Simplistic mosFET HV Shunt Regs

Jump to Latest
#3,543
Salas said:
OK, we cross posted. Those numbers SSLV1.1 can do with IRF9530 at CCS position also as it has on output already. And its better spec than the the BJT special one for 1.5V-2.5V I designed for disco once. You set it at 1.5A and Bob's your uncle.
Click to expand...

Salas.......For Q101, have you changed to use IRF9530 as well?? better??

What is CCS current setting and CCS-LoadCurrent?? The filament is burning at 1.25-1.50A....will there be lots of heat at Q106??

Could I use 9V-0V-9V 3.3A transformer per channel??

Cheers,

King
 
#3,544
rickmcinnis said:
There is not useful schematic for the PCB. Plenty of schematics for the circuit, itself.

Here is a link to the manual at Broskie's site. http://tubecad.com/2008/07/13/PH-1 Phono preamp.pdf

Look on page 11.

One can easily use the resistor positions on the B+ rail for the regulators but the grounds ....

Thanks for your interest.
Click to expand...

What's the problem with the grounds? Or do you use two regulators with different B+ for each channel?
 
#3,547
rickmcinnis said:
I am building four of the regulators to power a Broskie Aikido phono board using TEA BAGS pcbs (thanks again, TB)

It is basically four of the AIKIDO circuits on one board.

I am using four since I have ECC99's in the cathode follower position and these seem to require more than average current so I figured why not use four?

It is simple to connect the positives to the individual "modules" and they are isolated but PCB surgery (not that I am afraid of this) is required to isolate the individual grounds. The question is: is it necessary?

My instinct is that it is but I thought I would ask before starting the procedure.

Help is appreciated and my apologies for not knowing the answer to this myself.

THANKS!
Click to expand...

Yes, it is necessary if you want the Kelvin sense system to work best, and its audible when it does so.
 
#3,556
Hi Salas...

I've built a second SSHV2 regulator, but for some reason, this one's not producing. I'm shooting for 350V output at 60mA across the load. For a test load, I have a 5800 ohm power resistor,
which works out to 60mA at 350V.

With both R4 (current) and R11 (voltage) wide open, the best I can get is 730mV (73mA) and 340V with 400V at the input. The bench supply is capable of about 400mA at 450V, so no problem at the supply side.

I should mention I'd like to get 80-85mA, so this should be well within spec.

Suggestions?

Thanks,
Gary
 
Last edited:
#3,557
Your test load should be 20mA less than CCS setting. Give it 370V input to see if the input Mosfets will produce 80mA. Else if they aren't particularly mighty for IDSS and VR4 at max, make the 10 Ohm TP resistor (R5) to 1 Ohm and translate mV for mA 1:1. That will detract less from top IDSS.
 
#3,559
Salas said:
If Vo is still not reaching, put a higher IDSS 2SK117.
Click to expand...

My input MOSFET, as discussed previously, is the IXTP08N50D2. It's rated at 500V and 800mA, and had no issues getting 350V at 80mA in my other board.

I'll try replacing the 2SK117 and will test one for a different Idss. What's the minimum Idss required to achieve the spec output of the regulator of 380V at 100mA? Is higher, or as high as possible, better?



Thanks again,
Gary
 
Last edited:
You must log in or register to reply here.
Top Bottom