Intelligent control circuit of air purifier

Abstract

An intelligent control circuit of an air purifier relates to the technical field of control circuits and comprises a voltage source circuit, a filter element detection circuit, a load circuit and a main stage control circuit, and the output end of the voltage source circuit is connected with the power supply ends of the filter element detection circuit, the load circuit and the main stage control circuit. The detection output end of the filter element detection circuit is connected with the input end of the main stage control circuit, the load control end of the main stage control circuit is connected with the controlled end of the load circuit, and the voltage source circuit is used for providing power needed by the main stage control circuit of the air purifier. The filter element detection circuit is used for detecting whether a filter element needs to be replaced or not, the primary control circuit is used for controlling the filter element detection circuit and the load circuit, and the load circuit is used for driving the load end of the air purifier. And the air quality deterioration caused by overuse of the filter element can be prevented.

Description

Technical Field

[0001] The present invention relates to the technical field of control circuits, and in particular to an intelligent control circuit for an air purifier. Background Art

[0002] Air purifiers can effectively remove dust, pollen, smoke, odors and various harmful gases in the air, providing a protective measure for living and office environments. In recent years, with the improvement of people's health awareness, the demand for air purification equipment has increased sharply, and air purifiers of various types and functions have emerged on the market to meet the needs of different consumers.

[0003] However, existing air purifiers lack an effective filter monitoring and replacement reminder system, making it difficult for users to judge the actual usage status and replacement timing of the filter. The filter is the most critical component of an air purifier. Once the performance of the filter deteriorates due to long-term use, not only will the purification efficiency be greatly reduced, but bacteria and pollutants will also accumulate on the filter, which will have a negative impact on indoor air quality. Summary of the invention

[0004] The purpose of the present invention is to address the defects and shortcomings of the prior art. In the first aspect, an intelligent control circuit for an air purifier is provided, comprising a voltage source circuit, a filter element detection circuit, a load circuit and a main-stage control circuit. The output end of the voltage source circuit is connected to the filter element detection circuit, the load circuit and the power supply end of the main-stage control circuit. The detection output end of the filter element detection circuit is connected to the input end of the main-stage control circuit. The load control end of the main-stage control circuit is connected to the controlled end of the load circuit. The voltage source circuit is used to provide the power supply required by the main-stage control circuit of the air purifier. The filter element detection circuit is used to detect whether the filter element needs to be replaced. The main-stage control circuit is used to control the filter element detection circuit and the load circuit. The load circuit is used to drive the load end of the air purifier.

[0005] Furthermore, the filter element detection circuit includes a display circuit, a secondary control circuit, a communication circuit, a timestamp circuit and a load module, the display circuit is connected to the control end of the secondary control circuit, the output end of the voltage source circuit is connected to the power supply end of the communication circuit, the power supply end of the display circuit and the power supply end of the timestamp circuit, the secondary control circuit is respectively connected to the output end of the communication circuit and the output end of the timestamp circuit, the display circuit is used to display air quality information, the secondary control circuit is used to control the operation of the display circuit, the communication circuit and the load module, the communication circuit is used to program the filter element detection circuit and perform data communication, the timestamp circuit is used to record the time of monitoring data, and the load module is used to connect to an air quality sensor.

[0006] Furthermore, the display circuit includes a display control circuit and an LCD driving circuit, wherein the display control circuit is used to control the LCD driving circuit, and the LCD driving circuit is used to drive the LCD display screen to display air quality information, wherein: The display control circuit includes a display screen LCD1, a resistor R32, a resistor R33, a resistor R34, a transistor Q4, a capacitor C11 and a capacitor C12, one end of the resistor R32 is connected to the ninth port of the display screen LCD1, the other end of the resistor R32 is connected to the tenth port of the display screen LCD1, one end of the capacitor C11, one end of the capacitor C12 and the voltage source circuit, the other end of the capacitor C11 and the other end of the capacitor C12 are connected to the ground terminal and the eleventh port of the display screen LCD1, the base of the transistor Q4 is connected to one end of the resistor R33 and one end of the resistor R34, the other end of the resistor R33 is connected to the secondary control circuit, the other end of the resistor R34 is connected to the emitter of the transistor Q4 and the ground terminal, and the collector of the transistor Q4 is connected to the sixth port of the display screen LCD1.

[0007] Further, the load circuit includes a transistor Q1, a transistor Q2, a resistor R4, a resistor R8, a resistor R10, a resistor R11, a resistor R7, a diode D1, a capacitor C3 and a connector J3, wherein: One end of the resistor R10 is connected to the main control circuit, the other end of the resistor R10 is connected to the base of the transistor Q2 and one end of the resistor R11, the other end of the resistor R11 is connected to the emitter and the base end of the transistor Q2, the collector of the transistor Q2 is connected to one end of the resistor R8, the other end of the resistor R8 is connected to the gate of the transistor Q1 and one end of the resistor R4, the other end of the resistor R4 is connected to the source of the transistor Q1 and the voltage source circuit, the drain of the transistor Q1 is connected to one end of the diode D1, one end of the capacitor C3 and the first port of the connector J3, the other end of the diode D1 is connected to the other end of the capacitor C3 and the second port of the connector J3, one end of the resistor R7 is connected to the third port of the connector J3, and the other end of the resistor R7 is connected to the main control circuit.

[0008] Furthermore, the voltage source circuit further includes a first voltage source subcircuit, wherein the first voltage source subcircuit includes a resistor R25, Capacitor EC1, capacitor EC2, inductor LX, diode D4, voltage regulator chip U1, connector J1, capacitor C1, among which: The second port of the connector J1 is connected to one end of the resistor R25 and the primary power supply port, the other end of the resistor R25 is connected to one end of the capacitor EC1 and the first port of the voltage stabilizing chip U1, the first port of the connector J1 is connected to the other end of the capacitor EC1, one end of the capacitor EC2, one end of the capacitor C1, the anode of the diode D4 and the fourth port of the voltage stabilizing chip U1, the other end of the capacitor EC2 is connected to the other end of the capacitor C1, one end of the inductor LX, the third port of the voltage stabilizing chip U1 and the output end of the first voltage source sub-circuit, the other end of the inductor LX is connected to the cathode of the diode D4 and the second port of the voltage stabilizing chip U1, and the fifth port, sixth port, seventh port and eighth port of the voltage stabilizing chip U1 are short-circuited with the fourth port of the voltage stabilizing chip U1.

