In 1955, American scientist G.H. Royer first developed a transistor DC converter that uses self-oscillation of the saturation of the core. Since then, various forms of DC converters using this technology have emerged, replacing the early-stage rotary and mechanical vibrator converters with short life, poor reliability, and low conversion efficiency. Since the power transistor in the transistor DC converter operates in the switching state, the stabilized power supply produced thereby has a large number of groups, variable polarity, high efficiency, small size, and light weight, and thus is widely used at that time. Aerospace and military electronic equipment. Since the microelectronic equipment and technology at that time were very backward, it was impossible to produce a transistor with high withstand voltage, high switching speed and high power. Therefore, the DC converter of this period can only use low voltage input, and the conversion speed is not Too high.

Since the 1960s, due to the rapid development of microelectronics technology, high back pressure transistors have emerged. From then on, the DC converter can be directly rectified and filtered by the mains, and the power frequency transformer is no longer required to be stepped down. Expanded its application range, and on this basis, the switching power supply without power frequency step-down transformer was born. The power frequency transformer is saved, and the volume and weight of the switching power supply are greatly reduced. The switching power supply is truly high in efficiency, small in size, and light in weight.

After the 1970s, high-frequency, high-pressure power transistors, high-frequency capacitors, switching diodes, and iron cores of switching transformers, which are related to this technology, are also continuously developed and produced, so that the power frequency-free transformer switching regulator The power supply has been rapidly developed, and is widely used in the fields of electronic computers, communications, aerospace, color televisions, etc., so that the power frequency-free transformer switching power supply has become a leader in various power sources.

The need to use a regulated power supply

With the rapid advancement of society, the use of electrical equipment is increasing. However, the aging and development of power transmission and distribution facilities are lagging behind, as well as the poor design and power supply, which cause the end user voltage to be too low, while the line users often have high voltages. As for the use of electrical equipment, especially high-tech and precision equipment with strict voltage requirements, it is like no insurance.

Unstable voltage can cause fatal injury or malfunction to the equipment, affecting production, resulting in many delays such as delay in delivery and unstable quality. At the same time, it accelerates the aging of equipment, affects the service life and even burns the accessories, so that the owners face the trouble of needing maintenance or update the equipment in a short period of time, wasting resources; in serious cases, even a safety accident occurs, causing incalculable losses. [1] [2]