On 17/01/2013 4:30 PM, IVP wrote:
>> I was thinking the PWM should allow Vout to be the same as Vin
>> (except for the MOSFET loss) when the PWM is at 100%
> Fig18 is a buck-boost I use
>
> http://www.intusoft.com/onsemipdfs/an920-d.pdf
>
> Very handy when the input DC can be wide-ranging. For example
> an SLA that could go from 11V+ to 14V and you need 12V out
> or being able to grab just about any wallwart (particularly if a bridge
> is added to the input to fix wrong polarity or AC)

Hmmm... after checking out that MC34063 app note, I think the PIC + PWM=20
design is the way to go.  Only one high current component (cheap MOSFET)=20
and I can also implement low voltage shut-down and other function very=20
easily in firmware.

I think the PIC method is also the safest bet for something I have to=20
build a prototype of and ship overseas in the next couple of days.  Once=20
we get client feedback (overall project needs to be approved by someone=20
else), we can go from there.
David...

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___________________________________________
David Duffy        Audio Visual Devices P/L
Unit 8, 10 Hook St, Capalaba 4157 Australia
Ph: +61 7 38235717      Fax: +61 7 38234717
Our Web Site: www.audiovisualdevices.com.au
___________________________________________

--=20
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