In the context of an academic project, I designed a PCB which includes an MCU (EFM32), a GSM module and a GPS module. One of the main target was for the system to be low power. However, now that it is time to measure my results with a DC Power Analyser I get surprisingly high values of current consumption.
Of course, it could be an hardware design problem and I won't omit this possibility but obtaining 5+ mA while my MCU is in sleep mode (should consume just some uA), the other modules are not powered and with low quiescent current voltage regulators (all < 20 uA) makes me question my measuring methods.
Here is some possible answers I am considering to my problems
- The PCB was in debug mode (wired to a Starter Kit) while I was measuring. Does it matter? If yes, what is the proper way of doing it?
- I plugged my DC Power Analyser directly on the pins of where a Li-Ion battery is supposed to be plugged. Therefore, it is under the control of a battery charge circuitry which could bias the measurement by trying to charge the DC Power Analyser. Is it possible?
What do you guys think?