I am trying to perform some energy measurements using smartphone. And to make sure that I am performing my calculations correctly, I been trying to find any examples of typical power circuit in today's smartphones (schematic, block diagrams....).
In particular what I am concerned about, is how to calculate energy consumption of smartphones when USB is connected to the device (thus it is charging). In this case, I am not just seeing current drawn from smartphone alone but also from USB... and probably the current that is drawn now from smartphone's battery is less than what it would be without USB connected to the device. Another problem is that battery and USB provides different voltage levels (~3.8-4.1V from battery and 5V from USB).
So, if I do have USB connected (in particular for ease of performing measurements)... How can I calculate or at least approximate true consumption of energy by smartphone (when battery is used alone)? Summing up currents drawn from battery and USB probably will not be correct. That's why I am trying to find some example of power circuits that maybe can lead me to the right direction.