DM42: The internal view (hardware components)

[jebem]

Estimate for battery current consumption:

Since SwissMicros is omitting the average current consumption on the DM42, here is a rough estimate for worst case scenarios:

- 11.4uA in power Off mode on average.
- 5.25mA in Power On state and running a non stop program
(Note that the power on state value will be higher when writing to the Flash ROM).

Can anyone with a current meter, an external 3VDC battery and a couple of wires take measurements for the benefit of all?


How did I get the above estimates:

Power On sate worst case scenario (running a non stopping program):
Avg: 45uA + 2400uA + 2800uA = 5.25mA
Max: 70uA + 2400uA + 4500uA = 6.97mA

Details:
LS027B7DH01: 1Hz refresh rate
35uA avg to 70uA max at 5V
3 to 5V step-up converter efficiency of 70% (guess value): 45uA to 91uA

STM32L476VGT6: on low power run mode:
100 μA/MHz x 24MHz = 2400uA

MX25R6435F: 100% reading mode only
2800uA avg to 4500uA max.


Power Off sate worst case scenario:
Avg. 10uA + 1.4uA = 11.4uA
Max. 25uA + 1.4uA = 26.4uA

Details:
LS027B7DH01: 1Hz refresh rate
10uA avg to 25uA

STM32L476VGT6: Stop 2 mode, with RTC:
1.4 μA

The larger consumer when in power off state would be the LCD display.