电源网络低频段S参数拓展方法

Low Frequency S-Parameter Extension Method of Power Network

电源网络S参数与芯片电源模型(Chip Power Module,CPM)级联可实现电源时域噪声仿真,完成电源完整性设计签核。当下部分仿真工具在AC阻抗优化过程中导出的S参数存在低频段无法覆盖的问题,影响时域纹波仿真精度,如果重新对S参数进行提取,又会增加仿真时间降低仿真效率。针对AC阻抗优化过程中导出的S参数无法覆盖低频段的问题,提出了一种电源网络S参数低频段拓展方法,结合电压调节模块(Voltage Regulator Module,VRM)的R-L模型,推导出低频段的S参数可以借用抽取的S参数中最低频点处的S参数实现低频段S参数的拓展。仿真和实验结果表明,通过对低频段S参数进行拓展,电源时域纹波噪声仿真的精度提升31%。同时,低频段的S参数直接借用已抽取的S参数中低频点的数值无须重复提取,在8 GB内存的配置下,仿真时间节约14%左右,提高了仿真效率。

The cascaded S-parameter of the power network and the chip power model(CPM)can realize the time-domain noise simulation of the power supply,and complete the integrity design check of the power supply.At present,the S-parameter derived by some simulation tools in the AC impedance optimization process has the problem that the low frequency band cannot be covered,which affects the accuracy of the time-domain ripple simulation.If the S-parameter is extracted again,the simulation time will be increased and the simulation efficiency will be reduced.In order to solve this problem,this paper proposes a low frequency band expansion method of S-parameter of power network.Combining with the R-L model of voltage regulator module(VRM),it is deduced that the S-parameter of low frequency band can be extended by using the S-parameter at the lowest frequency point of the extracted S-parameter.The simulation and experimental results show that the accuracy of power ripple noise simulation in time domain is improved by 31%by expanding the S-parameter in low frequency band,and the S-parameter of the low frequency band directly borrows the value of the low frequency point from the extracted S parameter without repeated extraction.Under the configuration of 8 GB memory,the simulation time is saved by about 14%,and the simulation efficiency is improved.