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Old 5th August 2010, 10:54 PM   #1
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Default Building a "stiff" supply and need some input...

Hey guys...
I'm at it again!!!

Here's the rough draft...
Click the image to open in full size.

2 x 1KVA Antek AN-10440 Trafos 40VAC @ 25A in parallel + 12V 2A + 18V 2A.
Cap Bank will be 10 x 15000uF 63V Nichicon KMH's ( 5 per Rail - Bought 24 of them HERE )

This supply was designed around 2 x 1KVA Antek 10440 Toroids with 40V Secondaries tied in parallel for maximum current output...
Each Transformer will feed each board separately. As you have noticed the positive and negative side is identical besides the polarities on caps and bridges...

C1, C2, C3, C4, C5, C6, C7, C8 ( typo for C9 ) -> 0.1uF 400V Vishay Film Caps
C11, C12, C13, C14, C15 -> 15000uF 63V Nichicon KMH
C16 & C17 -> 1000uF 100V Nichicon FW
C20, C21, C22 -> 4700uF 35V Nichicon FW
C18 & C23 -> 150uF 63V Film EPCOS
C19 -> 15uF 100V Film EPCOS

Main rectifiers ( D1 ) are 2X Crydom M5060SB600
Secondary Bridges are standard 10A off the shelf units.

Driver Board will supplied separately from the output board at a higher voltage which can be selectable from SW1 and SW2 at 80VDC or 88VDC.
Also thinking C11 through C15 instead of 1 cap run 2 caps in series, but need to figure out the proper resistance to keep an equal voltage across both caps.

INPUT PLEASE !

Last edited by Adrculda; 5th August 2010 at 10:57 PM.
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Old 7th August 2010, 02:12 PM   #2
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Red on black? I can hardly read that...
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Old 8th August 2010, 12:42 AM   #3
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Quote:
Originally Posted by Sch3mat1c View Post
Red on black? I can hardly read that...
It hurts my eyes.
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Old 8th August 2010, 08:13 PM   #4
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Here's a better shot of the schematic...
Click the image to open in full size.

Better ??

Last edited by Adrculda; 8th August 2010 at 08:20 PM.
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Old 8th August 2010, 10:45 PM   #5
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what about being conventional and using black over white?
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Old 8th August 2010, 11:12 PM   #6
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What is the application? Have you got a scope or spectrum analyser to help determine the correct inductor?
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Old 8th August 2010, 11:52 PM   #7
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Quote:
Originally Posted by AndrewT
What about being conventional and using black over white?
I'm used to high contrast white on black as that's how my laptops desktop is set up and grew quite fond of it.

Quote:
Originally Posted by richie00boy
What is the application? Have you got a scope or spectrum analyser to help determine the correct inductor?
I don't at this time but will be trying to "simulate" circuit in LTSpice once i figure out how to use it.
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Old 9th August 2010, 12:36 PM   #8
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Well, it's visible now..

1. Why all the caps?
2. Why all the film caps?
3. Why four transformers? If you don't have enough VA capacity in one, I can understand that. Then,
4. Why four FWBs? You only need one for the main +/-63V rails, not two.
5. Why two extra transformers for the +/-80V supplies? How much current is required? Why not use a DC-DC converter to generate these, especially if they are low current?
6. You claim you need a "stiff" supply. Can you put a number on that? What impedance is actually required? If it's for an amplifier driving 4 ohm speakers, I'm guessing at most 10% of that, or under 0.4 ohms. Is that reasonable?

Tim
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Old 9th August 2010, 12:50 PM   #9
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For a simulation there is a freeware that is designed for power supplies, I can't recall the name, but it should be easy enough to find.

The problem with doing a simulation will be getting all the paramaters for each component "correct". Raw capacitance, for example, will not tell you how one cap will perform over another - so in that case all the "extra" caps you have there will do nothing more than simulate like a single larger cap.

Also, the power supply will only show "issues" with a real world load - which is often a dynamic load. That is beyond the capabilities of LTSpice, afaik (well there may be some workarounds, but that is really complex).

If you want an exercise in simulation, start with simple, and work up. Also LTSpice afaik will not simulate a real-world transformer...

And a "stiff supply" is simply a low output Z supply WRT what it is loaded with. The same supply with a bigger load isn't quite so 'stiff' anymore??

_-_-bear

PS. what software are you using to draw the schematic btw??
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Old 9th August 2010, 03:39 PM   #10
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Quote:
Originally Posted by Sch3mat1c View Post
Well, it's visible now..

1. Why all the caps?
2. Why all the film caps?
3. Why four transformers? If you don't have enough VA capacity in one, I can understand that. Then,
4. Why four FWBs? You only need one for the main +/-63V rails, not two.
5. Why two extra transformers for the +/-80V supplies? How much current is required? Why not use a DC-DC converter to generate these, especially if they are low current?
6. You claim you need a "stiff" supply. Can you put a number on that? What impedance is actually required? If it's for an amplifier driving 4 ohm speakers, I'm guessing at most 10% of that, or under 0.4 ohms. Is that reasonable?

Tim
1. For the most part they are there to filter out noise, and the other part is to store and dampen the large transient currents drawn by the amp.

2. Film caps are there to decouple the large electrolitics
See this THREAD for more details...

3&4. There are actually only 2 transformers but the program that i'm using only has a single secondary, hence why i used multiple. Also would like to have 25A of current on tap on each side of the "median". Since the 2 transformers are not center tapped its easier to build 2 mirrored supplies to deliver the needed voltage and current.
Also the start up will place large amounts of stress on the bridge rectifiers when the caps charge and maybe a peak of 200-300A flowing through the rectifiers upon the charge of the caps. By using 2 rectifiers the current draw will be theoretically half of what i would be drawing across 2.

5. There is no extra transformers, they are meerly a second set of secondaries of each transformer. They will be used as the supply the LME49810's and at most 1A will be needed there.

6. The amplifier itself uses 8 Complimentary pairs of NJL4302DG & NJL4281DG.
Its basicly a current dumping amplifier and hopeing that it could drive loads as difficult as 0.5Ohms ( not that i will ever use it, but why not overbuild things to be able to withstand abuse from reactive and capacitive loads )
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