Working Principle of Switching Power Supply

Switch Mode Power Supply (SMPS for short), also known as switching power supply, switching converter, is a high-frequency power conversion device and a type of power supply. Next, I will tell you in detail the working principle of the switching power supply and the precautions for the use of the switching power supply.

Working principle of switching power supply

The working principle of switching power supply is different from linear power supply. Linear power supply makes power transistor work in linear mode, while switching power supply makes power transistor work in two working states of on and off, in other words, through "chopping" , that is, the amplitude of the input DC voltage is chopped into a pulse voltage equal to the amplitude of the input voltage. This working principle of the switching power supply makes the volt-ampere product applied to the power transistor very small (in the on state, the voltage is low and the current is large; in the off state, the voltage is high and the current is small), that is the loss generated on the power transistor， very small.

Notes on the use of switching power supply

1. The input voltage of the switching power supply can be 220V or 110V, and the input voltage range is reasonably selected according to the circuit design. Otherwise, it will cause damage to the switching power supply.

   
   

2. Pay attention to distinguish the ground terminal and the neutral terminal of the output voltage terminal of the switching power supply. And ensure that the grounding of the switching power supply is reliable.

   
   

3. The metal shell of the switching power supply The power supply shell is generally connected to the ground (FG), and it must be grounded reliably to ensure safety, and the shell should not be connected to the zero line by mistake;

   
   

4. Before installing the switching power supply, please check and proofread the connection on each terminal again, and make sure that the input and output, AC and DC, single-phase and multi-phase, positive and negative, voltage and current values are correct. , before it can be powered on and run;

   
   

5. For high-power switching power supplies, there are generally two or more "+" output terminals and "-" output terminals. In fact, they belong to the same output electrode, just to make wiring convenient for users, and multiple terminals are connected. separately internally and joined together;

   
   

6. In order to achieve sufficient heat dissipation, the general switching power supply should be installed in a position with better air convection conditions, or installed on the chassis shell to transfer heat to the outside through the shell;

   
   

7. The switching power supply is tested with a resistive load before it leaves the factory. If it needs to be used as a capacitive or inductive load, it should be explained in the order contract in advance;

   
   

8. For dual-channel switching power supply output symmetrical load, the symmetrical output power supply is preferred;

   
   

9. For users whose switching power supply FG is grounded, it is normal to feel numbness when touching the casing or output. When floating, the FG has about 110V AC output to the ground, which is determined by the internal structure of the power supply.

   
   

10. The switching power supply is 100% full and aging before leaving the factory. Generally, the power usage rate is controlled within 80% or lower, which can greatly improve the service life of the power supply. Generally, the life of the capacitor is reduced by half every time the power supply temperature increases by 10 °C;

    
    

11. The ripple and noise of the switching power supply are the AC components superimposed on the DC output voltage, which are generally expressed by the peak value of millivolts;

    
    

12. For all switching power supplies, when there is a sudden change in the load, there will be a certain response time. During this sudden change, the output voltage of the power supply will have a short overshoot process instantaneously, and then return to the normal output state, which is Dynamic Response;

    
    

13. Once the switching power supply fails, the factory should be notified as soon as possible, and the factory will be responsible for maintenance or technical guidance free of charge, except for those who disassemble the power supply without permission.