【作者】 王君；

【导师】 来新泉； 李玉山；

【作者基本信息】 西安电子科技大学 ， 电路与系统， 2017， 博士

【摘要】 电源完整性已成为高速电路设计的主要问题之一。随着电子系统向高频、高速、和高集成度的趋势发展,未来十年电源完整性设计会面临更加严峻的挑战。电源分配网络是高速数字系统中最复杂的无源互连结构。随着时钟频率的提高,电源分配网络逐渐表现出分布特性,去耦电容逐渐表现出局部效应。基于分布式电源分配网络的去耦设计的重心逐渐转移到去耦电容在电源分配网络上的放置问题,并且分布式电源分配网络去耦设计的基础算法仍有待完善。本文重点研究了高速电路系统中电源分配网络的建模和去耦设计方法,并详细分析了建模方法和去耦设计方法的效率和精度。主要的研究成果归纳如下:1)针对谐振腔算法不能计算带负载的电源地平面结构和任意形状的电源地平面结构的频域阻抗问题,提出了基于谐振腔算法的带电容电源地平面的建模方法,扩展了谐振腔算法的适用范围。该方法不仅能计算带电容电源地平面结构的频域阻抗,也能处理带其他单端口负载的电源地平面结构。该算法的计算效率及精度依赖于谐振模式数量。使用的谐振模式越多,计算精度越高,但计算效率越低。将该算法与电感近似的快速算法和双频点近似的快速算法相结合,显著提高了该算法的计算效率。通过与分割法和反向补偿法相结合,将该算法的应用范围推广到了不规则的电源地平面结构。该算法为分布式电源分配网络的去耦设计提供了算法基础。通过与专业电磁仿真软件HFSS的仿真结果对比,验证了该算法的准确性。2)针对谐振腔算法不能计算多层电源地平面结构的频域阻抗问题,提出了基于谐振腔算法的带多端口负载的电源地平面建模方法。在多层电源地平面结构中,具有相同电势的平面被过孔连接成一个整体。当观察端口位于顶层平面对时,其余平面对可以看作第一层平面对的多端口负载。该算法可以有效计算多层电源地平面结构的频域特性,将谐振腔算法的应用范围扩展到多层电源地平面结构。该算法为多层电源分配网络去耦设计提供了算法基础。通过与专业电磁仿真软件HFSS的仿真结果对比,验证了该算法的准确性。3)针对多层PCB电路中差分信号过孔的残桩引起的反射问题,提出了高阻抗端接策略。利用反射改善接收端的信号质量,减小过孔残桩的影响。通过在差分过孔残桩末端进行过高阻抗电阻端接,补偿信号的直流损耗,改善接收信号的眼高。由于反射的影响,信号的上升边产生了严重的延时。通过在传输线末端端接高阻抗电感元件,提升接收信号的上升边。4)根据电源地平面阻抗的实际分布,提出了去耦电容去耦半径的计算方法。在去耦半径刻画的区域内,电源地平面的阻抗都小于目标阻抗。去耦电容可以放置在该区域内的任何位置处。针对去耦电容在电源地平面上放置的问题,提出了基于去耦半径的去耦设计方法。在得到去耦电容种类和数量的同时,也能获得去耦电容在电源地平面上的位置信息。5)基于片上电源分配网络的一维RL等效模型提出了去耦电容去耦半径的计算方法。去耦电容的充电半径受目标噪声的约束,放电半径的长度取决于充电半径的长度和目标噪声的大小。基于一维RL模型的去耦电容充放电半径被转化到二维RL模型中,两个模型中去耦半径的转化系数为一个常数。通过与HSPICE的仿真结果对比,验证了转化系数的准确性。二维RL模型中去耦电容的充放电半径同样适用于二维RLC网络模型。本文系统的研究了电源分配网络的建模方法及去耦设计方法,研究结果均通过严格的仿真验证。可以直接应用于高速数字电路系统中电源地平面的建模及电源分配网络的去耦设计。更多还原

