Re: 1KV buck converter

On Sun, 25 May 2025 04:21:16 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:

On 25/05/2025 3:35 am, john larkin wrote:

On Sat, 24 May 2025 12:23:52 -0400, legg <legg@nospam.magma.ca> wrote:
 

On Fri, 23 May 2025 08:05:28 -0700, john larkin <jl@glen--canyon.com>
wrote:
>

>
https://www.dropbox.com/scl/fi/f64mv46qk4g4nca00bgoe/1KV_Buck.jpg?rlkey=f0qnaliz7nyoowe6w4wx2gkua&raw=1

>
The highest diac rep rate will likely be in the tens of hertz range.
(think cicada)
>
RL

 
Why? Diacs and sidacs turn on in under a microsecond. I can't imagine
them taking milliseconds to turn off.

>
Step recovery diodes do turn off a lot faster than that, but it does
take while for the stored charge to get swept out of the diode.
>
Step recovery diode are great for getting a fast edge out of relatively
slowly changing current, but the fast edge only shows up after the
stored charge has been cleared from the diode, so it's hard get it to
show up exactly when you want it.
>

Interestingly, sidacs have been used in series strings up to many
kilovolts, which suggets a kilovolt step-down converter with
diacs/sidacs as the only active components.

>
Probably not a step-down converter trying to convert 10uA from a 1kV
source into about a 3mA at 3.3V.

You are right. A diac isn't the best choice to make a 99% efficient
converter.