What are the components of the switching power supply?

Switching power supply is mostly used in automation equipment as the power supply of PLC, field digital quantity, and instrument. Its appearance structure is divided into two types: one is the ordinary switching power supply, which is fixed with screws during installation, which is not very convenient for disassembly and replacement. The other is what we call the rail switching power supply. The shell is designed with a 35mm rail buckle, which can be directly clamped on the 35mm rail in the cabinet like contactors, relays, and terminals. It is very convenient and quick to disassemble and replace. DR-Din rail power supply is also a kind of switching power supply. Let us introduce in detail what are the components of the switching power supply.

Here is the content list:

• Electrolytic capacitor

• Thermistor

• Switching power supply transformer

• Switching power supply circuit

Electrolytic capacitor

Vaporized electrolyte leaks from the sealing part of an electrolytic capacitor. This phenomenon will accelerate with the increase in temperature. It is generally believed that the leakage rate will increase to twice as long as the temperature rises by 10°C. Therefore, it can be said that the electrolytic capacitor determines the life of the switching power supply device.

Thermistor

The thermistor, as a component of the inrush current protection circuit, is used in a power supply with a small capacity (not more than 70W). When the switching power supply is connected, the current reaches the maximum value, and the resistance value of the thermistor decreases as the temperature rises. Usually, the temperature will rise to 70～90℃. Although the thermistor is made of heat-resistant materials, thermal fatigue will still affect the life of the switching power supply.

Switching power supply transformer

The switching power supply transformer and the switching tube together constitute a self-excited (or other) intermittent oscillator, thereby modulating the input DC voltage into a high-frequency pulse voltage. In the flyback circuit, when the switch tube is turned on, the transformer converts the electric energy into magnetic field energy and stores it and releases it when the switch tube is turned off. In the forward circuit, when the switch tube is turned on, the input voltage is directly supplied to the load and the energy is stored in the energy storage inductor. When the switch is turned off, the energy storage inductor will continue to flow to the load.

Switching power supply circuit

On the one hand, the control circuit of the switching power supplytakes samples from the output terminal, compares them with the set value, and then controls the inverter to change its pulse width or pulse frequency to stabilize the output. On the other hand, according to the data provided by the test circuit, identification of the protection circuit, providing a control circuit for various protection measures for the power supply. The detection circuit of the switching power supply provides various operating parameters and various instrument data in the protection circuit.

The components of the DR-Din rail power supply are also similar to the components of the switching power supply, you can compare them before choosing. Zhejiang Ximeng Electronic Technology Co., Ltd. is a high-tech enterprise with rich production experience, you may consider buying our products.