The core technology of switching power supply lies in its high-frequency switching conversion and pulse width modulation (PWM) control. It achieves DC to AC inversion by quickly switching switching switching devices such as MOSFETs and IGBTs, and then outputs stable DC through transformers and rectification filtering. This high-frequency switching technology is the key to achieving high efficiency and small size. PWM technology adjusts the output voltage by precisely controlling the conduction and cutoff time of the switching devices, ensuring the stability of the power output.

The core technology of switch mode power supply goes far beyond topology selection and control strategy. It is a complete technical system covering from devices to systems. In addition to the previously learned topology structures (such as flyback, LLC) and control strategies (such as PWM), there are several key technologies that are crucial:

1. Application of high-efficiency power devices

This is the key to improving efficiency. Gallium nitride (GaN) and silicon carbide (SiC) devices, due to their high-frequency and low loss characteristics, can significantly improve the efficiency of switching power supplies and reduce their size. Synchronous rectification technology replaces traditional diodes with MOSFETs, which can reduce conduction losses by more than 70%.

2. Electromagnetic compatibility (EMC) design

Ensure that the switch power supply does not interfere with other devices and is self anti-interference. This includes conducted interference suppression (using X/Y capacitors, common mode inductors), radiated interference suppression (optimizing PCB layout, adding shielding), and grounding design (single point grounding, power ground and signal ground separation).

3. Thermal design and reliability

It is directly related to the lifespan of the switching power supply. It is necessary to optimize the heat dissipation path, select suitable heat dissipation devices (such as heat sinks or fans), and use high-temperature resistant components. Increasing the copper foil area and adding heat dissipation vias are also common methods in PCB design.

4. Magnetic component design

Inductors and transformers are the core components. It is necessary to select magnetic core materials based on frequency and current (such as ferrite suitable for high frequencies), optimize winding methods (such as sandwich winding to reduce leakage inductance), and accurately calculate magnetic core losses and copper losses.

5. Protection mechanism design

Ensure the safety of the switch power supply. Including overcurrent protection (OCP), overvoltage protection (OVP), over temperature protection (OTP), etc., it can automatically derate or turn off in abnormal situations.