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

0 Preface

With the rapid advancement of electronic technology, there's an increasing demand for home appliance controllers that are compact, lightweight, and cost-effective. This has driven the evolution of power supplies towards smaller sizes, lighter weights, and higher efficiency. While traditional linear power supplies have reached a high level of maturity, boasting excellent stability, minimal ripple voltage, and reliable usage, they come with significant drawbacks. They require large, cumbersome power transformers and isolation units, along with bulky filters, resulting in low power supply efficiency—typically around 45%. These limitations make it challenging to meet the evolving needs of modern electronics. In contrast, switching power supplies eliminate the need for heavy transformers and offer numerous advantages, including reduced size and weight, a wider input voltage range, and significantly improved efficiency. As switching frequencies continue to rise, these power supplies are becoming even more compact, making their applications in home appliances increasingly promising.

1 How Switching Power Supplies Work

Switching regulated power supplies typically employ power semiconductor devices as switches to control the output voltage by adjusting the duty cycle of the switch. In switching regulator circuits, the adjustment transistor operates in a switching state, minimizing power loss and maximizing circuit efficiency. There are several types of switching power supplies, classified according to how the regulating transistor connects to the load. Series-type switching regulators are step-down circuits, while parallel-type regulators function as step-up circuits. Modulation techniques include pulse-width modulation (PWM), pulse-frequency modulation (PFM), and hybrid methods. PWM is the most widely used approach, and this article will focus primarily on PWM-based switching power supplies.

Generally, the operating principles of various switching power supplies are quite similar. Figure 1 presents the basic structural block diagram of a switching power supply. Its core functionality revolves around using feedback circuits to adjust the duty cycle of the switch based on changes in the input and output voltages. This controls the width of the control pulses, converting the input voltage into a pulse signal. After being processed by a pulse transformer, the signal is passed through the output rectification and filtering circuits, eventually smoothing out to produce a DC output voltage proportional to the output pulse width.