Vlper12A switching power supply chip in the application of household dishwasher controller - News - Global IC Trade Starts Here Free Join

0 Preface

With the development of electronic technology, the miniaturization, light weight and low cost requirements of home appliance controllers have made the power supply move toward light, small, and efficient. Although the traditional linear power supply technology is now mature, it also has a large number of integrated linear regulated power supply modules, and the stability is good, the output ripple voltage is small, and the use is reliable. However, it usually requires a large and bulky power frequency transformer and isolation unit, and the filter is also bulky and heavy, so its power supply efficiency is very low, generally only about 45%, which is difficult to meet the requirements of electronic equipment development. The switching power supply does not require a heavy power transformer, and has the advantages of small size, light weight, wide input voltage range, and high efficiency. At the same time, with the increasing frequency of the switching power supply, the volume is also smaller, and therefore, the switch The application prospect of power supply in home appliances is also broader.

1 switching power supply works

Switching regulated power supplies typically use power semiconductor devices as switches to regulate the output voltage by controlling the duty cycle of the switch. Since the adjustment tube in the switching regulator circuit operates in the switching state, the power consumption is small and the circuit efficiency is high. There are many types of switching power supplies. According to the connection mode of the adjusting tube and the load, it can be divided into series type and parallel type. The series switching switching regulator circuit is a step-down type circuit, and the parallel switching type voltage regulator circuit is a step-up type circuit. The modulation method can be divided into pulse width modulation (PWM), pulse frequency modulation (PFM) and hybrid modulation. Among them, PWM is the most popular, this article mainly introduces PWM switching power supply.

Under normal circumstances, the working principle of the switching power supply of various modes is basically the same. Figure 1 shows the basic structural block diagram of the switching power supply. The working principle of the switching power supply is mainly based on the input voltage level and the change of the output voltage, the feedback circuit is used to control the duty cycle of the switch to change the width of the control pulse, and the input voltage is converted into a pulse signal, and then the pulse transformer After the voltage is applied, it is applied to the output rectification filter circuit, and finally smoothed to generate a DC output voltage proportional to the output pulse width.