What are the applications of MOSFET in air purifiers?

What are the applications of MOSFET in air purifiers?

As people pay more and attention to the quality of the air, air purifiers have become standard equipment for families and workplaces. It integrates multi-domain technologies, and the common types are pure physical filtration type relies on HEPA filter to intercept dust and other particulate matter; electrostatic dust collection type uses static electricity to adsorb charged particles; photocattic purification type uses ultraviolet rays to activate catalysts to decompose harmful gases, creating a fresh indoor environment.

MOSFET  Applications in Air Purifier Circ

In air purifier circuits, the YFW65R380AD is recommended, with the following parameters:

- Single polarity N-

- VDS(V): 200

- VGS(±V): 20

- Vth(V): 3

--state resistance (mΩ) at VGS=10V: 55

- ID (A): 30

- Technology: Trench

 Package: TO-252

Precise control of the fan motor: The fan propels the air circulation, and theMOSFET uses PWM to its speed. When the air quality is good, reduce the PWM duty cycle, so that the fan runs slowly and saves energy; when the pollution is heavy, the duty cycle, and the fan runs fast and purifies strongly. The YFW65R380AD's 30A current carrying capacity 200V withstand voltage ensure the stable operation of the fan.

Fine control of negative ion release: Negative ions can adsorb dust, the MOSFET controls the high voltage circuit of the negative ion generator. When turned on, it quickly conducts to produce negative ions, and when turned off, it quickly off, and also finely adjusts the production according to the air quality, and its fast switching characteristics ensure precise control.

Power supply and signal conversion of the system: PM2.5, VOC and other sensors monitor the air quality, and theMOSFET  supplies power to them and converts signals. It controls the power to reduce power consumption, and also periodically conducts to convert the sensor's weak current signal into a voltage signal, which helps the purifier accurately control the air quality achieve intelligent and efficient operation.

Key points for selection

(1) Voltage level

The MOSFET 's drain-source breakdown voltage (ds) should exceed the circuit's maximum working voltage, leaving a margin of 20% - 30% to prevent voltage fluctuations. The gate- voltage (Vgs) should be compatible with the drive circuit to ensure reliable conduction without exceeding the limit.

(2) Current capacity

The current of fan motor changes with the speed, and theMOSFET 's drain current (Id) parameter should be determined according to the motor's rated and maximum current, an additional margin of 30% - 50% to ensure that it can handle the starting surge and pulse current, and stably drive the motor.

(3) On-state resistance

The smaller the on-state resistance (Rds (on)), the lower theMOSFET 's conduction loss, is very beneficial for the energy saving of the fan motor drive circuit. When the heat dissipation is good, it is also necessary to ensure that the resistance change after heating small, to maintain energy saving and system stability, and generally try to select below 50mΩ at room temperature.

(4) Switching speed

Since fan speed control and negative ion control often use PWM technology, MOSFET switching fast is required to reduce loss and improve response. However, switching too fast cause electromagnetic interference, so it is necessary to combine the drive circuit to make the MOSFET's output resistance and capacitance parameters compatible, to achieve fast and stable and cutoff.

(5) Packaging form

The internal space of the purifier is limited, TO-220 packaging has good heat dissipation takes up a lot of space; for medium power, choose TO-263; for small power and tight space, use SOT-23. Considering cost and reliability, choose the packaging with the highest cost performance.

MOSFET  plays an irreplaceable important role in the fan motor drive of air purifiers, negative ion generator control, and power supply and signal of sensors, significantly improving the performance and quality of air purifiers, and providing people with a more comfortable and healthy indoor air environment. With the continuous development of semiconductor, the performance ofMOSFET  will be further improved, and its application prospects in air purifiers and other various electrical equipment will be broader.