×
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

remote sense on power supplies

remote sense on power supplies

remote sense on power supplies

(OP)
I'm used to using the remote sense lines on a power supply when I have a widely varying load, so the line loss is compensated to keep the voltage constant at the load independent of current draw.  I've only done this with the load fairly close to the supply though.  

A colleague is suggesting using this technique across a long cable between the power supply (controller) and a sensor head.  I would think the delay along the cable could cause loop instabilities, and potential EMC/EMI pickup on the cable could drive the power supply crazy.  Am I being overly concerned, or does it really depend upon the application?  Any success or horror stories out there?  

Z
 

RE: remote sense on power supplies

A shielded remote sense wire would certainly reduce the EMC/EMI issues you are concerned of.  I wouldn't worry abouth the a delay but I'm not sure what kind of distance you are speaking of.

RE: remote sense on power supplies

Shouldn't be anything to worry about on the loop stability, and good design practice should keep keep the EMI under control. Include a low-ish value resistor between the main output and the sense lines to cope with the day when the sense line gets disconnected.
  

----------------------------------
  
If we learn from our mistakes I'm getting a great education!
 

RE: remote sense on power supplies

1 km  roundtrip at c = 6.7 microseconds, so unless your load is violently changing at 150 kHz, there should be little problem.  

However, I doubt if the the sense circuit has that fast a response time, in which case, you'd be seeing a low-pass filtered response to the load, which should be OK.

TTFN

FAQ731-376: Eng-Tips.com Forum Policies

RE: remote sense on power supplies

(OP)
Thanks all!  I'll keep that option open.  

Z
 

RE: remote sense on power supplies

I have seen the following done - at the power supply, connect the remote sense to each supply terminal with a 100 Ohm resistor. Then run the long length sense line to the remote load. Normally, this is done so if the sense line should open, the power supply and load will remain within reasonable limits. But with a long sense length this should make it very difficult to couple any significant noise to the sense line even given any phase delay.

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