Isolated Switching DC Load

[dman66]

Does anyone have any suggestions for switching an isolated DC load other than using a mechanical relay?

If it was AC (or periodic in some way) I'd use a solid state relay.

The DC load is not very great (under 50v, low current).

Right now I'm using an open collector output - but that is sharing a ground and causing other issues (connecting my board via USB to a PC makes a ground loop, etc.).

Thanks!

[viperidae]

What about... a solid state relay?
https://www.jaycar.co.nz/medias/sys_master/images/9001015738398/SY4086-dataSheetMain.pdf
That's 30VDC at up to 100A, I'm sure you can find something with a higher voltage if you need to. Or something smaller with a lower current capability.
>4000V isolation

[dman66]

I should have also mentioned that the DC load doesn't have a fixed polarity.

Most of the solid state relays I've seen that work with DC have a fixed polarity.

[nidlaX]

An H-Bridge??

https://en.wikipedia.org/wiki/H_bridge

[Jeroen3]

I should have also mentioned that the DC load doesn't have a fixed polarity.

Most of the solid state relays I've seen that work with DC have a fixed polarity.

Most solid state relays I've seen use two fets, and have no polairty. Search for AC,DC solid state relays.
This one for example: CPC1916.

[Zero999]

An H-Bridge??

https://en.wikipedia.org/wiki/H_bridge

An h-bridge will not do, since it's used for changing the polarity of the load, not switching an unknown polarity.

What's the load current?

[nidlaX]

An H-Bridge??

https://en.wikipedia.org/wiki/H_bridge

An h-bridge will not do, since it's used for changing the polarity of the load, not switching an unknown polarity.

Thanks.

[David Hess]

Solid state relays which use a pair of back-to-back power MOSFETs may be used in DC applications.

[floobydust]

Consider using a photo-voltaic optocoupler i.e Vishay VOM1271 to drive a couple MOSFETs. Basically you're making a bi-directional SSR, good for AC/DC.

Crydom make DC SSR's but unidirectional (like GN series) but they are pretty expensive. I'm not sure if they have a bi-directional DC offering.