suggested power supply

[roofingboom]

I am looking for sugestions of a suitable chip for a 5 and 3.3v power supply from either a 12 or 24 volt battery. problem is i must survive starter dip which is about 3 volts for 80ms and then 6 volts while the starter is cranking.
I really do not want to use a flyback in this situation. I would like to use a buck boost so i am looking for suggestions please!
thanks
the output will be 3 amps for 3.3v and the 5 volts will only use like 500mA max. i was thinking of a buck boost to 3.3v and then boosting 3.3v to 5 volts since i will not be using much current at 5 votls.
let me know what you guys think
THanks

 

[doss]

I think u can use pt6303,6302 switching regulator from texas intruments thank u,

Added after 1 minutes:

I think u can use pt6303,6302 switching regulator from texas intruments thank u,

 

[dfullmer]

Hi roofingboom,

If space and cost are not a big deal then you might want to solve the problem by making ourself a mini-UPS for the supply. You could use a small gel cell battery to supply power to your regulator for the short time it needs while the starter is running and then revert back to a charge mode once your power comes back. The regulator could then switch over to the 12-24v source.

more costly but pretty sure fire way around the problem and sometimes thats what counts.

good luck

dfullmer