The design and application of the PowerPC 405LP energy-efficient system-on-a-chip

The PowerPC® 405LP system-on-a-chip (SoC) processor, which was developed for high-content, battery-powered application space, provides dynamic voltage-scaling and on-the-fly frequency-scaling capabilities that allow the system and applications to adapt to changes in their performance demands and power constraints during operation. The 405LP operates over a voltage supply range of 1.95 to 0.9 V with a range of power efficiencies of 1.0 to 3.9 MIPS/mW when executing the Dhrystone benchmark. Operating system and application software support allow the applications to take full advantage of the energy-efficiency capabilities of the SoC. This paper describes the organization of the SoC design, details the capabilities provided in the design to match the performance and power consumption with the need of the application, describes how these capabilities are employed, and presents measured results for the PowerPC 405LP processor.