first rising edge is recorded as t R1 , the instant of the Nth falling edge is recorded as t Fn , and the instant of the Nth rising edge is recorded as t Rn .

[0145] The relationship between the pulse signal output by the damped oscillation signal processing circuit and the damped oscillation signal is shown in FIG. 2. The middle instant between the instant of the rising edge and the instant of the falling edge of any pulse signal can be determined as a target instant, and the amplitude corresponding to the target instant is determined as a target amplitude. Figure 9

[0146] Specifically, the falling edge instant and the rising edge instant of each pulse signal generated by the damped oscillation signal can be determined according to the pulse signal. Then, based on the falling edge instant and the rising edge instant of the Mth pulse signal and the falling edge instant and the rising edge instant of the Nth pulse signal, the middle instants of generating the Mth pulse signal and the Nth pulse signal are determined as two target instants, respectively; M and N are two different natural numbers.

[0147] Since the damped oscillation curve is a sine wave, the amplitude VA n of the Nth period can be calculated by a trigonometric function, and the relationship between VA Fn , t Rn and the edge instants t TH , t N-n is as follows, where the switching threshold V N and the oscillation period T have been calculated:

[0148]

[0149] A complete damped oscillation curve generates N pulses, and the corresponding amplitude calculated by the Nth-nth pulse and the Nth pulse is VA N-n and VA N . For example, the corresponding amplitude can be calculated by the last 6th pulse and the last 1st pulse.

[0150] In some embodiments, step S2 can also include the following processing: determining the initial amplitude of the damped oscillation signal as one of the target amplitudes, and determining the threshold voltage for generating the pulse signal as the other target amplitude; and determining the number of the pulse signals generated by the pulse signal as the target period number.

[0151] In practical applications, in order to reduce the operation amount of the MCU and the design complexity of the digital logic unit, the embodiment can simplify the calculation process by taking an approximate value.

[0152] Since the initial amplitude VA0 of the damped oscillation signal is fixed (i.e., the amplitude of the step signal, which can be selected according to the application scenario), i.e., the amplitude of the 0th pulse VA0 is equal to a target amplitude of the step signal; when the last pulse, the edge time t Fn is very close to t Rn , and the end amplitude VA N is approximately equal to V TH , i.e., V TH can be used as another target amplitude. The initial amplitude VA0 and the end amplitude VA N are both fixed, so the two variables can be pre-calculated and converted into a constant K. Accordingly, the quality factor Q can be obtained according to the function calculation relationship: Q = K1πN.

[0153] The simplified Q value calculation formula also has obvious resolution, which can realize the function of foreign object detection in the wireless charging application scenario.

[0154] In other embodiments, the damped oscillation signal processing circuit includes two sets of voltage dividing circuits and two sets of pulse output circuits, and the two sets of voltage dividing circuits have different threshold voltages. The above step S2 can also include the following processing: determining the number of first pulse signals and the number of second pulse signals generated by the two threshold voltages respectively; and then determining the two threshold voltages as two target amplitudes, and determining the difference between the number of first pulse signals and the number of second pulse signals as the target period number.

[0155] In practical applications, in order to reduce the operation amount of the MCU and the design complexity of the digital logic unit, but relative to "Simplified Scheme One", higher anti-interference is required, and the present case proposes a scheme idea of designing two switch threshold values.

[0156] By designing two voltage dividing circuits and a triode amplifying circuit, and setting the voltage dividing parameters to threshold values V TH_HIGH and V TH_LOW , respectively.

[0157] The switch threshold value of one path is V TH_LOW , and there are N LOW pulses; the switch threshold value of the other path is V TH_HIGH , and there are N HIGH pulses. The amplitude of the last pulse output by the two logic outputs is approximately equal to the switch threshold value. Since the preset switch threshold value is a fixed value, the logarithmic function can be pre-calculated, and the constant K can be obtained, thereby saving the operation amount of the MCU.

