一种低功耗高电压转换速率的模拟运算放大器设计

发布时间：2017-12-28 11:37

本文关键词：一种低功耗高电压转换速率的模拟运算放大器设计　出处：《电子科技大学》2016年硕士论文　论文类型：学位论文

【摘要】：在各种电子设备中,运算放大器是常用的重要器件之一,它常用于电子设备的模拟信息处理电路中,是组成放大、滤波、检波、采样、变换等各种电路的重要元件,其性能指标直接影响电子设备的总体性能。电压转换速率和低功耗是运算放大器的重要参数指标。低电压转换速率会造成信号失真,而低功耗是当今时代电子产品的发展趋势。但是,为了提高电压转换速率通常需要更大的供电电流,这会消耗更多的功耗,并且输出信号会产生更大的过冲和震荡,造成系统不稳定。为了让系统稳定,则需要更大的频率补偿电容,而这会导致电压转换速率的下降。因此,在不影响频率补偿,系统保持稳定,低功耗的情况下,提高电压转换速率是急需解决的问题。本文首先设计了一种基于Rohm 0.18μm技术的运算放大器,该运算放大器具有可以控制偏置电流的控制端,用于分析偏置电流大小与运算放大器参数之间的关系。然后对样片进行了测试,获得了偏置电流与截止频率,相位裕度,电压增益等参数的关系曲线,同时,研究了放大器功耗与响应的关系,分析了电压转换速率的形成原因和影响因素,为得到低功耗、高速度的设计提出了理论依据。在上述仿真和实际测试的基础上,本文提出了一个能保持低功耗的同时又提高电压转换速率的改进设计方案,并利用HSPICE对其进行了性能仿真和验证。该设计方案巧妙利用了运算放大器在分别输入大信号和小信号时不同的响应特性,结合电容倍增器以及电流控制电路,将米勒频率补偿电容成功的缩小了三倍,有效的节约了芯片的面积。并且该低功耗高速运算放大器可以在不影响频率补偿的情况下,有效提高电压转换速率至5倍以上,极大程度地提高了信号传输速度和质量。本文设计的高速运算放大器在典型供电±1.65V时,电压转换速率达到94V/μs,而功耗只有672μW,实现了低功耗的同时,兼顾了高速化的设计。该运算放大器可广泛应用于高速通信、高速数据采集、多媒体电子等产品设计中。
[Abstract]:In various kinds of electronic equipment, operational amplifier is one of the important devices commonly used, analog information processing circuit which is commonly used for electronic devices, is composed of amplification, filtering, detection, sampling, and other important components of various transform circuit, its performance directly affects the overall performance of electronic equipment. Voltage conversion rate and low power consumption are important parameters of operational amplifier. Low voltage conversion rate will cause signal distortion, and low power consumption is the development trend of electronic products in the present era. However, in order to improve the voltage conversion rate, more power supply is usually needed, which will consume more power and output signal will cause greater overshoot and shock, resulting in instability of the system. In order to stabilize the system, a larger frequency compensation capacitor is needed, which will lead to a decrease in the rate of voltage conversion. Therefore, it is an urgent problem to improve the voltage conversion rate without affecting the frequency compensation, keeping the system stable and low power consumption. In this paper, we first designed an operational amplifier based on Rohm 0.18 M technology. The operational amplifier has a control terminal which can control the bias current, which is used to analyze the relationship between the bias current and the operational amplifier parameters. And then tested the samples, the bias current and the cutoff frequency, phase margin, curve, voltage gain and other parameters at the same time, studied the relationship between the power amplifier and a response, analyzes the causes and influencing factors of voltage conversion rate, provide the theoretical basis for the design of low power consumption and high speed. Based on the above simulation and practical test, this paper proposes an improved design scheme that can maintain low power consumption while improving voltage conversion rate, and use HSPICE to simulate and verify its performance. The design scheme cleverly utilizes the different response characteristics of operational amplifiers when they input large signal and small signal respectively. Combined with capacitor doubler and current control circuit, the Miller frequency compensation capacitor is reduced by three times, which effectively saves the area of the chip. Moreover, the low power and high speed operational amplifier can effectively increase the voltage conversion rate to more than 5 times without affecting the frequency compensation, which greatly improves the speed and quality of signal transmission. The high speed operational amplifier designed in this paper has a voltage conversion rate of 94V/ s at typical power supply of + 1.65V, and the power consumption is only 672 W, which realizes low power consumption while taking account of the design of high speed. The operational amplifier can be widely used in the design of high speed communication, high-speed data acquisition, multimedia electronics and other products.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN722.77

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