Low-power Embedded Systems Research

As the development of computer technology, the embedded system is being used more and more widely. It is widely applied with portable devices which use battery. Because of the restriction of the battery capacity, the energy consumption of the embedded system is an important performance parameter. It is very important to minimize the energy consumption of an embedded system and extend the lifetime of battery without losing its performance. On the other hand, in order to improve the performance of the embedded system, it is necessary to improve the speed of microprocessor and to add the peripheral equipments. However, this will increase the system energy consumption. The gap is becoming wider between high performance and limited capacity of battery.Low power design is an effective approach to solve above problem. It consists of hardware low energy design and software energy design.Hardware is substantial platform for computer system and consists of microprocessor and peripheral equipments. Low power design of the hardware is divided into two levels: device level and system level. In device level, low power design mainly focuses on decreasing load capacity and leaking current. In system level, the goal is to decrease unused logic units and circuit activity. In fact, it is more effective in system level. Low power technique of microprocessor is composed of clock-gating, close part of cache, and DVS(dynamic voltage scaling).Low power technique of peripheral equipments design is composed of closing the idle parts of the equipment and degrading the service quality satisfied with lowest requirement.Low power design of software relates to OS, compiler and application software. In OS, scheduling algorithm, drivers and power policy are correlative to power management. DVS scheduler decreases the power of processor by reducing the voltage and frequency. The power of processor can obtain striking power savings if the supply voltage and clock frequency...