跨导恒定性自适应的低电压Rail-to-Rail放大器  

Low Voltage, Rail-to-rail Amplifier with Self-adaptive Constant g_m

作　　者：李晴[1] 邵丙铣[1] 

机构地区：[1]复旦大学国家微电子材料与元器件微分析中心,上海200433

出　　处：《复旦学报（自然科学版）》2004年第1期110-114,134,共6页Journal of Fudan University：Natural Science

摘　　要：利用"较小电流选择电路"实现的低电压恒跨导Rail to Rail放大器输入级具有跨导gm随共模输入电压Vcm变化小、设计简单的优点.分析了该设计思想中的两个基本假设,提出一种改进型偏置电路,"跨导稳定"部分能随工艺漂移自适应地调整gm使之保持恒定;输出阻抗高且工作压降小的恒流源部分能提高输入对管的饱和工作范围及其偏置的恒流特性,从而提高gm的恒定性.Vcm在整个VDD范围内,跨导gm变化仅3.1%.Two premises to realize the constant transconductance ( g_m ) amplifier with 'mini current selecting circuit' are analyzed. An improved biasing is proposed, in which ' g_m equalizer' adjusts g_m self-adaptively to keep it constant according to the process mismatch, while the current source of input pair of high output impedance and low compliance voltage can widen the operation region, which is beneficial to a constant g_m . The variation of g_m is only 3.1% for rail to rail common mode input.

关 键 词：半导体技术 低电压放大器 全摆幅 恒跨导 

分 类 号：TN722.77[电子电信—电路与系统]