A Peak Current Sensing Method Combined with the Dynamic Voltage Scaling Technique for Primary Side Control in Wireless Power Transfer System

• Main Authors: Yu-ChunYing, 應佑君
• Other Authors: Tai-Haur Kuo
• Format: Others
• Language: en_US
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/56134905505529220991

碩士 === 國立成功大學 === 電機工程學系碩博士班 === 101 === A peak current sensing method combined with the dynamic voltage scaling technique for primary side control in a wireless power transfer system is proposed, which can be applied to portable 3C products and wireless charger. In recent years, the main issues for wireless power transfer systems are: detection of load transient for sufficient output power transfer and system efficiency improvement. In conventional wireless power transfer systems, an additional feedback circuit is utilized to detect the load transient, this technique results in higher cost. The variable frequency control method is proposed to change the output power when load transient, however, this technique leads to poor system efficiency. Impedance matching technique is proposed for system efficiency improving, the disadvantage of this approach is that the additional inductors and capacitors cost large PCB area. In this thesis, the peak current sensing method combined with the dynamic voltage scaling technique is proposed for detection of load transient and sufficient output power transfer. Compared to conventional wireless power transfer system, the proposed method result in lower system cost and PCB area; the system can be implemented with easier control circuit including a peak current sensor, a division circuit, a dynamic voltage scaling circuit and a driver for inductive coupler. Moreover, topologies comparisons, optimized operating frequency and sensing methods for load transients are analyzed for improving system efficiency, so that the system provides a potential in application, research and marketing and can be easily integrated in portable devices and biomedical instruments. This chip will be fabricated with the TSMC 0.25um CMOS high voltage mixed signal general purpose IIA based BCD 1P5M 5V/40V process. The total chip area is 1.9 x 1.635 mm2, the input and output voltages are 19V and 5V, respectively, and the operating frequency is 130 kHz.