Wireless charging Q value detection circuit and electronic device

Abstract

The utility model provides a wireless charging Q value detection circuit and an electronic device. One end of the Q value detection circuit is connected with an MCU, and the other end of the Q value detection circuit is connected with a charging coil CoilN; the wireless charging Q value detection circuit comprises a first switch SW1, a U1 operational amplifier connected with the first switch SW1, and a triode Q1 connected with the first switch SW1. The collector electrode of the triode Q1 is connected with the signal rectification circuit, and the signal rectification circuit is further connected with the MCU. The collector electrode of the triode Q1 is also connected to a charging coil CoilN through a diode DN; and one end of the second switch SW2 is connected with the LC resonance circuit, and the other end of the second switch SW2 is connected with the MCU. Before wireless charging is carried out through the wireless charging Q value detection circuit, the wireless charger carries out Q value scanning at first, and metal foreign matter at the charging coil end is detected, so that the potential risk of battery damage or overheating is avoided.

Description

Technical Field

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

[0002] Q-value detection for wireless charging involves checking for metallic foreign objects on the TX charging coil before wireless charging begins. This is done to prevent heat loss caused by metallic foreign objects being trapped in the coil. Users sometimes place metal objects such as coins, keys, and aluminum foil on the TX coil. If a Qi wireless charging phone is placed on the coil during charging, the metallic foreign objects will be heated to high temperatures by the magnetic field energy. Currently, the most common Q-value detection method is the attenuation method, but this is not particularly stable. The attenuation method relies on the attenuation of the measured signal to calculate the Q value. Very small signal attenuation can lead to measurement errors. Especially at low Q values, where the signal attenuation is very weak, detection can be difficult. Furthermore, the attenuation method is sensitive to noise, which affects Q-value accuracy. The attenuation method's short Q-value oscillation time and weak signal lead to large Q-value measurement errors, making it difficult to accurately identify metallic foreign objects. Conventional attenuation Q-value circuits lack frequency detection and cannot identify the type of foreign object on the TX coil. Therefore, a more robust Q-value detection circuit is needed. Summary of the Invention

[0003] In response to the above-mentioned defects of the prior art, the present application provides a wireless charging Q-value detection circuit. Before wireless charging, the wireless charger first performs a Q-value scan through the wireless charging Q-value detection circuit to detect metal foreign objects at the charging coil end, thereby preventing mobile phones or Qi devices from charging under the influence of metal objects, thereby avoiding potential battery damage or overheating risks.

[0004] To achieve the above objectives, the present application provides a wireless charging Q value detection circuit, one end of which is connected to the MCU and the other end is connected to the charging coil CoilN;

[0005] The wireless charging Q value detection circuit includes:

[0006] A first switch SW1, an operational amplifier U1 connected to the first switch SW1, and a base of a transistor Q1 also connected to the first switch SW1; the collector of the transistor Q1 is connected to a signal rectifier circuit, which is also connected to the MCU; the collector of the transistor Q1 is also connected to a charging coil CoilN via a diode DN;

[0007] The second switch SW2 has one end connected to the LC resonant circuit and the other end connected to the MCU.

[0008] The signal rectification circuit includes a diode D4 and a capacitor C2. One end of the capacitor C2 is grounded, and the other end is connected to the MCU. One end of the diode D4 is connected to the transistor Q1, and the other end is connected to the MCU.

[0009] The charging coil CoilN is connected in parallel with the capacitor Cser and the capacitor Cpar to form an LC resonant circuit;

[0010] The LC resonant circuit sends the LC resonant waveform to the inverting input terminal of the U1 operational amplifier through the capacitor C1.

[0011] The output of the U1 operational amplifier is connected to the MCU.

[0012] The emitter of the transistor Q1 is connected in series with a resistor R1.

[0013] The resistor R1 is connected in parallel with the resistor R2. One end of the resistor R2 is connected to the base of the transistor Q1 through the resistor R3. The other end of the resistor R2 is connected to the power supply.

[0014] The first switch SW1 and the second switch SW2 are controlled by an MCU.

[0015] The wireless charging Q-value detection circuit improves the efficiency, safety, and reliability of the wireless charging system by accurately measuring the Q-value, providing real-time feedback, detecting anomalies, and optimizing system performance.

