Ken: See Zeta and lowerable Vref

On 18 April 2015 at 04:50, Dwayne Reid <dwayner@planet.eon.net> wrote:

> The TPS40200 is relatively inexpensive and is easy to work with -
> it's in a SOIC-8 package.  Layout seems to be fairly non-critical.
>
> Although I haven't yet found any existing SEPIC designs using that
> part online, it's pretty easy to adapt the standard app note for the
> chip into a SEPIC design.  All you need to do is add the coupled
> inductor and the coupling capacitors.  The voltage feedback stuff
> stays the same.
>

Russian TPS40200 / SEPIC version here.
Page translates well enough with Google translate

               http://www.scanti.ru/bulleten.php?v=3D211&p=3D34



Notice below it the Zeta converter - this topology will be new to many
people and can have some significant advantages.
Bends the brain at first if you've not seen it. Converter runs on
(Vin-Vout) :-).

______________________

Just to be "opposite' :-)

The TPS40200 is a non-synchronous voltage mode converter wity P channel
drive emphasis.
Datasheet       http://www.ti.com/lit/ds/symlink/tps40200.pdf

And ....

The TPS40210 is a synchronous current mode converter with Boost & N Channel
drive emphasis

Product page
http://www.ti.com/product/tps40210

TPS4021x data sheet
Alludes to SEPIC use but no circuits

         http://www.ti.com/lit/ds/symlink/tps40210.pdf

*TPS40210 SEPIC cct*

          http://www.mikrocontroller.net/topic/122685

____________________

Useful SEPIC discussion page here (2009)

          http://www.mikrocontroller.net/topic/122685

Presumably has been auto-translated (or they all have really interesting
English :-) ).

__________________________

TPS61170
"Nice & compact" [TM] in 2mm x 2mm QFN

             http://www.ti.com/lit/ds/symlink/tps61170.pdf


SEPIC fig 19 page 21.
1.2A switch
1.2 MHz fixed freq
3V-18V in
<=3D 38V out.

"EASYSCALE" Vref alteration!
Nominally a 1.229 V reference but can be lowered either with 1-wire comms
or just application of PWM to 'Ctrl' pin.
Vref of nominally as low as you want in PWM mode if graph fig 7 p8
believeable.

In 1 wire mode seems to have 32 steps with lowest =3D 0.0, next =3D 31 mV, =
....

That could be useful.



                         Russell
--=20
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