Wireless charging device capable of automatically identifying non-specified wireless power receiving load

Abstract

A wireless charging device capable of automatically identifying a non-specified wireless power receiving load comprises a charging end circuit and a receiving end circuit, the charging end circuit comprises an MCU control circuit, a switch circuit, a resonant cavity circuit and a resonance waveform sampling and shaping circuit, and the receiving end circuit comprises a coupling resonance and rectification filter circuit and a charging control switch circuit. The MCU control circuit is provided with a negative slope fixed value of voltage to time, the MCU control circuit outputs a pulse signal to control and drive the switching circuit to excite the resonant cavity circuit to generate sine resonance, resonance energy passes through the power receiving end circuit and the resonance waveform sampling and shaping circuit to obtain a voltage value needing to be judged, and the voltage value needs to be judged. And the voltage value needing to be judged is sent back to the MCU control circuit, and the negative slope value of the voltage value needing to be judged and time and the negative slope fixed value are compared and analyzed, so that whether the power receiving end is a specified receiving load or not is judged.

Description

Technical Field

[0001] The utility model relates to the technical field of wireless charging, and in particular to a wireless charging device capable of automatically identifying a non-specified wireless power receiving load. Background Art

[0002] As people's living standards continue to improve, they pay more and more attention to oral health. Electric toothbrushes have begun to enter thousands of households with their efficient cleaning functions. This type of toothbrush uses a rechargeable battery to drive a DC motor to achieve different speeds and directions as well as a vibration function to drive the toothbrush head to achieve efficient and seamless cleaning of teeth. Considering the environmental conditions of its use, it needs to have a certain level of dust and water resistance. The wired charging method has its limitations. The traditional charging method for electric toothbrushes is electromagnetic coupling wireless charging, that is, there is no physical contact between the charger and the wireless power receiving load receiving circuit, and wireless charging is achieved when the charging power is large enough. In order to avoid the risk of abnormal charging of non-designated wireless power receiving loads (mainly metal foreign objects) and heat generation, automatic identification of the charged object is a conventional means.

[0003] In the prior art, the Qi wireless charging standard protocol is mainly used for automatic identification of the charged object. The protocol is transmitted by using standard charging and receiving coils at both the charger and the receiving end, and a control chip that complies with the standard is used to send and receive the protocol for identification. This method can achieve two-way identification of the charging and receiving ends for charging. However, the use of this standard requires expensive membership fees, and the corresponding control chip is also expensive, which increases the cost of the overall circuit and makes the overall product price have no competitive advantage. At the same time, the current Qi technology needs to cover different wireless charging requirements, resulting in a very complex and large software and hardware system. Utility Model Content

[0004] In order to overcome the shortcomings and deficiencies of the prior art, the utility model provides a wireless charging device that automatically identifies non-specified wireless power receiving loads, which solves the technical problems of low circuit utilization, high cost, low cost performance and high communication protocol cost of complex circuits used in the prior art.

[0005] The utility model is implemented through the following technical solutions to achieve the above-mentioned purpose: a wireless charging device for automatically identifying non-specified wireless power receiving loads, including a charging end circuit and a receiving end circuit, the charging end circuit including an MCU control circuit, a switch circuit, a resonant cavity circuit, and a resonant waveform sampling and shaping circuit, the receiving end circuit including a coupled resonance and rectification filter circuit, a charging control switch circuit, and a rechargeable battery, the MCU control circuit sets a fixed value of a negative slope of voltage to time, the MCU control circuit outputs a pulse signal to control and drive the switch circuit to stimulate the resonant cavity circuit to generate a sinusoidal resonance, the energy of the resonance passes through the receiving end circuit and the resonant waveform sampling and shaping circuit to obtain a voltage value to be determined, the voltage value to be determined is sent back to the MCU control circuit, and the negative slope value of the voltage value to be determined and time is compared and analyzed with the negative slope fixed value.

[0006] Preferably, if the negative slope value of the voltage value and time to be determined reaches the fixed negative slope value, the charging requirement is met, and the receiving end is automatically determined to be a designated wireless power receiving load. The MCU control circuit continuously outputs a pulse signal to control and drive the switch circuit to excite the resonant cavity circuit, and continuously outputs energy to the receiving end circuit to realize the battery charging function.

[0007] Preferably, if the negative slope of the voltage value and time to be determined does not reach the fixed negative slope value, the charging requirement is not met, the MCU control circuit stops outputting the pulse signal, and automatically determines that the power receiving end is a non-designated wireless power receiving load.

