Air purifier control circuit

Abstract

The utility model relates to an air purifier control circuit, which comprises a power supply module, an MCU module, a voltameter module, a control panel and a fan module, the MCU module, the control panel and the fan module are all connected with the power supply module to take electricity, and the voltameter module, the control panel and the fan module are all connected with the MCU module; the voltameter module detects the voltage of the input end of the power supply module and feeds back the voltage to the MCU module; the control panel is internally provided with an identification resistor used for marking the type of equipment, one end of the identification resistor is grounded, the other end of the identification resistor is connected with the power supply module through a divider resistor to take electricity, a detection point is arranged between the identification resistor and the divider resistor, and the detection point is connected with the type identification input end of the MCU module. According to the utility model, the equipment model can be identified after the equipment is electrified, so as to judge whether the input voltage is matched with the equipment model or not, and the equipment is reliably protected.

Description

TECHNICAL FIELD

[0001] The utility model relates to air purifier technical field especially relates to an air purifier control circuit. BACKGROUND

[0002] The air purifier used in industry usually includes two layers of filter screen, namely activated carbon filter screen and inner layer HEPA filter. Among them, the activated carbon filter screen can be conveniently removed and cleaned, and whether the outer activated carbon filter screen is dirty can be directly observed, while the inner layer HEPA filter is blocked by the activated carbon filter screen, and because of the structure of the HEPA filter, even if the activated carbon filter screen is removed, the dirtiness (or clogging degree) of the HEPA filter cannot be directly determined, and the HEPA filter often needs to be removed for judgment, which is relatively complex to operate.

[0003] In addition, the rated voltage is different in different countries, and the voltage range supported by the control module is relatively large, while the fan module (mainly motor, starting capacitor, etc.) of the air purifier is often divided into high and low voltage, if the input voltage of the air purifier does not match the working voltage of the fan module, the fan module will be damaged or not work normally or not work, especially when the input voltage is too high, the fan module will be burned, which will inevitably increase the after-sales cost. CONTENT OF THE UTILITY MODEL

[0004] The utility model aims at providing an air purifier control circuit, which can identify the equipment model after the equipment is powered on, so as to judge whether the input voltage is matched with the equipment model, and play a reliable protection role for the equipment.

[0005] In order to achieve the above purpose, the utility model discloses an air purifier control circuit, which comprises a power supply module, an MCU module, a power meter module, a control panel and a fan module, the MCU module, the control panel and the fan module are all connected to the power supply module for power supply, the power meter module, the control panel and the fan module are all connected to the MCU module, the power meter module detects the input end voltage of the power supply module and feeds back the MCU module, the control panel is provided with an identification resistor for marking the equipment model, one end of the identification resistor is grounded, the other end of the identification resistor is connected to the power supply module for power supply through a voltage dividing resistor, a detection point is arranged between the identification resistor and the voltage dividing resistor, and the detection point is connected to the model identification input end of the MCU module.

[0006] After the above setting, different models of air purifiers adopt different resistance values of identification resistors, the voltage of the detection point is collected by the MCU module to identify the equipment model, the input end voltage of the power supply module is collected by the electric quantity meter, and the MCU can judge whether the input forging pressure is matched with the equipment model (mainly referring to the fan module), thereby reliably protecting the equipment. After the above setting, only the control panel and the fan module need to be matched and unified, the remaining modules can use general parts, the MCU module can run a program suitable for all models, and different control programs are not needed for different models of equipment. The control circuit board of the equipment can be mass-produced and mass-programmed, improving production efficiency and after-sales efficiency.

