PCB for currents upto 8A

[FootTea]

Hello!

I'm currently would like to make this circuit. I'm going to modify a little bit the transformer by adding a voltage doubler and using the 90mA version of it so it can output upto 1500W. This will create currents in the MOSFET around 8A. That's huge.

How is it implemented on a board?

 

[c_mitra]

8A mosfet current is not HUGE. But you need to check all the component values grounds up; particularly the lines indicated thick- these tracks should be wide (for high power). If you are particularly concerned, use two parallel tracks joined at the end.

What is the real question? What you mean by

How is it implemented on a board?

 

[n4alpaca]

Understand that working with this stuff is dangerous and without proper safety procedures and equipment you are at risk of being electrocuted. Insulate yourself from your circuit when working on it and make sure the circuit is totally discharged before touching anything.

That being said, what is the goal? Why would you need to build such a power supply when you could buy a neon power supply or a similar such thing without the safety hazard.

If you are going to insist on building this, make sure the wires or traces can handle the max current x2 and that all of the components are rated x2 or x3 the power that they will see at any point during normal operation.

I don't think modifying this is a great Idea. If you insist on doing so maybe use a dc-dc multiplier after the physical transformer.
I'm not a professional, all these are just my opinions.

 

[marce]

Spacing's for high voltages... creepage and clearance

 

[FootTea]

8A mosfet current is not HUGE.

Yeah, I realized it after I have posted it already. I'm referring to wire size here though.

But you need to check all the component values grounds up; particularly the lines indicated thick- these tracks should be wide (for high power).

I have only done etching on thin traces. I have typical house wiring using solid wire. When I was imagining it, I would be using a way thicker trace to compensate the cross-sectional area. I asked how it is implemented on a board because it's kinda weird since thick traces will be new to me.

- - - Updated - - -

Spacing's for high voltages... creepage and clearance

Yes, will definitely deal with that one. Thanks!

- - - Updated - - -

Understand that working with this stuff is dangerous and without proper safety procedures and equipment you are at risk of being electrocuted. Insulate yourself from your circuit when working on it and make sure the circuit is totally discharged before touching anything.

Aye aye! Safety first!

That being said, what is the goal? Why would you need to build such a power supply when you could buy a neon power supply or a similar such thing without the safety hazard.

This will power an electron beam. Our parameters would be 35kV at 30mA. I saw neon supplies but it's just around 20kV at 30mA.

If you are going to insist on building this, make sure the wires or traces can handle the max current x2 and that all of the components are rated x2 or x3 the power that they will see at any point during normal operation.

Definitely will add some safety factor.

If you insist on doing so maybe use a dc-dc multiplier after the physical transformer.

I think the output should still be rectified, filtered and multiplied.

 

[c_mitra]

This will power an electron beam. Our parameters would be 35kV at 30mA. I saw neon supplies but it's just around 20kV at 30mA.

35kV at 30mA is just around 100W; why you want 1500W?

Anyway, 8A current will need wide traces; using standard PCB, you will need to use 5mm wide traces. If you are using double sides board, use multiple vias to connect both sides (if you need to switch sides). You need to consider sufficient spacing between power traces.

 

[FootTea]

35kV at 30mA is just around 100W; why you want 1500W?

35kV at 30mA = 1050W

Anyway, 8A current will need wide traces; using standard PCB, you will need to use 5mm wide traces. If you are using double sides board, use multiple vias to connect both sides (if you need to switch sides). You need to consider sufficient spacing between power traces.

Gotcha. Thanks.

 

[c_mitra]

35kV at 30mA = 1050W .

Sorry! I goofed!!

 

[marce]

Er you are entering a dangerous world here. I have done electron-microscope power supplies, with that voltage you need special connectors and your harware needs to be enclosed in a metal box, in a plastic enclosure with 20mm clearance between the metal and the plastic...
Your trace with for 8A will depend on the PCB copper thickness, get Saturn PCB toolkit, you also have to factor in temp rise of the trace and ambient operating temperature, so we can't give a figure without these parameters.

 

[FootTea]

Er you are entering a dangerous world here.

I will be cautious on this.

I have done electron-microscope power supplies, with that voltage you need special connectors and your harware needs to be enclosed in a metal box, in a plastic enclosure with 20mm clearance between the metal and the plastic.

Cool! What's the output of your power supply? I haven't done things in this voltage/power level but I do know how this changes things up. Thank you so much for the advise. I will definitely check out Saturn PCB Toolkit.

 

[c_mitra]

If you are planning to use a voltage doubler, the output of the transformer should be around 17kV at 60mA; this should not come out on the PCB pins of the transformer but should go directly to the voltage multiplier. But you need great care in winding the transformer and insulation between the windings...

 

[FootTea]

If you are planning to use a voltage doubler, the output of the transformer should be around 17kV at 60mA.

Got it!

this should not come out on the PCB pins of the transformer but should go directly to the voltage multiplier.

Just like what I have in mind.

But you need great care in winding the transformer and insulation between the windings...

Nice! I'm aware of the arcing due to high voltage. Transformer is wound up already. Here is the link of the transfomer.

 

[Relayer]

Hello FootTea,

Our parameters would be 35kV at 30mA.

As been stated already, you are playing with a very dangerous project.
Not even a large screen CRT TV uses 35kV at the ultor cap.
Have you seen the arching that can occur with an ultor cap set loose on any exposed
circuitry or metal heatsinks and shielding while the unit is switched on?
However you make your high voltage circuit, DO NOT turn it on without placing
any circuitry involved with the HV into a plastic case and then buying some potting
glue to totally seal it. Also make sure the circuit has been assembled correctly
first go, otherwise you'll pot it and find it won't work.
Remember: 35kV at 30mA ha been known to kill or cause heart arrhythmia and burns.
Let alone hurting your pride.
Take care my friend, DON'T take any risks and don't lose your concentration...
Regards,
Relayer

 

[c_mitra]

...I'm aware of the arcing due to high voltage. Transformer is wound up already. Here is the link of the transfomer.

This does not need a voltage doubler (or does it? It says 40kV pk to pk); the output is single ended with a common ground and you need to be careful whether you need +ve or -ve output at the high voltage end...

You should not use it without a load (the voltage may rise unexpectedly and cause arching within the transformer secondary)- some load of 1-2mA should be ok.