Does anyone know, do the common 1xAA drivers that work with li-ion as well as nimh/alkaline just have a separate linear channel for lithium, or does the input range for the buck/boost also cover lithium ion voltages?
I think most are just boost + linear stage (or the step-up converter runs in pass-through mode with Li cells), AFAIK there is no buck-boost chip in existence that goes down to 1xAA voltage levels. (2xAA, yes, TPS63000/TPS63020, but pointless since 2xLiIon voltage is way over maximum input voltage.)
Well the BW-ET1 has a step-up + a step-down converter in series but it’s a humongous driver for a 1xAA that wouldn’t fit in most other lights.
- some may have a separate channel, something on the higher end like a ZL may have that, but I haven’t seen one yet.