[0007] Preferably, the identification resistor comprises a first identification resistor and a second identification resistor, the voltage dividing resistor comprises a first voltage dividing resistor and a second voltage dividing resistor, and the model identification input end comprises a first identification input end and a second identification input end; one end of the first identification resistor is grounded, the other end of the first identification resistor is connected to the first identification input end and one end of the first voltage dividing resistor, the other end of the first voltage dividing resistor is connected to the power supply module; two ends of the second identification resistor are grounded, the other end of the second identification resistor is connected to the second identification input end and two ends of the second voltage dividing resistor, and the other end of the second voltage dividing resistor is connected to the power supply module. After the above setting, more identification signal groups can be obtained to adapt to more equipment models; of course, the first identification resistor can also be equal to the second identification resistor to play a double protection role.

[0008] Preferably, it further comprises an air pressure sensor and a HEPA button for outputting a start HEPA test signal; a HEPA filter and an activated carbon filter screen are sequentially arranged between the air inlet and the air outlet of the air purifier and in the air outlet direction; the air pressure sensor is arranged at the air outlet of the air purifier; the air pressure sensor and the HEPA button are both connected to the MCU module. The HEPA button is used to start the test of the HEPA filter. During actual testing, the activated carbon filter screen is removed first, and then the fan module is controlled to run at a constant power. By comparing the air pressure value fed back by the air pressure sensor at this moment with a preset value, the clogging degree of the HEPA filter can be determined, which is convenient and fast.

[0009] Preferably, the HEPA button is arranged between the activated carbon filter screen and the HEPA filter. In this way, the HEPA test can only be started after the activated carbon filter screen is removed, thereby ensuring the reliability of the HEPA test, and the problem of accidental pressing of the HEPA button can also be avoided.

[0010] Preferably, a particle sensor is arranged at the air outlet of the air purifier, and the particle sensor is connected to the MCU module. By arranging the particle sensor, PM2.5 can be detected to obtain the current air quality and the effect feedback after the device is operated.

[0011] Preferably, the air purifier further comprises a zero potential detection module and a control trigger module; the MCU module has a feedback input end and a PWN output end.

[0012] The zero potential detection module comprises a rectifier unit, a first optocoupler and a feedback output unit connected in sequence; the rectifier unit is connected to the input end of the power supply module and is used to rectify alternating current into direct current; the feedback output unit is connected to the feedback input end of the MCU module; when the light emitter of the first optocoupler is turned on, the feedback output unit outputs a first signal; when the light emitter of the first optocoupler is not turned on, the feedback output unit outputs a second signal.

[0013] The control trigger module comprises a trigger control unit, a second optocoupler and a silicon-controlled voltage regulating unit connected in sequence; the silicon-controlled voltage regulating unit is connected in series with the live wire of the input end of the power supply module; the PWM output end of the MCU module is connected to the trigger control unit; the MCU module sends a PWM signal to control the light emitter of the second optocoupler to be turned on or off according to the first signal and / or the second signal; the light receiver of the second optocoupler controls the silicon-controlled voltage regulating unit to be turned on or off; and the power input live wire end of the fan module is connected to the output end of the silicon-controlled voltage regulating unit.

[0014] After the above arrangement, the zero potential detection module detects the zero potential of the input power supply of the air purifier and feeds back to the MCU module; when the current of the input power supply is zero, the MCU module outputs a PWM signal to the control trigger module, so as to accurately realize the chopping function of the input alternating current voltage, realize voltage reduction, achieve the purpose of controlling the rotating speed of the alternating current fan, and ensure the stability of the output voltage. The hysteresis time of the PWM signal trigger level relative to the zero potential of the input power supply can be adjusted to conveniently adjust the voltage reduction range, and the speed of the alternating current fan is convenient and accurate. In addition, the first optocoupler is used for isolation in the zero potential detection module, and the second optocoupler is used for isolation in the control trigger module, which can ensure the safety of the MCU module. In addition, the above circuit structure is simple, stable and relatively low in cost.

[0015] Preferably, the rectifier unit comprises a rectifier bridge D9, a resistor R70, a resistor R68 and a resistor R71; the input end of the rectifier bridge D9 is connected to the input end of the power supply module; the output negative pole of the rectifier bridge D9 is connected to one end of the resistor R70, one end of the resistor R68 and the anode of the light emitter of the first optocoupler; the other end of the resistor R68 is connected to one end of the resistor R71 and the cathode of the light emitter of the first optocoupler; and the output negative pole of the rectifier bridge D9 is connected to the other end of the resistor R71 and the cathode of the light emitter of the first optocoupler.

[0016] The feedback output unit comprises a resistor R69, a resistor R112, a resistor R111, a triode Q3 and a capacitor C43, one end of the resistor R69, one end of the resistor R112 and the base of the triode Q3 are connected to the collector of the light receiver of the first optocoupler, the other end of the resistor R112 is connected to one end of the resistor R111, the collector of the triode Q3, one end of the capacitor C43 and the feedback input end of the MCU module, the other end of the resistor R69 and the other end of the resistor R111 are connected to the power input end of the MCU module; the emitter of the triode Q3 and the other end of the capacitor C43 are grounded.

[0017] Preferably, the trigger control unit comprises a resistor R109, a resistor R110, a resistor R75 and a triode Q2, one end of the resistor R109 is connected to the PWM output end of the MCU module, the other end of the resistor R109 is connected to one end of the resistor R110 and the base of the triode Q2, the other end of the resistor R110 and the emitter of the triode Q2 are grounded; the collector of the triode Q2 is connected to the cathode of the light emitter of the second optocoupler through the resistor R75, and the anode of the light emitter of the second optocoupler is connected to the power supply module.

[0018] The silicon controlled voltage regulating unit comprises a resistor R77, a resistor R80, a resistor R78, a resistor R79, a capacitor C46, a capacitor C45 and a silicon controlled rectifier K1, the collector of the light receiver of the second optocoupler is connected to the anode of the silicon controlled rectifier K1, one end of the resistor R78, one end of the resistor R79 and the live wire of the input end of the power supply module through the resistor R77, the other end of the resistor R78 is connected to the other end of the resistor R79 and one end of the capacitor C45, the other end of the capacitor C45 is connected to the fan module, the cathode of the silicon controlled rectifier K1, one end of the capacitor C46 and one end of the resistor R80, the other end of the resistor R80 is connected to the other end of the capacitor C46, the control pin of the silicon controlled rectifier K1 and the emitter of the light receiver of the second optocoupler.

[0019] Preferably, the power supply module comprises an AC / DC unit, a first step-down unit, a second step-down unit and a third step-down unit connected in sequence, the AC / DC unit rectifies alternating current into direct current, the first step-down unit reduces the direct current output by the AC / DC unit to 12V, the second step-down unit reduces the 12V voltage to 5V, and the third step-down unit reduces the 5V voltage to 3.3V; the power supply module further comprises a voltage detection module, which detects at least the output voltages of the first step-down unit and the second step-down unit, and the voltage detection module is connected to the MCU module. By setting the voltage detection module, the power consumption safety of the control circuit can be ensured, and fault elimination can also be facilitated.

[0020] Preferably, a state light bar, an alarm and a memory are further included, and the state light bar, the alarm and the memory are connected with the MCU module.

[0021] The utility model has the following beneficial effects:

[0022] The utility model discloses a kind of air purifiers, which is equipped with MCU module, voltage detection module, power meter module, control panel, HEPA button, air pressure sensor, particle sensor, zero potential detection module, rectifier unit, feedback output unit, control trigger module, trigger control unit, thyristor voltage regulating unit, state light bar, alarm and memory, and the MCU module is connected with voltage detection module, power meter module, control panel, HEPA button, air pressure sensor, particle sensor, zero potential detection module, rectifier unit, feedback output unit, control trigger module, trigger control unit, thyristor voltage regulating unit, state light bar, alarm and memory. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is the principle diagram of the utility model.

[0024] Figure 2 It is the schematic diagram of voltage detection module.

[0025] Figure 3 It is the schematic diagram of control module.

[0026] Figure 4 It is the schematic diagram of zero potential detection module.

[0027] Figure 5 It is the schematic diagram of control trigger module.

[0028] Main component symbol explanation:

[0029] MCU module 1, power supply module 2, voltage detection module 3, power meter module 4, control panel 5, HEPA button 6, air pressure sensor 7, particle sensor 8, zero potential detection module 9, rectifier unit 91, feedback output unit 92, control trigger module 10, trigger control unit 101, thyristor voltage regulating unit 102, fan module 11, state light bar 12, alarm 13, memory 14. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical scheme and advantages of the utility model more clear and obvious, the utility model is further explained in detail in the following with the help of drawings and examples.

[0031] like Figure 1 As shown, this utility model discloses an air purifier control circuit, which includes a power supply module 2, an MCU module 1, a power meter module 4, a control panel 5, a fan module 11, a pressure sensor 7, a particle sensor 8, a HEPA button 6, a zero-potential detection module 9, a control trigger module 10, a voltage detection module 3, a status light bar 12, an alarm 13, and a memory 14. The status light bar 12 can be used to display fault codes and the operating status of the main components of the equipment. The alarm 13 can promptly notify nearby personnel when a fault occurs. The memory 14 is used to store preset programs, operating parameters, etc.

[0032] The input terminal of power supply module 2 is the power input terminal of the air purifier. Power supply module 2 includes an AC / DC unit, a first-stage step-down unit, a second-stage step-down unit, and a third-stage step-down unit connected in sequence. The AC / DC unit rectifies the alternating current into direct current. The first-stage step-down unit steps down the direct current output from the AC / DC unit to 12V. The second-stage step-down unit steps down the 12V voltage to 5V. The third-stage step-down unit steps down the 5V voltage to 3.3V. Power supply module 2 is a mature existing technology and will not be described in detail here. MCU module 1, control panel 5, fan module 11, fuel gauge module 4, etc., are all connected to power supply module 2 for power. MCU module 1 is a microcontroller, and its operating voltage is generally 3.3V. Fuel gauge module 4 is generally connected to 5V, and control panel 5 is generally connected to 5V.

[0033] Voltage detection module 3 detects the output voltage of at least the first-stage and second-stage buck converters. Voltage detection module 3 is connected to MCU module 1. By setting up voltage detection module 3, the electrical safety of the control circuit's power supply modules can be ensured, and troubleshooting can be facilitated. Figure 2 As shown, voltage detection module 3 detects 12V and 5V voltages. Voltage detection module 3 includes resistors R15, R16, R18, R19, R72, R73, capacitors C24 and C25. One end of resistor R15 is connected to the output terminal (12V) of the first-stage buck unit. The other end of resistor R15 is connected to one end of resistor R18 and one end of resistor R72. The other end of resistor R72 is connected to the TP9 input terminal of MCU module 1 and one end of capacitor C24. The other end of capacitor C24 and the other end of resistor R18 are grounded. One end of resistor R16 is connected to the output terminal (5V) of the second-stage buck unit. The other end of resistor R16 is connected to one end of resistor R19 and one end of resistor R73. The other end of resistor R73 is connected to the TP10 input terminal of MCU module 1 and one end of capacitor C25. The other end of capacitor C25 and the other end of resistor R19 are grounded. The MCU module 1 reads the resistor voltage divider value to determine whether the 12V and 5V voltages are normal. If they are abnormal, the fan module 11 stops running.

[0034] The power meter module 4 is connected to the MCU module 1 via serial communication. The power meter module 4 generally includes a voltage acquisition unit and a current acquisition unit. It is used to acquire the power supply voltage and current of the air purifier (i.e., the input voltage and current of the power supply module 2) and feed them back to the MCU module 1. The power meter module 4 is existing technology and will not be described further.

