×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

mosfet relay control board

mosfet relay control board

mosfet relay control board

(OP)
I am developing a PCB to control turning on various fans and electric motors.  The control circuitry uses an ARM processor and via a CAN bus is sent signals from a main controller to turn devices on and off.   Power for the processor and control circuit is fed from a 5 volt supply from the main controller via a cable.  The 5 volt and ground are 26 gauge.

The PCB uses P-channel mosfet to switch the devices.  The fets are fed from a 6 gauge battery cable connected to the PCB.

I assume I will need some Transient Voltage Suppressors on the mosfet drains to handle back EMF when the mosfet is turned off and if I want to be able to soft start the motors via PWM.

Question is will I need a separate ground to allow Back EMF directly to chassis ground instead of back through 26 gauge ground wire?  I assume it would be best to have a separate ground on the PCB that only the TVS is attached to so that it does not cause a ground loop with the rest of the system?
 

RE: mosfet relay control board

Please Red Flag this duplicate post.
In the dialog box, ask that it be removed.
Please refrain from multiple posting.
Thank you.
 

Mike Halloran
Pembroke Pines, FL, USA

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources