Hi
I can't find any info regarding a cut off feature for the nPM1300 if the battery voltage is to low.
we are using a battery with PMC but that is meant as last resort. (PMC is in accurate and low Lithium polymer batt <2.9V)
I was under de impression that the nPM1300 has a low voltage cut off feature.
At what voltage level is this set and what will the nPM1300 do?
Cut the battery power of to the system and preventing the system from draining the battery?
or will it keep resetting with a delay?
Hi,
Thank you for the quick replay.
I have tested the POF feature, set it to 3V4 for testing.
when I lower the battery voltage to below 3V4 the nPM1300 resets 7/1sec. (the only connected power source is the battery)
the POF feature is not usable because the current consumption is still around 1.39mA (AVG) and this will still drain the battery to 2.9V. Also the buck converters provides a short 0.6V burst every 1 second. (voltage is to low to power the MCU but not we don't know the negative effects on the rest of the circuit)
2.9V is a on the low side, at this voltage level the Battery protection circuit on the battery will kick in and cut of the power. With the very small voltage recovery of the battery the system will start-up again and drain the battery further down. Also lithium polymer has a leakage of around 4% per month on its own so 2.9V does not give a lot of time between empty battery and charging. (without damaging the battery)
design requirements:
the product is placed in shipment mode (the most low power solution (so far I know).
movement detected by a reed switch will pulldown the SHPHLD pin starting up the nPM1300. (long press reset is disabled)
if battery is below set value, for example 3.4V, the system needs to go to ultra low power mode and stay there as long as there is no USB power (Vbus).
Problem:
The SHPHLD pin will still be pulled down multiple times a second (because of motion detecting) but the SHPHLD may not wake up the nPM1300. (that was the hope if the batt low cut off voltage is reached.)
so fare I see, this is not possible, or is there a solution/feature I have missed?
possible disabling the SHPHLD pin?
(possible solution:
MCU sets the nPM1300 in shipment mode when Vbat is 3.4V or lower, additional electronics components cut of the connection to the SHPHLD pin. Vbus voltage will trigger the nPM1300 and it will start-up, voltage above 2.4V the connection to SHPHLD is established again.)