[0035] Control panel 5 is used to operate the air purifier, such as power switch, start / stop, fan speed selection, and alarm display. Control panel 5 connects to MCU module 1 via an interface. Specifically, control panel 5 includes an identification resistor for marking the device model. One end of the identification resistor is grounded, and the other end is connected to power supply module 2 via a voltage divider resistor. A detection point is set between the identification resistor and the voltage divider resistor, and this detection point is connected to the model identification input terminal of MCU module 1. Specifically, for example... Figure 3 As shown, the identification resistors include a first identification resistor RA and a second identification resistor RB; the voltage divider resistors include a first voltage divider resistor R17 and a second voltage divider resistor R94; and the device identification input terminals include a first identification input terminal and a second identification input terminal. One end of the first identification resistor RA is grounded, and the other end of the first identification resistor RA is a detection point TP11, which connects the first identification input terminal (Device Type 1) and one end of the first voltage divider resistor R17. The other end of the first voltage divider resistor R17 is connected to the power supply module 2 (3.3V). Both ends of the second identification resistor RB are grounded, and the other end of the second identification resistor RB is a detection point TP12, which connects the second identification input terminal (Device Type 2) and the two ends of the second voltage divider resistor R94. The other end of the second voltage divider resistor R94 is connected to the power supply module 2 (3.3V).

[0036] Different resistance values ​​are used for identification resistors of different air purifier models. The MCU module 1 collects the voltage at the detection point to identify the device model, and the power meter collects the input voltage of the power supply module 2. The MCU can then determine whether the input voltage is compatible with the device model (mainly the fan module 11), thus providing reliable protection for the device. Furthermore, the first identification resistor RA and the second identification resistor RB are different, allowing for the generation of more identification signal groups to adapt to more device models. Alternatively, the first identification resistor RA can be equal to the second identification resistor RB for double protection. After the above settings, only the control panel 5 and the fan module 11 need to be paired and unified; the other modules can use general-purpose components. The MCU module 1 can run a program compatible with all models, eliminating the need for different control programs for different device models. The control circuit boards can be mass-produced and programmed in batches, improving production and after-sales efficiency.

[0037] In the case, the air inlet and the air outlet of the air purifier are sequentially provided with the HEPA filter and the activated carbon filter screen along the air outlet direction, the air pressure sensor 7 and the particle sensor 8 are arranged at the air outlet of the air purifier, and the air pressure sensor 7 and the particle sensor 8 are connected to the MCU module 1 to feed back data. The HEPA button 6 is arranged between the activated carbon filter screen and the HEPA filter, and the HEPA button 6 can be seen only when the activated carbon filter screen is removed. The HEPA button 6 is connected to the MCU module 1 to output a HEPA test signal. When the HEPA filter is tested, the activated carbon filter screen is removed first, and then the HEPA button 6 is triggered, so that the fan module 11 is controlled to run at a constant power, the air pressure value fed back by the air pressure sensor 7 is obtained, and the air pressure value is compared with a preset value (when the device is initially operated, the activated carbon filter screen is removed first, and then the HEPA test is performed, and the air pressure value at this time is the preset value), so that the clogging degree of the HEPA filter can be determined, and the operation is convenient and fast.

[0038] The feedback input end and the PWN output end are arranged on the MCU module 1 to participate in the control of the fan module 11. Figure 4 As shown in the figure, the zero potential detection module 9 is used to detect the zero potential of the power input end (L1) of the air purifier, and includes the rectifier unit 91, the first optocoupler U11 and the feedback output unit 92 connected in sequence. The rectifier unit 91 is connected to the power input end of the air purifier, and is used to rectify alternating current into direct current. The rectifier unit 91 includes the rectifier bridge D9, the resistor R70, the resistor R68 and the resistor R71. The input end of the rectifier bridge D9 is connected to alternating current (L1 and N). The output negative pole of the rectifier bridge D9 is connected to one end of the resistor R68 through the resistor R70, one end of the resistor R68 is connected to one end of the resistor R71 and the anode of the light emitter of the first optocoupler U11, and the other end of the resistor R71 is connected to the cathode of the light emitter of the first optocoupler U11.

