SIL pad connected to GND.

[boyddotee]

Hi All,

Hoping someone may be able to answer why, I'm currently working for a company that specialises in rail and road lighting. This particular device is a power supply for a HID headlamp.

The question is why would the engineer that designed the board specify electrically connecting the SIL pad to ground when the SIL is not conductive (I've checked).

In advance, I cannot unfortunately share the schematic for IP reasons.

Thank in advance for any ideas.

Chris.

[boyddotee]

Photo attached.

[Phoenix]

The pcb has scrn which could mean screen. Sometimes an electrically conductive screen is placed between a switching device and the heat sink. This is used to guide capacitively coupled currents to a friendly node instead of say earth where it can radiate out.

In this specific scenario I can't see any screen unless it's built into the silpad.

[boyddotee]

Thanks Phoenix, the SIL pad in none conductive in this case which is why its puzzling.

The SCRN although not easily visible could also refer to a guard trace that's under there, and ultimately runs along the transformers pins which on that side have no connection.

[boyddotee]

Other side, I think with the distance there would be little to no coupling effect.

The heatsink itself is not connected to GND.

[Sacodepatatas]

Thanks Phoenix, the SIL pad in none conductive in this case which is why its puzzling.

It is puzzling deliberately. It's an authenticity check. Do you know the issue that had Van Halen music band with brown colored M&Ms? That's the same sort of thing.

Think of It: If you find a copycat device trying to pass as genuine, but they don't include such special feature because looks silly, that's an evidence of counterfeit. If a design from another brand is so suspiciously similar that also includes such a feature just because, then the original designer can alledge that their IP was stolen.

It's like a watermark.

[Conrad Hoffman]

Another possibility is that it ensures some other aspect of the assembly is done correctly or it provides some mechanical protection. Think outside the electronic function.

[sleemanj]

Or it silences an unconnected component/pin error in the Schematic/PCB editor.