Dual battery setup

Basil

Hi All,

Me yet again.

I just want to run my design for the dual-battery setup for my device past people who know what they are doing [noparse]:)[/noparse]
I have 2 designs in mind. First one is the one I think would work better.

What I need to achieve

*With 1 battery connected (for low power pyro devices, ie sub 1A maybe 2A)*
-Battery needs to charge capacitor, power regulators without brownout and provide current to 9V (pyro channels) along with the capacitor.

*With both batterys connected (for higher power pyro devices, ie up to 10A)*
-Battery needs to charge capacitor, partially power regulators and provide current to 9V (pyro channels) along with the capacitor.
-Battery 2 is soley to power the regulators. When Pyros are fired, I want no power from this battery to go to the 9V channel. This will prevent brownout.

#1 Switching_PVE -I like this one. Although the 9V channel will stay connected when the power switch is off, there is no power being drawn by the 9V channel when the MCU is off. And once the capacitor is charged there will be very little or no current drawn by it. Most people would disconnect the battery's anyway if the device is to be left off for a long period.
There is no chance of the pyros firing as the MCU controls the firing signal to the FET's.

#2 Switching_GND -Also works but Its very hard to route on the PCB (in fact I cant do it lol)

I should note, that D1 in both cases I guess would need to be a high current schoktty (spelling) in a SMB package, D2 does not need ot be I should think?

Let me know what you think [noparse]:)[/noparse]

Thanks,
Alec