AoE x-Chapters, 1.5kV 1us precision ramp

[Winfield Hill]

Here's an interesting circuit problem, make
a precision 1.5kV 1500V/us ramp, good to 1%.

https://www.dropbox.com/s/yo6njt3rzfe85mu/3x.20_Precision-1.5kV-1us-Ramp_WH.pdf?dl=1

It features a HV MOSFET current source with
a feedback circuit to maintain a constant
output slew rate. Related to the thread,
"op-amp-controlled MOSFET cucrrent-source",
the circuit uses a BUF634 gate driver, but
without any "R2 C2" loop feedback elements.



--
Thanks,
- Win

 

[John Miles, KE5FX]

On Wednesday, July 31, 2019 at 6:00:40 PM UTC-7, Winfield Hill wrote:

Here's an interesting circuit problem, make
a precision 1.5kV 1500V/us ramp, good to 1%.

https://www.dropbox.com/s/yo6njt3rzfe85mu/3x.20_Precision-1.5kV-1us-Ramp_WH.pdf?dl=1

Neat footnote about the 5D21. As might be expected, the Japanese have
beaten them into plowshares for the golden-ear crowd:
( https://www.youtube.com/watch?v=re_ITPnM2TU ).

-- john, KE5FX

 

[Winfield Hill]

John Miles, KE5FX wrote...

On Wednesday, July 31, 2019, Winfield Hill wrote:
Here's an interesting circuit problem, make
a precision 1.5kV 1500V/us ramp, good to 1%.

https://www.dropbox.com/s/yo6njt3rzfe85mu/3x.20_Precision-1.5kV-1us-Ramp_WH.pdf?dl=1

Neat footnote about the 5D21. As might be expected,
the Japanese have beaten them into plowshares for
the golden-ear crowd:
( https://www.youtube.com/watch?v=re_ITPnM2TU ).

At first glance its amazing they'd use a 20kV 15A
tube for a hi-fi amp, but then the 15A part of the
spec perhaps reveals the reason. I purchased some
5D21 on eBay, and was preparing to use them in the
10kV ramp, but then noticed the 26V 2A = 52 watts
filament requirement, and shifted my thinking to a
set of ten cascode HV MOSFETs. Haha, I noticed in
the video they had a separate heater-supply box in
the shelf below the two amplifiers.


--
Thanks,
- Win