[0009] Furthermore, the voltage source circuit further includes a second voltage source sub-circuit, and the second voltage source sub-circuit includes a voltage stabilizing chip U12, a capacitor C26, a capacitor C27, a capacitor C28, a capacitor C29 and a capacitor C30, wherein: One end of the capacitor C26 is connected to the output end of the first voltage source sub-circuit, one end of the capacitor C27 and the third port of the voltage stabilizing chip U12, the other end of the capacitor C26 is connected to the other end of the capacitor C27 and the ground, the first port of the voltage stabilizing chip U12 is grounded, the second port of the voltage stabilizing chip U12 is connected to one end of the capacitor C28, one end of the capacitor C29, one end of the capacitor C30 and the output end of the second voltage source sub-circuit, and the other end of the capacitor C28 is connected to the other end of the capacitor C29, the other end of the capacitor C30 and the ground.

[0010] Furthermore, it also includes an LED control circuit, which includes a transistor Q3, a resistor R1, a resistor R3, a resistor R6, a resistor R18, a resistor R19, a resistor R20, an LED driver chip U3, an LED driver chip U4, an LED driver chip U5, and an LED driver chip U6, wherein: One end of the resistor R6 is connected to the output end of the first voltage source sub-circuit, one end of the resistor R18, one end of the resistor R19 and one end of the resistor R20, the other end of the resistor R6 is connected to the second port of the LED driver chip U3, the other end of the resistor R18 is connected to the second port of the LED driver chip U4, the other end of the resistor R19 is connected to the second port of the LED driver chip U2, the other end of the resistor R20 is connected to the second port of the LED driver chip U6, one end of the resistor R1 is connected to the first port of the LED driver chip U3, the other end of the resistor R1 is connected to the main control circuit, and the second end of the LED driver chip U3 is connected to the second port of the LED driver chip U4. The three ports are connected to the first port of the LED driver chip U4, the third port of the LED driver chip U4 is connected to the first port of the LED driver chip U2, the third port of the LED driver chip U2 is connected to the first port of the LED driver chip U6, the collector of the transistor Q3 is connected to the fourth port of the LED driver chip U2, the fourth port of the LED driver chip U3, the fourth port of the LED driver chip U4 and the fourth port of the LED driver chip U6, the base of the transistor Q3 is connected to one end of the resistor R3, the other end of the resistor R3 is connected to the main control circuit, and the emitter of the transistor Q3 is grounded.

[0011] Further, it also includes an LED driving circuit, which includes a resistor R2, a resistor R5, a resistor R9, a resistor R12, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a resistor R17, a light emitting diode LED1, a light emitting diode LED2, a light emitting diode LED3, a light emitting diode LED4, a light emitting diode LED5, a light emitting diode LED6, a connector J2, a connector J4 and a connector J5, wherein: The cathode of the light-emitting diode LED1 is connected to the cathode of the light-emitting diode LED2, the cathode of the light-emitting diode LED3, the cathode of the light-emitting diode LED4, the cathode of the light-emitting diode LED5, the cathode of the light-emitting diode LED6 and the ground terminal, the anode of the light-emitting diode LED1, the anode of the light-emitting diode LED2, the anode of the light-emitting diode LED3, the anode of the light-emitting diode LED4, the anode of the light-emitting diode LED5 and the anode of the light-emitting diode LED6 are connected to the main-level control circuit through resistors R12, R13, R14, R15, R16 and R17 respectively, and the connector J2, connector J4 and connector J5 are connected to the main-level control circuit through resistors R2, R5 and R9 respectively.

[0012] In a second aspect, the present invention further provides an air purifier, comprising an intelligent control circuit of the air purifier according to the above technical solution.

[0013] In a third aspect, the present invention further provides a filter element detection method, comprising: Obtain the pollutant concentration before air purification and the pollutant concentration after air purification; Obtaining a use status parameter of the filter element according to the pollutant concentration before the air purification and the pollutant concentration after the air purification; When the usage status parameter of the filter element is lower than a first preset threshold, a first signal is generated; When the usage status parameter of the filter element is lower than a second preset threshold, generating a second signal; adjusting the fan power according to the second signal; When the usage status parameter of the filter element is lower than a second preset threshold, a third signal is generated.

[0014] The embodiment of the present invention uses a newly added filter element detection circuit to monitor the usage status of the filter element in real time, ensuring that the performance of the filter element is always maintained at an optimal level. When the filter element detection circuit finds that the filter element performance has dropped to a certain critical point, it will send a signal to the main-level control circuit, and the main-level control circuit will further analyze the data and decide whether to issue a prompt to replace the filter element. This not only improves the air purification efficiency, but also helps prevent the deterioration of air quality due to excessive use of the filter element. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0016] Figure 1 is a structural block diagram of a first embodiment of the present invention; Figure 2 is a circuit diagram of a voltage source circuit in a second embodiment of the present invention; Figure 3 is a circuit diagram of a display control circuit in a second embodiment of the present invention; Figure 4 is a circuit diagram of an LCD driving circuit in a second embodiment of the present invention; Figure 5 is a circuit diagram of a secondary control circuit in a second embodiment of the present invention; Figure 6 is a circuit diagram of a communication circuit in a second embodiment of the present invention; Figure 7 is a circuit diagram of a time stamp circuit in a second embodiment of the present invention; Figure 8is a circuit diagram of a load module in a second embodiment of the present invention; Fig. 9 is a circuit diagram of a load circuit in a second embodiment of the present invention; Fig.10 is a circuit diagram of a primary control circuit in a second embodiment of the present invention; Fig.11 is a circuit diagram of an LED control circuit in a second embodiment of the present invention; Fig.12 is a circuit diagram of an LED driving circuit in a second embodiment of the present invention.

