A condensate water level detection and alarm circuit

Abstract

The present application relates to a condensate level detection and alarm circuit, belonging to the field of circuit technology. The condensate level detection and alarm circuit includes a float level switch, a power supply circuit, an MCU, and an alarm circuit; the power supply circuit includes a battery pack, an inductor, and a boost chip. The positive electrode of the battery pack is connected to the first end of the float level switch, and the negative electrode is grounded; the first end of the inductor is connected to the second end of the float level switch, and the second end is connected to the VL pin of the boost chip; the VT pin of the boost chip is connected to the VDD pin of the MCU, and the GND pin is grounded; the float level switch is used to conduct the connection between the battery pack and the inductor when the water level of the condensate detected reaches the warning water level; the battery pack is used to supply power to the boost chip after storing energy through the inductor; the boost chip is used to supply power to the MCU after being powered by the battery pack; the MCU is used to output a high level to the alarm circuit after being powered by the boost chip to control the alarm circuit to output an alarm signal. Using the present application, condensate level detection and alarm can be realized.

Description

Technical Field

[0001] The present application relates to the field of circuit technologies, and particularly to a condensate water level detection and alarm circuit. Background Art

[0002] Currently, condensing wall-mounted boilers improve the heat exchange efficiency of the whole machine and the energy efficiency of the unit by utilizing high-temperature flue gas for secondary heat exchange. However, the resulting condensate water has also become a problem that needs to be considered and addressed in the design of condensing wall-mounted boilers.

[0003] In the structure of a condensing wall-mounted boiler, a condensing heat exchanger is a device for recovering the waste heat of flue gas. The condensate water generated by the secondary heat exchange of high-temperature flue gas accumulates in a condensate water collector and is discharged through the condensate water drain pipe of the condensate water collector. However, when the condensate water drain pipe is blocked, the condensate water in the condensate water collector cannot be discharged in time, and the condensate water continuously accumulates in the condensate water collector. During the continuous rising process of the condensate water, it will backflow into the furnace, causing the core components such as the blower, proportional valve, and burner to be flooded with water, resulting in malfunction and damage of the unit. Summary of the Invention

[0004] Based on this, in view of the above technical problems, it is necessary to provide a condensate water level detection and alarm circuit.

[0005] In a first aspect, a condensate water level detection and alarm circuit is provided. The condensate water level detection and alarm circuit includes a float level switch, a power supply circuit, an MCU, and an alarm circuit;

[0006] Among them, the power supply circuit includes a battery pack, an inductor, and a boost chip. The positive electrode of the battery pack is connected to the first end of the float level switch, and the negative electrode of the battery pack is grounded; the first end of the inductor is connected to the second end of the float level switch, and the second end of the inductor is connected to the VL pin of the boost chip; the VT pin of the boost chip is connected to the VDD pin of the MCU, and the GND pin of the boost chip is grounded; the MCU is connected to the alarm circuit;

[0007] The float level switch is configured to conduct the connection between the battery pack and the inductor when detecting that the water level of the condensate water reaches the warning water level;

[0008] The battery pack is configured to supply power to the boost chip after energy storage through the inductor;

[0009] The boost chip is configured to supply power to the MCU after being powered by the battery pack;

[0010] The MCU is configured to output a high level to the alarm circuit after being powered by the boost chip, and control the alarm circuit to output an alarm signal.

[0011] As an alternative implementation, the power supply circuit further includes a first filter protection circuit, and the first filter protection circuit includes a first resistor, a first electrolytic capacitor, and a first ceramic capacitor;

[0012] Wherein, a first end of the first resistor is connected to a second end of the float level switch, and a second end of the first resistor is connected to a first end of the inductor;

[0013] A first end of the first electrolytic capacitor is connected to the first end of the inductor, and a second end of the first electrolytic capacitor is grounded;

[0014] A first end of the first ceramic capacitor is connected to the first end of the inductor, and a second end of the first ceramic capacitor is grounded.

[0015] As an alternative implementation, the power supply circuit further includes a second filter protection circuit, and the second filter protection circuit includes a second electrolytic capacitor and a second ceramic capacitor;

[0016] Wherein, a first end of the second electrolytic capacitor is connected to the VT pin of the boost chip, and a second end of the second electrolytic capacitor is grounded;

[0017] A first end of the second ceramic capacitor is connected to the VT pin of the boost chip, and a second end of the second ceramic capacitor is grounded.

