PC Board Trace Width:Current and Distance:Voltage

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PC Board Trace Width:Current and Distance:Voltage

Postby k3tue » Tue Jun 13, 2006 8:11 pm

Is there a calculation/chart/rule-of-thumb to use when determining PC Board trace width:current and distance:voltage? I ask because I want to make sure I don't make them too narrow or too close when laying out the PC board for the Power Supply for the Class H modulator.
David, K3TUE
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Postby steve_qix » Wed Jun 14, 2006 6:25 am

Hi!!

There are a couple of layouts already out there. KD1J has a class H layout, and I have one as well.

The KD1J layout has the low voltage power supplies seperate from the main board. My layout has the power supplies integral to the board.

By power supplies, I mean low voltage (12v, 5v) supplies, NOT the high voltage, high current supply.

For the low voltage supplies, I found a .050 trace was just fine! There's not much current involved.

Regards,

Steve
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Visit the class E web site at:

http://www.classeradio.com
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Postby k3tue » Wed Jun 14, 2006 12:53 pm

Oh, I was refering to the 125/62VDC power supply. After studying the schematic I realized that the secondary section would be best run with point-to-point and perhaps some barrier strips (AFAICT), and I'm starting to think the same about the primary. That only leaves the overload circuit to make a board for, but it's so small I might just ugly-bug it (thought leaning against it).

QUESTION:
Is the 360W class E tx and class H mod power supply a reasonable bother to make even when I plan on starting with lower power, just so I can re-use it and not bother to make another?
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Postby frank carcia » Wed Jun 14, 2006 3:05 pm

low to high power is just the number of fets. Lower power will just run cooler. Build it right once and fa get abot it. gfz
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Postby k3tue » Wed Jun 14, 2006 5:35 pm

In the power supply schematic on the class E site

http://www.classeradio.com/psm_modulato ... supply.gif

I see only 1 ground arrow. Is this the ground for both the +12v for the modulator and the +125v and +62v ?

And what's the thick ground bar in the overload circuit the ground for ? Is this the ground for the +125v and +62v ?
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PS ground

Postby kf1z » Wed Jun 14, 2006 5:46 pm

k3tue wrote:In the power supply schematic on the class E site

http://www.classeradio.com/psm_modulato ... supply.gif

I see only 1 ground arrow. Is this the ground for both the +12v for the modulator and the +125v and +62v ?

And what's the thick ground bar in the overload circuit the ground for ? Is this the ground for the +125v and +62v ?



The "ground arrow" is the ground point, for the Power Supply and the 'ground referenced' 12v supply etc.
I look at it as any ground with an arrow, is the same ground.

You are grounding the power supply THROUGH a 0.1 ohm resistor (to provide the overload circuit with a reference voltage to detect an overload condition.)

The "thick ground bar in the circuit" is actually 'floating' at 0.1ohm above ground.

Bruce g
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Postby k3tue » Wed Jun 14, 2006 10:26 pm

How much lower can I go for filter capacitance than 80,000uF before I start suffering ill effects?

I have a feeling that the most expensive components of this PS will be the filter caps and a toroidal transformer.
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Postby kf1z » Thu Jun 15, 2006 6:36 am

k3tue wrote:How much lower can I go for filter capacitance than 80,000uF before I start suffering ill effects?

I have a feeling that the most expensive components of this PS will be the filter caps and a toroidal transformer.



Well, not sure how low you can go...
But I know some folks were using 60,000, and I assume all was well.

( I have a couple 60,000uf / 75v caps if you need them. )
You can look for those on ebay as well, I believe they are pulls from
TelCo equipment. They are about 3" diam, 9" long. each.

Also toroidial transformers on ebay, got one there myself for bout $60.
There's a fellow selling them regularly, Believe these were made for industrial stepper motor use. (CNC tools).
He usually has a few different ones listed.

HOWEVER, Steve WA1QIX may still have some cheap ones available.


Look at his site, he mentions them in there.http://www.classeradio.com/power.htm

bruce
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nice pcb track width calculator link

Postby N9NEO » Thu Jun 15, 2006 1:27 pm

Here is width calculator link below. Hope it woiks.

I design for 30c rise in a 100c ambient. Yes, that's 130c. I use 4 layer boards with 3 oz copper. My heatsinks run 100c so you see my boards are a tad warm.

If you got a prob fitting in power tracks you can always lay some solder wick on top of track and solder it down.



http://www.geocities.com/CapeCanaveral/ ... eWidth.htm
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