Hi all- posting because trying to figure out how the (Boron) PMIC works (or doesn’t) during ultra-low-power state (ULP) w/ respect to charging an attached (LiPo) battery?
I have setups w/ Boron CAT-M1 EtherSIM (BRN402/404, not BRN404x) running deviceOS 4.0.0 and powered solely by 3.7V LiPo battery- each device turns on, calls home once a day at a set time, then goes into ULP mode after 10min*, can get ~200+ boot-ups/connections per charge on a 2500mAh battery.
*given recent cellular service minimum connection intervals 11/2022
Using a typical wallplug / portable microUSB charger (1A / 2.1A / etc.) connected to the Boron microUSB connector, I’m noticing that there is no (or ? minimal) re-charging of the 3.7 LiPo battery (attached via LiPo JST connector) while the Boron is in ULP sleep mode. Since the overall setup is configured to minimize time in a fully-powered/“on” state (and w/o the option for continuous wall power), I’ve circumvented this by intermittently placing the devices manually (using reset/mode buttons) in device firmware upgrade (DFU) mode and charging only while in that state (i.e., setup is offline/charging) for several hours.
Is this how Boron power management should be working (i.e., LiPo battery charging and/or PMIC is disabled/off in ULP mode?), and if so, is there a way to circumvent the inability to charge?
Appreciate any input!