Simplistic MosFET HV Shunt Regs

[merlin el mago]

Connected this morning with 10K dummy load for 280V 28mA, Vout max 3.7V R2 100R burned.

 

[Salas]

Don't know if the Jung mod you tried has anything to do with that, but look if there's anything wrong elsewhere in the circuit parts too.

 

[merlin el mago]

ok

 

[merlin el mago]

Both DN2540 burned, the rest of semis are ok.

 

[vgeorge]

Check the zeners also.

 

[merlin el mago]

I didn't used zeners, used the holes for Jung mod.

 

[merlin el mago]

Any idea how to fix the issue?

 

[Salas]

Its the safe troubleshooting procedure you know and followed before. We have a link of such a recent practical example in post#1. Maybe find a way to include the Zeners this time and/or make a matrix board of the full circuit including the Jung mod to have ease of construction and test/repair.

 

[merlin el mago]

Is a good idea I will make a matrix board with only the CCS Jung mod using the zeners.

 

[Joshua_G]

Is a good idea I will make a matrix board with only the CCS Jung mod using the zeners.

Indeed a good idea. Test it on low voltage first.

 

[merlin el mago]

Glad to see you here Joshua.

 

[merlin el mago]

Zeners placed like attached schematic?

 

[Joshua_G]

Zeners placed like attached schematic?

No, the lower zener is turned around.

 

[merlin el mago]

Now?

 

[Joshua_G]

Now?

Now it's correct.

 

[merlin el mago]

Thanks Joshua, how's going your Calvin buffer?

 

[Joshua_G]

Thanks Joshua, how's going your Calvin buffer?

Welcome, Felipe.
I'm waiting for some parts ordered via eBay from China (a long wait) before making my order with Mouser. It will take few weeks.

 

[AndrewT]

re-check your dummy load voltage and current.
1.070V across 6r8 is NOT 30mA.

 

[merlin el mago]

Thanks Andrew, Salas told me, the posted schematic is referenced only for zener diodes.

 

[merlin el mago]

Attached pics: schematics with measurements & populate pcb used big heatsinks tall 5 cm, gate resistors 2W and most important: used 12V 0.5W zeners to protect the DN2540.

I left powered 1/2 hour if nothing happens could I try o add the rest of SSHV2?