Study on the Influencing Factors of Insulation Failure on Surface of PCB in Switching Power Supply

The miniaturisation and high-power density of switching power supplies encountered internal insulation problems where the printed circuit board (PCB) should be considered carefully. In order to investigate the influencing factors of insulation failure on the surface of PCB in switching power supplies, this paper explores the surface flashover conditions of PCBs by varying the distance between the electrodes, the air pressure, and the external environment. The results showed that the distance between the electrodes and the structure of the electrodes significantly affect the electric field distribution and the surface flashover voltage. Besides, the surface flashover voltage under varied air pressure approximately conforms to the general law of the Paschen’s curve, that is, the surface flashover voltage decreases and then increases with the the air pressure increasing. Additionally, it is indicated that the more complex the surface environment of the PCB is, the lower the corona voltage is.