应用于压电能量源的高效同步电容开关能量收集芯片设计

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

针对压电能量源,提出了一种具有压电能量源极性判定的高效改进型单脉冲序列可配置能量收集接口电路芯片。该芯片通过采用同步电容开关接口电路,实现了在压电能量源内部电流源过零时的电荷再分享,将压电能量源内部电容上的电荷转移至外部电容,再通过开关控制,实现外部电容上的电荷翻转,最后将翻转后的电荷输送回压电能量源内部电容。该方法避免了压电能量源内部电容上存储的电荷被内部电流源过零后中和而造成的能量损失,实现了较高的能量俘获效率。通过采用0.18μm标准CMOS工艺完成电路和版图设计,芯片版图有效面积仅需0.06 mm^(2)。仿真结果显示:在压电能量源开路电压为2.8 V时,能够实现最高81.8%的电压翻转效率,与标准的全桥整流结构压电接口电路相比较,所提出的结构在能量俘获能力方面实现了最大8.1倍的提升。

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 0.18μm CMOS process,with an active area of about 0.06 mm^(2).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.