3.3 System-On State

In the System-On state, the switching regulator is enabled while the system monitors the output voltage, battery voltage, battery temperature and communications port.
  1. If a turn-off request is received from the communications port, the switching regulator is disabled and the state machine will switch to the Idle state.
  2. If the output is not greater than 4.8V after 2 seconds after the start-up, the switching regulator is disabled and the state machine will switch to the Error state.
  3. If the battery temperature is below 0°C or greater than 30°C, the switching regulator is disabled and the state machine will switch to the Error state.
  4. If the battery voltage drops below 6.4V, the switching regulator is disabled and the state machine will switch to the Error state.
  5. If the battery current is greater than 1A, the switching regulator is disabled and the state machine will switch to the Error state.
  6. If a status request is received from the communications port, then the status will be returned.

The System-On state also uses accumulated periodic readings of the discharge current to estimate the total charge remaining in the battery. However, while the charge current is reasonably constant, the discharge current can fluctuate more, requiring the system to poll more frequently to generate an accurate reading of the discharge. As a result, the other parameters are polled less frequently.