Optimization of Power Conversion Efficiency in Threshold Self-Compensated UHF Rectifiers With Charge Conservation Principle
Optimization of Power Conversion Efficiency in Threshold Self-Compensated UHF Rectifiers With Charge Conservation Principle
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DOI：
10.1109/tcsi.2017.2695650
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发表时间：
2017-09-01
影响因子：
5.1
通讯作者：
Kulah, Haluk
中科院分区：
文献类型：
--
作者：
Gharehbaghi, Kaveh;Kocer, Fatih;Kulah, Haluk
本文提出了一种紧凑的阈值自补偿整流器模型，可用于在设计阶段的早期优化电路参数，而不是耗时的瞬态仿真。提出了一种设计程序，用于找到转换器中使用的晶体管的最佳纵横比和整流级数量，以实现最大功率转换效率。在所提出的分析中，利用输出直流电压变化时功率转换效率和负载电流之间的关系来寻找最佳设计参数。准确近似稳态期间进入和离开整流器的电荷有助于在不同负载电流值下预测的输出直流电压和仿真结果之间获得良好的一致性。使用 MOS 晶体管的 Enz-Krummenacher-Vittoz 模型，推导出精确的优化公式。该模型在弱、中和强反转区域的能力有助于找到适合广泛射频电压变化的最佳设计参数。所提出的估计最佳尺寸和级数的公式与模拟显示出良好的一致性。通过将模型预测与工作频率为 900 MHz 的四级自补偿整流器的测量结果进行比较，可以提供进一步的验证，该整流器是在商用 0.18 μm 部分耗尽绝缘体上硅工艺中实现的。
This paper presents a compact model for threshold self-compensated rectifiers that can be used to optimize circuit parameters early in the design phase instead of time-consuming transient simulations. A design procedure is presented for finding the optimum aspect ratio of transistors used in the converter and number of rectifying stages to achieve the maximum power conversion efficiency. In the presented analysis, the relation between the power conversion efficiency and the load current over the variation of the output dc voltage is used to find the optimum design parameters. Accurate approximation of the charge entering to and exiting from the rectifier during the steady state helps to get good agreement between the predicted output dc voltage and simulation results under different load current values. Using the Enz-Krummenacher-Vittoz model for the MOS transistor, an accurate formula is derived for optimization. The ability of the model in weak, moderate, and strong inversion region aids to find the optimum design parameters for broad range of RF voltage variation. The presented formula for estimating the optimum size and number of stages shows good agreement with simulations. Further validation is provided by comparing model predictions with measurement results of a four-stage self-compensated rectifier operating at 900 MHz, which is implemented in a commercial 0.18-mu m partially-depleted silicon-on-insulator process.