Optimization of power delivery network design for multiple supply voltages

Great power demands and low-power techniques have increased the requirements on the power delivery network, especially with multiple supply voltages. In this paper, methods for optimizing decoupling capacitor allocation and placement for multiple power nets are presented. Based on a physics-based circuit model extraction for the PCB-PDN structures, a two-level optimization procedure is proposed. First, stackup and potential locations and patterns for power and ground vias are optimized based on design guidelines. In the second step, distribution and allocation of decoupling capacitors are optimized targeting for the system-level PDN performance among multiple supply voltages by an integer linear programming (ILP) algorithm. The physical properties of the decoupling capacitors are described as circuit elements in the equivalent circuit model. Thus, instead of full-wave analysis, only efficient circuit simulations are needed in the optimization process. The proposed optimization methods are applied in a complex system including integrated circuit with multiple supply voltages. Compared to the original unoptimized design, the optimized PDN impedance for the worst designed power nets improved 400% with the same cost of decoupling.