[0016] Specifically, the electrical principle of the wireless charging Q value detection circuit is as follows:

[0017] S1: Start the wireless charging Q value detection circuit and turn off the wireless charging function; this ensures that there will be no other charging interference during the measurement process, thereby obtaining more accurate Q value data.

[0018] S2: The MCU controls the first switch SW1 and the second switch SW2 to be closed, and the transistor Q1 is turned on for a short time. The current of the transistor Q1 flows through the diode D1 to the charging coil Coil1;

[0019] S3: The LC resonant circuit generates an LC resonant waveform and sends the LC resonant waveform to the inverting input terminal of the U1 operational amplifier through capacitor C1;

[0020] S4: Detect the voltage at the signal rectifier circuit end and the LC resonance waveform at the output end of the U1 operational amplifier respectively, and perform Q-FOD calibration based on the detection results.

[0021] The step S3 further comprises:

[0022] The U1 operational amplifier amplifies the LC resonant waveform in the reverse direction by 180°, and the first switch SW1 controls the transistor Q1 according to the amplified signal. The transistor Q1 amplifies the output coil resonance by 180° in the reverse direction to supply energy, so that the charging coil Coil1 forms a stable sinusoidal resonant signal during normal operation.

[0023] The step S4 of detecting the voltage at the signal rectifier circuit end further includes:

[0024] After the MCU performs ADC conversion on the voltage at the signal rectifier circuit end, it determines whether the voltage drops. If it drops, there is a foreign object; otherwise, the charging coil Coil1 is normal.

[0025] The LC resonance waveform at the output end of the U1 operational amplifier is detected in step S4, further comprising:

[0026] The MCU detects the LC resonance waveform. If it detects that the amplitude of the LC resonance waveform increases and the LC resonance frequency decreases, there is a magnetic foreign object on the charging coil Coil1.

[0027] The LC resonance waveform at the output end of the U1 operational amplifier is detected in step S4, further comprising:

[0028] The MCU detects the LC resonant waveform. When it detects that the amplitude of the LC resonant waveform decreases and the LC resonant frequency increases, it determines that there is a metal foreign object on the charging coil Coil1.

[0029] The type of the metal foreign matter may also be determined according to different amplitudes and different LC resonance frequencies of the LC resonance waveform.

[0030] In this solution, when there is a metal foreign body, the Q-FOD alarm is triggered; otherwise, no foreign body alarm is triggered;

[0031] The detection method can be used to simultaneously detect the Q values of multiple coil solutions.

[0032] To achieve the above objectives, the present application also provides an electronic device, which includes the wireless charging Q-value detection circuit as described above.

[0033] Compared with the prior art, the present invention has the following advantages:

[0034] This application proposes a wireless charging Q-value detection circuit and electronic device. The wireless charging Q-value detection circuit in this application includes two parts: Q-value-correlated voltage detection and LC resonant frequency change detection. The Q-value-correlated voltage detection can identify the presence of metal foreign objects in the charging coil, while the LC resonant frequency change detection can further determine the type of metal foreign object based on the LC resonant waveform frequency. This improves the accuracy and reliability of the measurement results of foreign object detection at the charging coil end, preventing potential safety hazards. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a wireless charging Q-value detection circuit diagram in one embodiment of the present application.

[0036] Figure 2 This is a diagram of the resonance signal generated by the coil when the charging coil is free of foreign matter and in normal working state in one embodiment of the present application.

[0037] Figure 3 This is a diagram of the resonance signal generated by the coil when there is a foreign object in the charging coil in one embodiment of the present application.

[0038] Figure 4 This is a diagram of the resonance signal generated by the coil when different foreign objects are present in one embodiment of the present application. DETAILED DESCRIPTION

[0039] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions will be clearly and completely described below in conjunction with the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application. Example

[0040] As attached Figure 1 As shown, in order to solve the above technical problems, the present application provides a wireless charging Q value detection circuit, one end of the Q value detection circuit is connected to the MCU, and the other end is connected to the charging coil CoilN;

[0041] The wireless charging Q value detection circuit includes:

[0042] A first switch SW1, an operational amplifier U1 connected to the first switch SW1, and a base of a transistor Q1 also connected to the first switch SW1; the collector of the transistor Q1 is connected to a signal rectifier circuit L1, and the signal rectifier circuit L1 is also connected to the MCU;

[0043] The collector of the transistor Q1 is also connected to the charging coil CoilN through the diode DN;

[0044] The second switch SW2 has one end connected to the LC resonant circuit and the other end connected to the MCU.

