Secondary-Power-Cell-Aware Detailed Placement in Multiple Power Domain Designs

Using multiple power domains is a common technique to achieve significant power savings in modern designs. However, providing power to cross-domain cells is challenging at advanced technology nodes, due to strict IR drop constraints and competition for routing resources between secondary power routing and signal routing. Despite its importance, this issue has received limited attention in recent literature. In this paper, we propose a detailed placement method that accounts for secondary power routing. Our approach employs an integer linear programming (ILP) model, complemented by targeted adjustments to the placement of cross-domain cells, to optimize the efficiency of secondary power routing. We validate our results with commercial design tools, showing that our approach effectively improves secondary power routing performance by reducing the wirelength of the secondary power distribution network (PDN) and decreasing violations due to secondary PDN constraints.