high current bidirectional switch

[fala]

Hello, I want to use a switch for high DC current (+/-1A to +/-3A), and I don't want to use a relay because switch may turns on/off relatively fast and for a long time. should I use a power mosfet? aren't they unidirectional? what is the usual method for switching high DC current bidirectionally? thank you in advance.

 

[IanP]

Have a look at this dual-MOSFET option (see picture below)..
For detailed desription of this circuit goto:
https://www.edn.com/archives/1997/071797/15di_03.htm

Regards,
IanP

 

[Davood Amerion]

you can use one N-channel and one P-channel MOSFET in parallel (Source to Drain and Drain to source) and connect 2 transistor gates with use of on inverter together.

see internal circuit of CD4066 IC.

Regards
Davood

 

[ptmsl]

The simplest solution if you dont mind the voltage drop is to use a diode bridge and a power mosfet (or power BJT) to switch the current. To turn on and off the mosfet use an optocoupler to get the neccesary isolation. The biasing of the power transistor is done through the transistor of the optocoupler.