What is a switching power supply

Switching power supply is a kind of power supply that uses modern power electronics technology to control the time ratio of switch on and off to maintain a stable output voltage, and the switching power supply is generally composed of pulse width modulation (PWM) control IC and MOSFET. Compared with switching power supplies and linear power supplies, the cost of both increases with the increase of output power, but the growth rate of both is different. The cost of a linear power supply is higher than that of a switching power supply at a certain output power point, which is called the cost reversal point.

With the development and innovation of power electronics technology, the switching power supply technology is also constantly innovating, and this cost reversal point is increasingly moving to the low output power end, which provides a broad development space for the switching power supply.

The high frequency of switching power supply is the direction of its development, and the high frequency makes the switching power supply miniaturized, and makes the switching power supply enter a wider range of application fields, especially in the application of high-tech fields, and promotes the miniaturization and lightness of high-tech products. In addition, the development and application of switching power supply is of great significance in saving energy, saving resources and protecting the environment.

The power electronics used in switching power supplies are mainly diodes, IGBTs and MOSFETs.

SCR has a small number of applications in switching power supply input rectifier circuits and soft-start circuits, and GTR is difficult to drive, and the switching frequency is low, and it is gradually replaced by IGBT and MOSFET.

Three conditions for switching power supplies.

1. Switch: The power electronics work in the switching state instead of the linear state.

2. High frequency: power electronics work at high frequency rather than low frequency close to power frequency.

3. DC: The output of the switching power supply is DC instead of AC.

Switching power supply is divided into frequency modulation and fat flush modulation.

It is mainly driven by high frequency to convert electrical energy into magnetic energy, and then into electrical energy.

Switching power supply means that the circuit is closed (energized, the electrical appliance works), and the circuit is disconnected (there is no current, the electrical appliance stops working).

A switched-mode power supply is a high-frequency power conversion device.

Switch-mode power supply, also known as switching power supply and switching converter, is a high-frequency power conversion device and a kind of power supply. Its function is to convert a quasi-voltage into the voltage or current required by the user through different forms of architecture.

The input of the switching power supply is mostly AC power supply or DC power supply, and the output is mostly equipment that requires DC power supply, such as a personal computer, and the switching power supply converts the voltage and current between the two.