Bidirectional solid state relay?

[Mosaic]

Can anyone advise on using a Pfet/NFet pair to create a bidirectional solid state relay?

Current range is up to 60Amps, Voltage up to 26 Vdc. But I won't know the polarity of the switching. viz hi side/lo side config.

thx!!

 

[unclejed613]

there are pre-made SSRs in the voltage and current ranges you're talking about.... neat little 4-terminal blocks that can be mounted to a heat sink if need be... use an AC model for bidirectional use.

 

[gilmanli]

Don't use discrete components to make the relay,it is not stable and not reliable.Using a complete component such as SSR.

 

[crutschow]

If you are switching DC, you can't use an AC relay, it must be a DC output unit such as this. The output is polarized so you have to place it in the circuit with the proper polarity. But it will work as either a high side or low side switch without modification since the input is opto isolated from the output.

 

[Diver300]

You could use a MOSFET and a bridge rectifier.

If you are using two MOSFETS to block current in either direction, they have to be in series. The body diode will let a MOSFET conduct in reverse.

 

[Mosaic]

I was looking at this as an option:
https://www.electro-tech-online.com/custompdfs/2012/02/dt94-5.pdf

Since it can handle ac, it should handle bidirectional DC, not so?

A voltage doubler could deliver the necessary Vgs voltage.

Is there a reason why this would be a bad approach?

 

[unclejed613]

You could use a MOSFET and a bridge rectifier.

If you are using two MOSFETS to block current in either direction, they have to be in series. The body diode will let a MOSFET conduct in reverse.

actually, the MOSFET and bridge idea will work well. the bridge needs to be able to handle the current, and so does the fet. the gate drive needs to be referenced to the fet source, but isolated from the switched voltage, so that may be somewhat of a challenge. let me work out some of the details and i'll post a better schematic. what you see below is the conceptual schematic. R1 is the load. D1-4 is the bridge