The service life of some components of the switching power supply

The rapid development of science and technology has also promoted the development of power supplies. Switching power supplies? Although we have made various innovations and technological improvements, we still cannot avoid the fatal problem of short service life of switching power supplies. Let’s take a look at which components will determine the switch. The life of the power supply!

Components that determine the life of the switching power supply:

①Electrolytic capacitor

The vaporized electrolyte will leak out from the sealing part of the electrolytic capacitor. This phenomenon will accelerate as the temperature increases. It is generally believed that the leakage rate will increase to 2 times for every 10°C increase in temperature. Therefore, it can be said that the electrolytic capacitor determines the life of the power supply unit.

② Fan

The depletion of spherical bearings and bearing lubricating oil, and the wear and tear of mechanical device components will accelerate the aging of the fan. In addition, in recent years, DC fan drive circuits have begun to use components such as electrolytic capacitors, so it is necessary to take factors such as the life of the circuit components into consideration.

③ Optocoupler

The current transfer ratio (CTR; Current Transfer Ratio) will gradually decrease over time. As a result, the current of the light-emitting diode continues to increase, sometimes reaching the maximum limit current, causing the system to run out of control.

④ switch

Most switching power supplies are equipped with a capacitor input rectifier circuit. When the power is supplied, a surge current will be generated, causing fatigue of the switch contacts and problems such as increased contact resistance and adsorption. It is theoretically believed that during the expected life of the power supply, the switch will be turned on and off approximately 5,000 times.

⑤ Inrush current protection resistor, thermal power resistor

In order to resist the inrush current generated when the power supply is turned on, designers use resistors in parallel with components such as SCRs. When the power is turned on, the power peak reaches tens to hundreds of times the rated value, resulting in thermal fatigue of the resistor and circuit breakage. Thermal fatigue will also occur in thermal power resistors under the same conditions.

Summary: Technology can be innovated and devices can be replaced, but the devices that affect the life of the switching power supply will not change. You must pay attention when designing the switching power supply, otherwise it will cause unnecessary trouble. The above is some analysis of some power supply components. I hope it will be helpful to everyone. Helps when choosing.