[0008] Preferably, the resonant waveform sampling and shaping circuit includes a resonant capacitor and a resonant inductor, and the voltage value to be determined is obtained through a voltage resonant waveform in the resonant capacitor or the resonant inductor.

[0009] Preferably, the resonant cavity circuit comprises a resonant cavity capacitor and a resonant cavity inductor.

[0010] Preferably, the resonant cavity inductor is an open magnetic circuit, and the resonant cavity inductor is a transmitting coil of the resonant energy.

[0011] Preferably, the voltage value to be determined passes through the resonant waveform sampling and shaping circuit and is then input into the A / D port of the MCU control circuit for waveform analysis and determination.

[0012] Preferably, when the negative slope fixed value is a specified wireless power receiving load by the receiving end, the MCU control circuit obtains and stores the negative slope value of the corresponding voltage value and time as the negative slope fixed value, or the internal part of the MCU control circuit is directly solidified and set to the negative slope fixed value.

[0013] Preferably, the specific connection mode of the resonant waveform sampling and shaping circuit is as follows: the resonant cavity capacitor includes a resonant cavity capacitor A end and a resonant cavity capacitor B end, the resonant cavity inductor includes a resonant cavity inductor A end and a resonant cavity inductor B end, the sampling signal is taken from the resonant cavity capacitor A end, the resonant cavity capacitor A end is connected to the resonant cavity inductor A end, and the resonant cavity capacitor B end is the reference ground; the sampling signal is sent to the anode of the rectifier diode D6, the cathode of the diode D6 is connected to one end of the current limiting resistor R30, and the other end of the current limiting resistor R30 is connected to one end of the filter capacitor C20 and the cathode of the voltage regulator tube Z2. The other end of the filter capacitor C20 is connected to the reference ground; the anode of the voltage-stabilizing tube Z2 is connected to one end of the voltage-dividing resistor R32, and the other end of the voltage-dividing resistor R32 is connected to the cathode of the voltage-stabilizing tube Z3 and one end of the filter capacitor C19 and one end of the voltage-dividing resistor R31, thereby completing the sampling, filtering and shaping, forming a shaped analysis signal and sending it to the A / D input port of the MCU control circuit 1; the anode of the voltage-stabilizing tube Z3, the other end of the filter capacitor C19 and the other end of the voltage-dividing resistor R31 are connected to the reference ground; the power supply Vss pin of the MCU control circuit 1 is also connected to the reference ground.

[0014] Preferably, the resonant cavity capacitor includes a resonant cavity capacitor A end and a resonant cavity capacitor B end, the resonant cavity inductor includes a resonant cavity inductor A end and a resonant cavity inductor B end, the sampling signal is taken from the resonant cavity inductor A end, the resonant cavity inductor A end is connected to the resonant cavity capacitor A end, and the resonant cavity inductor B end is the reference ground; the sampling signal is sent to the anode of the rectifier diode D6, the cathode of the diode D6 is connected to one end of the current limiting resistor R30, the other end of the current limiting resistor R30 is connected to one end of the filter capacitor C20 and the cathode of the voltage regulator tube Z2, the filter capacitor C20 The other end is connected to the reference ground; the anode of the voltage-stabilizing tube Z2 is connected to one end of the voltage-dividing resistor R32, and the other end of the voltage-dividing resistor R32 is connected to the cathode of the voltage-stabilizing tube Z3 and one end of the filter capacitor C19 and one end of the voltage-dividing resistor R31, thereby completing the sampling, filtering and shaping, forming a shaped analysis signal and sending it to the A / D input port of the MCU control circuit; the anode of the voltage-stabilizing tube Z3 and the other end of the filter capacitor C19 and the other end of the voltage-dividing resistor R31 are connected to the reference ground; the power supply Vss foot of the MCU control circuit is connected to the reference ground.