[0017] Reference numerals: 100, voltage source circuit; 110, first voltage source sub-circuit; 120, second voltage source sub-circuit; 200, filter element detection circuit; 210, display circuit; 211, display control circuit; 212, LCD drive circuit; 220, secondary control circuit; 230, communication circuit; 240, timestamp circuit; 250, load module; 300, load circuit; 400, primary control circuit; 500, LED control circuit; 600, LED drive circuit. DETAILED DESCRIPTION

[0018] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0019] This specific embodiment is only an explanation of the present invention, and it is not a limitation of the present invention. After reading this specification, those skilled in the art can make non-creative modifications to this embodiment as needed, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

[0020] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely indicates that the selected embodiments of the present invention are based on the embodiments in the present invention. All other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention. First embodiment: Reference Figure 1The present invention provides an intelligent control circuit for an air purifier, comprising a voltage source circuit 100, a filter element detection circuit 200, a load circuit 300 and a main control circuit 400, wherein the output end of the voltage source circuit 100 is connected to the filter element detection circuit 200, the load circuit 300 and the power supply end of the main control circuit 400, the detection output end of the filter element detection circuit 200 is connected to the input end of the main control circuit 400, the load control end of the main control circuit 400 is connected to the controlled end of the load circuit 300, the voltage source circuit 100 is used to provide the power supply required by the main control circuit 400 of the air purifier, the filter element detection circuit 200 is used to detect whether the filter element needs to be replaced, the main control circuit 400 is used to control the filter element detection circuit 200 and the load circuit 300, and the load circuit 300 is used to drive the load end of the air purifier.

[0021] The embodiment of the present invention uses a newly added filter element detection circuit to monitor the usage status of the filter element in real time, ensuring that the performance of the filter element is always maintained at an optimal level. When the filter element detection circuit finds that the filter element performance has dropped to a certain critical point, it will send a signal to the main-level control circuit, and the main-level control circuit will further analyze the data and decide whether to issue a prompt to replace the filter element. This not only improves the air purification efficiency, but also helps prevent the deterioration of air quality due to excessive use of the filter element.

[0022] Embodiments of the present invention.

[0023] Second embodiment: Reference Figure 2-12 Optionally, the filter element detection circuit 200 includes a display circuit 210, a secondary control circuit 220, a communication circuit 230, a timestamp circuit 240 and a load module 250. The display circuit 210 is connected to the control end of the secondary control circuit 220. The output end of the voltage source circuit 100 is connected to the power supply end of the communication circuit 230, the power supply end of the display circuit 210 and the power supply end of the timestamp circuit 240. The secondary control circuit 220 is respectively connected to the output end of the communication circuit 230 and the output end of the timestamp circuit 240. The display circuit 210 is used to display air quality information. The secondary control circuit 220 is used to control the operation of the display circuit 210, the communication circuit 230 and the load module 250. The communication circuit 230 is used to program and communicate data for the filter element detection circuit 200. The timestamp circuit 240 is used to record the time of monitoring data. The load module 250 is used to connect an air quality sensor.

[0024] The air purifier intelligent control circuit provided in this embodiment realizes comprehensive monitoring and management of the air purification process through its highly integrated design, thereby significantly improving the air purification efficiency and user interaction experience.

[0025] First, this embodiment uses the display circuit to enable users to easily understand the working status of the air purifier and perform necessary maintenance in a timely manner. The display circuit is connected to the secondary control circuit, which is responsible for the core control function of the entire system to ensure the accuracy and real-time updating of the displayed information.

[0026] The secondary control circuit is further connected to the communication circuit and the timestamp circuit, which enables the device to not only perform remote programming and data transmission through the communication circuit, thus improving the intelligence level of the device, but also record the specific time of each monitoring through the timestamp circuit, thus providing reliable data support for subsequent data analysis and maintenance.

[0027] Finally, the design of the load module allows the control circuit to be directly connected to the air quality sensor, which not only simplifies the hardware design, but also optimizes the signal processing path, reduces the system response time, and enables the air purifier to quickly respond to environmental changes and adjust the purification strategy accordingly.

[0028] Optionally, the display circuit 210 includes a display control circuit 211 and an LCD driving circuit 212, wherein the display control circuit 211 is used to control the LCD driving circuit 212, and the LCD driving circuit 212 is used to drive an LCD display screen to display air quality information, wherein: The display control circuit 211 includes a display screen LCD1, a resistor R32, a resistor R33, a resistor R34, a transistor Q4, a capacitor C11 and a capacitor C12, one end of the resistor R32 is connected to the ninth port of the display screen LCD1, the other end of the resistor R32 is connected to the tenth port of the display screen LCD1, one end of the capacitor C11, one end of the capacitor C12 and the voltage source circuit 100, the other end of the capacitor C11 and the other end of the capacitor C12 are connected to the ground terminal and the eleventh port of the display screen LCD1, the base of the transistor Q4 is connected to one end of the resistor R33 and one end of the resistor R34, the other end of the resistor R33 is connected to the secondary control circuit 220, the other end of the resistor R34 is connected to the emitter of the transistor Q4 and the ground terminal, and the collector of the transistor Q4 is connected to the sixth port of the display screen LCD1.

[0029] Specifically, the resistor R32 connects the ninth port and the tenth port of the display screen LCD1 to the voltage source circuit 100 to provide a stable power supply for the LCD display screen, thereby ensuring the normal operation of the display screen.

[0030] Specifically, capacitors C11 and C12 work together with resistor R32, and after receiving power from the voltage source circuit 100, they are respectively connected to the eleventh port of the display screen LCD1 and the ground terminal. Capacitors C11 and C12 help filter out noise and voltage fluctuations in the power supply, ensuring that the power reaching the LCD display screen is stable and clean.

[0031] Specifically, transistor Q4 is used to adjust and amplify the signal to the display screen LCD1, and the base of transistor Q4 receives the control signal from the secondary control circuit 220 through resistors R33 and R34, wherein resistors R33 and R34 play the role of stabilizing the base voltage and limiting the current to protect the transistor from being damaged by overcurrent.

[0032] Specifically, the collector of transistor Q4 is connected to the sixth port of display screen LCD1. Through this connection, transistor Q4 adjusts the current flowing to the sixth port of LCD1 according to the strength of the control signal, thereby controlling the brightness and other display parameters of the displayed content.

[0033] The display circuit design in this embodiment significantly improves the user interaction experience of the air purifier. By integrating the display control circuit and the LCD drive circuit, the system can effectively drive the LCD display screen to display air quality information in real time.

[0034] Specifically, the configuration of resistor R32 and capacitors C11 and C12 optimizes the power distribution and signal shaping, ensuring the reliability and stability of the display output, while the use of transistor Q4 further enhances the signal driving capability, ensuring that the LCD display can clearly display relevant information under different lighting conditions.

[0035] Optionally, the communication circuit comprises: USB interface (USB1): has multiple pins, including V_BUS, GND, D+, D-, etc.

