Meaning
Minimum achievable power consumption level for a system in its deepest low power mode. Measurement of the sleep current floor is the primary way to estimate the maximum possible standby time of a battery powered sensor.
Static Consumption
Base leakage through the silicon and the internal pull up resistors defines the lower limit of energy use. A low sleep current floor requires the disabling of all non essential internal clocks and voltage regulators. This state is maintained until an external interrupt or a timer wakes the processor.
Peripheral Shutdown
Power gates and isolation switches disconnect the supply from sensors and radios when they are not in use. Optimizing the sleep current floor involves identifying every component that remains active during the idle period. Small improvements at this level can add months to the life of a coin cell battery.
Energy Budget
Calculations for the total power consumption include the time spent in active mode and the time spent at the floor. If the sleep current floor is higher than expected the device will fail to meet its advertised battery life. Verification in a shielded chamber prevents electromagnetic noise from skewing the sensitive current measurements.
Technicians use specialized micro ammeters capable of resolving nanoampere changes to confirm the accuracy of the power profile.