[0015] Compared with the prior art, the beneficial effects obtained by the utility model are:

[0016] The utility model discloses a wireless charging device for automatically identifying non-designated wireless power receiving loads. The MCU control circuit outputs a pulse signal to control and drive the switch circuit to stimulate the resonant cavity circuit to generate a sinusoidal resonance. The resonant energy passes through the receiving end circuit and the resonant waveform sampling and shaping circuit to obtain a voltage value to be determined. The voltage value to be determined is fed back to the MCU control circuit. The negative slope value of the voltage value to be determined and time is compared and analyzed with the negative slope fixed value to determine whether the receiving end is a designated receiving load. The utility model solves the technical problems of low circuit utilization, high cost, low cost performance and high communication protocol cost in the prior art using complex circuits. The utility model has the advantages of simple circuit, high utilization, compact circuit device, avoiding communication protocol cost and low use cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0018] Figure 1 The utility model shows a circuit diagram of a wireless charging device for automatically identifying a non-specified wireless power receiving load.

[0019] Figure 2 The utility model shows a charging end circuit diagram of a wireless charging device for automatically identifying a non-specified wireless power receiving load.

[0020] Figure 3 The utility model shows a circuit diagram of a wireless charging device receiving end that automatically identifies a non-specified wireless power receiving load.

[0021] Figure 4 FIG. 1 is a schematic diagram showing a negative slope of a specified wireless power receiving load voltage versus time in Example 1 of the wireless charging device of the present invention.

[0022] Figure 5 FIG. 2 is a schematic diagram showing a negative slope of a non-specified wireless power receiving load voltage versus time in Example 2 of the wireless charging device of the present invention.

[0023] Figure numerals: 1-MCU control circuit; 2-switch circuit; 3-resonant cavity circuit; 4-resonant waveform sampling and shaping circuit; 5-coupled resonance and rectification filter circuit; 6-charging switch and control circuit; 7-rechargeable battery. DETAILED DESCRIPTION

[0024] The present invention is further described below in conjunction with the drawings and specific embodiments of the specification, but the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example

[0025] Please refer to the attached Figure 1 To Attachment Figure 3 And attached Figure 4 A wireless charging device that automatically identifies non-specified wireless power receiving loads includes a charging end circuit and a receiving end circuit. The charging end circuit includes an MCU control circuit 1, a switch circuit 2, a resonant cavity circuit 3, and a resonant waveform sampling and shaping circuit 4. The receiving end circuit includes a coupled resonance and rectification filter circuit 5, a charging control switch circuit 6, and a rechargeable battery 7. The switch circuit 2 is a half-bridge switch circuit.

[0026] The MCU control circuit 1 sets a fixed negative slope value of voltage to time. When the negative slope fixed value is set by the power receiving end for a specified wireless power receiving load, the MCU control circuit 1 obtains and stores the negative slope value of the corresponding voltage value to time as the negative slope fixed value.

[0027] The resonant waveform sampling and shaping circuit 4 includes a resonant capacitor and a resonant inductor. The voltage value to be determined is obtained through the voltage resonant waveform in the resonant capacitor. The resonant cavity circuit 3 includes a resonant cavity capacitor and a resonant cavity inductor. The resonant cavity inductor is an open magnetic circuit, and the resonant cavity inductor is the transmitting coil of the resonant energy.

[0028] The MCU control circuit 1 outputs a pulse signal to control and drive the half-bridge switch circuit 2 to excite the resonant cavity circuit 3 to generate a sinusoidal resonance. The resonant energy passes through the receiving end circuit and the resonant waveform sampling and shaping circuit 4 to obtain a voltage value to be determined. The voltage value to be determined is sent back to the MCU control circuit 1 and input into the A / D port of the MCU control circuit 1 for waveform analysis and judgment. The negative slope value of the voltage value to be determined and the time is compared and analyzed with the negative slope fixed value. When the negative slope value of the voltage value to be determined and the time reaches the negative slope fixed value, it meets the charging requirement, and the receiving end is automatically determined to be a designated wireless power receiving load. The MCU control circuit 1 continuously outputs a pulse signal to control and drive the half-bridge switch circuit 2 to excite the resonant cavity circuit 3, and continuously outputs energy to the receiving end circuit to realize the battery charging function. When the negative slope value of the voltage value to be determined and the time does not reach the negative slope fixed value, it does not meet the charging requirement, and the receiving end is automatically determined to be a non-designated wireless power receiving load, and the MCU control circuit 1 stops outputting the pulse signal.