[0036] Resistors (R42, R43): used to limit current or divide voltage.

[0037] Integrated circuit (U10): USB to serial port interface chip, used for converting USB signals and serial port signals.

[0038] Capacitor (C18): Used to remove noise on the power line and stabilize the power supply voltage.

[0039] Specifically, pin 1 (V_BUS) is connected to the power input line of the circuit through a wire, pin 4 (GND) is connected to the ground line, and the data lines D+ and D- (pins 3 and 2) are connected to the corresponding pins (USB_D+ and USB_D-) of the U10 chip through resistors R42 and R43.

[0040] Resistors R42 and R43 are connected between data lines D+ and D- of USB1 for signal shaping or impedance matching.

[0041] Integrated circuit U10 receives data signals from the USB interface and converts them into serial communication signals (such as TXD, RXD). At the same time, the power pin VCC of U10 is connected to V_BUS, and the GND pin is connected to the ground line.

[0042] Capacitor C18 is connected between the power pin (+3V3) of U10 and ground to stabilize the power supply and filter out high-frequency noise.

[0043] Specifically, the V_BUS pin of the USB interface provides power to the entire circuit, including the integrated circuit U10. The power is filtered through the capacitor C18 to eliminate noise on the power line and ensure stable operation of the circuit. The D+ and D- data lines of the USB interface are connected to the USB_D+ and USB_D- pins of the U10 chip through resistors R42 and R43 respectively. These two resistors help protect the USB data lines and properly adjust and impedance match the signals. The integrated circuit U10 converts the data signal received from the USB interface into a signal in a serial communication format. The converted serial port signals (TXD and RXD) are output through the corresponding pins of U10 and connected to other serial port devices or further processing circuits. The RTS# and CTS# pins are used for flow control to ensure the correctness and reliability of data transmission.

[0044] Optionally, the secondary control circuit comprises: Integrated Circuit U7: A microcontroller or application specific integrated circuit (IC) with multiple pins for different input / output functions.

[0045] Resistors R26, R27, R28, R29, R30, R31: used to limit current or divide voltage.

[0046] Capacitor C10: used to remove noise on the power line and stabilize the power supply voltage.

[0047] Pin markings: including ESP_EN, SENSOR_VP, SENSOR_VN, ADC1, TXD1, A_RST, BLED, etc., corresponding to different functions and signals.

[0048] Among them, ENSOR_VP and SENSOR_VN are used to connect sensors, ADC1 is used for analog signal input, TXD1 is used for data transmission, A_RST is used for reset, and BLED is used for LED control.

[0049] Specifically, the U7 integrated circuit controls various signal processing and data transmission. U7 receives sensor signals from SENSOR_VP and SENSOR_VN, converts them into digital signals through ADC1 for processing by the microcontroller. The ESP_EN pin is stabilized by capacitor C10 and is used to control the power management or wake-up function of U7. The TXD1 pin is used for serial communication to send processed data to external devices. The A_RST pin is used for reset control, and the BLED pin controls a status indicator. The entire circuit design supports signal reception, processing and transmission, and is suitable for data acquisition and control applications, especially in environments that require multiple sensor inputs and communication interfaces.

[0050] Optionally, the display control circuit includes: Integrated circuit U8; Capacitors C13, C14: used for power supply stabilization and noise removal.

[0051] Touch screen interface pins: including X+, X-, Y+, Y-, used to receive position signals from the touch screen.

[0052] Among them, capacitor C13 is connected between the +3V3 power supply and the ground for filtering and power supply stabilization.

[0053] Capacitor C14 is also connected between the +3V3 power supply and ground to enhance the stability of the power line.

[0054] Integrated Circuit U8: Power supply and ground: VCC is connected to +3V3 and GND is connected to ground to provide the necessary operating voltage and current for the chip.

[0055] Touch screen signals: X+, X-, Y+, Y- are used to receive signals from the touch screen, which usually represent the coordinates of the touch point.

[0056] Communication pins: such as DCLK, CS#, DIN, DOUT, etc. are used to exchange data with external devices.

[0057] Specifically, the U8 chip is mainly used to process input signals from the touch screen, signals received through the X+, X-, Y+, and Y- pins. The addition of capacitors C13 and C14 is intended to ensure the stability of power supply, reduce power supply noise, and ensure accurate transmission of touch screen control signals. The controller receives external instructions through the DIN pin and sends responses through the DOUT pin. Control signals such as DCLK (data clock) and CS# (chip select signal) are used to synchronize and select devices for communication. The entire circuit design makes the touch screen operation more sensitive and accurate, improving the user interaction experience.

[0058] Optionally, the timestamp circuit includes: Integrated circuit U9: Real-time clock (RTC), with I2C communication interface.

[0059] Capacitor C17: used for power stabilization or filtering.

[0060] Battery interface BAT1: provides backup power to ensure continued power supply when the main power supply is cut off.

[0061] Specifically, VCC is connected to a +3V3 power supply to provide operating voltage for the chip.

[0062] GND is connected to ground to form the return path for the power supply.

[0063] SCL and SDA are used for I2C communication to connect to the host controller.

[0064] The BAT1 backup battery interface is connected to the V_BAT pin to provide power to the chip when the main power supply is disconnected.

[0065] INT# / SQW outputs interrupt signal or square wave signal.

[0066] The battery interface BAT1 provides backup power for U9, ensuring that the device can still maintain basic time tracking functions without external power.

[0067] Capacitor C17 is connected between the +3V3 power line and ground to help filter high-frequency noise on the power line and keep the power supply stable.

[0068] Among them, U9 chip is used as a real-time clock module, which is mainly responsible for tracking and maintaining time. It communicates with the main controller through the built-in I2C interface (SCL and SDA pins) to send or receive time-related data. The battery interface BAT1 ensures that when the main power fails, U9 can continue to run through the backup battery without losing time information. The function of capacitor C17 is to ensure the cleanliness and stability of the power supply and prevent power fluctuations from affecting the time accuracy of U9. The INT# / SQW pin outputs an interrupt signal or a square wave signal for time-related reminders or synchronous operations to enhance the functionality and reliability of the system.

[0069] Optional load modules include: ZE08 electrochemical module; CO2 SGP30 module: Panteng PMS7003 module; AHT10 temperature and humidity module.