[0018] As an alternative implementation, the alarm circuit includes a sound alarm circuit, and the sound alarm circuit includes a second resistor, a third resistor, a fourth resistor, a triode, a freewheeling diode, and a buzzer;

[0019] Wherein, a first end of the second resistor is connected to the P26 / AN1 pin of the MCU, and a second end of the second resistor is respectively connected to a first end of the third resistor and the base of the triode;

[0020] A second end of the third resistor and the emitter of the triode are grounded;

[0021] A first end of the fourth resistor is connected to the collector of the triode, and a second end of the fourth resistor is respectively connected to the positive electrode of the freewheeling diode and a first end of the buzzer;

[0022] The negative electrode of the freewheeling diode and a second end of the buzzer are connected to the positive electrode of the battery pack.

[0023] As an alternative implementation, the alarm circuit includes a light alarm circuit, and the light alarm circuit includes a fifth resistor and a light-emitting diode;

[0024] Among them, the first end of the fifth resistor is connected to the AN8 / PO2 pin of the MCU, and the second end of the fifth resistor is connected to the positive electrode of the light-emitting diode;

[0025] The negative electrode of the light-emitting diode is grounded.

[0026] As an optional implementation manner, the condensate water level detection and alarm circuit further includes an MCU programming interface circuit, and the MCU programming interface circuit includes a sixth resistor, a seventh resistor, and an interface chip;

[0027] Among them, the first end of the sixth resistor is connected to the P31 / CLK pin of the MCU, and the second end of the sixth resistor is connected to the CLK pin of the interface chip;

[0028] The first end of the seventh resistor is connected to the P27 / DIO pin of the MCU, and the second end of the seventh resistor is connected to the TDO pin of the interface chip;

[0029] The VCC pin of the interface chip is connected to the VT pin of the boost chip, and the GND pin of the interface chip is grounded.

[0030] As an optional implementation manner, the condensate water level detection and alarm circuit further includes an MCU reset circuit, and the MCU reset circuit includes an eighth resistor, a ninth resistor, a first capacitor, and a second capacitor;

[0031] Among them, the first end of the eighth resistor is connected to the VT pin of the boost chip, and the second end of the eighth resistor is respectively connected to the first end of the first capacitor and the nRST pin of the MCU;

[0032] The second end of the first capacitor is grounded;

[0033] The first end of the ninth resistor is connected to the P34 / VC2 pin of the MCU, and the second end of the ninth resistor is respectively connected to the VSS pin of the MCU and the first end of the second capacitor, and is grounded;

[0034] The second end of the second capacitor is connected to the VACP pin of the MCU.

[0035] The present application provides a condensate water level detection and alarm circuit. The technical solutions provided by the embodiments of the present application at least bring the following beneficial effects: The condensate water level detection and alarm circuit includes a float level switch, a power supply circuit, an MCU, and an alarm circuit. Among them, the power supply circuit includes a battery pack, an inductor, and a boost chip. The positive pole of the battery pack is connected to the first end of the float level switch, and the negative pole is grounded; the first end of the inductor is connected to the second end of the float level switch, and the second end is connected to the VL pin of the boost chip; the VT pin of the boost chip is connected to the VDD pin of the MCU, and the GND pin is grounded; the MCU is connected to the alarm circuit. The float level switch is used to conduct the connection between the battery pack and the inductor when the water level of the condensate water is detected to reach the warning water level. The battery pack is used to supply power to the boost chip after energy storage through the inductor. The boost chip is used to supply power to the MCU after being powered by the battery pack. The MCU is used to output a high level to the alarm circuit after being powered by the boost chip to control the alarm circuit to output an alarm signal. In this way, the battery pack in the condensate water level detection and alarm circuit only supplies power to the MCU when the water level of the condensate water is detected to reach the warning water level, thereby enabling the battery pack to have ultra-low standby power consumption.

[0036] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. Brief Description of the Drawings

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0038] Figure 1 It is a schematic structural diagram of a float level switch provided by an embodiment of the present application;

[0039] Figure 2 It is a schematic circuit structure diagram of a power supply circuit provided by an embodiment of the present application;

[0040] Figure 3 It is a schematic circuit structure diagram of an MCU provided by an embodiment of the present application; Detailed Embodiments

[0041] In order to make the objectives, technical solutions, and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0042] The following will combine with specific implementation manners to provide a detailed description of a condensate water level detection and alarm circuit provided by an embodiment of the present application. The condensate water level detection and alarm circuit includes a float level switch CN1, a power supply circuit, an MCU, and an alarm circuit.

[0043] Among them, the power supply circuit includes a battery pack BT1, an inductor L1, and a boost chip U2. The positive electrode of the battery pack BT1 is connected to the first end of the float level switch CN1, and the negative electrode of the battery pack BT1 is grounded. The first end of the inductor L1 is connected to the second end of the float level switch CN1, and the second end of the inductor L1 is connected to the VL pin of the boost chip U2. The VT pin of the boost chip U2 is connected to the VDD pin of the MCU. The GND pin of the boost chip U2 is grounded. The MCU is connected to the alarm circuit.

