【摘要】 介绍了一种带宽可调的二阶低通开关电容滤波器,带宽调节范围为100～500Hz,调节精度约为100Hz。该滤波器用双层金属、双层多晶硅1.2μm的N阱MOS工艺实现,用于一个加速度传感器电路中。设计着重考虑了由时钟信号引起的、严重制约开关电路性能的各种因素,通过优化开关的时序,消除了电荷注入引起的非线性效应,并采用高电源电压抑制比的折叠结构运算放大器,以减轻电源噪声的影响,从而有效地改善了电路的精度。更多还原

【Abstract】 A second-order low-pass switched-capacitor filter is presented,which has a tunable bandwidth ranging from 100 Hz to 500 Hz with a step of 100 Hz.The filter,which is used in an accelerometer sensor circuit,is fabricated in a 1.2 μm double-metal double-poly N-well CMOS technology. Emphasis is placed on minimizing the signal error induced by the clock signal inherent in switched-capacitor circuits. Dedicated switch timing is proposed to reduce the charge injection,and an operational amplifier with high PSRR is designed to suppress power supply noise.更多还原