MOS器件失配对开关电流滤波器的影响

EFFECTS OF MOS DEVICE MISMATCH ON THE PERFORMANCE OF SWITCHED-CURRENT FILTERS

提出了一种ＭＯＳ器件失配时开关电流镜（ｓｗｉｔｃｈｅｄｃｕｒｒｅｎｔｍｉｒｒｏｒ）的简单模型，对开关电流（ＳＩ）非理想通用积分器进行了时域分析。以及积分器转移函数误差、Ｑ值及灵敏度的计算，并与开关电容（ＳＣ）原型做比较。文中还以ＳＩ非理想通用积分器模型为基块，导出了器件失配时双二次滤波电路的直流失调电流和转移函数表达式，为研究器件失配对ＳＩ滤波器的影响提供了一条有效的途径。

A generalised switched-current(Sl)nonideal integrator is analyzed in the time domainby using a simple model of switched current mirror with MOS device mismatch proposed inthis paper,The error in the transfer function,Q value and the sensitivities of the integratorsare calculated and compared with switched-capacitor(SC)counterparts,The dc offset cur-rent and the transfer function of a biquadratic filter with device mismatch are also derivedwith the proposed model of the SI nonideal integrator as the basic building block.Themethod presented in the paper is systematic,and so it provides an effective approach for thestudy of effects of device mismatch on the performance of SI filters.