Efficiency enhanced magnetic resonance wireless power transfer system and High Voltage integrated chip power recovery scheme

Recently, several works have been proposed on wireless technology based efficient power utilization in consumer electronics and biomedical applications. Magnetically coupled resonators with high quality factor achieve constant wireless power transfer efficiency over a greater range. However, impedance variations at source & load due to change in distance between coils affects power transfer efficiency. Therefore, high power transfer efficiency can be achieved at frequency of interest, by introducing proper impedance matching algorithms. The implemented impedance matching network automatically tunes the source impedance to match load and attain higher power transfer efficiency. Experimental results obtained with the proposed scheme showed an average of 7.21% improvement in power efficiency when distance between coils are varied from 10cm to 110cm. An on-chip High Voltage power recovery scheme with an effort to reduce the power loss in the rectifier and low dropout voltage regulator is designed and fabricated. The chip was realized in Dongbu HiTek´s 0.35μm High Voltage BCD technology based on LOCOS 0.35μm CMOS process. In addition, a charging control circuit was designed for safe and reliable charging in portable battery applications. A maximum overall efficiency of 72.31 % was determined for the system.