Power PCB Layout Issues

bluefox0919

Power PCB Layout Issues [Copy link]

This is a partial layout of a power supply. I have never worked on a large power supply so I don't understand some of it. Blue is the Bottom Layer, and the pink-purple Bottom Solder. PG is the ground, and Vbus is the high voltage and current point. The questions are: 1 Why should the Bottom Solder not be laid out directly as a whole piece but should be spaced apart? 2 Why are the screw holes made in that shape? (I made a mistake, that is a large capacitor pin, not a screw hole)

ksniper

Is the window opening for heat dissipation? Is the tinning increasing the current carrying capacity? But why not open all the windows? I can't think of it. Is it to control the amount of tin when tinning? Waiting for the answer.

topwon

Tinning copper increases the current capacity. If it is spread over a large area, the tinning effect after wave soldering is difficult to control. It is probably related to the surface tension of the liquid to make it more uniform and full. The star-shaped pad below (large plug-in foot, not a screw hole) is also for fuller tinning. About 20 years ago, I was asked to modify this star-shaped pad according to the Japanese reference board to observe the effect. At that time, AUTOCAD was used to draw the PCB board. . . . . .

bluefox0919

topwon posted on 2019-5-9 13:24 Tinning copper increases the current capacity. If it is laid flat over a large area, the tinning effect after wave soldering is difficult to control. It is estimated that the opening of the window in the shape of a thin strip will be in contact with the liquid surface...

Yes, I made a mistake. That is a large capacitor pin, not a screw hole.