Simplistic mosFET HV Shunt Regs

[Salas]

What's on TP now?

 

[Salas]

Modify it with a Salas circuit.

Maybe challenging some CC limit he set on the bench PSU or oscillating now...

 

[merlin el mago]

I adjusted to 30mA, if I remember well I measured 0.069V = 6.9mA!!!!!!!!!

Yes the bench psu is working at full voltage 30V.

 

[Salas]

Make sure all is well and voltages stay OK for long on power before trying HV.

 

[merlin el mago]

There is a way to reduce the CCS current to 30mA with load?

 

[merlin el mago]

Half hour is enough?

 

[Salas]

Half an hour is good. Make sure the one naked MOSFET does not get too hot with new VGS. The first question what is it about? Your trimmer does respond, doesn't it?

 

[merlin el mago]

The naked DN2540 isn't too hot. Yes the trimmer respond: now it's adjusted for 30mA waiting 30 minutes to see if it's something happen. The bench PSU now is solid at 24V.

 

[merlin el mago]

Nothing happened😉

 

[merlin el mago]

Salas I haven't on hand any 10uF for C2, could I use 2 caps 4.7uF in parallel?

To adjust the Vout R11 trimmer still 1K or other value?

 

[Salas]

Nothing happened😉

Alright, good luck on HV and I hope you can hear something better too but don't listen with expectation bias.

 

[Salas]

Salas I haven't on hand any 10uF for C2, could I use 2 caps 4.7uF in parallel?

Yes why not.

 

[merlin el mago]

To adjust the Vout R11 trimmer still 1K or other value?

 

[Salas]

Original guide's value. Has not to do with CCS mod.

 

[merlin el mago]

Thanks, I asked only to be sure.

 

[merlin el mago]

I don't have any IRF840, could I use some equivalent meanwhile arrives the transistors mini-kit ordered to Tea-Bag?

 

[Salas]

Tell type to see about.

 

[merlin el mago]

I got a couple in a local electronic store.

 

[merlin el mago]

Salas will be enough 30mA for ECC81 mu-follower?

 

[Salas]

(183.7-85)/33=2.99mA. 6mA for two channels. 30mA seems covering it well including some current swing and what the reg eats for itself.