Low Power Design Of DSP Embedded System

With the explosive growth in the portable electronics market, the embedded system is being used more and more widely. Portable device is one of the embedded systems. 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.The purpose of low power design is to minimize the energy consumption of an embedded system and extend the lifetime of battery without losing its performance. Low power design is an effective approach to solve above problem. It consists of hardware low energy design and software energy design. Our paper is based on ECG embedded system and designs a low power system through software and hardware.This portable device is satisfied with requirement. It can sample the heart signal, compress the ECG data, then send to the hospital by GPRS wireless communication. My main work includes analyzing the electrochemical principle of the work of the battery, and study two important effects of the battery: rate capacity effect and recovery effect. We build an advanced battery analytical model. That model can predict the battery life and the remaining energy of the battery, reflect rate capacity effect and recovery effect. It is suitable for regular load and variable load situation. Based on the model and our system, we introduce one method for battery life optimization: dynamic voltage and frequency scaling method. Then we design an effective hardware circuit on that method, using DSP embedded system. Finally, our ECG system has a good effect in both performance and power consumption.