Wearable devices should have a long battery life. Generally, if consumers have to charge their devices every day, they will be unhappy. With many of the best smartphones now having to be charged once a day or two, end users are clearly looking forward to improvements. The entire power management should be able to provide a high-efficiency power conversion system, including: regulator efficiency, and regulators and battery chargers should provide low quiescent current, low standby current and low leakage current. Power management devices with extremely low leakage current and standby current as well as low quiescent current are more difficult to design.