[0070] Optionally, the load circuit 300 includes a transistor Q1, a transistor Q2, a resistor R4, a resistor R8, a resistor R10, a resistor R11, a resistor R7, a diode D1, a capacitor C3 and a connector J3, wherein: One end of the resistor R10 is connected to the main control circuit 400, the other end of the resistor R10 is connected to the base of the transistor Q2 and one end of the resistor R11, the other end of the resistor R11 is connected to the emitter and the base end of the transistor Q2, the collector of the transistor Q2 is connected to one end of the resistor R8, the other end of the resistor R8 is connected to the gate of the transistor Q1 and one end of the resistor R4, the other end of the resistor R4 is connected to the source of the transistor Q1 and the voltage source circuit 100, the drain of the transistor Q1 is connected to one end of the diode D1, one end of the capacitor C3 and the first port of the connector J3, the other end of the diode D1 is connected to the other end of the capacitor C3 and the second port of the connector J3, one end of the resistor R7 is connected to the third port of the connector J3, and the other end of the resistor R7 is connected to the main control circuit 400.

[0071] Specifically, resistor R10 receives a control signal from the main control circuit 400 and transmits the signal to the base of transistor Q2. Resistors R10 and R11 together form a voltage divider network to adjust and stabilize the voltage at the base of Q2. Transistor Q2 acts as an amplifier, and the signal received at its base determines the amount of current passing through its collector to emitter.

[0072] Specifically, the collector of transistor Q2 is connected to the gate of transistor Q1 through resistor R8, which further adjusts and stabilizes the signal transmitted to Q1. Transistor Q1 acts as a main amplifier of the final output signal and adjusts the output current according to the signal strength received from Q2.

[0073] Specifically, the drain of the transistor Q1 is connected to the diode D1, the capacitor C3 and the first port of the connector J3 to form an output part. The diode D1 protects the circuit from reverse current damage, and the capacitor C3 stabilizes the power supply voltage and eliminates noise.

[0074] Specifically, the first port of connector J3 is the output interface of the load circuit, providing processed signals or power to the external load, and the second port and the third port are respectively connected to the diode D1 and the main control circuit 400 through the capacitor C3 and the resistor R7 to form a feedback or additional control path.

[0075] This embodiment achieves effective amplification and precise control of the signal through precisely configured transistors and resistor networks: the layout of resistors R10 and R11 ensures that transistor Q2 receives a stable input signal, and transistor Q1 further amplifies the signal to drive an external load. This design ensures the stability and reliability of the output signal through the protection and filtering of diode D1 and capacitor C3, thereby improving the response speed and processing efficiency of the overall device, and effectively supporting the continuous and efficient operation of the air purifier.

[0076] Optionally, the voltage source circuit 100 further includes a first voltage source sub-circuit 110, wherein the first voltage source sub-circuit 110 includes a resistor R25, Capacitor EC1, capacitor EC2, inductor LX, diode D4, voltage regulator chip U1, connector J1, capacitor C1, among which: The second port of the connector J1 is connected to one end of the resistor R25 and the primary power supply port, the other end of the resistor R25 is connected to one end of the capacitor EC1 and the first port of the voltage stabilizing chip U1, the first port of the connector J1 is connected to the other end of the capacitor EC1, one end of the capacitor EC2, one end of the capacitor C1, the anode of the diode D4 and the fourth port of the voltage stabilizing chip U1, the other end of the capacitor EC2 is connected to the other end of the capacitor C1, one end of the inductor LX, the third port of the voltage stabilizing chip U1 and the output end of the first voltage source sub-circuit 110, the other end of the inductor LX is connected to the cathode of the diode D4 and the second port of the voltage stabilizing chip U1, and the fifth port, sixth port, seventh port and eighth port of the voltage stabilizing chip U1 are short-circuited with the fourth port of the voltage stabilizing chip U1.

[0077] In this embodiment, the initial power supply is input through the second port of the connector J1 and is transmitted to the capacitor EC1 through the resistor R25. The function of the resistor R25 is to limit the input current and prevent power supply shock, while the capacitor EC1 starts the first level of power supply filtering processing to stabilize the input voltage fluctuation. The voltage processed by the capacitor EC1 is transmitted to the first port of the voltage regulator chip U1 for further adjustment and stabilization. At the same time, the other end of the capacitor EC1 is connected to the capacitor EC2 and the capacitor C1. These two capacitors, together with the inductor LX, constitute a filtering and energy storage network to improve the overall stability and response speed of the power supply. One end of the inductor LX is connected to the third port of the voltage regulator chip U1, and the other end is connected through the cathode of the diode D4 to form a reverse protection path to avoid damage caused by reverse flow of the power supply. Multiple control ports (the fifth port to the eighth port) of the voltage regulator chip U1 are short-circuited to the fourth port for accurately controlling the output voltage to ensure the accuracy and stability of the output voltage. The circuit configured in this way can not only effectively supply power, but also ensure the long-term stable operation of the circuit through meticulous power management.

[0078] The first voltage source subcircuit 110 of this embodiment provides a stable and reliable voltage output through a carefully designed power management architecture: the capacitors and inductors in the circuit cooperate with the voltage regulator chip U1 to achieve efficient voltage regulation and excellent power filtering functions. This configuration ensures that the electronic components of the air purifier obtain a constant power supply, thereby optimizing the performance of the equipment and extending its service life, ensuring that the equipment can work stably under various power conditions.

[0079] Optionally, the voltage source circuit 100 further includes a second voltage source sub-circuit 120, and the second voltage source sub-circuit 120 includes a voltage stabilizing chip U12, a capacitor C26, a capacitor C27, a capacitor C28, a capacitor C29 and a capacitor C30, wherein: One end of the capacitor C26 is connected to the output end of the first voltage source sub-circuit 110, one end of the capacitor C27 and the third port of the voltage stabilizing chip U12, the other end of the capacitor C26 is connected to the other end of the capacitor C27 and the ground, the first port of the voltage stabilizing chip U12 is grounded, the second port of the voltage stabilizing chip U12 is connected to one end of the capacitor C28, one end of the capacitor C29, one end of the capacitor C30 and the output end of the second voltage source sub-circuit 120, and the other end of the capacitor C28 is connected to the other end of the capacitor C29, the other end of the capacitor C30 and the ground.

