Torbjörn Holmberg and Per-Johan Wiberg
Ericsson

This paper presents a detailed analysis of how digital techniques compare with traditional analog approaches in a Board Mounted Power Supply (BMPS). The analysis is based on a case study of a product from an actual production batch. It is shown that replacing some of the analog content with digital circuitry can provide performance benefits to the end user without incurring any penalties in the form of additional cost or design complexity. Power density, in particular, is significantly improved. In addition, work is presented showing how a simple, cost effective communication interface can be added to the basic design so that the additional functionality of digital power management can be made available.