[0044] The float level switch CN1 is used to conduct the connection between the battery pack BT1 and the inductor L1 when the water level of the condensate water is detected to reach the warning water level.

[0045] The battery pack BT1 is used to supply power to the boost chip U2 after energy storage through the inductor L1.

[0046] The boost chip U2 is used to supply power to the MCU after being powered by the battery pack BT1.

[0047] The MCU is used to output a high level to the alarm circuit after being powered by the boost chip U2 to control the alarm circuit to output an alarm signal.

[0048] During implementation, as Figure 1 shown, the float level switch CN1 includes a float ball and a float sensor. The float ball floats up and down with the height of the water level of the condensate water. When the water level of the condensate water does not reach the warning water level, the float sensor is in an off (i.e., OFF) state. At this time, the battery pack BT1 is disconnected from the inductor L1, and the battery pack BT1 cannot store energy through the inductor L1 to supply power to the boost chip U2. When the water level of the condensate water reaches the warning water level, the float sensor is in an on (i.e., ON) state. At this time, the battery pack BT1 is conducted with the inductor L1, and the battery pack BT1 stores energy through the inductor L1 to supply power to the boost chip U2. Among them, after the inductor L1 stores energy and filters out miscellaneous ripples, it supplies power to the boost chip U2, and the boost chip U2 outputs a stable VCC to supply power to the MCU. After the MCU obtains a stable and smooth voltage, it indicates that the condensate water level reaches the warning water level at this time, and the MCU drives the alarm circuit to give an alarm.

[0049] As an optional implementation manner, as Figure 2 shown, the power supply circuit further includes a first filter protection circuit. The first filter protection circuit includes a first resistor R1, a first electrolytic capacitor EC1, and a first ceramic capacitor C1.

[0050] Among them, the first end of the first resistor R1 is connected to the second end of the float level switch CN1, and the second end of the first resistor R1 is connected to the first end of the inductor L1. The first end of the first electrolytic capacitor EC1 is connected to the first end of the inductor L1, and the second end of the first electrolytic capacitor EC1 is grounded. The first end of the first ceramic capacitor C1 is connected to the first end of the inductor L1, and the second end of the first ceramic capacitor C1 is grounded.

[0051] In implementation, the first resistor R1 mainly prevents the impact on the float sensor when the float conducts instantaneously upward and prevents excessive current, which may cause damage to the float induction sensor. After the battery pack BT1 in the power supply circuit is connected through the float level switch CN1, a voltage UEC1 is obtained through the first resistor R1. The first electrolytic capacitor EC1 filters the AC pulsating part, and the filtered AC pulsating part flows into the ground. The first ceramic capacitor C1 filters out the high-frequency interference part.

[0052] As an alternative implementation, as Figure 2 shown, the power supply circuit further includes a second filter protection circuit. The second filter protection circuit includes a second electrolytic capacitor EC2 and a second ceramic capacitor C2.

[0053] Among them, the first end of the second electrolytic capacitor EC2 is connected to the VT pin of the boost chip U2, and the second end of the second electrolytic capacitor EC2 is grounded. The first end of the second ceramic capacitor C2 is connected to the VT pin of the boost chip U2, and the second end of the second ceramic capacitor C2 is grounded.

[0054] In implementation, the second electrolytic capacitor EC2 filters the AC pulsating part, and the filtered AC pulsating part flows into the ground. The second ceramic capacitor C2 filters out the high-frequency interference part.

[0055] As an alternative implementation, as Figure 3 shown, the alarm circuit includes a sound alarm circuit. The sound alarm circuit includes a second resistor R12, a third resistor R11, a fourth resistor R10, a triode Q1, a freewheeling diode D2, and a buzzer BUZ1.

[0056] Among them, the first end of the second resistor R12 is connected to the P26 / AN1 pin of the MCU, and the second end of the second resistor R12 is respectively connected to the first end of the third resistor R11 and the base of the triode Q1.

[0057] The second end of the third resistor R11 and the emitter of the triode Q1 are grounded.

[0058] The first end of the fourth resistor R10 is connected to the collector of the triode Q1, and the second end of the fourth resistor R10 is respectively connected to the positive pole of the freewheeling diode D2 and the first end of the buzzer BUZ1.

[0059] The negative electrode of the freewheeling diode D2 is connected to the second terminal of the buzzer BUZ1, and the positive electrode of the battery pack BT1.