[0080] In this embodiment, capacitor C26 receives the adjusted power supply from the first voltage source sub-circuit 110, and passes it to the third port of the voltage regulator chip U12 and capacitor C27. Capacitors C26 and C27 work together to perform preliminary filtering on the power supply to remove existing high-frequency noise. At the same time, the other end of capacitor C26 is connected to the ground to form a stable power ground plane. The voltage regulator chip U12 then performs precise voltage stabilization on the power supply that has undergone preliminary filtering to ensure the stability and accuracy of the output voltage. The output power supply is passed to capacitors C28, C29 and C30 through the second port of the voltage regulator chip U12. These capacitors constitute a complex filtering network to further stabilize the power supply and reduce voltage fluctuations at the output end. The other ends of all capacitors are connected to the ground to ensure the integrity and stability of the power supply system.

[0081] This embodiment uses a filter network composed of multiple capacitors to effectively reduce power supply noise and improve the quality of the output voltage. This stable and clean power output is particularly critical for sensitive electronic devices, helping to improve device performance and reduce failures caused by power supply problems.

[0082] Optionally, it further includes an LED control circuit 500, wherein the LED control circuit 500 includes a transistor Q3, a resistor R1, a resistor R3, a resistor R6, a resistor R18, a resistor R19, a resistor R20, an LED driver chip U3, an LED driver chip U4, an LED driver chip U5, and an LED driver chip U6, wherein: One end of the resistor R6 is connected to the output end of the first voltage source sub-circuit 110, one end of the resistor R18, one end of the resistor R19 and one end of the resistor R20, the other end of the resistor R6 is connected to the second port of the LED driver chip U3, the other end of the resistor R18 is connected to the second port of the LED driver chip U4, the other end of the resistor R19 is connected to the second port of the LED driver chip U2, the other end of the resistor R20 is connected to the second port of the LED driver chip U6, one end of the resistor R1 is connected to the first port of the LED driver chip U3, the other end of the resistor R1 is connected to the main control circuit 400, the LED driver chip U3 The third port of the LED driver chip U4 is connected to the first port of the LED driver chip U4, the third port of the LED driver chip U4 is connected to the first port of the LED driver chip U2, the third port of the LED driver chip U2 is connected to the first port of the LED driver chip U6, the collector of the transistor Q3 is connected to the fourth port of the LED driver chip U2, the fourth port of the LED driver chip U3, the fourth port of the LED driver chip U4 and the fourth port of the LED driver chip U6, the base of the transistor Q3 is connected to one end of the resistor R3, the other end of the resistor R3 is connected to the main control circuit 400, and the emitter of the transistor Q3 is grounded.

[0083] In this embodiment, transistor Q3 plays a key role and is responsible for receiving and amplifying the control signal from the main control circuit 400. Resistor R3 connects the base of transistor Q3 to the main control circuit 400 and is responsible for providing appropriate bias for the transistor to ensure that it responds to the appropriate control signal. The emitter of transistor Q3 is grounded, and the collector is connected to the control port of each LED driver chip (U2, U3, U4, U6) to distribute signals to control the brightness of different LED groups.

[0084] Resistors R6, R18, R19 and R20 are used to distribute and stabilize the power output from the first voltage source sub-circuit 110 to each LED driver chip. These resistors ensure that each driver chip obtains the appropriate voltage to prevent overvoltage from damaging the chip. Resistor R1 serves as a connecting line to further adjust the signal strength from the main control circuit 400 to the LED driver chip U3, and assist in controlling the state of the LED display. Through this layout, the LED control circuit can adjust the output of each LED as needed to adapt to different display requirements or working conditions, thereby ensuring the accuracy and effect of the LED display.

[0085] Optionally, an LED driving circuit 600 is further included, wherein the LED driving circuit 600 includes a resistor R2, a resistor R5, a resistor R9, a resistor R12, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a resistor R17, a light emitting diode LED1, a light emitting diode LED2, a light emitting diode LED3, a light emitting diode LED4, a light emitting diode LED5, a light emitting diode LED6, a connector J2, a connector J4 and a connector J5, wherein: The cathode of the light-emitting diode LED1 is connected to the cathode of the light-emitting diode LED2, the cathode of the light-emitting diode LED3, the cathode of the light-emitting diode LED4, the cathode of the light-emitting diode LED5, the cathode of the light-emitting diode LED6 and the ground terminal, the anode of the light-emitting diode LED1, the anode of the light-emitting diode LED2, the anode of the light-emitting diode LED3, the anode of the light-emitting diode LED4, the anode of the light-emitting diode LED5 and the anode of the light-emitting diode LED6 are connected to the main-level control circuit 400 through resistors R12, R13, R14, R15, R16 and R17 respectively, and the connector J2, connector J4 and connector J5 are connected to the main-level control circuit 400 through resistors R2, R5 and R9 respectively.

[0086] In this embodiment, the cathodes of all light-emitting diodes LED1 to LED6 are connected together and grounded to form a common ground terminal, and the anode of each LED is connected to the main control circuit 400 through a series of resistors (R12 to R17). These resistors play a current limiting role to protect the LED from being damaged by overcurrent, while also ensuring that the LED can work normally under a stable current, thereby extending the service life of the LED.

[0087] Connectors J2, J4 and J5 are connected to the main control circuit 400 through resistors R2, R5 and R9. These connectors are used to output LED control signals to other system components or external indication devices, or to receive signals from other system components to affect the display status of the LED. This setting allows flexible control configuration and expansibility, so that the LED drive circuit is not only limited to internal LED control, but also works in conjunction with external systems or devices.

[0088] The present invention also provides a filter element detection method, comprising: S100, obtaining the pollutant concentration before air purification and the pollutant concentration after air purification; S110, obtaining a use status parameter of the filter element according to the pollutant concentration before the air purification and the pollutant concentration after the air purification; S120, when the usage status parameter of the filter element is lower than a first preset threshold, generating a first signal; S130, when the usage status parameter of the filter element is lower than a second preset threshold, generating a second signal; S140, adjusting the fan power according to the second signal; S150: When the usage status parameter of the filter element is lower than the second preset threshold, a third signal is generated.

[0089] Among them, step S100 involves the use of two key modules: one is located at the air inlet of the air purifier (before air purification), and the other is located at the air outlet (after air purification). These sensors are responsible for measuring the concentration of pollutants in the air entering and leaving the air purifier, such as the levels of dust, pollen, smoke and other harmful chemicals. The measured pollutants include particulate matter (such as PM2.5 and PM10), volatile organic compounds (VOCs), formaldehyde, etc. The specific configuration refers to the filter element detection circuit.

