[Milsurplus] MOSFET High Voltage Regulator Circuit

[Al Klase]

Mark,

Basically, what you want is a "source follower" with the gate connected 
to a 200-volt shunt regulator made up of your two Zeners to ground, and 
an appropriate series resistor to +600.  Keep in mind that about 8 watts 
(400 V x 0.02 A) is going to turn into heat somewhere.  Personally, I'd 
do an "emitter follower" with a TV horizontal-output transistor.  Then 
the output voltage is predictable as one diode drop (base-emitter = 0.6 
volts) below the Zener voltage.

Al

Mack wrote:
> Merry Christmas!
>
> I've almost completed my ARC-5 transmitter/receiver project but I have a small amount of chirp when keying. I've confirmed it's the 200V I'm feeding  to the oscillator plate not being stable. I can eliminate the chirp by using my regulated bench HV supply.
>
> Please help with with a link or send me a schematic for a MOSFET HV regulator that would work at 200V. I've looked about eight hours on Google and nothing fruitful has developed. I'm looking for a simple circuit with few parts. For example, could I just take a HV Power MOSFET and bias the gate with two 100 volt zener diodes in series? The trouble is I don't have a lot of experience designing with MOSFETS and I'm really out of my league. I even tried SPICE but after two hours made only a little progress with this complex program.
>
> The T-22 oscillator plate is 200V at 20 ma and it is only applied when the code key is pressed and a relay is closed. The input to the regulator circuit is the B+ for the plates of the 1625's at 550-600 VDC. Therefore I need to drop from 600 VDC to 200 VDC at 20 ma and have reasonable regulation. 
>
> I know a much simpler and perhaps more authentic solution would be to have two OC3's in series with an appropriate dropping resistor. However, I may at some point want to have a circuit for higher regulated voltages. I would also like to minimize the use of high wattage resistors in the power supply with the resultant heat.
>
> Thanks as always for everyone's help. I'm really stuck on this one. BTW, I restuffed all the bathtub caps in the transmitter and receiver and you can barely notice they're not the originals. I'll post pictures of everything once I'm finished. 
>
> 73,
>
> Mack de WB4MAK
> www.nfarl.org
> www.sedxc.org
> ______________________________________________________________
> Milsurplus mailing list
> Home: http://mailman.qth.net/mailman/listinfo/milsurplus
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Milsurplus at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>   

-- 
Al Klase - N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net/