[0045] There are at least one or more charging coils CoilN. When there are multiple charging coils CoilN, each can be connected to the MCU via transistor Q1 for wireless charging Q value detection. N is a natural number.

[0046] The signal rectification circuit L1 includes a diode D4 and a capacitor C2. One end of the capacitor C2 is grounded, and the other end is connected to the MCU. One end of the diode D4 is connected to the transistor Q1, and the other end is connected to the MCU.

[0047] When a metallic foreign object MF1 approaches the TX coil, the LC resonance waveform voltage decreases. When the metallic foreign object MF1 is removed from the TX coil, the LC resonance waveform voltage increases. This decrease or increase in the LC resonance waveform voltage affects the pulse voltage at the point where transistor Q1 outputs D1 in the circuit diagram. The TX coil generates a dynamic voltage divider. The pulse voltage output by transistor Q1 passes through diode D4 and filter capacitor C2 to generate a DC voltage level, which is then fed into the MCU ADC for voltage measurement. If this Q-value voltage level becomes very low, it indicates that a large metallic foreign object MF1 is present above the charging TX coil.

[0048] Any of the charging coils CoilN is connected in parallel with the capacitor Cser and the capacitor Cpar to form an LC resonant circuit;

[0049] The LC resonant circuit sends the LC resonant waveform to the inverting input terminal of the U1 operational amplifier through the capacitor C1.

[0050] The output of the U1 operational amplifier is connected to the MCU.

[0051] The emitter of the transistor Q1 is connected in series with a resistor R1.

[0052] The resistor R1 is connected in parallel with the resistor R2. One end of the resistor R2 is connected to the base of the transistor Q1 through the resistor R3. The other end of the resistor R2 is connected to the power supply.

[0053] The first switch SW1 and the second switch SW2 are controlled by an MCU.

[0054] During Q value detection, the charging coil CoilN receives synchronous resonance signal input through capacitor C1, and after passing through operational amplifier U1 and transistor Q1, diode DN outputs synchronous resonance energy supply of charging coil CoilN, forming a positive feedback energy supply circuit. This circular energy supply circuit can supply energy of the same frequency and phase, which enables the waveform of LC resonance to be maintained and the voltage to be stable. When there is no foreign matter in the charging coil CoilN and it is in normal working state, a stable sinusoidal resonance signal (such as Figure 2 shown).

[0055] like Figure 3 As shown in the figure, when a foreign metal object MF1 is present at the charging coil, the coil's energy loss increases, reducing the amplitude of the resonant waveform in the LC resonant circuit. Furthermore, this reduced amplitude reduces the DC voltage at the signal rectifier L1. After the MCU converts the Q-value level to the ADC, it detects a decrease in voltage, indicating the presence of a foreign metal object MF1. Therefore, Q-value-correlated voltage detection can be used to identify the presence of a foreign metal object MF1 at the charging coil.

[0056] Furthermore, when there is a metal foreign object MF1 at the charging coil end, the LC resonant waveform is amplified and shaped into a square wave. The output end of the U1 operational amplifier sends the square wave to the MCU for Q resonant frequency detection, and then determines the metal type of the foreign object, thereby distinguishing it from the metal material of the mobile phone.

[0057] like Figure 4 As shown in the table below, placing different foreign objects on the TX coil may cause changes in the LC resonant frequency: Placing a magnetic foreign object MF2 on the TX coil increases the coil inductance and decreases the LC resonant frequency. Placing a metallic foreign object MF1 (such as copper) on the TX coil decreases the coil inductance and increases the LC resonant frequency. See the table below for details.

[0058] In this embodiment, the specific detection method of the wireless charging Q value detection circuit is as follows:

[0059] S1: Start the wireless charging Q value detection circuit and turn off the wireless charging function; this ensures that there will be no other charging interference during the measurement process, thereby obtaining more accurate Q value data.

[0060] S2: The MCU controls the first switch SW1 and the second switch SW2 to be closed, and the transistor Q1 is turned on for a short time. The current of the transistor Q1 flows through the diode D1 to the charging coil Coil1;

[0061] S3: The LC resonant circuit generates an LC resonant waveform and sends the LC resonant waveform to the inverting input terminal of the U1 operational amplifier through capacitor C1;

[0062] S4: Detect the voltage at the end of the signal rectifier circuit L1 and the LC resonance waveform at the output end of the U1 operational amplifier respectively, and perform Q-FOD calibration based on the detection results.

