The control board serves as the core control unit of the disinfection cabinet, responsible for receiving user operation signals, driving disinfection components such as ultraviolet lamps, ozone generators and heating tubes, realizing timing, mode switching, over-temperature protection and other core functions. Reasonable circuit design can guarantee stable operation, safety and low power consumption of the whole machine, which is the key to reliable long-term operation of household and commercial disinfection cabinets.

1. Overall Working Principle of Disinfection Cabinet Control Board

The whole control system takes the single-chip microcomputer as the main control chip. After the user triggers touch keys or physical buttons, the signal is transmitted to the MCU through the key detection circuit. The single-chip microcomputer judges the selected disinfection mode (ultraviolet disinfection, high-temperature drying, ozone disinfection, composite disinfection) and sets the working countdown time according to the signal. During operation, the MCU outputs control signals to the relay drive circuit to switch on and off the corresponding disinfection loads. The temperature sensing circuit feeds back real-time cavity temperature to the chip. Once the temperature exceeds the safety threshold, the main control board will cut off the heating load immediately to prevent high-temperature safety hazards. When the countdown ends, all disinfection modules stop working automatically, and the indicator light prompts the completion of disinfection.

2. Main Module Circuit Composition of Control Board

2.1 Power Supply Circuit: Convert AC mains into stable DC low voltage for the single-chip microcomputer, display screen and signal detection circuit. It is equipped with over-current, over-voltage and anti-surge protection circuits to avoid chip damage caused by unstable grid voltage.

2.2 MCU Main Control Circuit: The core processing unit, which stores solidified control programs, completes signal acquisition, logic judgment, timing calculation and load driving command output, and supports multi-mode program switching.

2.3 Key & Display Circuit: The touch sensing or mechanical key circuit collects human operation signals; the digital tube or LED display circuit feeds back the current working mode and remaining disinfection time for real-time human-computer interaction.

2.4 Relay Drive Load Circuit: The weak current signal of the single-chip microcomputer cannot directly drive high-power loads such as heating tubes and UV lamps, so the relay isolation drive circuit is used to realize weak current controlling strong current, and a freewheeling diode is matched to absorb the reverse electromotive force of the coil to protect the circuit.

2.5 Temperature Detection Protection Circuit: Composed of thermistor and voltage division sampling circuit, it collects internal temperature data of the disinfection cabinet in real time and transmits it to the single-chip microcomputer to realize automatic over-temperature power-off protection.

2.6 Door Switch Interlock Circuit: Linked with the cabinet door contact switch. When the door is opened during operation, the circuit instantly cuts off the ozone and ultraviolet output to avoid harm to human bodies caused by ultraviolet radiation and ozone leakage.

3. Key Points of Optimized Circuit Design

Isolation design is adopted between strong current and weak current areas of the PCB to reduce electromagnetic interference and prevent strong current signals from interfering with the single-chip microcomputer program disorder. The power supply circuit adds filter capacitors to stabilize voltage and suppress ripple. The door lock interlock circuit is set as a hardware forced power-off circuit, which can still cut off the disinfection load reliably even if the single-chip microcomputer fails. The whole circuit reserves anti-static and waterproof design for the production environment inside the disinfection cabinet to adapt to high humidity working conditions for a long time.

4. Matching Logic of Different Disinfection Modes

In the single UV disinfection mode, the control board only drives the ultraviolet lamp circuit; under the high-temperature drying mode, the heating tube relay is turned on and the temperature is maintained within the set constant temperature range; the composite disinfection mode makes UV and ozone work alternately according to the program logic to avoid excessive ozone concentration. All modes share the same timing and temperature protection logic to ensure unified safety standards for each function.

5. Circuit Stability Test Standards for Mass Production

After the completion of circuit design, the control board needs to pass aging test, high and low temperature alternating test, humidity resistance test and surge voltage impact test. The circuit parameters such as relay pull-in voltage, temperature sampling accuracy and key signal response time are calibrated uniformly to ensure the consistency of the control board performance of mass-produced disinfection cabinets, reduce post-market failure rates and improve product safety performance.