3k volts 100k~300kHz sine wave generator

Thread Starter

vhong999

Joined Apr 10, 2017
14
I will need a sine wave generator capable of creating high voltage (~3kv), low current (<10mA), easy to adjust the frequency between 100k~300kHz. I searched on the web and found mostly talking about Tesla driver, which dose not seem to be easy to change the frequency. Could someone advise me of any other way to implement such a sine wave generator, preferable a reference circuit, or any commercial product available (but can't afford expensive one due to budget constraints.)

Many thanks in advance for all your help.
 

ScottWang

Joined Aug 23, 2012
6,873
You can design or buy a 100~300Khz sinewave generator with 5V output voltage level and design a 3KV amplifier with 100~300Khz frequency response, this will be a business project.
 

Thread Starter

vhong999

Joined Apr 10, 2017
14
Thanks Scott. Since it is new for me to design such a high voltage amplifier, I tried to find a reference circuit, but only amplifiers for low frequency power supply. Any hint or reference for me?

Thanks again for your help.
 

ScottWang

Joined Aug 23, 2012
6,873
What exactly is a "business project"?
What I mean is that if no any one design for him then this case will be as a business project, because this case needs more knowledge and designing skills, so he needs hire someone to design for him who has that kind of experience, if has any member could design for him then this case can be a normal project.
 

Thread Starter

vhong999

Joined Apr 10, 2017
14
Thanks Scott. I may design it myself, but a hint or reference can be helpful. It will be much appreciated if anyone who had similar experience can help.
 

MrChips

Joined Oct 2, 2009
20,190
I will need a sine wave generator capable of creating high voltage (~3kv), low current (<10mA), easy to adjust the frequency between 100k~300kHz. I searched on the web and found mostly talking about Tesla driver, which dose not seem to be easy to change the frequency. Could someone advise me of any other way to implement such a sine wave generator, preferable a reference circuit, or any commercial product available (but can't afford expensive one due to budget constraints.)

Many thanks in advance for all your help.
At 3kV, 10mA is not considered low.
What are you going to do with this generator?
 

ScottWang

Joined Aug 23, 2012
6,873
Thanks Scott. I may design it myself, but a hint or reference can be helpful. It will be much appreciated if anyone who had similar experience can help.
If you want to design the high voltage amplifier, specially for the last stage, probably you can't be easy to get the high Vds for mosfet or Vce for bjt, so you can in series with two mosfets or maybe three or more, you could google "how to in series two mosfets" to get the info you want.
 

AnalogKid

Joined Aug 1, 2013
8,299
3 kV and 10 mA works out to 30 W. A 30 W, 300 kHz amplifier is not a simple design. As Alec said, this is more like a broadband RF amplifier than a normal signal amplifier. Is the 3 kV peak, peak-to-peak, or RMS?

ak
 

Thread Starter

vhong999

Joined Apr 10, 2017
14
Thanks ak. The 3kv is RMS. So a great challenge indeed.
Thanks MrChips. This device will be used for lab experiment, not for a commercial product.
Thanks Alex_t for your reminder.
Thanks Scott. I will Google it for the info.
Hi all,
If I amplify sine wave to 100~200V by MOSFETs, then find a transformer to step up to 3kv, is this idea workable? If yes, what kind of transformer and MOSFET I may need? If 10mA is big at this high voltage, I may start with 1mA.
 

AnalogKid

Joined Aug 1, 2013
8,299
To do what? A step up transformer is an option only if whatever this is driving does not need a very low source impedance. The output impedance of a step-up transformer is by definition higher that the output impedance of the circuit driving it. What is the load?

ak
 

Thread Starter

vhong999

Joined Apr 10, 2017
14
Thanks ak. The output will be connected to 2 plates as electrodes to provide electrical fields for experiments. Per the dimension and the distance btw the plates, I estimate a few hundreds pf capacitance load there.
 

ScottWang

Joined Aug 23, 2012
6,873
If the current is only 1mA then you can design as:
5V sinewave generator amplifying to 24V or a 24V sinewave generator and using a 24V to 3Kv step up transformer.
 

MrChips

Joined Oct 2, 2009
20,190
Thanks ak. The output will be connected to 2 plates as electrodes to provide electrical fields for experiments. Per the dimension and the distance btw the plates, I estimate a few hundreds pf capacitance load there.
Then why are you calling for 10mA?
 

Thread Starter

vhong999

Joined Apr 10, 2017
14
The requirement is 1 mA but I wanted some margin before I know 10mA may make it much more difficult for the implementation. I think I should forget about the margin and stick to 1 mA for the moment.

To Scott: thanks for the good suggestion. I may proceed to try it. Just googled for a high frequency transformer, so far no clear idea for which to choose. Most of high frequency transformer work with flyback coil which in general specifies only tens of kHz. I need a transformer for 300kHz. Do you know a transformer that could be suitable for my requirements?
Thanks again for your time and help.
 

ScottWang

Joined Aug 23, 2012
6,873
Try it start from 1mA when you get sucess and try some bigger current, you could google "high frequency high voltage transformer", if you can't get the products from market and then you have to diy.
 

Thread Starter

vhong999

Joined Apr 10, 2017
14
Indeed, Scott, I would start with 1mA and try to find a transformer or diy. Many thanks for your help so far.

To MrChips: the 1mA requirement is based on 3kv/300kHz over ~200pf plate capacitance load, nearly 1mA displacement current will be drawn. This is in fact only preliminary. The experiment conditions are not finalized yet. Starting with 1mA should help me to get some experience first.
 
Last edited by a moderator:

LesJones

Joined Jan 8, 2017
2,494
200 pF at 300Khz will have a reactance of 2653 ohms.To develop 3000 volts across 2653 ohms you would need a current of 3000/2653 = 1.13 amps. Do I have the wrong understanding of your setup ?

Les.
 
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