On 28/04/2011 12:33, Olin Lathrop wrote:
> One possibility is to use a different switcher that can take the full ran=
ge
> of 5 (or even less) to 36 volts in and produce the 5V for the circuit.

I came across this Buck-Boost chip from TI the other day whilst looking=20
for switchers, haven't looked closely but it may be suitable (various=20
other SEPIC, buck/boost on LT, AD etc worth checking too):
http://focus.ti.com/docs/prod/folders/print/tps55065-q1.html
Price is $1.55 @ qty 1k

                         TPIC74100-Q1     TPS55065-Q1
Vin(Min)(V)    1.5      1.5
Vin(Max)(V)    40      40
Preset Vout(V)    5
Vout(Min)(V)    5      5
Vout(Max)(V)    5      5
Switch Current Limit(Typ)(A)    1.5
Iq(Typ)(mA)    0.1      0.1
Iout(Max)(A)    1      0.5
Switching Frequency(Max)(kHz)    440      440
Regulated Outputs(#)    1
Topology    Buck/Boost      Buck/Boost
Operating Temperature Range(=B0C)    -40 to 125      -40 to 125
Pin/Package    20HTSSOP      20HTSSOP

--=20
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