| Title |
Design of 3-Dimensional Magnetic Resonance Coil and DC-DC Buck Converter for Uniform Wireless Power Transmission of a Smartphone |
| Authors |
김민구(Min Gu Kim) ; 김윤우(Yoon Woo Kim) ; 조건희(Kunhee Cho) ; 최준림(Jun Rim Choi) |
| DOI |
https://doi.org/10.5573/ieie.2020.57.12.25 |
| Keywords |
Wireless power transfer; Magnetic resonance; DC-DC converter; System on chip |
| Abstract |
In this paper, the resonance coil structure for magnetic resonance-type uniform wireless power transmission, and current-mode DC-DC buck converter are designed. The transmission coil is designed in a cylindrical shape with a height of 100 mm and a diameter of 100 mm, and the receiving coil is inserted inside to charge smartphones and medical devices. The receiving coils are designed in a flat spiral coil structure of . A capacitor is connected to adjust the resonant frequency of 13.56 MHz, and the transmission efficiency according to the angle and location of the receiving coil is optimized by the simulation and experiment. The peak efficiency of 77.1 % is achieved when the receiving coil is at an angle of 60° inside the transmitting coil while above the efficiency of 60 % is obtained at all locations inside the transmitting coil. To provide a stable DC voltage from the coil output, a step-down DC-DC converter is required. The current-mode DC-DC buck converter is designed in 0.18 μm CMOS process and the switching frequency is set to operate at 3 MHz. |