加速自校正直流漂移的可编程增益放大器  

A Programmable Gain Amplifier with Speed-Enhanced DC-Offset Correction

作　　者：易青[1] 杨洪文[1] 郭桂良[1] 阎跃鹏[1] 

机构地区：[1]中国科学院微电子研究所,北京100029

出　　处：《微电子学与计算机》2008年第8期92-95,共4页Microelectronics & Computer

摘　　要：设计了一种应用于移动数字多媒体广播系统终端的可编程增益放大器。该可编程增益放大器采用源极反馈电阻可变的差分放大器结构，且带有直流漂移校正电路。分析了校正直流漂移时间的决定因素，通过采用双带宽切换的方法加速校正过程。分析了引发输出直流漂移发生变化的因素，设计了增益控制信号触发的双带宽控制信号发生电路。可编程增益放大器采用TSMC0.25μm CMOS工艺。仿真结果表明，放大器的动态范围为30-84db，2db步进，对输入直流漂移的校正效果为-21.45db，加速后的直流漂移校正时间约15ps。A programmable gain amplifier （PGA） is designed for the client of mobile multimedia broadcasting system. The PGA consists of the differential amplifier with variable source degeneration resistor and the DC-offset correction circuit, The decisive factor of the time of DC-offset correction is analyzed, The speed of DC-offset correction is accelerated by alternation of dual bandwidth. The factors which cause the change of output DC-offset are also analyzed. The signal genera- tion circuit which controls the dual bandwidth is designed to be sensitive to gain-controlling signal. The PGA is fabricated using TSMC 0.25μm CMOS technology. The result of simulation reveals that the gain range is 30-84db with 2db step resolution. The effect of DC-offset correction is -21.45db, and the time consumption of the DC-offset correction is about 15us because of the speed-enhancement.

关 键 词：可编程增益放大器 直流漂移 双带宽 加速自校正 

分 类 号：TN722.1[电子电信—电路与系统]