[0158] The quality factor Q can be calculated according to the function relationship: Q=K2(N HIGH -N LOW ).

[0159] In comparison, the scheme actually increases the analog scale to reduce the digital scale, and specifically, the MCU software complexity or the size of the digital logic unit can be simplified. Similarly, the simplified Q value calculation formula has sufficient resolution and higher anti-interference, and is sufficient to realize the function of foreign object detection in the wireless charging application scenario.

[0160] In other embodiments, the foreign object detection method can further include the following processing: detecting a logic change of the pulse signal, detecting an actual voltage of a voltage division node of the damped oscillation signal processing circuit; and calibrating a threshold voltage of the damped oscillation signal processing circuit based on the actual voltage.

[0161] In actual application, due to the temperature characteristics of the triode, the scheme will have certain temperature drift, which needs to be calibrated. In most wireless charging systems, the main control MCU already has DAC and ADC peripherals, and any one of them can be used to realize parameter calibration. Because the application is based on the existing carrier, the module does not increase the cost, and is very friendly to cost-sensitive products.

[0162] Specifically, U2 can be connected to the DAC output of the MCU, and calibrated before measuring the Q value, so that U2 decreases from 3.3V, and U T_OUT The DAC voltage value U 2_DAC When the output logic changes, because V TH = 0V, we have:

[0163]

[0164] Set V DAC_SET = V DAC_TH -ΔV,

[0165]

[0166] For example, V′ TH = 80mV is required, and R3 = 4.7kΩ and R1 = 1kΩ, only ΔV = 17mV needs to be set, so that the system temperature drift can be dynamically and real-timely eliminated by the DAC.

[0167] Because when the NPN is turned on, U T1 = V OFF , only the MCU needs to start ADC acquisition after the logic of U T_OUT changes, and V T1 can be obtained by measuring U T1_ADC voltage by ADC, so that the current voltage threshold VTH ′.

[0168]

[0169] Just add the compensated V TH Substituting the ′ value into the Q value calculation can eliminate the effect of temperature drift.

[0170] For example, some MCUs have a maximum ADC frequency of about 850KHz, which is sufficient to complete several ADC sampling cycles in this application scenario.

[0171] Step S3: Based on the two target amplitudes and the target number of cycles, determine the current oscillation frequency and the current quality factor of the wireless power transmitter under test.

[0172] After determining the two target amplitudes and the target number of periods, the formula for calculating the oscillation frequency f is:

[0173]

[0174] The quality factor Q can be obtained from the function formula: Q = f(VA) N-n ,VA N ,n).

[0175] The specific formula for calculating the Q value is as follows:

[0176]

[0177] The calculated Q value is relatively accurate, but due to the high computational complexity, a typical MCU requires approximately 1ms of calculation time. In wireless charging applications, the foreign object detection interval is at least 300ms, which is sufficient for the MCU to perform the calculations.

[0178] Step S4: Based on the current oscillation frequency, the current quality factor, and the preset standard quality factor and preset standard oscillation frequency, determine whether there are foreign objects within the operating range of the power transmitter under test.

[0179] Among them, the preset standard quality factor and the preset standard oscillation frequency are the standard quality factor and standard oscillation frequency measured when the transmitter of the power supply under test leaves the factory or before use.

[0180] In combination with the above Figures 4-6The damped oscillation curve shown, along with the changes in Q value and oscillation frequency f within the alternating electromagnetic field of the wireless power transmitter, can determine whether there are foreign objects within the operating range of the wireless power transmitter under test. Specifically, if the Q value decreases significantly while the oscillation frequency remains constant, it indicates that only a metallic foreign object (inductive load) exists within the alternating electromagnetic field of the wireless power transmitter under test; if the Q value decreases slightly and the oscillation frequency also changes (determined by the natural frequency of the wireless power receiver), it indicates that a wireless power receiver (capacitive load) exists within the alternating electromagnetic field of the wireless power transmitter under test; if the Q value remains unchanged relative to the standard value and the oscillation frequency remains constant due to the transmitter's natural oscillation frequency, it indicates that no metallic components exist within the alternating electromagnetic field of the wireless power transmitter under test.

