Low Power Design Of Embedded System

With the development of wireless communication technology, mobile Internet technology and integrated circuit manufacturing technology, the application of embedded systems has grown rapidly in the world. To smart phones as the representative of embedded systems is becoming increasingly popular. But with more and more features integrated into the smart phone, the issue of power consumption becomes the focus of attention. How to design a low-power system is one of the most critical issues during the smart phone development.This dissertation systematically studies of the low-power design solutions about one smart phone based on the low power design theory of embedded system. Firstly, this paper analyzes the factors of affecting the power consumption of smart phone, and then studies the key points of low-power design. It is from two sides of hardware and software to achieve low-power design. For the hardware side, it introduces the detailed principles and implementation about three aspects which are the application processor selection, the power supply of RF PA and LCD backlight CABC control. Through the power and performance comparison, it chooses low-power and high-performance OMAP3630 applications processor to build the low-power hardware platform. In this paper, it designs separated power supply for RF PA to reduce the power consumption of RF PA, and it reduces the talking current by 10% and the date service current by 13%. With the CABC technology, the low power design of LCD backlight is archived. Especially when the background picture is much darker, the CABC can save power consumption by 40%.From the software side, at first, this thesis analyzes the power management mechanism of the Android system. And then, on the one side, when the system is in sleep mode, the power consumption is reduced by 30% by optimizing the driver program design. On the other side, when the system is in AWAKE state, it analyzes common usage scenarios of smart phone users. According to these scenarios, it designs power-saving mode and phone call power-saving to archive software low power design. The power-saving mode is a kind of scenario modes which optimizes the setting of ring bell, LCD backlight and keypad backlight based on normal mode. The phone call power-saving is to optimize the setting of LCD backlight and keypad backlight during phone call. In the software design, it fully takes into account the impact on the user experience, when minimizing power consumption. It designs one-key power-saving and reasonable user interface to do that.Finally, by doing the whole laboratory test about standby and talking power consumption on the smart phone in this research, the standby power consumption is reduced by 30%. Based on the low power design of RF PA, the talking power consumption is reduced by 10%. The phone call power-saving make the talking power consumption to reduce by 8%. The desired objectives of low-power design have been archived.