Electric Power ›› 2021, Vol. 54 ›› Issue (10): 125-133.DOI: 10.11930/j.issn.1004-9649.202009095

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Synchronized Switch Harvesting on Capacitor Integrated Circuit for Piezoelectric Energy Harvesting Application

FAN Shiquan, CHEN Yunxiang, XIE Ying, YUAN Chenxi   

  1. School of Microelectronics, Xi'an Jiaotong University, Xi'an 710049, China
  • Received:2020-09-09 Revised:2021-08-31 Online:2021-10-05 Published:2021-10-16
  • Supported by:
    This work is supported by National Natural Science Foundation of China (Study on Key Issues of High Efficiency Acoustic Energy Harvesting IC for Ultra-Band Sound Field, No. 62074124) and Fundamental Research Funds for the Central Universities ( Study on Key Techniques of High Efficiency Acoustic Energy Harvesting IC for Ultra-Band Sound Field Application, No. xzy012020011).

Abstract: An improved efficient energy harvesting integrated circuit is proposed for piezoelectric energy sources. By using the synchronized switch harvesting on capacitor (SSHC) interface circuit, the charge re-sharing is realized when the internal current source of the piezoelectric energy source crosses zero. The charge on the internal capacitance of the piezoelectric energy sources is transferred to the external capacitor, and then the charge on the external capacitor is reversed through switch control, and finally the reversed charge is transferred back to the internal capacitor. This method avoids the energy loss caused by the charge stored on the internal capacitance of the piezoelectric energy source being neutralized after the internal current source crosses zero, which achieves higher energy harvesting efficiency. The designed SSHC circuit is fabricated with standard 0.18 μm CMOS process, with an active area of about 0.06 mm2. The post-simulation results show that when the open-circuit voltage (OCV) of the piezoelectric energy sources is 2.8 V, the maximum voltage flip rate of 81.8% can be achieved. Compared with the standard full bridge rectifying structure, the proposed structure achieves the maximum 8.1X improvement in energy harvesting capability.

Key words: energy harvesting chip, piezoelectric energy harvesting, synchronized switch harvesting on capacitor, active rectifier, interface circuit, integrated circuit