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EDY19

Sun Oct 01 2006, 06:16PM

Registered Member #105 Joined: Thu Feb 09 2006, 08:54PM
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Posts: 408

Does anyone have a simple PLL based SSTC/DRSSTC board file that they could post so I can play around with EAGLE a little bit? I just got it, and I am used to ExpressPCB, so having somewhere to start and experiment on eagle for a possible upcoming project would be nice. It seems like we have talked about having a PCB database type thing before, and noone seems to have problems with it... Is there a reason that has never been done? If for some reason this is against the board rules, feel free to delete my post, but somewhere to start on EAGLE would be really nice

Avalanche

Sun Oct 01 2006, 08:48PM

Registered Member #103 Joined: Thu Feb 09 2006, 08:16PM
Location: Derby, UK
Posts: 845

I was going to have a small PCB database on my website for popular things like sstc boards, because I've designed loads but I never got around to it.

I know this isn't Eagle, but if you're interested I have quite a nice little PLL sstc board on my site here. It's a single sided board, and I eventually got it down to only 1 wire link (I never use autorouting!) I only have it in PDF format now, but maybe it could be replicated in Eagle, because I know it needs the frequency limiting resistor adding. It works for small coils very well though as it is.

Marko

Sun Oct 01 2006, 09:07PM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145

Enjoy your B-day avalanche.... I just wanted to recommend avalanche's board, but it wasn't in eagle format.

I usually do my stuff on perfboard and if I need boards I build them completely manually

as transfer techniques usually mess up (wouldn't be able for more than DIP with very wide and ugly leads).

It's not cool if you can't put SMD on it.

EDY19

Mon Oct 02 2006, 01:57AM

Registered Member #105 Joined: Thu Feb 09 2006, 08:54PM
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Posts: 408

Do you have the schematic for that PLL board Avalanche? It looks really nice and I may build it as soon as I get a break from school!

...

Mon Oct 02 2006, 02:00AM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

The schematic he used was origianlly (to the best of my knowledge) Steve Ward's design, and can be found here

Avalanche

Mon Oct 02 2006, 12:48PM

Registered Member #103 Joined: Thu Feb 09 2006, 08:16PM
Location: Derby, UK
Posts: 845

Yes that's the one (steve conners circuit). The board I designed doesn't quite match that schematic though, as it was only intended for tiny coils. I replaced the resistor on pin 11 with a 50k preset, so I could quickly change the board between different coils. This means I also removed the other resistor on pin 12 which limits the frequency! There's also a few more capacitors 'dotted around' the board, wherever I had a long power trace, and I've gone and forgotten to add the UCC clamping diodes as well.

Ideally it needs the resistors putting back to normal, but I found the coil starts up a bit less destructively if you can set the startup frequency to match your coil (I don't have a variac). It seems to behave itself without the frequency limiting as well, but I would probably want to put it back anyway.

EDY19

Mon Oct 02 2006, 02:21PM

Registered Member #105 Joined: Thu Feb 09 2006, 08:54PM
Location:
Posts: 408

How much do the 1N5819's really effect the UCC? I have heard of people not using them and still not having any problems. Have you had problems, Avalanche? Also, I see that you have a 15V regulator- isn't that the maximum voltage for the HEF4046? Also, the 10 Ohm resistor is removed from that schematic, is there really any purpose for that?

Avalanche

Mon Oct 02 2006, 02:39PM

Registered Member #103 Joined: Thu Feb 09 2006, 08:16PM
Location: Derby, UK
Posts: 845

I've never had any problems at all without the clamping diodes, but all my coils have been CW (or halfwave). I think I would want to add them if I was using an interrupter (which you can't with that board anyway

)

Also I didn't have any problems with using 15v on that circuit, no chip failures or anything. I wanted to get the voltage as high as possible to the UCCs, to try and improve the drive to the transformer. That's also the reason I removed the 10R resistor as well, I couldn't see much point in it being there. Other boards I have built up use a 12 volt regulator, and they are fine also.

EDY19

Mon Oct 02 2006, 05:49PM

Registered Member #105 Joined: Thu Feb 09 2006, 08:54PM
Location:
Posts: 408

What do you mean you can't add an interrupter? Cant I just solder a little tag wire on the enable pins of the UCCs and interrupt it from there? And clamping diodes could be added to the GDT output terminal without too much trouble I think, so we'll give that a try.

Marko

Mon Oct 02 2006, 06:01PM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145

How much do the 1N5819's really effect the UCC?

A lot, especially if you use high frequency design with direct gate drive.

They kill off all ringing on UCC output wich can easily cause it to die a horrid death.

In direct drive systems they clamp voltage induced trough miller plateau, wich is potentially harmful for both mosfet and UCC.

PS. I used to leave audio in open, and it worked trough 100ohm resistor well.
I'm not sure if this affects anything except detuning the PLL a bit..

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