DC Power Distro Verification
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DC Power Distro Verification

by Jin597 on Thu Feb 14, 2013 10:00 pm

Hi,
I have never made a PCB before, so this is all new to me.
I'm making a DC power distro board for a project I'm working on. I was wondering if someone could verify the design as sound.

I am using the Traco TSR-1 series bucks for this, and the spec sheet said no capacitors required which is great. But maybe I have over simplified or does the below work?
12Vto5Vwiththrough.jpg
12Vto5Vwiththrough.jpg (81.58 KiB) Viewed 280 times
Jin597
 
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Re: DC Power Distro Verification

by Zener on Thu Feb 14, 2013 10:25 pm

The schematic looks OK. You need to make sure the switch (and any connectors) can handle whatever load current is required, total load for the switch, including inrush if any. If excessive it could shorten the life of the switch. You will find more questions in the PCB layout probably. Use thick traces, and make sure the hole sizes and footprints are correct. Also double check the regulator datasheet to make sure you are compliant with input voltage range, and any other details, so you don't have any surprises. Read and understand every spec. Good luck!
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Re: DC Power Distro Verification

by Jin597 on Thu Feb 14, 2013 10:32 pm

Thanks for the response and confirmation Zener!
The datasheet was a good source of info for the Traco units. they actually accept a pretty good range of voltages, so I'm pretty safe with 12 and good up to 24 if needed.

The switch was the hard part... Adafruit has a nice fancy one with LED built in, but the specs didn't quite look right, so I'm opting for a more traditional flip switch that should be able to accept the load I am putting to it.

I have already laid out the PCB, but you're right... questions. The layout went really smoothly overall in Eagle. I was using a 10mil trace. I have no idea if that is enough or not, but it seemed to be a common trace.... maybe need a bigger trace?
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Re: DC Power Distro Verification

by Zener on Fri Feb 15, 2013 1:42 am

I like 30. Much better if you have to rework something. You don't have much there. Should be plenty of room. If you have lots of parts then it's a different story.
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Re: DC Power Distro Verification

by Jin597 on Sat Feb 16, 2013 11:52 am

Thanks again Zener.

I went with a 30 mil trace and now wondering if even that is enough.
I will be driving a couple Arduinos & 3 motors over these lines.
The motors will output 20-25 Amps with a 40 Amp surge.

I'm not worried about the arduinos as those have very low power draw, but wondering if I'll burn out the circuit with the motors.
Jin597
 
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Re: DC Power Distro Verification

by Zener on Sat Feb 16, 2013 2:31 pm

40 Amps?? Yeah you need to go bigger than .030"! There are charts for this info. It depends on the copper thickness you order, 1oz, 2oz etc. maybe you need .200"? Don't know. Make sure your connectors can handle that also.
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Re: DC Power Distro Verification

by Jin597 on Sat Feb 16, 2013 3:00 pm

yup... learning though :) (as said, this is my first go at this)...

so the motors are at a higher amp... this will not be drawn from the 5V converters... those have a max of 1amp according to specs.
The higher amp draw is for the 12V passthroughs....

So I guess these don't really need to be on the PCB itself (etched I mean), but could rather be a terminal bus separate from the PCB all together.
That way, I don't have to worry about burning out the PCB.

I guess a fuse at the power in might make sense as well....
Jin597
 
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