Power Deregulation: Eliminating off-chip voltage regulation circuitry from embedded systems

In battery-powered embedded systems, dedicated circuitry is used to convert stored energy into a form that can be directly used by processors. These power regulation devices seek to mask non-ideal aspects of the battery and present an ideal, fixed-voltage power source to the processor. However, this comes at a high price in terms of form factor, component cost, and energy efficiency. We describe and evaluate a new method for eliminating voltage regulation circuitry from battery-powered embedded systems. This method makes use of power gating, frequency scaling, and thread migration in chip-level multiprocessors to dynamically adjust to varying battery voltage. The key advantages of this approach are reduction in printed circuit board area (by 1/3 in many embedded applications) and the elimination of bulky unreliable discrete components such as electrolytic capacitors while maintaining similar battery lifespan. We have evaluated the power consumption, performance, and reliability implications of the proposed method using analytical techniques, power models, and detailed full-system simulation of numerous benchmarks from the ALPBench and Me-diaBench benchmark suites. For a number of battery technologies, the proposed technique holds the potential to eliminate power regulation circuitry and maintain battery lifespan while maintaining the same performance as systems using Buck-Boost voltage regulators.