[0029] Further, the power receiving end is an electric toothbrush that specifies wireless power reception. Figure 4 In the figure, the electric toothbrush is put in at time t1, and the MCU control circuit 1 detects and determines that the voltage rises. After a specified time, since the charging switch at the power receiving end is turned on at time t2 within a specified range, a voltage peak Vpk is observed at time t2, and the voltage starts to drop. Before the specified time range t4, the voltage drops to form a valley point Vvl. The MCU control circuit 1 determines that it is a specified wireless power receiving load (electric toothbrush) by judging the time difference (t2-t1) and the amplitude difference between the voltage peak Vpk and the voltage valley Vvl found within the specified time range t2 to t4, that is, the negative slope of the voltage to time exceeds the specified set value, thereby entering the normal charging process.

[0030] Furthermore, the specific connection mode of the resonant waveform sampling and shaping circuit 4 is as follows: the resonant cavity capacitor includes a resonant cavity capacitor A end and a resonant cavity capacitor B end, the resonant cavity inductor includes a resonant cavity inductor A end and a resonant cavity inductor B end, the sampling signal is taken from the resonant cavity capacitor A end, the resonant cavity capacitor A end is connected to the resonant cavity inductor A end, and the resonant cavity capacitor B end is the reference ground; the sampling signal is sent to the anode of the rectifier diode D6, the cathode of the diode D6 is connected to one end of the current limiting resistor R30, and the other end of the current limiting resistor R30 is connected to one end of the filter capacitor C20 and the cathode of the voltage regulator tube Z2, The other end of the filter capacitor C20 is connected to the reference ground; the anode of the voltage-stabilizing tube Z2 is connected to one end of the voltage-dividing resistor R32, and the other end of the voltage-dividing resistor R32 is connected to the cathode of the voltage-stabilizing tube Z3 and one end of the filter capacitor C19 and one end of the voltage-dividing resistor R31, thereby completing the sampling, filtering and shaping, forming a shaped analysis signal and sending it to the A / D input port of the MCU control circuit 1; the anode of the voltage-stabilizing tube Z3, the other end of the filter capacitor C19 and the other end of the voltage-dividing resistor R31 are connected to the reference ground; the power supply Vss pin of the MCU control circuit 1 is also connected to the reference ground. Example

[0031] Please refer to the attached Figure 1 To Attachment Figure 3 And attached Figure 5 A wireless charging device that automatically identifies non-specified wireless power receiving loads includes a charging end circuit and a receiving end circuit. The charging end circuit includes an MCU control circuit 1, a switch circuit 2, a resonant cavity circuit 3, and a resonant waveform sampling and shaping circuit 4. The receiving end circuit includes a coupled resonance and rectification filter circuit 5, a charging control switch circuit 6, and a rechargeable battery 7. The switch circuit 2 is a full-bridge switch circuit.

[0032] The MCU control circuit 1 sets a fixed negative slope value of voltage to time. When the receiving end is a specified wireless power receiving load, the internal setting of the MCU control circuit 1 is a fixed negative slope value theoretically determined based on external measurement of the specified load.

[0033] The resonant waveform sampling and shaping circuit 4 includes a resonant capacitor and a resonant inductor. The voltage value to be determined is obtained through the voltage resonant waveform in the resonant inductor. The resonant cavity circuit 3 includes a resonant cavity capacitor and a resonant cavity inductor. The resonant cavity inductor is an open magnetic circuit and the resonant cavity inductor is the transmitting coil of the resonant energy.

[0034] The MCU control circuit 1 outputs a pulse signal to control and drive the full-bridge switch circuit 2 to excite the resonant cavity circuit 3 to generate a sinusoidal resonance. The resonant energy passes through the receiving end circuit and the resonant waveform sampling and shaping circuit 4 to obtain a voltage value to be determined. The voltage value to be determined is sent back to the MCU control circuit 1 and input into the A / D port of the MCU control circuit 1 for waveform analysis and judgment. The negative slope value of the voltage value to be determined and the time is compared and analyzed with the negative slope fixed value. When the negative slope value of the voltage value to be determined and the time reaches the negative slope fixed value, it meets the charging requirement, and the receiving end is automatically determined to be a designated wireless power receiving load. The MCU control circuit 1 continuously outputs a pulse signal to control and drive the full-bridge switch circuit 2 to excite the resonant cavity circuit 3, and continuously outputs energy to the receiving end circuit to realize the battery charging function. When the negative slope value of the voltage value to be determined and the time does not reach the negative slope fixed value, it does not meet the charging requirement, and the receiving end is automatically determined to be a non-designated wireless power receiving load, and the MCU control circuit 1 stops outputting the pulse signal.

