Wireless power charger for wearable medical devices with in-band communication

A wireless power charger integrated circuit has been developed for wearable medical devices in a 0.18-mu m Bipolar, Complementary metal-oxide-semiconductor, and Lightly-Doped Metal-Oxide-Semiconductor (BCDMOS) process. A passive full-wave rectifier consisting of Schottky diodes and cross-coupled n-type Metal-Oxide-Semiconductor (nMOS) transistors performs the alternating current to direct current power conversion without any reverse leakage current. To charge a battery, a linear charger circuit follows the passive rectifier instead of a switching charger circuit for the small form factor of wearable medical devices. An in-band communication circuit notifies the proper connection of the wireless power receiver and the battery charging status to the charging pad (wireless power transmitter) through the wireless power transmission channel. The wireless power charger integrated circuit occupies 1.44-mm(2) silicon area and shows 31.7% power efficiency when the charging current is 26.6 mA. Copyright (C) 2015 John Wiley & Sons, Ltd.