"My" 'GSR' hysteretic buck converter worked quite happily over say12V
to 200Vin and 12V out.

Ask further if no COTS parts offered.

I have an App note somewhere for two stage and 1 stage wide range bucks,

__________________________

The GSR is very well behaved at changeover from Vin =3D undervoltage to
Vin > Varget.

 For Vin <=3D say 12.6V, Vout =3D Vin -0.6 - wiring losses.
For Vin > 12.6V the converter runs.
Vout is essentially constant across that range.

For a 200:12V output range the top end efficiency was poor - only 50%
but this increased as voltage came own.
Even 50% efficient is highly worthwhile at high Vin.
eg imagine 12V, 1A out, 200V in
Losses =3D50% =3D 12 Watt.
BUT a linear regulator is 12/200 ~=3D 6% efficient and dissipates 188
Watt - if you let it !!! :-).





     Russell
--=20
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