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From: Bill Sloman <bill.sloman@ieee.org>
Newsgroups: sci.electronics.design
Subject: Re: LTSpice model for a SiC MOSFET
Date: Wed, 21 May 2025 03:25:11 +1000
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On 21/05/2025 12:04 am, john larkin wrote:
> On Mon, 19 May 2025 09:33:28 -0400, legg <legg@nospam.magma.ca> wrote:
>>>
>>> The drain swing is actually 1.67 times the supply voltage, but it does
>>> need two switching devices and a specially wound transformer (and we
>>> know how reluctant you are to design them or get them made).
>>>
>>> It is probably going to be too expensive for the application, and we'd
>>> be grateful for your insights into a cheaper alternative. I can't think
>>> of one.
>>
>> I'd keep it simple and repurpose a backwards commodity CCFL ($0.50)
>> transformer, in a low frequency (20-50KHz) buck regulator 'of sorts'.
> 
> A ccfl transformer is ideal for the HV step-down application, and dirt
> cheap is a side benefit.
> 
> They often have several windings, which helps build oscillators. More
> details might involve using a search engine.

It's not the sort of component that a search engine will find for you.

A manufacturer and a part number would be helpful.

<snip>

> I'd expect that the transformer and one transistor and a few passives would
> make a basic step-down converter without low-side logic to power up.
> Parts cost could get below $3 for a regulated 1K to 3.3 supply, $2 in
> quantity.

So post an LTSpice simulation - an .asc file rather than some screen 
shot. That way we can run the simulation for long enough to see that it 
really does settle down, rather than just looking okay at some point 
during start-up.

-- 
Bill Sloman, Sydney