[0181] The foreign object detection method provided in this embodiment, based on the pulse signal output by the damped oscillation signal processing circuit, can collect sufficient parameters and calculate them according to the physical meaning of the LC oscillation circuit, thus obtaining a more accurate and reliable oscillation frequency and quality factor. Furthermore, since this embodiment can measure the oscillation frequency f of the wireless power transmitter under test, it meets the "foreign object detection method based on the system's inherent frequency" requirement in Qi protocol version 1.3, increasing the applicability of this foreign object detection method. In addition, since this embodiment can measure the Q value and oscillation frequency f of the wireless power transmitter under test, it can determine whether there are metallic foreign objects in the alternating electromagnetic field of the wireless power transmitter, whether there is a possible power receiver, whether there is a situation where a receiving device and a metallic foreign object coexist, and even determine the degree of influence of the foreign object on the charging efficiency, thereby enabling more detailed foreign object identification.

[0182] Example 4

[0183] Based on the same concept as the damped oscillation signal processing circuit described above, this embodiment also provides a foreign object detection device for wireless charging, such as... Figure 10 As shown, the device includes: the aforementioned damped oscillation signal processing circuit, and further includes a parameter calculation module and a foreign object detection module. The damped oscillation signal processing circuit processes the damped oscillation signal of the wireless power transmitter under test to obtain a corresponding pulse signal; the parameter calculation module determines the current oscillation frequency and current quality factor of the wireless power transmitter under test based on the pulse signal; the foreign object detection module determines whether a foreign object exists within the operating range of the wireless power transmitter based on the current oscillation frequency, current quality factor, and preset standard quality factor and preset standard oscillation frequency.

[0184] The foreign matter detection device provided in the embodiment is based on the same concept as the damping oscillation signal processing circuit, and can at least achieve the beneficial effects of the damping oscillation signal processing circuit. Any implementation of the damping oscillation signal processing circuit can be applied to the foreign matter detection device provided in the embodiment, and thus will not be described here.

[0185] In some embodiments, as shown in Figure 11 The foreign matter detection device further includes a calibration module. The calibration module is configured to detect an actual voltage of the voltage division node of the damping oscillation signal processing circuit when the pulse signal logic changes, and calibrate the threshold voltage of the damping oscillation signal processing circuit based on the actual voltage.

[0186] Embodiment five

[0187] Based on the same concept as the foreign matter detection device for wireless charging, the embodiment further provides a wireless charging device. The wireless charging device includes a wireless power transmitter and the foreign matter detection device for wireless charging.

[0188] The wireless charging device provided in the embodiment is based on the same concept as the foreign matter detection device, and can at least achieve the beneficial effects of the foreign matter detection device. Any implementation of the foreign matter detection device can be applied to the wireless charging device provided in the embodiment, and thus will not be described here.

[0189] Embodiment six

[0190] The electronic device provided in the embodiment can execute the foreign matter detection circuit. Please refer to Figure 12 , which shows a schematic diagram of a power consumption device provided in some embodiments of the application. As shown in Figure 12 The power consumption device 40 includes a processor 400, a memory 401, a bus 402, and a communication interface 403. The processor 400, the communication interface 403, and the memory 401 are connected through the bus 402. The memory 401 stores a computer program that can run on the processor 400. When the processor 400 runs the computer program, it executes the foreign matter detection method provided in any of the preceding embodiments.

[0191] The memory 401 can include a high-speed random access memory (RAM) and can also include a non-volatile memory, such as at least one disk memory. The communication interface 403 can be wired or wireless, and can be used to implement the communication connection between the device network element and at least one other network element, and can use the Internet, a wide area network, a local area network, a metropolitan area network, etc.

