A Methodology for the Simultaneous Design of Supply and Signal Networks

Abstract

Abstract-We present an early-stage global wire-design methodology that simultaneously considers the performance needs for both signal lines and power grids under congestion considerations. An iterative procedure is employed in which the global routing is performed according to a congestion map that includes the resource utilization of the power grid, followed by a step in which the power grid is adjusted to relax the congestion in crowded regions. This adjustment is in the form of wire removal in noncritical regions, followed by a wire-sizing step that overcomes the voltage noise after wire removal and a wire-width resizing that meets the maximum current-density constraint. Experimental results show that the overall routability can be significantly improved while the power-grid noise is maintained within both the voltage-drop and current-density constraints.

Overcoming Variations in Nanometer-Scale Technologies

“…Effective techniques for optimization include pin assignment [66], [67], topology optimization [68], [69], wire sizing [70], [71], and decoupling capacitor (decap) insertion [72]. The last of these deliberately inserts capacitors into the power grid: these act as charge reservoirs that damp down the effects of fast transients by providing a nearby source of charge to feed the current drawn by the functional blocks.…”

Electromigration for microarchitects

“…Power supply and ground grids involve large amounts of wires that occupy a vast area of some metal layers [Choi et al 2002;Su et al 2004]. Such grids are typically designed as interleaved identical stripes of metal at different metal layers, whose width decreases when moving to lower metal layers [Choi et al 2002;Cadence 2002b;Cai et al 2005].…”

Practical Problems in VLSI Physical Design Automation

“…The authors of [Su et al, 2004] presented an early-stage interconnect planning methodology that simultaneously considers signal wires and power grid wires under the congestion constraints. The authors start with initial Steiner trees and improve the routing congestion with SMMT-based rip-up-and-reroute [Chiang et al, 1990].…”