[0039] The feedback output unit 92 includes the resistor R69, the resistor R112, the resistor R111, the triode Q3 and the capacitor C43. The collector of the light receiver of the first optocoupler U11 is connected to one end of the resistor R69, one end of the resistor R112 and the base of the triode Q3. The other end of the resistor R112 is connected to one end of the resistor R111, the collector of the triode Q3, one end of the capacitor C43 and the feedback input end (AC_SYNC) of the MCU module 1. The other end of the resistor R69 and the other end of the resistor R111 are connected to the power input end (VCC3V3) of the MCU module 1. The emitter of the triode Q3 and the other end of the capacitor C43 are grounded.

[0040] The firewire L1 and zero line N of the alternating current input alternating voltage signal, and output direct current voltage signal after rectification bridge D9 rectification, when the alternating voltage signal is not zero potential, the direct current voltage signal can make the light emitting device of the first optocoupler U11 emit light signal after voltage reduction through resistance R70, resistance R68 and resistance R71. The light signal is converted into electrical signal through the light isolation structure inside the first optocoupler U11, and the light receiver of the first optocoupler U11 is turned on, so that the triode Q1 is cut off, and the feedback input end AC_SYNC receives DC 3.3V high level (i.e. the first signal), indicating that the input AC voltage signal is not zero potential. When the input alternating voltage is zero potential, the light receiver of the first optocoupler U11 is not turned on, the triode Q1 works, and the voltage of AC_SYNC port is pulled down, and the feedback input end AC_SYNC detects low level (i.e. the second signal), indicating that the input AC voltage signal is zero potential.

[0041] As shown in Figure 5 The control trigger module 10 includes a trigger control unit 101, a second optocoupler U12 and a silicon controlled voltage regulating unit 102 connected in sequence. The control unit includes resistance R109, resistance R110, resistance R75 and triode Q2, one end of resistance R109 is connected with the PWM output end (FAN_CTR) of MCU module 1, the other end of resistance R109 is connected with one end of resistance R110 and the base of triode Q2, the other end of resistance R110 and the emitter of triode Q2 are grounded; the collector of triode Q2 is connected with the cathode of the light emitting device of the second optocoupler U12 through resistance R75, and the anode of the light emitting device of the second optocoupler U12 is connected with 5V power supply.

[0042] The silicon controlled voltage regulating unit 102 includes resistance R77, resistance R80, resistance R78, resistance R79, capacitor C46, capacitor C45 and silicon controlled rectifier K1, the collector of the light receiver of the second optocoupler U12 is connected with the anode of silicon controlled rectifier K1, one end of resistance R78, one end of resistance R79 and the firewire (L1) of alternating current, the other end of resistance R78 is connected with the other end of resistance R79 and one end of capacitor C45, the other end of capacitor C45 is connected with the fan module 11 (P11) used in the fan module 11, the cathode of silicon controlled rectifier K1, one end of capacitor C46 and one end of resistance R80, the other end of resistance R80 is connected with the other end of capacitor C46, the control pin of silicon controlled rectifier K1 and the emitter of the light receiver of the second optocoupler U12. Figure 5

[0043] ​The MCU module 1 sends out a PWM signal according to the first signal and / or the second signal to control the on-off of the light emitter of the second optocoupler U12, and the light receiver of the second optocoupler U12 controls the on-off of the thyristor voltage regulating unit 102. Specifically, when the MCU module 1 detects that the AC current is zero, the MCU module 1 outputs a PWM signal of DC 3.3V through the FAN_CTR port to control the on-off of the triode Q2 through the resistor R109. When the triode Q2 is on, the light emitter of the second optocoupler U12 emits a light signal, which is converted into an electric signal through the internal light isolation structure of the second optocoupler U12. The photoelectric effect in the photoconductive diode causes it to generate a current, which drives the control pin (3 pin) of the thyristor K1, so that the anode (2 pin) and the cathode (1 pin) of the thyristor K1 are on, thereby realizing the chopping function of the input AC voltage L1.

