一种高精度二阶曲率补偿带隙基准源设计

Design of a second-order curvature compensation bandgap reference

针对双极型晶体管基极-发射极电压VBE含有二阶温度非线性项导致带隙基准源温漂系数较高的问题,提出了一种新颖的二阶曲率补偿电路,根据基尔霍夫电压定律以及MOS管饱和区漏电流与栅源电压成平方关系,产生一个与热力学温度平方成正比的补偿电流,对基极-发射极电压VBE的二阶温度项进行补偿,从而有效地降低基准输出电压的温漂系数。基于0.5μm CMOS工艺库,使用Spectre对电路进行仿真,结果表明,在电源电压5V,温度范围为-35～+130℃时,温漂系数为2.213ppm/℃,低频时电源抑制比可达到-116d B,在10k Hz时抑制比为-74d B。电源电压在1.6V～5V范围内变化时基准输出电压线性调整率为0.094%。

Aiming at the problem that the bipolar transistor base-emitter voltage VBE contains a second-order temperature nonlinear term causing a high temperature drift coefficient of the bandgap reference source.A novel second-order curvature compensation circuit is proposed.According to Kirchhoff voltage law and the square relation between the drain current in the saturation region of MOS transistor with the gate-source voltage,the compensation circuit generates a compensation current being proportional with the square of the thermodynamic temperature,and compensates the second-order temperature term of the base-emitter voltage VBE,thus effectively reducing the temperature drift coefficient of the reference output voltage.Based on the 0.5μm CMOS process library,Spectre is used to simulate the circuit.The results show that the temperature drift coefficient is 2.213 ppm/℃when the power supply voltage is 5V and the temperature range is-35^+130℃.The power supply rejection ratio can reach-116dB at low frequencies and achieve-74dB at 10kHz.The linear adjustment rate of the reference output voltage is 0.094%when the power supply voltage varies from 1.6V to 5V.