[0090] Step S110 uses the pollutant concentration before and after air purification to evaluate the performance of the filter element (filter element usage status parameter). By comparing the difference in pollutant concentration before and after air purification, the purification efficiency of the air purifier is calculated. This efficiency reflects the ability of the filter element to remove pollutants from the air. If the pollutant concentration is significantly reduced after air purification, it indicates that the filter element is efficient; if it is not reduced much, it indicates that the filter element is saturated or damaged.

[0091] Specifically, the status parameters used are as follows: Purification efficiency = (1 - concentration after purification / concentration before purification) * 100%.

[0092] S120: Generate a first signal.

[0093] When the usage status parameter of the filter element is lower than the first preset threshold, the system will generate a first signal. This stage is the primary warning stage of filter element performance monitoring, indicating that the filter element has begun to fail but has not yet reached the level of emergency replacement. The first preset threshold is set based on the normal service life of the filter element and the expected performance degradation rate. Usage status parameters above this threshold indicate that the filter element can continue to be used, while those below this threshold indicate that the filter element performance has begun to decline. The generated first signal will trigger a warning on the user interface, reminding the user to start considering replacing the filter element. The purpose of this signal is to ensure that the user has enough time to prepare or purchase a new filter element, thereby avoiding a sudden deterioration in air quality due to complete failure of the filter element.

[0094] S130: Generate a second signal.

[0095] When the filter element's usage status parameter further decreases and falls below the second preset threshold, the system will generate a second signal. The second preset threshold is set lower, indicating that the filter element's performance has seriously declined and urgently needs to be replaced. The signal at this stage is a more urgent warning, which will be displayed as a red warning light on the user interface or accompanied by a sound alarm, strongly prompting the user to replace the filter element immediately. The generation of the second signal is based on considerations of indoor air quality safety to prevent pollutants caused by excessive use of the filter element from penetrating the filter element and re-entering the environment.

[0096] S140: Adjust the fan power.

[0097] Based on the second signal, the system automatically adjusts the fan power. If the filter performance deteriorates, the fan speed is reduced to reduce the burden on the filter, extend its remaining service life, and save energy.

[0098] In addition, adjusting the fan power can also help maintain the most stable indoor air flow and purification effect, and avoid incomplete air purification due to insufficient filter performance.

[0099] S150: Generate a third signal.

[0100] When the filter element's usage status parameter continues to be lower than the second preset threshold, in addition to the second signal, the system will also generate a third signal. The third signal is introduced to protect the user's health in extreme cases and prevent serious air pollution incidents caused by complete failure of the filter element. This signal is accompanied by the system's emergency shutdown measures and a clear shutdown indication is displayed on the user interface. The system can only resume operation after the user replaces the filter element and resets the system.

[0101] The above is only used to illustrate the technical solution of the present invention rather than to limit it. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in this field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. An intelligent control circuit for an air purifier, characterized in that: The invention comprises a voltage source circuit (100), a filter element detection circuit (200), a load circuit (300) and a main control circuit (400); the output end of the voltage source circuit (100) is connected to the filter element detection circuit (200), the load circuit (300) and the power supply end of the main control circuit (400); the detection output end of the filter element detection circuit (200) is connected to the input end of the main control circuit (400); the load control end of the main control circuit (400) is connected to the controlled end of the load circuit (300); the voltage source circuit (100) is used to provide the power required by the main control circuit (400) of the air purifier; the filter element detection circuit (200) is used to detect whether the filter element needs to be replaced; the main control circuit (400) is used to control the filter element detection circuit (200) and the load circuit (300); and the load circuit (300) is used to drive the load end of the air purifier.

2. An intelligent control circuit for an air purifier according to claim 1, characterized in that: The filter element detection circuit (200) comprises a display circuit (210), a secondary control circuit (220), a communication circuit (230), a timestamp circuit (240) and a load module (250); the display circuit (210) is connected to a control end of the secondary control circuit (220); the output end of the voltage source circuit (100) is connected to a power supply end of the communication circuit (230), a power supply end of the display circuit (210) and a power supply end of the timestamp circuit (240); the secondary control circuit (220) is connected to the communication circuit (230), the power supply end of the display circuit (210) and the power supply end of the timestamp circuit (240); The output end of the filter element detection circuit (200) and the output end of the timestamp circuit (240) are connected to each other, the display circuit (210) is used to display air quality information, the secondary control circuit (220) is used to control the operation of the display circuit (210), the communication circuit (230) and the load module (250), the communication circuit (230) is used to program and communicate data with the filter element detection circuit (200), the timestamp circuit (240) is used to record the time of monitoring data, and the load module (250) is used to connect to an air quality sensor.

3. The intelligent control circuit of an air purifier according to claim 1, characterized in that: The display circuit (210) comprises a display control circuit (211) and an LCD drive circuit (212), wherein the display control circuit (211) is used to control the LCD drive circuit (212), and the LCD drive circuit (212) is used to drive an LCD display screen to display air quality information, wherein: The display control circuit (211) comprises a display screen LCD1, a resistor R32, a resistor R33, a resistor R34, a transistor Q4, a capacitor C11 and a capacitor C12, one end of the resistor R32 is connected to the ninth port of the display screen LCD1, the other end of the resistor R32 is connected to the tenth port of the display screen LCD1, one end of the capacitor C11, one end of the capacitor C12 and the voltage source circuit (100), the other end of the capacitor C11 and the other end of the capacitor C12 are connected to the ground terminal and the eleventh port of the display screen LCD1, the base of the transistor Q4 is connected to one end of the resistor R33 and one end of the resistor R34, the other end of the resistor R33 is connected to the secondary control circuit (220), the other end of the resistor R34 is connected to the emitter of the transistor Q4 and the ground terminal, and the collector of the transistor Q4 is connected to the sixth port of the display screen LCD1.

4. The intelligent control circuit for an air purifier according to claim 1, characterized in that: The load circuit (300) comprises a transistor Q1, a transistor Q2, a resistor R4, a resistor R8, a resistor R10, a resistor R11, a resistor R7, a diode D1, a capacitor C3 and a connector J3, wherein: One end of the resistor R10 is connected to the main control circuit (400), the other end of the resistor R10 is connected to the base of the transistor Q2 and one end of the resistor R11, the other end of the resistor R11 is connected to the emitter and the base end of the transistor Q2, the collector of the transistor Q2 is connected to one end of the resistor R8, the other end of the resistor R8 is connected to the gate of the transistor Q1 and one end of the resistor R4, the other end of the resistor R4 is connected to the source of the transistor Q1 and the voltage source circuit (100), the drain of the transistor Q1 is connected to one end of the diode D1, one end of the capacitor C3 and the first port of the connector J3, the other end of the diode D1 is connected to the other end of the capacitor C3 and the second port of the connector J3, one end of the resistor R7 is connected to the third port of the connector J3, and the other end of the resistor R7 is connected to the main control circuit (400).

5. The intelligent control circuit for an air purifier according to claim 1, characterized in that: The voltage source circuit (100) further comprises a first voltage source sub-circuit (110), wherein the first voltage source sub-circuit (110) comprises a resistor R25, Capacitor EC1, capacitor EC2, inductor LX, diode D4, voltage regulator chip U1, connector J1, capacitor C1, among which: The second port of the connector J1 is connected to one end of the resistor R25 and the primary power supply port, the other end of the resistor R25 is connected to one end of the capacitor EC1 and the first port of the voltage stabilizing chip U1, the first port of the connector J1 is connected to the other end of the capacitor EC1, one end of the capacitor EC2, one end of the capacitor C1, the anode of the diode D4 and the fourth port of the voltage stabilizing chip U1, the other end of the capacitor EC2 is connected to the other end of the capacitor C1, one end of the inductor LX, the third port of the voltage stabilizing chip U1 and the output end of the first voltage source sub-circuit (110), the other end of the inductor LX is connected to the cathode of the diode D4 and the second port of the voltage stabilizing chip U1, and the fifth port, the sixth port, the seventh port and the eighth port of the voltage stabilizing chip U1 are short-circuited with the fourth port of the voltage stabilizing chip U1.

6. An intelligent control circuit for air purifier according to claim 5, characterized in that: The voltage source circuit (100) further comprises a second voltage source sub-circuit (120), wherein the second voltage source sub-circuit (120) comprises a voltage stabilizing chip U12, a capacitor C26, a capacitor C27, a capacitor C28, a capacitor C29 and a capacitor C30, wherein: One end of the capacitor C26 is connected to the output end of the first voltage source sub-circuit (110), one end of the capacitor C27 and the third port of the voltage stabilizing chip U12; the other end of the capacitor C26 is connected to the other end of the capacitor C27 and the ground; the first port of the voltage stabilizing chip U12 is grounded; the second port of the voltage stabilizing chip U12 is connected to one end of the capacitor C28, one end of the capacitor C29, one end of the capacitor C30 and the output end of the second voltage source sub-circuit (120); the other end of the capacitor C28 is connected to the other end of the capacitor C29, the other end of the capacitor C30 and the ground.

7. An intelligent control circuit for an air purifier according to claim 1, characterized in that: It also includes an LED control circuit (500), the LED control circuit (500) including a transistor Q3, a resistor R1, a resistor R3, a resistor R6, a resistor R18, a resistor R19, a resistor R20, an LED driver chip U3, an LED driver chip U4, an LED driver chip U5, and an LED driver chip U6, wherein: One end of the resistor R6 is connected to the output end of the first voltage source sub-circuit (110), one end of the resistor R18, one end of the resistor R19 and one end of the resistor R20; the other end of the resistor R6 is connected to the second port of the LED driver chip U3; the other end of the resistor R18 is connected to the second port of the LED driver chip U4; the other end of the resistor R19 is connected to the second port of the LED driver chip U2; the other end of the resistor R20 is connected to the second port of the LED driver chip U6; one end of the resistor R1 is connected to the first port of the LED driver chip U3; the other end of the resistor R1 is connected to the main control circuit (400); the LED driver chip U The third port of the LED driver chip U3 is connected to the first port of the LED driver chip U4, the third port of the LED driver chip U4 is connected to the first port of the LED driver chip U2, the third port of the LED driver chip U2 is connected to the first port of the LED driver chip U6, the collector of the transistor Q3 is connected to the fourth port of the LED driver chip U2, the fourth port of the LED driver chip U3, the fourth port of the LED driver chip U4 and the fourth port of the LED driver chip U6, the base of the transistor Q3 is connected to one end of the resistor R3, the other end of the resistor R3 is connected to the main control circuit (400), and the emitter of the transistor Q3 is grounded.

8. An intelligent control circuit for an air purifier according to claim 1, characterized in that: The device also includes an LED driving circuit (600), wherein the LED driving circuit (600) includes a resistor R2, a resistor R5, a resistor R9, a resistor R12, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a resistor R17, a light emitting diode LED1, a light emitting diode LED2, a light emitting diode LED3, a light emitting diode LED4, a light emitting diode LED5, a light emitting diode LED6, a connector J2, a connector J4 and a connector J5, wherein: The cathode of the light-emitting diode LED1 is connected to the cathode of the light-emitting diode LED2, the cathode of the light-emitting diode LED3, the cathode of the light-emitting diode LED4, the cathode of the light-emitting diode LED5, the cathode of the light-emitting diode LED6 and the ground terminal; the anode of the light-emitting diode LED1, the anode of the light-emitting diode LED2, the anode of the light-emitting diode LED3, the anode of the light-emitting diode LED4, the anode of the light-emitting diode LED5 and the anode of the light-emitting diode LED6 are connected to the main-level control circuit (400) through resistors R12, R13, R14, R15, R16 and R17 respectively; the connector J2, the connector J4 and the connector J5 are connected to the main-level control circuit (400) through resistors R2, R5 and R9 respectively.

9. An air purifier, characterized in that: It comprises an intelligent control circuit for an air purifier as described in any one of claims 1 to 8.

10. A filter element detection method, characterized in that: include: Obtain the pollutant concentration before air purification and the pollutant concentration after air purification; Obtaining a use status parameter of the filter element according to the pollutant concentration before the air purification and the pollutant concentration after the air purification; When the usage status parameter of the filter element is lower than a first preset threshold, a first signal is generated; When the usage status parameter of the filter element is lower than a second preset threshold, generating a second signal; adjusting the fan power according to the second signal; When the usage status parameter of the filter element is lower than a second preset threshold, a third signal is generated.

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