MontaVista Technologist Bill Weinberg has written an overview of the changing landscape of device power management schemes, with a focus on dynamic power management (DPM) architectures being specified and soon to be deployed by embedded companies and standards organizations.

Weinberg differentiates relatively crude legacy Advanced Power Management (APM) strategies for throttling CPU cycles from modern DPM strategies that will regulate power use in many subsystems such as CPU, memory, displays and even radio interfaces. In concert with or independently from CPU frequency and voltage scaling, such systems will support rapid scaling — up to hundreds of times a second — of a variety of voltages and clocks.

He describes the architecture of DPM, and how it relates to BIOS, kernel, drivers and applications. He also talks about power management in real-time systems, something that is only now becoming possible due to the capability of modern embedded processors to accept voltage and frequency changes with very low latency, allowing for instance power consumption changes between video frames.

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