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New HV Member would need some help on a class E PLL design

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LAN_403

Anubisbot-HV

Sun Aug 31 2008, 03:42PM

Registered Member #1664 Joined: Fri Aug 29 2008, 02:05PM
Location:
Posts: 5

Hi,
i am planing on building a tesla coil. It will be my first coil, and i was now reading all over the internet about different coils i can build or kits i can buy.But i guess my goals are different from other, since i would like a small coil, the spark only needs to be 2 inch max. and should not be so dangerous, so i would like max 24 volt to use from my bench power supply.

So i foud here on the forum the circuit for Uzzors Clas E PLL coil and driver. It seems to be almost what i want. since i would like to have 4
similar coils , so i can run then with Dolby Digital surround sound.

i don't want them to be loud but just save. ( 70 watt ) they will be in my show car as only tweeters.

So would it be possible to make a small coil and run it from 12 to 24 Volt and would it be good to use UZZORS schematic or is there a newer version.

I want to get some PCB made, so if some one would like to have some let me know, but first i have to make the PCB layout, and i will post it as soon i have it done, so i would appreciate if u pros could take a look at them , and let me know if that will work what i do.

Since its my first time with a tesla coil, so please be patient with me.
And sorry for my bad English i am German

Best Regards
Anubisbot

Anubisbot-HV

Sun Aug 31 2008, 09:12PM

Registered Member #1664 Joined: Fri Aug 29 2008, 02:05PM
Location:
Posts: 5

Sorry when i double post, but i was not able to edit the attachments later on , so here is the layout of the PCB and i have left the gnd planes out so it is easier to view. All the green lines are gnd lines and they will be gone once the gnd planes are in place.

The only thing what i still miss is the 470nf cap four decoupeling , since i dint know the rating on the voltage for it?? does somebody know??

Here is the layout based on uzzors schematic so far i hope i dint mess around to much :)

Best regards Anubisbot

...

Mon Sept 01 2008, 02:22AM

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

If you haven't had the board made yet, I would greatly increase the size of the traces. There is no reason not to use like 20-30mil traces if you have room. Like use traces the size of your power traces for the signal, and make your power twice as large as it is currently. Where you run out of room you can shrink them back down, but the board will probably work better (especially if you are making it yourself) if you use thicker traces. Saves etchant too

As to the 470nf cap, what is it connected to? If it is on the logic you can use a 20v one, if it is on the power part of the circuit it needs to handle whatever voltage you are planning to feed the circuit times like 5 to be safe.

uzzors2k

Mon Sept 01 2008, 02:05PM

Registered Member #95 Joined: Thu Feb 09 2006, 04:57PM
Location: Norway
Posts: 1308

The 470nF decoupling capacitors are clamped between Vcc and ground leaving them fairly safe from voltage deviations. A random low inductance film cap of 100nF - 1ÂµF will work, I used a few standard MKT 250V ones. You seem to have left very little space for the Cmatch capacitors, high quality film capacitors should be used there too to avoid heating problems. They tend to be fairly large.

If you plan on using this coil in your car as a tweeter you should breadboard it first to optimize the circuit for better sound quality. As said earlier I wasn't pleased with the audio-modulation and would still recommend Reaching's coil over my own.

The circuit will work, but it's buggy and not what you will want from your first coil.

Anubisbot-HV

Mon Sept 01 2008, 04:29PM

Registered Member #1664 Joined: Fri Aug 29 2008, 02:05PM
Location:
Posts: 5

Thanks, for the info , i have overred the part where u stated the part that the audio is not so great.
The circuit from Reaching's is also nice, i wonder if it would be possible to use my Propeller chip (32bit over kill)
and use it ability to generate PLL frequencies from 500Htz to 80. Mhz. So i could easily tune the fres from the primary with a kind of sweep function. And since the IC has 8 processors inside, i can use a second one for Sensing when its in tune...

Mhh i cant wait until i get my scope what i ordered...

Since i want to make a drive what can go on different coils.

But thanks for the info that helped me a lot further

As soon i have the new PCB layout i will post it
And i will try to make the traces bigger so more power levels can be used.

Best regards Anubisbot

101111

Mon Sept 01 2008, 07:38PM

Registered Member #575 Joined: Sun Mar 11 2007, 04:00AM
Location: Norway
Posts: 263

If you check Uzz0rs page he also got a very nice Fres finder.

Firefox

Tue Sept 02 2008, 12:14AM

Registered Member #1389 Joined: Thu Mar 13 2008, 12:50AM
Location: Pittsburgh, PA
Posts: 346

For Reaching's coil, you should use a 4MHz secondary. You may ask why, as it is easier (by a long shot) to tune a circuit to a coil rather than the other way around. However, this is not the case with Reaching's class E, as he told me himself in his thread. The entire circuit is designed around running at 4 MHz, and therefore works the best at that frequency.

Anubisbot-HV

Tue Sept 02 2008, 03:27PM

Registered Member #1664 Joined: Fri Aug 29 2008, 02:05PM
Location:
Posts: 5

Hi, thanx for the info, i just stardet the layout of my PCB for the schematic from Reaching's
. I just have some questions regarding values from res and caps for surcing from digikey, to make a part list..

c10 c11 what kind of cap is there to use? Digikey number if possible,
All the Res what watt rating should they be?

Best regards Anubisbot

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