Re: 1KV buck converter

On Sun, 25 May 2025 10:40:54 -0400, legg <legg@nospam.magma.ca> wrote:

On Sat, 24 May 2025 10:35:21 -0700, john larkin <jl@glen--canyon.com>
wrote:
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On Sat, 24 May 2025 12:23:52 -0400, legg <legg@nospam.magma.ca> wrote:
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On Fri, 23 May 2025 08:05:28 -0700, john larkin <jl@glen--canyon.com>
wrote:
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>
https://www.dropbox.com/scl/fi/f64mv46qk4g4nca00bgoe/1KV_Buck.jpg?rlkey=f0qnaliz7nyoowe6w4wx2gkua&raw=1

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

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

Punch some numbers.

Numbers are cheap. 2 nF charged to 1 KV stores a millijoule. Transfer
that at 10 Hz and you get the required 10 mW.

The problem is the circuit.

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Cap size - charge rate - dV.
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Turn-0ff time is only a small part of it.
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Diacs turn off when discharge current < hold current.

Really? That's amazing.

They also have significant internal impedance.

Compared to a kilovolt, their ON voltage drop won't matter.

The idea of using diacs for this application was just a speculation.
Transistors make more sense.

>
RL