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From: firstname.lastname@example.org ()
Subject: Re: low loss transformer availability?
User-Agent: slrn/0.9.6.3 (Linux)
Date: 04 Jan 2003 20:02:57 GMT
In article ,
Smile, it can only get WORSE wrote:
>I need help with a transformer design, or perhaps just a nudge in the
>My transformer needs to be small (physically), and have extremely low
Standby losses for just about any transformer will be by definition 100%.
I'm guessing from your other comments that your aim for standby losses
might be in the milliwatt range - hard to do.
Maybe you should be thinking about a switched-capacitor inverter or
> It will operate around 3 mhz in a linear AC power
Millihertz? Really? Megahertz might make more sense but then we'd be
doing RF design, not power supply design... (Maybe that's really what
>supply (not switching mode). It's output capability will vary between
>1 microamp and 150 microamps and it only needs to supply 50 milliwatts
>of power. It should be capable of a 10 to one primary/secondary
>voltage ratio (12 volts in and 120 volts out).
This is not too far out of range for a capacitor-based voltage multiplier;
they're very good at low currents. Something like the one at the top of
Don Klipstein's page at
but you don't need the stepup transformer beforehand.
>PS: Please don't send me any switching power supply design messages.
>My input is AC, my output has to be AC and I can't use switching mode
Unfortunately all the voltage multipliers that I know of make DC (and
not even pulsating-very-much DC).
120 VAC out could be done with an oscillator on the output... some oldish
(1960's) TI transistor handbooks have examples IIRC. It's not clear to
me whether you are building a power supply or a matching transformer (does
the AC out have to have the same frequency as the AC in?)
What kinds of transformers have you been looking at, just power transformers?
Audio matching transformers often have 10:1 turns ratios and just might
be able to approach standby losses in the 10's of mW's.
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