Old 11-22-2014, 07:31 PM #17
DashApple's Avatar
Class 3R Laser
 
Join Date: Jan 2009
Location: Someplace on earth
Posts: 1,395
Rep Power: 143433
DashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond repute
DashApple DashApple is online now
Class 3R Laser
DashApple's Avatar
 
Join Date: Jan 2009
Location: Someplace on earth
Posts: 1,395
Rep Power: 143433
DashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond repute
Default Re: 10A Driver with Modulation , First attempt

Update , I have remade the circuit as small as I could The OpAmps are on SOIC to DIP baords to keep wire lengths down with a Lipo supply for +-12V , this is the current results with a current flow of 0.5A

The first picture is the voltage on the mosfet gate , so there is oscillations on the output and the second picture is the current waveform though the sense resistor .

Thanks , I will try as you said and see if there are any improvements

NewFile5 by TwirlyWhirly555, on Flickr

NewFile6 by TwirlyWhirly555, on Flickr

IMG_0733[1] by TwirlyWhirly555, on Flickr


__________________
I don't know what you had in mind
But here we stand on opposing sides .

Last edited by DashApple; 11-22-2014 at 07:52 PM.
DashApple is online now   Reply With Quote


















Old 11-23-2014, 01:37 AM #18
djQUAN's Avatar
Class 3R Laser
 
Join Date: May 2013
Location: Philippines
Posts: 1,128
Rep Power: 1738
djQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond repute
Send a message via Yahoo to djQUAN
djQUAN djQUAN is offline
Class 3R Laser
djQUAN's Avatar
 
Join Date: May 2013
Location: Philippines
Posts: 1,128
Rep Power: 1738
djQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond repute
Send a message via Yahoo to djQUAN
Default Re: 10A Driver with Modulation , First attempt

You can also try adding local decoupling. 100nF caps between V+ to gnd, and gnd to V- VERY close to the op amps.

Also try increasing the 10pF caps to slow down the op amps. Then once it is stable, you can decrease the value to the minimum possible to meet your maximum modulation speed.
djQUAN is offline   Reply With Quote
Old 11-28-2014, 04:47 PM #19
DashApple's Avatar
Class 3R Laser
 
Join Date: Jan 2009
Location: Someplace on earth
Posts: 1,395
Rep Power: 143433
DashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond repute
DashApple DashApple is online now
Class 3R Laser
DashApple's Avatar
 
Join Date: Jan 2009
Location: Someplace on earth
Posts: 1,395
Rep Power: 143433
DashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond repute
Default Re: 10A Driver with Modulation , First attempt

Thanks for the help , I replaced the first op Amp with a LF356N and re jigged a few components .

Now at 5V I get 8.1A , 256mV across the resistor and there is no oscillations and I can adjust the current too , there a tiny amount of ripple but nothing like before .

Ill get some scope shots soon
__________________
I don't know what you had in mind
But here we stand on opposing sides .

Last edited by DashApple; 11-28-2014 at 04:48 PM.
DashApple is online now   Reply With Quote
Old 11-29-2014, 09:52 AM #20
DashApple's Avatar
Class 3R Laser
 
Join Date: Jan 2009
Location: Someplace on earth
Posts: 1,395
Rep Power: 143433
DashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond repute
DashApple DashApple is online now
Class 3R Laser
DashApple's Avatar
 
Join Date: Jan 2009
Location: Someplace on earth
Posts: 1,395
Rep Power: 143433
DashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond repute
Default Re: 10A Driver with Modulation , First attempt

Well I tested the 7W diode up to the 8A , Didn't on / off modulate it just used the variable current setting .

It worked , as this was just to test it ill now move over to a proper driver .

IMG_0748[1] by TwirlyWhirly555, on Flickr
__________________
I don't know what you had in mind
But here we stand on opposing sides .

