Application
application
Brief introduction of humidifier products
Hardware principle of humidifier
Frequency pursuit principle
Water detection principle
Advantages of HS23P3411 scheme in humidifier
Extended function description
Generally, the humidifier adopts ceramic high-frequency atomizer to atomize the water to 1-5 μm. The commonly used frequency (resonant frequency) of ceramic atomizer is 3MHz, 2.4MHz, 1.7MHz or 110k. Here we used 1.7MHz.
Hs23p3411, as the master control, outputs a square wave close to the resonant frequency (1.7MHz) of the atomizer through the built-in 16mhz main frequency PWM frequency division, duty cycle 40%, Through the triode push-pull circuit, the MOS tube is driven to make the atomizer work near the resonant frequency. Judge whether it works at the resonant frequency through the voltage at both ends of AD sampling atomizer.
The accuracy of 1.7MHz atomizer is ± 50KHz, that is, between 1.65mhz and 1.75MHz, so the resonant frequency of each atomizer is different.In order to achieve the best atomization effect, the frequency of PWM wave drive should be near the resonant frequency of the atomizer, and the difference should not be too much.
In the traditional humidifier, each oscillating plate is manually adjusted to make the frequency of the circuit reach the resonance frequency of each oscillating plate.Such an approach is not only time-consuming and laborious, but also inefficient. With the passage of time, the resonant frequency of the oscillating plate will shift. If it is not manually adjusted, the atomization effect of the humidifier will become very poor.
The humidifier developed based on hs23p3411 single chip microcomputer can automatically track the frequency to the resonance point.Its implementation principle is as follows:
The relationship between the voltage at both ends of the atomizer and its oscillation frequency is positive distribution, as shown in the following figure:
Through the relationship between voltage and frequency, the software algorithm can be used to track the best frequency point, so that the atomizer can always work at the best frequency point.
