I'm prototyping an ultra low power wireless sensor. To consume less I run an Arduino Mini Pro at 1.8V at 8MHz with sleep 99% of time.
The power comes from a LIR2032 coin cell and the 1.8V is generated from a LDO regulator HT7318. I use the regulator because my NRF24L01 will not support such as 4V voltage and cause an atmega328p consumes less with a lower voltage.
I want the consumption to be as low as possible (nA/pA if possible.)
But to preserve battery life I have to know when voltage goes down.
I'm interested in the Nick scheme:
But I have some problems:
- A direct battery measurement is fully stable but drain battery.
- With Nick scheme it doesn't drain battery but I would like to reduce the measurement time needed because of the capacitor C14. (I added a capacitor to the Arduino output to cut off the measurement a short time after switching)
- If I remove the capacitor from Nick scheme, the measurement is absolutely not stable, but I don't understand why.
I read there are some all integrated solutions like LTC4150, are they better or worse considering ultra-low consumption?
Other links I found: