With the increase of the operating frequency for the space camera,the power noise in the imaging electronic system will have a significant impact on the image quality, and excessive noise would disturb the signal transmission, blur the image sharpness and produce more system noise. In a traditional design method, the "target impedance" was used to evaluate the power impedance, which often resulted in "over design" due to lack of the accurate analysis of the power noise and setting the current in the power/ground (P/G) network to the maximum load current value. In the paper, a new method was proposed based on the mixed simulation model, which combined the signal analysis with the P/G network analysis. In the mixed model, the signal transmissions model, the P/G network model and the package model were all included, and the current caused by the I/O state change and signal circumfluence path in the P/G network was also taken into account. The transient power noise can be simulated and then noise reduction can based on the simulation results, thus effectively controlling the variation of the noise in the P/G network. The method was valid to control the adding number of the decoupling capacitors, making the power integrity design more efficient and feasible.%随着遥感相机工作频率的提高,成像电子学系统中的电源噪声成为影响图像质量的一个重要的因素,过大的电源噪声会干扰所传输视频信号,并影响到成像的清晰度和系统噪声.传统设计方法仅通过"目标阻抗"来判断电源阻抗是否满足要求,缺少对电源噪声的准确分析,且该方法将电源/地网络(P/G网络)中的电流设定为负载最大电流,容易造成电源"过设计"的情况.为此,文章提出一种新型的电源设计方法,该法将信号分析和电源设计结合一体进行,通过建立混合仿真模型对电源噪声进行分析计算,该混合模型包含了信号的传输通道模型、P/G网络模型、器件封装模型,并将器件驱动端口翻转引起的电流变化以及信号产生的回流引入仿真模型中.通过仿真计算不仅可以得到电源的瞬态噪声,还能够根据计算结果进行降噪设计,有效的控制了P/G网络上噪声的变化,采用本方法可以有效控制去耦电容的添加数量,保证了电源完整性设计的有效性和可行性.
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