Analysis of modern switching power supply technology: from principle to application

As an indispensable power supply device in modern electronic equipment, switching power supply is widely used in electronic equipment, communication equipment, computer equipment, industrial control system and other fields for its high efficiency, small size, light weight and good stability. This paper will deeply discuss the principle, working principle, classification of modern switching power supply technology and its application in various fields.

The basic principle of switching power supply

The core principle of switching power supply is to convert the input DC power supply or AC power supply into high-frequency pulse signals through high-frequency switching devices (such as MOSFET or IGBT). This process mainly includes the following steps:

Input rectifier filter: the AC is rectified into direct current through the rectifier bridge, and then the ripple in the direct current is filtered through the filter capacitor to obtain a relatively smooth DC voltage. This step provides a stable DC input for the subsequent conversion process.
High frequency inverter: Through the control circuit to switch the switch tube in accordance with a certain frequency of switching action, the direct current into high frequency pulse voltage. In this process, the switching device is turned on and off at extremely high frequencies, usually between tens of kilohertz and hundreds of kilohertz.
Transformer step-down: The high frequency pulse voltage is step-down through the high frequency transformer to convert the high voltage pulse into a low voltage pulse suitable for output. The transformer plays a key role in the switching power supply, not only realizing the voltage conversion, but also isolating the input and output circuits, improving the safety and stability of the power supply.
Output rectifier filtering: the low-voltage pulse is rectified into direct current through the rectifier diode, and then filtered through the filter capacitor to obtain a smooth DC output voltage.
Feedback control: In order to ensure the stability of the output voltage, the switching power supply usually adopts a feedback control mechanism. The output voltage is sampled through a sampling circuit and compared to a set reference voltage. According to the comparison results, the control circuit adjusts the on-time of the switching device, so as to realize the accurate control of the output voltage.

Classification of switching power supplies

Switching power supplies can be classified according to different classification standards, the following are several common classification methods:

AC-DC switching power supply: Converts alternating current to direct current.
Dc-dc switching power supply: Converts direct current into another DC voltage.
Single-ended switching power supply: Only one switching tube, suitable for low power applications.
Double-ended switching power supply: There are two switching tubes for high power applications.

According to the topology, switching power supplies can also be divided into Buck (Buck), Boost (Boost), buck-boost (Buck-Boost), Flyback (flyback), Forward (forward) and other types. Each type has its own specific application scenarios and advantages and disadvantages.

Advantages of switching power supply

High efficiency: Because the loss of the switching device is relatively small when it is switched on and off, the efficiency of the switching power supply can reach a very high level, usually more than 80%, and even more than 90%.
Small size, light weight: due to the high operating frequency, the volume of the transformer and filter capacitor can be greatly reduced, so that the overall volume and weight of the switching power supply can be reduced.
Wide input voltage range: Switching power supply can adapt to a wide input voltage range, with strong versatility.
Good output characteristics: The switching power supply can provide stable output voltage and current, and the output ripple is small, which can meet the requirements of various electronic devices for power quality.

Application of switching power supply

The application range of switching power supply is extremely wide, involving almost all electronic equipment that needs electricity. Here are a few main application areas:

Computer field: Whether it is a desktop computer or a laptop computer, it needs a stable power supply to ensure its normal operation. Switching power supply occupies a dominant position in computer power supply because of its high efficiency, stability and reliability.
Communication equipment field: Communication equipment needs long-term stable operation, and is extremely sensitive to power supply fluctuations and interference. With its excellent stability and anti-interference ability, the switching power supply provides a reliable power supply guarantee for the communication equipment.
Industrial control field: In the field of industrial control, switching power supplies are widely used in various automation equipment and control systems. These devices often need to withstand harsh working environments, such as high temperature, high humidity, and strong electromagnetic interference. With its excellent adaptability and stability, switching power supply provides reliable power support for industrial control equipment.
Home appliances: TV sets, refrigerators, air conditioners and other home appliances need a stable power supply to ensure their normal operation. With its high efficiency and stability, switching power supply provides high quality power supply solutions for home appliances.
New energy vehicles: New energy vehicles need an efficient and stable power supply to support the normal operation of their power systems and battery management systems. With its characteristics of high efficiency, energy saving, stability and reliability, the switching power supply provides a high-quality power solution for new energy vehicles.

Modern switching power supply technology has become an indispensable power supply solution in modern electronic equipment because of its high efficiency, compact and high performance. By deeply understanding the working principle, advantages and application fields of switching power supply, we can better understand the importance and development prospects of this technology. With the continuous development of electronic technology, the performance of switching power supplies will continue to improve, providing more reliable and powerful power support for the development of various electronic devices.