[0063] The step S3 further comprises:

[0064] The U1 operational amplifier amplifies the LC resonant waveform in the reverse direction by 180°, and the first switch SW1 controls the transistor Q1 according to the amplified signal. The transistor Q1 amplifies the output coil resonance by 180° in the reverse direction to supply energy, so that the charging coil Coil1 forms a stable sinusoidal resonant signal during normal operation.

[0065] The step S4 of detecting the voltage at the end of the signal rectifier circuit L1 further includes:

[0066] After the MCU performs ADC conversion on the voltage at the end of the signal rectifier circuit L1, it determines whether the voltage drops. If it drops, there is a foreign object; otherwise, the charging coil Coil1 is normal.

[0067] The LC resonance waveform at the output end of the U1 operational amplifier is detected in step S4, further comprising:

[0068] The MCU detects the LC resonance waveform. If it detects that the amplitude of the LC resonance waveform increases and the LC resonance frequency decreases, it indicates that a magnetic foreign object MF2 is present on the charging coil Coil1.

[0069] The LC resonance waveform at the output end of the U1 operational amplifier is detected in step S4, further comprising:

[0070] The MCU detects the LC resonance waveform. When it detects that the amplitude of the LC resonance waveform decreases and the LC resonance frequency increases, it determines that a metal foreign object MF1 is present on the charging coil Coil1.

[0071] The type of the metal foreign matter MF1 can also be determined according to different amplitudes and different LC resonance frequencies of the LC resonance waveform.

[0072] In this solution, when there is a metal foreign body MF1, a Q-FOD alarm is issued; otherwise, no foreign body alarm is issued;

[0073] The detection method can be used to simultaneously detect the Q values of multiple coil solutions. Example

[0074] The present application also provides an electronic device, which includes the wireless charging Q-value detection circuit as described above.

[0075] The specific embodiments described above further illustrate the objectives, technical solutions, and beneficial effects of this application. It should be understood that the above descriptions are merely specific embodiments of this application and are not intended to limit the scope of protection of this application. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of this application by those skilled in the art should be included within the scope of protection of this application.

Claims

1. A wireless charging Q value detection circuit, characterized in that: One end of the Q value detection circuit is connected to the MCU, and the other end is connected to the charging coil CoilN; the wireless charging Q value detection circuit includes: A first switch SW1, an operational amplifier U1 connected to the first switch SW1, and a transistor Q1 also connected to the first switch SW1; the collector of the transistor Q1 is connected to a signal rectifier circuit, which is also connected to the MCU; the collector of the transistor Q1 is also connected to a charging coil CoilN via a diode DN; The second switch SW2 has one end connected to the LC resonant circuit and the other end connected to the MCU.

2. A wireless charging Q value detection circuit according to claim 1, characterized in that: The signal rectification circuit includes a diode D4 and a capacitor C2. One end of the capacitor C2 is grounded, and the other end is connected to the MCU. One end of the diode D4 is connected to the transistor Q1, and the other end is connected to the MCU.

3. The wireless charging Q value detection circuit according to claim 1, characterized in that: The charging coil CoilN is connected in parallel with the capacitor Cser and the capacitor Cpar to form an LC resonant circuit.

4. A wireless charging Q value detection circuit according to claim 3, characterized in that: The LC resonant circuit sends the LC resonant waveform to the inverting input terminal of the U1 operational amplifier through the capacitor C1.

5. A wireless charging Q value detection circuit according to claim 4, characterized in that: The output end of the U1 operational amplifier is connected to the MCU.

6. The wireless charging Q value detection circuit according to claim 1, characterized in that: The emitter of the transistor Q1 is connected in series with a resistor R1.

7. The wireless charging Q value detection circuit according to claim 6, characterized in that: The resistor R1 is connected in parallel with the resistor R2. One end of the resistor R2 is connected to the base of the transistor Q1 through the resistor R3. The other end of the resistor R2 is connected to the power supply.

8. The wireless charging Q value detection circuit according to claim 1, characterized in that: The first switch SW1 and the second switch SW2 are controlled by an MCU.

9. An electronic device, characterized in that: The electronic device includes the wireless charging Q-value detection circuit according to any one of claims 1-8.

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