Switching to backup power

[Moriambar]

Hello,
I'm bit in a pickle with this one.

i have a battery powered circuit with very low quiescent power consumption,that spends most time in this mode. Some components in this have an inbuilt "backup battery switch" that, when the main power is too low, switches them to the CR2032 battery automatically.

The problem arises with the LT2956-1 which is featured to occasionally wake up part of the circuit: the LT2956 must always be powered, in order to retain its time frequency, even when the ordinary batteries are substituted. So I need to switch the LT2956 power when the main goes out.
I actually don't know how to implement this, except than with two diodes at V+ pin of the 2956 (which I don't think is the best), connecting both power supply rails to it. Hence I came here.

Please mind that neither an RTC nor a micro can be part of the solution...

Is there any other way?

Thanks

[capt bullshot]

Either connect the LT2956 to your backup battery only - its power consumption is low enough,
or just use the diodes. Using diodes to provide backup supply is rather common and was widely used before the advent of all these fancy controllers with built-in power switch.

[Moriambar]

Either connect the LT2956 to your backup battery only - its power consumption is low enough,
or just use the diodes. Using diodes to provide backup supply is rather common and was widely used before the advent of all these fancy controllers with built-in power switch.

Ah, ok, thanks!