need help with constant current PWM conversion from 12v to 24v

SgtWookie

Joined Jul 17, 2007
22,230
I'm still fiddling with re-creating the Eagle schematic from my original, but using parts similar to what you're using. Having to make a few library parts, like the MCP14628.

After looking at your photo some more and then reading back in the thread, looks like you decided to use a single 6v regulator instead of individual 5v and 6v regulators. That's not good; the MCP14628 isn't rated to run on that much voltage.
 

Thread Starter

samuraimarc

Joined Mar 28, 2009
48
No, I've got the two regulators on there, the 5v is just for the MCP14628. I draw on it in paint so I can label everything and post it next. Thanks
 
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SgtWookie

Joined Jul 17, 2007
22,230
Hello again.

Sorry I haven't made any progress on this. Although it worked in simulation, I'm thinking there needs to be some changes made.

One problem is that I don't have a SPICE model for the MCP14628 driver IC.

Another is that after considering the circuit further, I may have been getting duped by the simulation appearing to change PWM percentage, when real-life parts may not.

Changing to a Darlington wouldn't help.
 

SgtWookie

Joined Jul 17, 2007
22,230
I have the mcp14628 model for spice, is there a way I can send it to you? What file extensions can I attach here?
Oh, great!

Rename it to a .TXT file, as that's what it should be.

You can then attach it using the "Go Advanced" and "Manage Attachments" buttons.
 

Thread Starter

samuraimarc

Joined Mar 28, 2009
48
they come as a .bxl format so I don't know if they will work as a .txt file to put it into your library. I'll give it a try but I might need to send it you in an Email. if it doesn't work, send me a private me3ssage with address and I'll send it to you. if your scared I can find the website where I got it
 
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