Power & Ground Bridging Trace Design for Improved Power Integrity

Nowadays, demand for slimmer and better performance consumer electronics increases dramatically. As PCB size keeps shrinking, power integrity issues such as high voltage drop and power loss arise due to lack of power and ground planes and broken power and ground shapes caused by densely-populated signal vias. In this paper, a novel design of power and ground bridging trace, placed between anti-pads of through-hole vias, the voltage drop issue can be greatly improved.

I. Introduction

As technology improves, consumer electronics such as computers seek for slim size and lighter weight. The best solution to achieve the smaller form factor is to decrease the layout area, the thickness of the printed circuit board (PCB), and the overall layer count. As a result, power and ground planes are usually shrunken. In addition, with the densely-populated signal vias, the power and ground shapes are usually made broken by the anti-pads. When power and ground shapes are broken, the overall power delivery path would deteriorate; as a result, voltage drop or IR drop from source to sink would increase and system would likely fail due to lack of enough supplied voltage. Recently, challenges in power integrity has been widely discussed especially in IR Drop [1] [2] [3]. In conventional designs, in order to improve on IR drop, increasing power and ground shapes, adding additional power via arrays are proven to be effective [4] [5] [6]. However, the abovementioned methods require additional PCB layout space and extra cost. In addition, by adding additional power via array, ground planes can be made broken, causing deterioration in signal integrity.