Requesting PCB Design Review – High Voltage DC-DC Converter Board

[rajugudala]

Hello everyone,

I’m new in PCB designing and I'm working on a DC-DC converter PCB project and would appreciate feedback from the community. The design involves a 2-layer PCB that converts 360V DC input to 25V DC output. I’m using the PH1200A28024 isolated DC-DC converter module in this design. The PCB has a copper thickness of 2 oz, and I’ve maintained a clearance of 1.2mm between the GND plane and other nets. On the top layer, there is a copper pour for the GND with a 1.2mm clearance as well. My main focus for this design is on ensuring safety, proper thermal management, and reliable electrical performance.

1. Do the current trace widths and copper pours appear appropriate and adequate for the specified voltage and current levels in this design?
2. Are there any suggestions for improving the creepage and clearance distances to enhance safety and reliability, particularly considering the high voltage involved?
3. Based on the design details provided, does the board appear likely to function correctly under the intended operating conditions?
4. I would also appreciate any general feedback regarding trace routing, component placement, thermal management, and overall PCB layout optimization.

I would really appreciate your feedback and suggestions for improvement.

[JohanH]

1. You don't specify any currents.

2. There is not much point in pouring the chassis ground over the PCB, as that is actually chassis ground, which is only connected to the converter housing and to the 4.7 nF and 22 nF capacitors that work as safety or EMI suppression capacitors (they play the same role as Y capacitors in an AC supply; but note that Y caps are not rated for DC). I would create separate ground planes for V- on primary and secondary (well separated), and keep the chassis ground, not as a plane, but with a separate connector, that should be connected to the metal casing (if this is housed in a metal enclosure).

3. The aforementioned capacitors C4, C5, C10, C11 as per the data sheet should be film capacitors rated for the high voltage, and they should be rated also for DC voltage. For C2, C3, C12, C13 use high voltage ceramics or use film caps in both places.

[PGPG]

1. You don't specify any currents.

It was also my first thought. I have searched for these modules. They are 1200W. In datasheet I see 50A at 24V output !

I’m new in PCB designing

These are isolated modules and you should make symbols such that all connections of input are on the other side than connections at output.
I am even not sure if at your schematic higher voltage is on the left or on the right.

[ahsrabrifat]

For high-current traces, proper width is essential to prevent excessive heating or voltage drop. The trace width depends on the current and the allowable temperature rise. Using 2 oz copper is fine for typical power converters, but you'll need to calculate the trace width for the current you're handling. Use an online trace width calculator (IPC-2221 standard) to verify the minimum trace width based on your expected current and copper thickness.  High-current paths, such as the input and output traces, should be wide enough to handle the current without significant heating. Copper Pour for GND: A 1.2mm clearance is acceptable. Consider increasing it to around 2mm or more for safety margins, especially when dealing with high voltages. Copper pours should be as continuous as possible to reduce the impedance and improve thermal dissipation. For some more info about high-power PCB design rules, you can see this article:
https://www.pcbway.com/blog/PCB_Design_Layout/Considerations_for_High_Power_PCB_Design_25a54c5a.html