[0044] In the control trigger module 10, the resistor R75, the resistor R77 and the resistor R80 play a role in limiting the current of the second optocoupler U12, protecting the devices and matching the signals in the circuit, thereby improving the performance and stability of the second optocoupler U12. The capacitor C46 is mainly used to limit the voltage rise rate in the circuit, prevent hard turn-on, and protect the thyristor K1. The resistor R78, the resistor R79 and the capacitor C45 are connected in series and are connected to the anode and the cathode of the thyristor K1, thereby forming an RC resistance-capacitance absorption circuit, limiting the voltage rise rate of the circuit, avoiding the discharge current of the capacitor being too large through the thyristor K1, protecting the thyristor K1, and ensuring that the thyristor K1 can operate safely.

[0045] The zero potential detection module 9 detects the zero potential of the input power supply of the air purifier and feeds back to the MCU module 1. When the current of the input power supply is zero, the MCU module 1 outputs a PWM signal to the control trigger module 10, thereby accurately realizing the chopping function of the input AC voltage, realizing voltage reduction, achieving the purpose of controlling the speed of the AC fan, and ensuring the stability of the output voltage. The hysteresis time of the PWM signal trigger level relative to the zero potential of the input power supply can be adjusted to conveniently adjust the voltage reduction amplitude, and the speed of the AC fan is convenient and accurate. In addition, the first optocoupler is used for isolation in the zero potential detection module 9, and the second optocoupler is used for isolation in the control trigger module 10, which can ensure the safety of the MCU module 1. In addition, the circuit structures of the two modules are simple, stable and relatively low in cost.

[0046] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited to this. Any skilled person in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A control circuit for an air purifier, characterized in that: The device includes a power supply module, an MCU module, a fuel gauge module, a control panel, and a fan module. The MCU module, control panel, and fan module are all connected to the power supply module for power, and the fuel gauge module, control panel, and fan module are all connected to the MCU module. The fuel gauge module detects the input voltage of the power supply module and feeds it back to the MCU module. The control panel includes an identification resistor for marking the device model. One end of the identification resistor is grounded, and the other end is connected to the power supply module via a voltage divider resistor. A detection point is set between the identification resistor and the voltage divider resistor, and this detection point is connected to the model identification input terminal of the MCU module.

2. The air purifier control circuit according to claim 1, characterized in that: The identification resistor includes a first identification resistor and a second identification resistor, the voltage divider resistor includes a first voltage divider resistor and a second voltage divider resistor, the model identification input terminal includes a first identification input terminal and a second identification input terminal; one end of the first identification resistor is grounded, the other end of the first identification resistor is connected to the first identification input terminal and one end of the first voltage divider resistor, and the other end of the first voltage divider resistor is connected to the power supply module; Two ends of the second identification resistor are grounded, the other end of the second identification resistor is connected to the second identification input terminal and the two ends of the second voltage divider resistor, and the other end of the second voltage divider resistor is connected to the power supply module.

3. The air purifier control circuit according to claim 1, characterized in that: It also includes a pressure sensor and a HEPA button for outputting a signal to start the HEPA test; a HEPA filter and an activated carbon filter are arranged sequentially between the air inlet and air outlet of the air purifier and along the air outlet direction; the pressure sensor is located at the air outlet of the air purifier; the pressure sensor and the HEPA button are both connected to the MCU module.

4. The air purifier control circuit according to claim 3, characterized in that: The HEPA button is located between the activated carbon filter and the HEPA filter.

5. The air purifier control circuit according to claim 1, characterized in that: It also includes a particle sensor located at the air outlet of the air purifier, the particle sensor being connected to the MCU module.

