一种新型高输出阻抗,高电流匹配精度电流镜的设计

Novel Design of Current Mirror with High Output Impedance and High Current Matching Accuracy

电流镜是模拟电路设计的基础单元之一，在高性能模拟电路设计中，电流镜的电流匹配精度和输出阻抗是决定电路性能的最重要的参数之一．设计一种新型高输出阻抗、高电流匹配精度电流镜，采用了一种新颖的五级负反馈增益方法来增加电流镜的输出阻抗，同时还通过改进DMCM电路结构提高了电流镜的电流匹配精度，使得设计的电流镜在任何Iin下都保证有较高的电流匹配精度，而且这种新型电流镜也有近似于传统两级共源共栅电流镜的摆幅．采用TSMC 0．18μm，1．8／3．3CMOS标准工艺，在3．3V电源下，输出阻抗能达到18GΩ以上，并且电流匹配精度接近于0．01％，输出电压摆幅为1．28～3．3v。

Current mirror is one of the basic cell in analog circuit design. The accuracy and output impedance are the key parameters to determine the performance of a current mirror in high performance analog circuit design. To design a novel current mirror with high output impedance and high current mathing accuracy , a novel feedback gain stage is used to increase the output impedance at the same time , the design promotes the matching accuracy significantly by improving the DMCM current mirror, it proposed that the new current mirror has high matching accuracy in any Iin Moreover the new current mirror also has output swing similar as traditional two stage cascade current mirror. When the supply voltage is 3.3 V, the output impedance can reach 18 GΩ, and the matching accuracy is under 0. 01%, output swing is 1.28-3. 3 V.