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Smart Watch/Fitness GPS
While our smartphones generally offer maps and GPS tracking options, sometimes a dedicated GPS tracker is the better option -- especially for hikers and others in remote areas, accurate location data is crucial. Whether it‘s a handheld device or a wearable device, these devices are increasingly integrated with a variety of functions -- including navigation, routing, real-time route tracking, and topographic maps
Functional block diagram
Product
Load switch: MOSFET, VDSS 12-20v
Battery MOSFET: VDSS 12-20v, p-channel
Boost MOSFET: VDSS 12-20v, N channel
TVS (ESD) : antenna protection/mobile applications
Diode (Schottky rectifier) : VR: 20-40V IF > 200ma
Control MOSFET: low current load switch 12-20V, n-channel

Design Considerations
There is a balance to be struck between ultra-long battery life and always-on functionality-energy efficiency is very important
Low power consumption is essential for these small wearable devices
Requires very small package or wafer-level chip occupation area
“For more energy-efficient wired charging, you can use two back-to-back mosfets instead of built-in Schottky diode.”