Study And Implement Of Embedded System Power Management

With the rapid development of computer applications, embedded systems extended its influence in all aspects of our life and industry. The performance of embedded systems which are applied to portable devices that had limited battery power rapidly increase, the processors have more high-frequency, the number of peripheral devices in embedded systems continue to raise. Meanwhile, the development of battery capacity was slower than increment speed of Power Consumption in embedded system.Therefore, in embedded system high performance and the restraint of battery capacity become contradictory elements. Power management consumption has been taken into account by the system designers as a hot spot of Embedded System Design.To resolve conflicts, this paper researches the system-level power management framework, and the major goal is to achieve an overall and flexible dynamic power management module in embedded Linux systems.First of all, Paper introduces low-power technology and power management technique of embedded systems. Second, according to the major goal of this paper the system power management module is designed and implemented, this part includes the hardware layer, the operating system layer and application layer design and implementation.1. The hardware layer is the physical platform to run the system, including processors and peripherals. According to whether hardware has power management functions, different low-power technologies are used, including:clock gating techniques, dynamic voltage scaling technology, dynamic power management technology, and so on.2. The operating system layer is the core of system power management, power management strategies, peripherals power management and system operating status scheduling closely contact with system low power. Design and implementation in this layer achieve power scaling technology by system operating status scheduler, changing processor frequency and voltage to reduce power consumption; using device drivers detects and controls peripherals for the system state, it also is used to be the condition of choosing operating point choose to use; The new structure of power strategies is introduced, so that it can provide a flexible power management strategies for embedded systems; API interfaces for power management are setting, in accordance with specific user needs the applications use these interfaces to complete power management tasks.3. The application layer is the system power management scheduler which is based on user specific needs and use suitable DPM and DVS scheduling algorithms to achieve system power management tasks.Finally, paper cites an implementation of embedded system power management, and using system power management scheduler, which includes AVGn algorithm, Time-out algorithm and power control strategy based on best utilization, makes system own dynamic power management function. Therefore, embedded system can reduce system power consumption without affecting the system performance.