bidirectional switch, MOSFET

[cypress2580]

i want to use a MOSFET as a bidirectional switch for circuit breaker applications. now the problem that i have is the body diode of the device. is there a way whereby i can bypass this diode (as if the MOSFET doesn't have it)?.

 

[Venkadesh_M]

yeah you can

but you will lose a 0.7V..

 

[KerimF]

This may be solved by two N-MOSFET in series and their drains connected.
The difficulty of this method is that one of the N-MOSFET (or both) should be driven by a floating driver.

 

[Venkadesh_M]

This may be solved by two N-MOSFET in series and their drains connected.
The difficulty of this method is that one of the N-MOSFET (or both) should be driven by a floating driver.

Then you will drive both the mosfets in every direction??

 

[KerimF]

Sorry Vankadesh, I didn't get your point. Obviously both MOSFETs should be turned ON or OFF.

Note:
Perhaps the two N-MOSFET in series with their sources in common may be suitable for some applications.

 

[FvM]

Perhaps the two N-MOSFET in series with their sources in common may be suitable for some applications.

Yes, that's the usual configuration, also used by bidirectional photovoltaic relays. Both MOSFETs can be controlled by one (floating) voltage.

 

[Venkadesh_M]

Yes, that's the usual configuration, also used by bidirectional photovoltaic relays. Both MOSFETs can be controlled by one (floating) voltage.

How to bias the two mosfets with same voltage..

 

[cypress2580]

thank you very much, i have done simulations and my system can conduct bidirectionally. :grin:

yeah you can

but you will lose a 0.7V..

 

[FvM]

How to bias the two mosfets with same voltage..

"Same voltage" means Vgs or Vds? By the connection shown in your schematic in post #7, both MOSFETs get the same Vgs, as required. Vds is of course different.

You don't need any diodes. But MOSFET substrate diodes are present.

 

[Venkadesh_M]

"Same voltage" means Vgs or Vds? By the connection shown in your schematic in post #7, both MOSFETs get the same Vgs, as required. Vds is of course different.

You don't need any diodes. But MOSFET substrate diodes are present.

Vgs, How It will switch ON in a reverse direction and I meant the internal substrate diodes to show the path....