Dong-Zo Kim

A 3.0-W wireless power receiver circuit with 75-% overall efficiency

Resonant magnetic coupling is utilized to transfer 3.0-W power without wire. The received AC power is rectified by an active rectifier and then converted to the desired DC level by a switching DC-DC converter. The reverse leakage of the active rectifier is prevented by a delay locked loop (DLL) based delay compensation circuit. The overall power efficiency of the wireless power receiver implemented in a 0.35-μm BCDMOS technology is 75-% when the resonant frequency of the magnetic resonator is 3.23-MHz.

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

Summary A wireless power charger integrated circuit has been developed for wearable medical devices in a 0.18-µm 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-mm2 silicon area and shows 31.7% power efficiency when the charging current is 26.6 mA. Copyright

Magnetic resonance wireless power transfer system for practical mid-range distance powering scenario references

Practical magnetic resonance wireless power transfer (WPT) system is presented. High-efficient power amplifier (PA) and adaptive tracking modules are combined with optimized wireless power links to propose mid-range wireless powering application scenarios in home-environments.

Wireless powering management by analog circuitry based in-band signaling controller

Efficient wireless charging control scheme for powering a single device unit is presented. The proposed scheme uses in-band communication and analog circuits to control the clock signal lengths. Since it can generate the control data packets without MCU, it is easy to implement a one-chip of the RX parts. We have verified the performance of the in-band communication for the WPT system while a mobile device is in charging.