Last edited by DashApple; 11-29-2014 at 12:59 PM.
DashApple is online now   Reply With Quote
Old 11-29-2014, 11:56 AM #21
djQUAN's Avatar
Class 3R Laser
 
Join Date: May 2013
Location: Philippines
Posts: 1,128
Rep Power: 1738
djQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond repute
Send a message via Yahoo to djQUAN
djQUAN djQUAN is offline
Class 3R Laser
djQUAN's Avatar
 
Join Date: May 2013
Location: Philippines
Posts: 1,128
Rep Power: 1738
djQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond reputedjQUAN has a reputation beyond repute
Send a message via Yahoo to djQUAN
Default Re: 10A Driver with Modulation , First attempt

glad you got it working
djQUAN is offline   Reply With Quote
Old 11-29-2014, 12:19 PM #22
The Lightning Stalker's Avatar
Class 3B Laser
 
Join Date: Aug 2013
Location: MI, US
Posts: 2,655
Rep Power: 6069
The Lightning Stalker has a reputation beyond reputeThe Lightning Stalker has a reputation beyond reputeThe Lightning Stalker has a reputation beyond reputeThe Lightning Stalker has a reputation beyond reputeThe Lightning Stalker has a reputation beyond reputeThe Lightning Stalker has a reputation beyond reputeThe Lightning Stalker has a reputation beyond reputeThe Lightning Stalker has a reputation beyond reputeThe Lightning Stalker has a reputation beyond reputeThe Lightning Stalker has a reputation beyond reputeThe Lightning Stalker has a reputation beyond repute
The Lightning Stalker The Lightning Stalker is offline
Class 3B Laser
The Lightning Stalker's Avatar
 
Join Date: Aug 2013
Location: MI, US
Posts: 2,655
Rep Power: 6069
The Lightning Stalker has a reputation beyond reputeThe Lightning Stalker has a reputation beyond reputeThe Lightning Stalker has a reputation beyond reputeThe Lightning Stalker has a reputation beyond reputeThe Lightning Stalker has a reputation beyond reputeThe Lightning Stalker has a reputation beyond reputeThe Lightning Stalker has a reputation beyond reputeThe Lightning Stalker has a reputation beyond reputeThe Lightning Stalker has a reputation beyond reputeThe Lightning Stalker has a reputation beyond reputeThe Lightning Stalker has a reputation beyond repute
Default Re: 10A Driver with Modulation , First attempt

Why does that TEC controller have such a
big coil on it?

+2 when I can
__________________
ALL NEW MEMBERS MUST READ THIS!!! --> http://www.laserpointersafety.com

"Where, now, is the way by which the light distributes itself" - Job 38:24

YouTube Channel
The Lightning Stalker is offline   Reply With Quote
Old 11-29-2014, 01:01 PM #23
DashApple's Avatar
Class 3R Laser
 
Join Date: Jan 2009
Location: Someplace on earth
Posts: 1,395
Rep Power: 143433
DashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond repute
DashApple DashApple is online now
Class 3R Laser
DashApple's Avatar
 
Join Date: Jan 2009
Location: Someplace on earth
Posts: 1,395
Rep Power: 143433
DashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond reputeDashApple has a reputation beyond repute
Default Re: 10A Driver with Modulation , First attempt

Quote:
Originally Posted by djQUAN View Post
glad you got it working
Thanks : D , I just need to still see if there are any spikes when its modulated on / off

Quote:
Originally Posted by The Lightning Stalker View Post
Why does that TEC controller have such a
big coil on it?

+2 when I can
Thanks : ) , Not sure really The controller is rated to 8A TEC current so that's probably why , The controller is " Bang Bang " style with a half bridge doing the switching ,
__________________
I don't know what you had in mind
But here we stand on opposing sides .

Last edited by DashApple; 11-29-2014 at 01:02 PM.
DashApple is online now   Reply With Quote
Reply





Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

























Privacy Policy | Advertising Disclaimer | Terms of Use


 


All times are GMT. The time now is 05:44 AM.


Powered by: vBulletin
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO
Privacy Policy | Advertising Disclaimer | Terms of Use
Copyright (C) 2017 Laser Pointer Forums, LLC