HV power supply 0-400V - 200 mA

[Zero999]

Thanks Zero999,
this circuit is interesting for low voltages,

Then change the parts, for higher voltages. The idea was to use the tap changing part, i.e. D1, D2, Tr1 etc. to switch to the centre tap of the transformer, not the LM317 part. A 400V circuit would benefit more from such an arrangement, than a 24V one.

Here's I posted in another thread, illustrating the concept.

https://www.eevblog.com/forum/beginners/transformer-tap-switching-between-serial-and-parallel/msg3555788/#msg3555788

An example of it implemented, using the TL431 (U2), to switch a MOSFET (M2), via a BJT in common base mode (Q3).

https://www.eevblog.com/forum/projects/looking-for-yours-opinions!-hv-stabilized-power-supply/msg1365710/#msg1365710

Using a centre tapped transformer can cut the power dissipation by half.

but I need to use  up to 400 volts for my job, so now my circuit with two mosfets IRFP460 is working quite well, and you can see from the SOA of mosfet that it can work well at ambient temoperature about up to 400 mA out, with 150v across, each.
This is useful for my work.
the image show safe area and the circuit working...

Which schematic did you build?

[marvi3]

I build the one with the two mosfet...

[marvi3]

Now I'm preparing the one with two transistors and with te sziklay configuration as in lm317 style, as soon as I try i will sand my impressions...
This is the schematic used...

[marvi3]

Tried the lm317 style circuit and it works very well, good voltage regulation, good current regulation ...
I will do further load tests for comparison with the other circuit arrangement ..
below
...

[Zero999]

Tried the lm317 style circuit and it works very well, good voltage regulation, good current regulation ...
I will do further load tests for comparison with the other circuit arrangement ..
below
...

Which LM317 circuit did you build?

[marvi3]

This circuit of 317, translated into HV PSU

[Zero999]

This circuit of 317, translated into HV PSU

Sorry, I don't understand.

Do you mean the LM317 design, but with the LR8K4 and higher voltage BJTs, as per the second drawing? You'll need a lot of BJTs in parallel, to ensure the safe operating area isn't exceeded and that 350mA fuse won't do much to protect them.

[marvi3]

Yes, I mimed the design of a similar 317 circuit, but using LR8K4 chip, I know that i need a lot of BJT for 250 mA but it was an idea to design o low side CC control and using the performances of LR8K4 chip.
I tested the circuit, and it works well.
Now I would like to test an ibrid using mosfet as finals...
Adapting the power stage with mosfets..., also changing the control of 1625 with a mosfet...