SMPS Related

[vrak]

Hi

any one please Let me know 1.Why Drain pin OF Link switch is Placed or routed in Shortest path i SMPS?(primary side)

2.Why isolation has to be given in the form Board cutout between Source and Drain pin?

 

[KrisBlueNZ]

1. The voltage on the drain of the main switching MOSFET has very fast edges and should be kept short to reduce (a) capacitive coupling, which will slow it down, and (b) emission of interference.

2. The source swings over a very wide voltage range - typically over 500V. A cutout is a convenient way to increase the creepage distance and reduce the chance of breakdown due to accumulation of dust and other impurities.

 

[vrak]

Thanks Kris Blue
Use ful information i got it