[0192] The bus 402 can be an ISA bus, a PCI bus, an EISA bus, or the like. The bus can be divided into an address bus, a data bus, a control bus, and the like. Among them, the memory 401 is used to store programs, and the processor 400 executes the programs after receiving execution instructions. The foreign matter detection method disclosed in any of the embodiments of the present application can be applied to the processor 400 or implemented by the processor 400.

[0193] The processor 400 can be an integrated circuit chip with signal processing capability. In the implementation process, each step of the above method can be completed by the integrated logic circuit of hardware in the processor 400 or the instruction in the form of software. The processor 400 described above can be a general processor, including a central processing unit (CPU), a network processor (NP), and the like; it can also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a ready programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component. Each method, step and logic block disclosed in the embodiments of the present application can be implemented or executed. The general processor can be a microprocessor or the processor can also be any conventional processor. The steps of the method disclosed in combination with the embodiments of the present application can be directly embodied as a hardware code processor for execution, or a combination of hardware and software modules in the code processor for execution. The software module can be located in a random access memory, a flash memory, a read only memory, a programmable read only memory or an electrically erasable programmable memory, a register, and the like mature storage medium in the art. The storage medium is located in the memory 401, and the processor 400 reads the information in the memory 401, and combines the hardware to complete the steps of the above method.

[0194] The power consuming equipment provided by the embodiments of the present application and the foreign matter detection method provided by the embodiments of the present application have the same beneficial effects as the method they adopt, run or implement.

[0195] Embodiment seven

[0196] The embodiments of the present application also provide a computer readable storage medium corresponding to the foreign matter detection method provided by the foregoing embodiments. Please refer to Figure 13 The computer readable storage medium shown is an optical disc 30, and a computer program (i.e. program product) is stored on the optical disc 30. When the computer program is run by the processor, the foreign matter detection method provided by any of the foregoing embodiments will be executed.

[0197] It should be noted that examples of the computer-readable storage medium can also include, but are not limited to, phase-change memories (PRAM), static random access memories (SRAM), dynamic random access memories (DRAM), other types of random access memories (RAM), read-only memories (ROM), electrically erasable programmable read-only memories (EEPROM), flash memories, or other optical, magnetic storage media, and the like, which are not listed one by one here.

[0198] The computer-readable storage medium provided by the above embodiments of the present application has the same beneficial effects as the method adopted, run or implemented by the application program stored therein, based on the same inventive concept as the foreign matter detection method provided by the embodiments of the present application.

[0199] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the specification of the present application. Especially, as long as there is no structural conflict, each technical feature mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A damped oscillation signal processing circuit, characterized by, The damping oscillation signal processing circuit comprises at least one set of voltage dividing circuit and at least one set of pulse output circuit. The voltage dividing circuit comprises a first resistor, a third resistor and a voltage dividing node, one end of the first resistor is connected to a second power supply voltage, and the other end is connected to the voltage dividing node; one end of the third resistor is connected to the damping oscillation signal, and the other end is connected to the voltage dividing node. The pulse output circuit comprises a second resistor, a transistor and a pulse output node, one end of the second resistor is connected to a first power supply voltage, and the other end is connected to the pulse output node; the base of the transistor is connected to the voltage dividing node, and the collector and the emitter of the transistor are respectively connected to the pulse output node and a common terminal. The damping oscillation signal processing circuit comprises two sets of voltage dividing circuits and two sets of pulse output circuits, and the two sets of voltage dividing circuits have different threshold voltages; the threshold voltage represents the amplitude of the damping oscillation signal when the transistor is in the off state.

2. The circuit of claim 1, wherein, Further comprising a clamping circuit, one end of the clamping circuit is connected to the common terminal, and the other end is connected to the voltage dividing node, and the clamping circuit is used to clamp the voltage of the voltage dividing node within a preset threshold.

