• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Jan's HV regulator

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#61
Hi Jan,

R11 is 690k, raw input is now 450 volt. I want to use the regulator for a fixed voltage for driver stages. Total current will be between 50 and 100 mA.

So far I built only one channel, so current is only 25 to 50 mA now.

What is the use of the little pushbutton? Reset after overload or shortage?

Regards, Gerrit
 
#62
I thought about where to post, but decided that technical things should not appear in a GB thread.
So here you are.

Jan is using the IXTP08N100 in his latest version.
I got a few and curve traced them.
They do not quite look like what the datasheet tells you though.

Vgs at 100mA is about -1.7V, and Yfs ~220mS.


Patrick

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#64
gerrittube said:
Hi Jan,

R11 is 690k, raw input is now 450 volt. I want to use the regulator for a fixed voltage for driver stages. Total current will be between 50 and 100 mA.

So far I built only one channel, so current is only 25 to 50 mA now.

What is the use of the little pushbutton? Reset after overload or shortage?

Regards, Gerrit
Click to expand...

Yes the push-button is to reset after over-current shut-off. The supply can also be reset by momentarily removing the load but the push-button is faster without having to disconnect all kinds of wires. Be careful though, don't touch high voltage points. I activate the button with the insulated end of a trim screwdriver ('trim-sleutel' in Dutch ;-).

Jan
 
#66
Hi Jan:

I do have a “trimsleutel” around, no problem. So far the regulator works fine, but heavier loads will be used soon (up to 72 mA @ 400 VDC out, 430-450 VDC in).

What do you think of Patricks device: IXFP3N120. When would it be needed? What’s the bonus you get using it?

Regards, Gerrit
 
#68
jan.didden said:
Yes the push-button is to reset after over-current shut-off. The supply can also be reset by momentarily removing the load but the push-button is faster without having to disconnect all kinds of wires. Be careful though, don't touch high voltage points. I activate the button with the insulated end of a trim screwdriver ('trim-sleutel' in Dutch ;-).
Jan
Click to expand...
As long as you are pushing the button I think the over-current protection is disabled.Before pushing be shure the cause is removed.
Mona
 
#75
Hi Jan,

The regulator is feeding 4 tubes and before they start conducting the raw voltage is around 600 VDC. When conducting, the serial resistors between the raw supply and the regulator lower the input voltage to the regulator.

Regards, Gerrit
 
#76
I am sure Jan will tell you that the basic circuit can cope with 600V Vin.
There are many N channel MOSFETs available that is rated higher than 600V.
If you intend to use the T-Reg anyhow, is it not just a matter of buying a few different types and try them out yourself ?

I have no idea when I shall build.
Most unlikely in the next 3 months.
And beyond 600V output, I have to do quite a few things differently.
Which are irrelevant to you.


Cheers,
Patrick
 
#77
It depends on the current limit you need. You can find higher voltage pass devices, if your max current and short circuit protection is, say, 200mA.
The device given is for 600V 400mA.

The thing to look for in the data sheet is the SOA (Safe Operating Area) DC rating.

Also, the capacitors on the PCB should be dimensioned for the higher voltage (I think most are at 630V).

Jan
 
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