[0060] In implementation, the MCU sets the "BUZ" port of the IO port to a high-level "1" signal according to the functional logic to realize the sounding prompt of the buzzer BUZ1. The MCU sets the "BUZ" port of the IO port to a high potential. At this time, the base voltage of the triode Q1 is greater than Vbe = 0.7V and conducts, and the buzzer BUZ1 starts to work and alarms the user to pour water according to the logical design prompt sound. Conversely, when the voltage of the triode Q1 is less than Vbe = 0.7V and is cut off, the buzzer BUZ1 does not work. Among them, the freewheeling diode D1 is used to prevent the buzzer BUZ1 from damaging the triode Q1 due to the superimposition of the backrush voltage when the triode Q1 is turned off.

[0061] As an alternative implementation, as Figure 3 shown, the alarm circuit includes a light alarm circuit. The light alarm circuit includes a fifth resistor R13 and a light-emitting diode LED1.

[0062] Among them, the first terminal of the fifth resistor R13 is connected to the AN8 / PO2 pin of the MCU, and the second terminal of the fifth resistor R13 is connected to the positive electrode of the light-emitting diode LED1. The negative electrode of the light-emitting diode LED1 is grounded.

[0063] In implementation, after the MCU obtains a stable and smooth voltage, it indicates that the condensate level has reached the warning water level at this time, and the MCU drives the light-emitting diode LED1 to emit light for alarm.

[0064] As an alternative implementation, as Figure 3 shown, the condensate level detection and alarm circuit further includes an MCU programming interface circuit. The MCU programming interface circuit includes a sixth resistor R4, a seventh resistor R5, and an interface chip CN2;

[0065] Among them, the first terminal of the sixth resistor R4 is connected to the P31 / CLK pin of the MCU, and the second terminal of the sixth resistor R4 is connected to the CLK pin of the interface chip CN2.

[0066] The first terminal of the seventh resistor R5 is connected to the P27 / DIO pin of the MCU, and the second terminal of the seventh resistor R5 is connected to the TDO pin of the interface chip CN2.

[0067] The VCC pin of the interface chip CN2 is connected to the VT pin of the boost chip U2, and the GND pin of the interface chip CN2 is grounded.

[0068] As an alternative implementation, as Figure 3 shown, the condensate level detection and alarm circuit further includes an MCU reset circuit. The MCU reset circuit includes an eighth resistor R2, a ninth resistor R3, a first capacitor C6, and a second capacitor C3;

[0069] Among them, the first end of the eighth resistor R2 is connected to the VT pin of the boost chip U2, and the second end of the eighth resistor R2 is respectively connected to the first end of the first capacitor C6 and the nRST pin of the MCU;

[0070] The second end of the first capacitor C6 is grounded;

[0071] The first end of the ninth resistor R3 is connected to the P34 / VC2 pin of the MCU, and the second end of the ninth resistor R3 is respectively connected to the VSS pin of the MCU and the first end of the second capacitor C3 and is grounded;

[0072] The second end of the second capacitor C3 is connected to the VACP pin of the MCU.

[0073] The embodiment of the present application provides a condensate water level detection and alarm circuit. The condensate water level detection and alarm circuit includes a float level switch, a power supply circuit, an MCU, and an alarm circuit. Among them, the power supply circuit includes a battery pack, an inductor, and a boost chip. The positive electrode of the battery pack is connected to the first end of the float level switch, and the negative electrode is grounded; the first end of the inductor is connected to the second end of the float level switch, and the second end is connected to the VL pin of the boost chip; the VT pin of the boost chip is connected to the VDD pin of the MCU, and the GND pin is grounded; the MCU is connected to the alarm circuit. The float level switch is used to conduct the connection between the battery pack and the inductor when detecting that the water level of the condensate water reaches the warning water level. The battery pack is used to supply power to the boost chip after energy storage through the inductor. The boost chip is used to supply power to the MCU after being powered by the battery pack. The MCU is used to output a high level to the alarm circuit after being powered by the boost chip to control the alarm circuit to output an alarm signal. In this way, the battery pack in the condensate water level detection and alarm circuit only supplies power to the MCU when detecting that the water level of the condensate water reaches the warning water level, so that the battery pack has ultra-low standby power consumption.

[0074] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, storage, database, or other medium used in the various embodiments provided in this application can include non-volatile and / or volatile memories. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and Rambus dynamic RAM (RDRAM), etc.

[0075] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including", or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article, or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the existence of additional identical elements in the process, method, article, or device comprising the element.

[0076] It should also be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for display, data for analysis, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0077] Each embodiment in this specification is described in a related manner. For the same or similar parts among the embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple. For the related parts, reference can be made to the description of the method embodiment.

