Electronics in today’s wearables are restricted to fit ever-shrinking PCB footprints and run for days on a small capacity battery. This is achieved by operating the wearable in a cyclic sleep scenario as shown in this timing diagram. The key is to optimize the average current drain across each power cycle by a combination of extending the sleep time, reducing the active state or ON time, and lowering the average current in each active state. Note the wake-up time contribution to the ON time.