【作者】 段晓峰；

【导师】 陈向东；

【作者基本信息】 西南交通大学 ， 信号与信息处理， 2006， 硕士

【摘要】 嵌入式系统低功耗设计的目标是在满足用户对性能需求的前提下,尽可能降低系统的能耗,延长设备的待机时间。随着市场对可移动式嵌入式设备在体积和性能方面要求的不断提升,嵌入式设备小体积、高性能与有限的电池能量之间的矛盾日益突出,嵌入式系统低功耗设计是解决这一矛盾的有效手段。本论文先对MP4从全局按照低功耗的要求进行设计,然后再设计了应用于MP4音视频芯片的低压低功耗电流反馈运算放大器。 对MP4进行全局低功耗设计,本文进行了详细的论述。MP4的硬件低功耗设计为整个系统的低功耗运行提供硬件支持。电路级的硬件低功耗设计主要围绕处理器的低功耗特性和外围芯片的特点,设计处理器的供电电路和外围芯片的电源控制电路,外围芯片的电源控制电路使处理器能够控制外围芯片电源的开启和关闭,从而能够减小外围芯片的功耗。设计的电路经过调试均能正常运行,满足MP4低功耗的要求,产品已经投入市场。 MP4音视频芯片中由于要处理的音视频信号频带很宽,而芯片中电压模式的放大器的频带受增益的限制,所以研究宽频带的电流反馈运算放大器具有实际意义。电流反馈运算放大器在高速高频电子领域得到广泛的发展,但目前市场上流行的基于互补双极性结构的电流反馈运算放大器的电源电压和功耗都较高。降低电源电压对模拟电路的设计是一个挑战。如今模拟电路的典型电源电压大约是2.5-3伏,但是发展的趋势表明电源电压将是1.5伏,甚至更低。在这种情况下,国内外研究人员的很多精力花在设计适用于标准CMOS工艺的低压电路结构。本篇论文主要设计了一种新型的CMOS电流反馈运算放大器,与典型的CMOS电流反馈运算放大器比较,本文在中间级用反向放大器来提高电路的开环增益,相位裕度用电容进行补偿,保障电路的稳定性。典型的CMOS电流反馈运算放大器的输出级是甲乙类互补射极输出单元,但由于输出阻抗太大而影响电路的动态性能,本文使用电阻反馈来减小输出阻抗以提高电路的动态指标。使更多还原

【Abstract】 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. With the developing requirement in size and performance of embedded devices from the market, the gap between small size, high performance and the limited battery life has become more and more wide, low power design of embedded system is an efficient approach to solve that problem. This paper firstly aims at the low power MP4 in the whole;then the low-voltage and low-power current-feedback operational amplifiers applied for audio /video chip is designed for MP4.The paper describes the MP4 overall low power design. The purpose of low power design of hardware is to give a hardware support to optimize the energy consumption of whole system. Low power design of hardware at circuit level focuses on low power character of processor and peripherals, designs the power supply circuit of processor and peripherals, the peripherals’ power supply circuit allows processor to control peripherals’ power supply, from these we can restrict energy consumption of the peripherals. The design circuit after the debugging can operate normally, satisfy the MP4 low power request, the product has put into the market.MP4 audio /video chip processes wide bandwidth of audio /video signal, but in the chip the voltage pattern amplifier bandwidth is limited by the gain, therefore the research on the wideband current feedback operational amplifier has the practical significance. Current-feedback operational amplifiers is widely used in the high speed and frequency electronic fields,but complementary-bipolar process CFOA is popular in the market for high voltage and high power. To the design of analog circuit, it is a challenge when its supply voltage is low.Now the typical supply voltage of analog circuit is about 2.5-3 v, but the trend suggests it will be 1.5v, even much lower .Under this condition, great effort of research members domestic and abroad is devoted to the design of low-voltage circuit structure with standard CMOS processes.The aim of this paper is to describe a new CMOS current-feedback operational amplifiers . Compared with the model CMOS current feedback operational amplifier, this paper enhances the open-loop gain in the among level with the reverse amplifier, capacitor compensates the phase margin safeguarding thecircuit the stability. The typical CMOS current feedback operational amplifier output stage is class AB complementary emitter output unit, but the high output impedance affects the circuit dynamic performance, this paper using the resistance feedback reduces the output impedance to enhance the circuit the dynamic performance. Simulation results of the CFOA,using 0.5um CMOS process parameters, result in a high slewrate as well as bandwidth gain-independence . Circuit parameters show a: 81db open loop gain-. 82 degree phase margin> 123db CMRR ■> and power consumption around 6.2mW from 1.5V supply voltage.更多还原