[0035] Further, the power receiving end is an electric toothbrush that is not a designated wireless power receiver. Figure 5 In the example, a non-specified wireless power receiving load is put in at time t1, and the MCU control circuit 1 detects and determines that the voltage rises. After a certain period of time, a voltage peak value Vpk is observed at time t2, and the voltage starts to drop. Before the specified time range t4, a voltage valley point Vvl is found. The MCU control circuit 1 determines that it is a non-specified wireless power receiving load by judging the time difference (t2-t1) and the amplitude difference between the voltage peak value Vpk and the voltage valley value Vvl found within the specified time range t2 to t4, that is, the negative slope of the voltage to time does not reach the specified set value, thereby judging that it is a non-specified wireless power receiving load and not entering the charging process.

[0036] Furthermore, the specific connection mode of the resonant waveform sampling and shaping circuit 4 is as follows: the resonant cavity capacitor includes a resonant cavity capacitor A end and a resonant cavity capacitor B end, the resonant cavity inductor includes a resonant cavity inductor A end and a resonant cavity inductor B end, the sampling signal is taken from the resonant cavity inductor A end, the resonant cavity inductor A end is connected to the resonant cavity capacitor A end, and the resonant cavity inductor B end is the reference ground; the sampling signal is sent to the anode of the rectifier diode D6, the cathode of the diode D6 is connected to one end of the current limiting resistor R30, and the other end of the current limiting resistor R30 is connected to one end of the filter capacitor C20 and the cathode of the voltage regulator tube Z2, The other end of the filter capacitor C20 is connected to the reference ground; the anode of the voltage-stabilizing tube Z2 is connected to one end of the voltage-dividing resistor R32, and the other end of the voltage-dividing resistor R32 is connected to the cathode of the voltage-stabilizing tube Z3 and one end of the filter capacitor C19 and one end of the voltage-dividing resistor R31, thereby completing the sampling, filtering and shaping, forming a shaped analysis signal and sending it to the A / D input port of the MCU control circuit 1; the anode of the voltage-stabilizing tube Z3 and the other end of the filter capacitor C19 and the other end of the voltage-dividing resistor R31 are connected to the reference ground; the power supply Vss pin of the MCU control circuit 1 is connected to the reference ground.

[0037] The above examples are only specific embodiments of the present invention. Obviously, the present invention is not limited to the above examples, and there are many similar modifications. All modifications that can be directly derived or associated with the contents disclosed by ordinary technicians in this field should be considered as the scope of protection of the present invention.

Claims

1. A wireless charging device for automatically identifying a non-specified wireless power receiving load, characterized in that: The invention comprises a charging end circuit and a receiving end circuit, wherein the charging end circuit comprises an MCU control circuit (1), a switch circuit (2), a resonant cavity circuit (3), and a resonant waveform sampling and shaping circuit (4); the receiving end circuit comprises a coupled resonant and rectifier filter circuit (5), a charging control switch circuit (6), and a rechargeable battery (7); the MCU control circuit (1) sets a fixed negative slope value of voltage to time; the MCU control circuit (1) outputs a pulse signal to control and drive the switch circuit (2) to excite the resonant cavity circuit (3) to generate sinusoidal resonance; the resonant energy of the sinusoidal resonance passes through the receiving end circuit and the resonant waveform sampling and shaping circuit (4) to obtain a voltage value to be determined; the voltage value to be determined is sent back to the MCU control circuit (1); and the negative slope value of the voltage value to be determined to time is compared and analyzed with the fixed negative slope value.

2. The wireless charging device for automatically identifying non-designated wireless power receiving loads as claimed in claim 1, characterized in that: If the negative slope value of the voltage value and time to be determined reaches the fixed negative slope value, the charging requirement is met, the receiving end is automatically determined to be a designated wireless power receiving load, and the MCU control circuit (1) continuously outputs a pulse signal to control and drive the switch circuit (2) to excite the resonant cavity circuit (3), and continuously outputs energy to the receiving end circuit, thereby realizing a battery charging function.

3. The wireless charging device for automatically identifying non-designated wireless power receiving loads as claimed in claim 1, characterized in that: If the negative slope of the voltage value to be determined and the time does not reach the fixed negative slope value, the charging requirement is not met, and the MCU control circuit (1) stops outputting the pulse signal and automatically determines that the power receiving end is a non-specified wireless power receiving load.

