基于失配控制的非线性补偿带隙基准电路设计

Design of nonlinear compensated bandgap reference based on mismatch control

在一阶线性补偿基准非线性温度特性分析基础上,提出了利用基准电路内部可控非线性失调电压实现高阶补偿的方法,即利用3路互偏结构代替传统基准电路中的2路自偏置结构,在宽温度范围内,理想状态下的基准温度系数相比一阶线性补偿明显降低.与其他类型的分段高阶补偿相比,基于失配补偿的带隙基准不仅结构简单,而且工艺稳定性更好.基于CSMC 0.18μmCMOS工艺完成了该基准电路的MPW验证,在-20～120℃温度范围内,基准温度系数的测试结果最低为6.2×10-6/℃.基于理论与实测结果误差产生原因的分析,提出了电阻修调以及面积功耗折中方面的改进措施.

Based on the analysis of the nonlinear-temperature characteristics of the first-order linear compensated bandgap reference（BGR）,a high-order nonlinear compensation method is proposed by utilizing the controllable systemic nonlinear offset voltage within the bandgap circuit,where the three-branches coupling biasing structures are used to replace the traditional two-branches self-biasing structures,and the ideal temperature coefficient within a wide temperature range is reduced significantly as compared to that of the first-order linear compensation one.Besides,compared with other types of segmental high-order compensated circuit,the mismatch compensated BGR is not only simple in circuit structure but also more stable in manufacture process.The proposed reference is fabricated in CSMC 0.18 μm CMOS process,and the tested minimum temperature coefficient within a temperature range from-20 to 120 ℃ is 6.2×10-6/℃.Finally,based on the error analysis between theory and experimental results,improvements in resistor trimming and tradeoffs between area and power are proposed.