6. The air purifier control circuit according to claim 1, characterized in that: It also includes a zero-potential detection module and a control trigger module; the MCU module has a feedback input terminal and a PWM output terminal; The zero-potential detection module includes a rectifier unit, a first optocoupler, and a feedback output unit connected in sequence. The rectifier unit is connected to the input terminal of the power supply module and is used to rectify AC power into DC power. The feedback output unit is connected to the feedback input terminal of the MCU module. When the light emitter of the first optocoupler is turned on, the feedback output unit outputs a first signal. When the light emitter of the first optocoupler is not turned on, the feedback output unit outputs a second signal. The control trigger module includes a trigger control unit, a second optocoupler, and a thyristor voltage regulator unit connected in sequence. The thyristor voltage regulator unit is connected in series with the live wire of the power supply module's input terminal. The PWM output terminal of the MCU module is connected to the trigger control unit. The MCU module sends a PWM signal according to a first signal and / or a second signal to control the on / off state of the emitter of the second optocoupler. The photodetector of the second optocoupler controls the on / off state of the thyristor voltage regulator unit. The live wire of the fan module's power input is connected to the output terminal of the thyristor voltage regulator unit.

7. The air purifier control circuit according to claim 6, characterized in that: The rectifier unit includes a rectifier bridge D9, resistors R70, R68, and R71. The input terminal of the rectifier bridge D9 is connected to the input terminal of the power supply module. The negative output terminal of the rectifier bridge D9 is connected to one end of resistor R68 via resistor R70. The other end of resistor R68 is connected to one end of resistor R71 and the anode of the first optocoupler. The negative output terminal of the rectifier bridge D9 is connected to the other end of resistor R71 and the cathode of the first optocoupler. The feedback output unit includes resistors R69, R112, and R111, transistor Q3, and capacitor C43. The collector of the photodetector of the first optocoupler is connected to one end of resistor R69, one end of resistor R112, and the base of transistor Q3. The other end of resistor R112 is connected to one end of resistor R111, the collector of transistor Q3, one end of capacitor C43, and the feedback input terminal of the MCU module. The other ends of resistors R69 and R111 are connected to the power input terminal of the MCU module. The emitter of transistor Q3 and the other end of capacitor C43 are grounded.

8. The air purifier control circuit according to claim 6, characterized in that: The trigger control unit includes resistors R109, R110, and R75, and transistor Q2. One end of resistor R109 is connected to the PWM output terminal of the MCU module, and the other end of resistor R109 is connected to one end of resistor R110 and the base of transistor Q2. The other end of resistor R110 and the emitter of transistor Q2 are grounded. The collector of transistor Q2 is connected to the cathode of the light emitter of the second optocoupler via resistor R75, and the anode of the light emitter of the second optocoupler is connected to the power supply module. The thyristor voltage regulation unit includes resistors R77, R80, R78, and R79, capacitors C46 and C45, and a thyristor K1. The collector of the photodetector of the second optocoupler is connected via resistor R77 to the anode of the thyristor K1, one end of resistor R78, one end of resistor R79, and the live wire of the power supply module input terminal. The other end of resistor R78 is connected to the other end of resistor R79 and one end of capacitor C45. The other end of capacitor C45 is connected to the fan module, the cathode of the thyristor K1, one end of capacitor C46, ​​and one end of resistor R80. The other end of resistor R80 is connected to the other end of capacitor C46, ​​the control pin of the thyristor K1, and the emitter of the photodetector of the second optocoupler.

9. The air purifier control circuit according to claim 1, characterized in that: The power supply module includes an AC / DC unit, a first-stage step-down unit, a second-stage step-down unit, and a third-stage step-down unit connected in sequence. The AC / DC unit rectifies AC power into DC power. The first-stage step-down unit steps down the DC power output from the AC / DC unit to 12V. The second-stage step-down unit steps down the 12V voltage to 5V. The third-stage step-down unit steps down the 5V voltage to 3.3V. The module also includes a voltage detection module that detects the output voltage of at least the first-stage and second-stage step-down units. The voltage detection module is connected to the MCU module.

10. The air purifier control circuit according to claim 1, characterized in that: It also includes status light bars, alarms, and a memory, all of which are connected to the MCU module.

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