Re: LTSpice model for a SiC MOSFET

john larkin <jl@glen--canyon.com> wrote:

On Thu, 22 May 2025 09:44:30 +0100, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:
 

john larkin <jl@glen--canyon.com> wrote:
>
[...]

Going from 1KV to 3.3v has interesting possibilities. The easy way is
a resistor and a zener. Efficiency about 0.3%.

>
Roughly 1W dissipation per mA , so if the current requirement isn't too
high, that is probably the most straightforward system with very little
to go wrong.
>
>

More efficient would be a resistor and a zener and then a buck
switcher. 5% maybe.

>
That's a lot of extra complication for very little improvement, the
resistor still has to carry the full load current.
>
For a cult market you could use an 807 and tap the 3.3v off the cathode
bias resistor.  (or better still, rectify the heater supply and use a
linear regulator but don't tell the customer).

 
I never liked 807's. Ugly tubes.

Ah yes.  For that market, appearance is everything. 

A much better-looking bottle would be a PY81 but, although it is
specified to withstand a peak anode voltage of 7 kV, the maunfacturers
only allow that under cutoff conditions.  It also uses a standard B9A
base, which is still easily obtainable.


--
~ Liz Tuddenham ~
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www.poppyrecords.co.uk