I just read the thread from start, and you’ve added a lot of useful info.
But if the goal is a B-Series (Boron SoM), then we are all guessing on the current demands.
Maybe a B-Series Engineering Sample could start floating around for 3’rd party testing (hint hint)
I believe it was previously mentioned that the B-Series can be powered via the 3V3 pin. I don’t remember if the intention was to require an external 3.3V source or not. This might change your power strategy, and maybe your sketch in Post #1. I wonder what the Vin(max) is for the B-Series. A SAFT O.C. voltage “might” be low enough to direct drive @ 3.60V, but probably not.
I still love the idea of an ATTiny for the exact purpose of this thread.
I started working out the Sleep code for a Tiny84 a while back, but never finished.
All Gen3 devices would benefit, since all have EN Pin.
We wouldn’t be limited to the 2-hour max sleep time for the TPL5111.
And the EN Pin will normally be the most efficient way to operate low-powered, low duty cycle, battery applications.
It looks like you are responding to an RFP.
If Particle could provide the Sleep Currents for the B-Series, then you can quickly estimate your Power Budget and nail down your req’d battery capacity.
If not, then your ATTiny (or similar) might be the only choice to meet the RFP spec’s. I’d be shocked if this doesn’t already exist (just not shared publicly).