ESL High Voltage supply

[geraldfryjr]

Cool, I want to try build one of those soon, Looking at about 500V to 2.5Kv at, at least 100ma to 500ma for my current design projects.
Maybe I can get them to send me some samples !!

In fact I just got a bunch of these for such projects,

512uH Coil

and some other smaller core that I see that they are sold out of now.

jer

 

[lcsaszar]

I did 5x 18M (90MΩ) on the output so a 10MΩ DVM to ground would form a 10:1 voltage divider. If you read 315VDC on the meter, it means 3150 VDC on the output.

Not quite true. It holds only if the internal resistance of the multiplier cascade is negligible. The internal resistance depends on the frequency, capacitor value, and the number of stages. Since the frequency is high, the internal resistance must not be too high, but I'd use a different method to verify it.

 

[stokessd]

Hi Guys, hope this is the right place to ask.
Need help to find a suitable transformer.
I tried my luck with this design :
http://www.quadesl.com/speaker/diyesl/hv_supply.pdf
Now I need some transformer like that 1.1 VA 6.3 V Microtran by Tamura any way one that can be directly driven by the IC555 in 15 kHz.
I am not sure what transformer specs will do the job and cannot find specs transformer specs with 15kHz.

That was a quick and sleazy design I did years ago. It did work quite well though. There is nothing sacred about the 15KHz. I used a function generator to find the resonant frequency of the transformer, and then I set the RC time constant of the 555 timer to match that. It's a sleazy way to get more output from the transformer.

If I were designing a new HV supply, I'd probably do a flyback transformer and drive chip.

Sheldon

 

[Edmund]

I tried a couple of things and the IC555 doesn’t deliver anything near 200mA, going up in frequency makes it worse. Connecting a 50Hz transformer and using higher frequencies result in near zero Volts output.
Which confirms what I have read about using transformers outside their frequency specs.
So I prefer something like the transformer you have used here :
ESL High Voltage supply
Model : PM61300-3
Of course searching for it gives : “Obsolete” for that model
I don’t know what winding ratio I must have since that doesn’t represent the actual voltage ratio in higher frequencies.
I never knew about the different IC555 types, checked it and you are right
“we” need the Bipolar type here, I will try that.
For now, I first need something like that PM61300-3 transformer.
Thank you for your help

 

[Edmund]

You have seen this: LT3751 Datasheet and Product Info | Analog Devices

They also offer a development board for $125.

Thanks for now I stick to my attempt.

 

[Edmund]

That was a quick and sleazy design I did years ago. It did work quite well though. There is nothing sacred about the 15KHz. I used a function generator to find the resonant frequency of the transformer, and then I set the RC time constant of the 555 timer to match that. It's a sleazy way to get more output from the transformer.

If I were designing a new HV supply, I'd probably do a flyback transformer and drive chip.

Sheldon

Interesting, unfortunately electronics is not my profession and don’t have a function generator ‘yet’.
How does that work how do you find the resonant frequency of a transformer?
I just recently found the name “ flyback transformer” and still don’t understand how that is suppose to work.
Why has this thing :
https://www.coilcraft.com/getmedia/eb987d97-6bee-4e60-8a64-a66d4e6e447b/ga3459.pdf
4 primaries and how do I get around 500 Volts out of it?

Another type are these :
https://www.coilcraft.com/getmedia/6651db01-d153-47d9-8a27-4758c28bff0d/fl.pdf

At least the turns ratio makes sense here but then there is a feedback winding. No idea what to do with that.
Help is appreciated.