3. The circuit of claim 2, wherein, The clamping circuit comprises a diode, the anode of the diode is connected to the common terminal, and the cathode of the diode is connected to the voltage dividing node.

4. A chip, characterized by The damping oscillation signal processing circuit is integrated on the chip.

5. A foreign object detection apparatus for wireless charging, characterized by, The damping oscillation signal processing circuit comprises: The damping oscillation signal processing circuit according to any one of claims 1-3 is used to process the damping oscillation signal of a wireless power transmitter to be tested, so as to obtain a corresponding pulse signal; A parameter calculation module is configured to determine a current oscillation frequency and a current quality factor of the wireless power transmitter to be tested according to the pulse signal; An alien object detection module is configured to determine whether there is an alien object in the working range of the wireless power transmitter based on the current oscillation frequency, the current quality factor, and a preset standard quality factor and a preset standard oscillation frequency.

6. The foreign object detection device of claim 5, wherein Further comprising a calibration module, the calibration module is used to detect the actual voltage of the voltage dividing node of the damping oscillation signal processing circuit when the pulse signal occurs logical change; and calibrate the threshold voltage of the damping oscillation signal processing circuit based on the actual voltage.

7. A wireless charging device comprising a wireless power transmitter, characterized in that, Further comprising the alien object detection device for wireless charging according to claim 5 or 6. 8.A wireless charging foreign object detection method, characterized by, The damping oscillation signal processing circuit according to any one of claims 1-3 is used to process the damping oscillation signal of a wireless power transmitter to be tested, so as to obtain a corresponding pulse signal; Determine two target amplitudes of the damping oscillation signal and a target period number between the two target amplitudes according to the pulse signal; Determine a current oscillation frequency and a current quality factor of the wireless power transmitter to be tested based on the two target amplitudes and the target period number; Determine whether there is an alien object in the working range of the wireless power transmitter to be tested based on the current oscillation frequency, the current quality factor, and a preset standard quality factor and a preset standard oscillation frequency. The determination of the two target amplitudes of the damping oscillation signal and the target period number between the two target amplitudes according to the pulse signal comprises:

9. The method of claim 8, wherein, ​ determining two target instants according to the change of the pulse signal, and a time difference between the two target instants is the target period number; determining two target amplitudes corresponding to the two target instants respectively.

10. The method of claim 9, wherein, The method according to the change of the pulse signal, comprising: determining a falling edge instant and a rising edge instant of each pulse signal generated by the damped oscillation signal according to the pulse signal; determining two target instants according to the falling edge instant and the rising edge instant of the Mth pulse signal and the falling edge instant and the rising edge instant of the Nth pulse signal, wherein M and N are two different natural numbers.

11. The method of claim 8, wherein, The method according to the change of the pulse signal, comprising: determining one of the target amplitudes as an initial amplitude of the damped oscillation signal, and determining the other target amplitude as a threshold voltage for generating the pulse signal; determining the target period number as a number of pulse signals generated by the pulse signal.

12. The method of claim 8, wherein, The damped oscillation signal processing circuit comprises two sets of voltage dividing circuits and two sets of pulse output circuits, and the two sets of voltage dividing circuits have different threshold voltages. The method according to the change of the pulse signal, comprising: determining a first number of pulse signals and a second number of pulse signals generated by the two threshold voltages respectively; determining the two threshold voltages as the two target amplitudes, and determining a difference between the first number of pulse signals and the second number of pulse signals as the target period number.

13. The method according to any one of claims 8-12, characterized in that, Further comprising: detecting an actual voltage of a voltage dividing node of the damped oscillation signal processing circuit when the pulse signal generation logic changes; calibrating the threshold voltages of the damped oscillation signal processing circuit based on the actual voltage.

14. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, The processor executes the computer program to implement the method according to any one of claims 8-13.

15. A computer readable storage medium having stored thereon a computer program, characterized in that, The program is executed by the processor to implement the method according to any one of claims 8-13.

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