【Abstract】 Power integrity has become one of the main problems in high-speed circuit design.With the development of electronic system to higher frequency,higher speed,and higher density,the design of power integrity in the next ten years will face more severe challenges.Power distribution network is the most complex interconnection structure in high-speed digital systems.With the increase of clock frequency,the power distribution network gradually shows the distribution characteristics.Decoupling capacitors gradually exhibit local effects.The focus of decoupling design is gradually shifted to the placement of decoupling capacitor on the power distribution network.And the basic algorithm of decoupling design of the distributed power distribution network is still to be improved.This paper focuses on modeling and decoupling design of power distribution network in highspeed circuit system.The efficiency and accuracy of the presented methods are analyzed and verified in detail.The main contributions of this dissertation are as follows:1)Since the resonant cavity algorithm cannot model the power/ground plane pairs with load and that with arbitrary shape,an algorithm was proposed to model the power/ground plane with capacitors,which extends the application of the resonant cavity algorithm.This method can not only deal with the power/ground plane with capacitor,but also can be applied to the power/ground plane with other single port load.The computational efficiency and accuracy of the algorithm depend on the number of resonant modes.The more resonant modes are used,the higher the computational accuracy,but the lower the computational efficiency.By being combined with the inductance approximation method and the Double-Frequency approximation method,the efficiency of the proposed algorithm is improved greatly.The application of the proposed method is extent to the power/ground plane with irregular shape by being combined with the segmentation method and the reverse compensation method.This proposed method can be the basic algorithm for the decoupling design of distributed power distribution network.The correctness of this algorithm is verified by the comparison with the simulated results by HFSS.2)Based on the resonant cavity algorithm,a modeling method for the power/ground with multi-port load is presented to solve the problem that the resonant cavity algorithm cannot be used to computed the impedance of the multi-layered power/ground structure.In the multi-layered power/ground plane structure,planes with the same potential are connected together by vias.When the observation port is on the top plane pair,the remaining plane pairs can be considered as the multi-port load of the first plane pair.This algorithm can effectively calculate the frequency domain characteristics of the multi-layered power/ground plane structure,and extend the application of the resonant cavity algorithm to the multilayered power/ground plane.It provides an algorithm basis for decoupling design of multilayered power distribution network.The correctness of this algorithm is verified by the comparison with the simulated results by HFSS.3)In view of the reflection caused by of the stub of differential via in multi-layered PCB,a high impedance termination method is proposed to improve the signal at the receiving end and to reduce the influence of the via stub.The reflection between differential open via stub and its high-impedance resistive termination is used to improve the DC voltage level.But due to the reflection,there is severe delay in the rising edge of the received signal.Then,the reflection gains between the receiving end and its high inductive termination is used to improve the rising edge of the received signal.4)According to the impedance distribution throughout the whole power/ground plane,the calculation method of the decoupling radius is put forward.In the area characterized by the decoupling radius,the impedance of the power/ground plane is smaller than the target impedance.In other words,the decoupling capacitor can be placed anywhere in the area characterized by the decoupling radius.According to the placement of decoupling capacitors on the power/ground plane,a decoupling method based on the decoupling radius is proposed.By using this method,not only the type and the number of the selected capacitors,but also the locations of the decoupling capacitors can be obtained.5)Based on a signal RL line model of the on-chip power distribution network,the computation method of the decoupling radius of decoupling capacitor is proposed.The charging radius of the decoupling capacitor is constrained by the target noise,and the length of the discharge radius depends on the length of the charge radius and the target noise.The conversion coefficient that converts the radii of a decoupling capacitor in a signal RL line model into the equivalent one in a meshed model is presented as a constant.By comparing the simulated results by HSPICE,the accuracy of the conversion coefficients is verified.The charge and discharge radii of the decoupling capacitor in the single line RL model can also be applicable to a RLC meshed network.The modeling and decoupling method of the power distribution network is studied systematically in this dissertation,and all results are validated by strict simulations.Hence,the results can be directly used in the actual designs.更多还原