Prevention of unexpected shutdown

A method comprising:

• generating an estimate of power that will be drawn from a battery over an upcoming window of time;
• generating an estimate of battery capability over the upcoming window of time, based on the estimate of power;
• generating a first power budget for a subsystem powered by the battery, the first power budget based on the estimate of battery capability;
• generating a second power budget for the subsystem, the second power budget based on a closed-loop feedback path;
• determining a final power budget for the subsystem, the final power budget based on the first power budget and the second power budget, wherein determining the final respective power budget comprises determining a weighted sum of the first respective power budget and the second respective power budget;
• providing the final power budget to the subsystem;
• and
• adjusting power usage of the subsystem based on the final power budget.

A power management device comprising:

• a long-term power estimator configured to generate an estimate of power that will be drawn from a battery over an upcoming window of time;
• a long-term battery capability predictor configured to generate an estimate of capability of the battery over the upcoming window of time, based on the estimate of power and a present state of the battery;
• a long-term controller configured to generate one or more long-term power budgets for respective one or more subsystems powered by the battery, wherein the long-term power budgets are configured to prevent the one or more subsystems from exceeding the capability of the battery over the upcoming window of time;
• a closed-loop controller configured to generate one or more closed-loop power budgets for the one or more subsystems, wherein the closed-loop power budgets are based on power levels observed over a past window of time;
• and
• a budget controller configured to provide one or more output power budgets to the one or more subsystems, wherein a respective one of the output power budgets comprises a weighted sum of a respected one of the long-term budgets and a respective one of the closed-loop budgets.