4. The wireless charging device for automatically identifying non-designated wireless power receiving loads as claimed in claim 1, characterized in that: The resonant waveform sampling and shaping circuit (4) comprises a resonant capacitor and a resonant inductor, and the voltage value to be determined is obtained through a voltage resonant waveform in the resonant capacitor or the resonant inductor.

5. The wireless charging device for automatically identifying non-designated wireless power receiving loads as claimed in claim 1, characterized in that: The resonant cavity circuit (3) comprises a resonant cavity capacitor and a resonant cavity inductor.

6. The wireless charging device for automatically identifying non-designated wireless power receiving loads as claimed in claim 5, characterized in that: The resonant cavity inductor is an open magnetic circuit, and the resonant cavity inductor is a transmitting coil of the resonant energy.

7. The wireless charging device for automatically identifying non-designated wireless power receiving loads as claimed in claim 1, characterized in that: The voltage value to be determined is input into the A / D port of the MCU control circuit (1) for waveform analysis and determination after passing through the resonant waveform sampling and shaping circuit (4).

8. The wireless charging device for automatically identifying non-designated wireless power receiving loads as claimed in claim 1, characterized in that: When the negative slope fixed value is set by the power receiving end for a designated wireless power receiving load, the MCU control circuit (1) acquires and stores the negative slope value of the corresponding voltage value and time as the negative slope fixed value, or the internal part of the MCU control circuit (1) is directly solidified and set to the negative slope fixed value.

9. The wireless charging device for automatically identifying non-designated wireless power receiving loads as claimed in claim 5, characterized in that: The specific connection mode of the resonant waveform sampling and shaping circuit (4) is as follows: the resonant cavity capacitor includes a resonant cavity capacitor A end and a resonant cavity capacitor B end, the resonant cavity inductor includes a resonant cavity inductor A end and a resonant cavity inductor B end, the sampling signal is taken from the resonant cavity capacitor A end, the resonant cavity capacitor A end is connected to the resonant cavity inductor A end, and the resonant cavity capacitor B end is the reference ground; the sampling signal is sent to the anode of the rectifier diode D6, the cathode of the diode D6 is connected to one end of the current limiting resistor R30, the other end of the current limiting resistor R30 is connected to one end of the filter capacitor C20 and the cathode of the voltage regulator tube Z2, and the filter The other end of the wave capacitor C20 is connected to the reference ground; the anode of the voltage regulator tube Z2 is connected to one end of the voltage divider resistor R32, and the other end of the voltage divider resistor R32 is connected to the cathode of the voltage regulator tube Z3 and one end of the filter capacitor C19 and one end of the voltage divider resistor R31, thereby completing the sampling, filtering and shaping, forming a shaped analysis signal and sending it to the A / D input port of the MCU control circuit (1); the anode of the voltage regulator tube Z3 and the other end of the filter capacitor C19 and the other end of the voltage divider resistor R31 are connected to the reference ground; the power supply Vss pin of the MCU control circuit (1) is connected to the reference ground.

10. The wireless charging device for automatically identifying non-designated wireless power receiving loads as claimed in claim 5, characterized in that: The specific connection mode of the resonant waveform sampling and shaping circuit (4) is as follows: the resonant cavity capacitor includes a resonant cavity capacitor A end and a resonant cavity capacitor B end, the resonant cavity inductor includes a resonant cavity inductor A end and a resonant cavity inductor B end, the sampling signal is taken from the resonant cavity inductor A end, the resonant cavity inductor A end is connected to the resonant cavity capacitor A end, and the resonant cavity inductor B end is the reference ground; the sampling signal is sent to the anode of the rectifier diode D6, the cathode of the diode D6 is connected to one end of the current limiting resistor R30, the other end of the current limiting resistor R30 is connected to one end of the filter capacitor C20 and the cathode of the voltage regulator tube Z2, and the filter The other end of the wave capacitor C20 is connected to the reference ground; the anode of the voltage regulator tube Z2 is connected to one end of the voltage divider resistor R32, and the other end of the voltage divider resistor R32 is connected to the cathode of the voltage regulator tube Z3 and one end of the filter capacitor C19 and one end of the voltage divider resistor R31, thereby completing the sampling, filtering and shaping, forming a shaped analysis signal and sending it to the A / D input port of the MCU control circuit (1); the anode of the voltage regulator tube Z3 and the other end of the filter capacitor C19 and the other end of the voltage divider resistor R31 are connected to the reference ground; the power supply Vss pin of the MCU control circuit (1) is connected to the reference ground.

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