Parallel Connectors for Increased Current...

[adamey]

I want to know itf it's OK to use multiple parallel connectors to increase current capacity for a circuit.

Specifically, I want to stack two PCB's using the same connectors you see on Arduino (those SIP header sockets/pins). I have a circuit that can draw up to 10A, but these connectors are only rated for 3A per position. I have several "spare" positions and it would be nice to use the same connector for both my signals and current.

I was thinking of paralleling 4 of these connector pins to handle my 10A circuit. I have seen manufacturers specifiy that when adjacent positions in a connector are both carrying higher currents that they often "de-rate" the current rating (they may say 5A per position, or 4A when several positions are carrying current simutaneously). But they don't say if it's OK for adjacent positions to share the current load for a single circuit.

I'm just wondering if there's any problems I'm missing here.

 

[crutschow]

You can parallel the pins to carry more current for a single circuit but you need to follow the derating guides. The reason for the derating is the heating of the pins due to the pin resistance.

 

[cachehiker]

It's fine. I think four contacts is a good number of they're rated for 3A each. Problems arise when they are connected in a manner that forms a ground loop though, especially when a high speed switching is involved.

The derating is because under loads approaching their rating, the contacts run hot. This reduces the rating of the contacts next to it which in turn reduce it's rating...

 

[crutschow]

It's fine. I think four contacts is a good number of they're rated for 3A each. Problems arise when they are connected in a manner that forms a ground loop though, especially when a high speed switching is involved.

Using multiple pins to carry power will not create a ground loop. Ground loops are created when there are multiple ground paths and one of them is unintended, such as a ground connection through the power line safety grounds.

 

[cachehiker]

Using multiple pins to carry power will not create a ground loop.

You need to work with some of the $h!the@ds I do. It can be done and it has been done. Use pin 1 and pin 14 at the opposite ends of a header for ground, connect them together with narrow tracks instead of a ground plane at the power supply end, and then run a great big loop around the perimeter of the control board instead of connecting them together where they enter the board 6-10 feet away. It does a very good job of broadcasting SMPS harmonics as well as coupling circuits that shouldn't be interacting with one another together.

"But Altium gives me errors if I don't connect them together!" Yes, it does, but that doesn't always mean just connecting them together in the most convenient manner is a good idea.

For some reason the audio circuits on these boards always seem to pick up only country music stations. Why is that?

 

[crutschow]

"For some reason the audio circuits on these boards always seem to pick up only country music stations. Why is that?

The circuits must have good taste in music.

 

[adamey]

Thanks for the replies. This makes things much easier. I'll make sure to keep the connector pins together in a block.