[0078] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0079] The above-described embodiments only represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A condensate water level detection and alarm circuit, characterized in that, The condensate water level detection and alarm circuit includes a float level switch, a power supply circuit, a microcontroller unit (MCU), and an alarm circuit; Among them, the power supply circuit includes a battery pack, an inductor, and a boost chip. The positive electrode of the battery pack is connected to the first end of the float level switch, and the negative electrode of the battery pack is grounded; the first end of the inductor is connected to the second end of the float level switch, and the second end of the inductor is connected to the VL pin of the boost chip; the VT pin of the boost chip is connected to the VDD pin of the MCU, and the GND pin of the boost chip is grounded; the MCU is connected to the alarm circuit; The float level switch is used to conduct the connection between the battery pack and the inductor when the water level of the condensate water is detected to reach the warning water level; The battery pack is used to supply power to the boost chip after energy storage through the inductor; The boost chip is used to supply power to the MCU after being powered by the battery pack; The MCU is used to output a high level to the alarm circuit after being powered by the boost chip to control the alarm circuit to output an alarm signal.

2. The circuit according to claim 1, wherein The power supply circuit further includes a first filter protection circuit, and the first filter protection circuit includes a first resistor, a first electrolytic capacitor, and a first ceramic capacitor; Among them, the first end of the first resistor is connected to the second end of the float level switch, and the second end of the first resistor is connected to the first end of the inductor; The first end of the first electrolytic capacitor is connected to the first end of the inductor, and the second end of the first electrolytic capacitor is grounded; The first end of the first ceramic capacitor is connected to the first end of the inductor, and the second end of the first ceramic capacitor is grounded.

3. The circuit according to claim 1, characterized in that, The power supply circuit further includes a second filter protection circuit, and the second filter protection circuit includes a second electrolytic capacitor and a second ceramic capacitor; Among them, the first end of the second electrolytic capacitor is connected to the VT pin of the boost chip, and the second end of the second electrolytic capacitor is grounded; The first end of the second ceramic capacitor is connected to the VT pin of the boost chip, and the second end of the second ceramic capacitor is grounded.

4. The circuit according to claim 1, characterized in that, The alarm circuit includes a sound alarm circuit, and the sound alarm circuit includes a second resistor, a third resistor, a fourth resistor, a triode, a freewheeling diode, and a buzzer; Among them, the first end of the second resistor is connected to the P26 / AN1 pin of the MCU, and the second end of the second resistor is respectively connected to the first end of the third resistor and the base of the triode; The second end of the third resistor and the emitter of the triode are grounded; The first end of the fourth resistor is connected to the collector of the triode, and the second end of the fourth resistor is respectively connected to the positive electrode of the freewheeling diode and the first end of the buzzer; The negative electrode of the freewheeling diode and the second end of the buzzer are connected to the positive electrode of the battery pack.

5. The circuit according to claim 1 or 4, characterized in that, The alarm circuit includes a light alarm circuit, and the light alarm circuit includes a fifth resistor and a light-emitting diode; Among them, the first end of the fifth resistor is connected to the AN8 / PO2 pin of the MCU, and the second end of the fifth resistor is connected to the positive electrode of the light-emitting diode; The negative electrode of the light-emitting diode is grounded.

6. The circuit according to claim 1, wherein The condensate level detection and alarm circuit further includes an MCU programming interface circuit, and the MCU programming interface circuit includes a sixth resistor, a seventh resistor, and an interface chip; Wherein, the first end of the sixth resistor is connected to the P31 / CLK pin of the MCU, and the second end of the sixth resistor is connected to the CLK pin of the interface chip; The first end of the seventh resistor is connected to the P27 / DIO pin of the MCU, and the second end of the seventh resistor is connected to the TDO pin of the interface chip; The VCC pin of the interface chip is connected to the VT pin of the boost chip, and the GND pin of the interface chip is grounded.

7. The circuit according to claim 1, characterized in that, The condensate level detection and alarm circuit further includes an MCU reset circuit, and the MCU reset circuit includes an eighth resistor, a ninth resistor, a first capacitor, and a second capacitor; Wherein, the first end of the eighth resistor is connected to the VT pin of the boost chip, and the second end of the eighth resistor is respectively connected to the first end of the first capacitor and the nRST pin of the MCU; The second end of the first capacitor is grounded; The first end of the ninth resistor is connected to the P34 / VC2 pin of the MCU, and the second end of the ninth resistor is respectively connected to the VSS pin of the MCU and the first end of the second capacitor, and is grounded; The second end of the second capacitor is connected to the VACP pin of the MCU.

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