Analysis and design of high linearity current reference for current mode circuits  

电流模逻辑电路中高线性度电流参考源的分析与设计(英文)

作　　者：周明珠[1] 朱恩[1] 王守军 王志功[1] 韩鹏[1] 李伟[1] 

机构地区：[1]东南大学射频与光电集成电路研究所,南京210096 [2]IDT-Shanghai,上海200233

出　　处：《Journal of Southeast University(English Edition)》2009年第1期18-22,共5页东南大学学报（英文版）

摘　　要：A complementary metal-oxide-semiconductor transistor （CMOS） voltage-to-current（VTC）converter with high linearity for current-mode analog and digital integrated circuits is described. A high gain operational amplifier （OPA） is utilized to form negative feedback. A proportional to absolute temperature （PTAT） current reference with transistors operated in a weak inversion is used as the bias circuit. The resistor and the OPA nonlinearity behavior are analyzed in detail. By optimizing parameters in OPA and adopting a small voltage coefficient polysilicon resistor as a linear device, a high linearity is achieved. The circuit is implemented in a standard 0. 6 μm CMOS technology. The low frequency gain of the OPA exceeds 90 dB. The test results indicate that the total harmonic distortion （THD）is 0. 000 2%. The common-mode input linearity range is 0 to 2. 6 V. Correspondingly, the output current range is 50 to 426μA. The sensitivity of the PTAT current reference to Vdd is approximately 0. 021 7. The chip consumes a power of less than 1.3 mW for a 5 V supply, and occupies an area of 0. 112 mm^2.描述了应用于电流模逻辑电路中的高线性度电压电流转换电路的设计与实现.该电路采用高增益两级运算放大器构成负反馈,偏置电路利用工作在弱反型区的MOS管电压电流呈指数律关系构成PTAT(proportional to absolute temperature)基准电流源.详细分析了电阻的类型以及运算放大器的参数对线性度的影响.通过优化运算放大器的参数并采用电压系数较小的多晶硅电阻作为线性器件获得了较高的线性度.本电路已采用CSMC0.6μm CMOS工艺实现,测试结果表明:输出的总谐波失真为0.000 2%.输入动态范围为0 ～2.6V,输出电流为50 ～426μA.PTAT基准电流源对电源变化的灵敏度为0.021 7.芯片采用5V供电,功耗约为1.3mW,芯片面积为0.112mm2.

关 键 词：linear voltage-to-current converter harmonic distortion operational amplifier PTAT current reference 

分 类 号：TN432[电子电信—微电子学与固体电子学]