基于MOSFET ZTC工作点的高阶曲率补偿电压基准

A High-Order Curvature Compensation Voltage Reference Based on MOSFET ZTC Operating Point

工作在饱和区的MOSFET存在零温度系数(ZTC)特定工作点,基于这一特性设计实现了一款具有低温度系数的电压基准芯片。所设计的电路利用ZTC工作点的温度系数接近于0这一特点,辅以高阶曲率补偿电路,实现极低温度系数的输出电压。此外,针对ZTC工作点对工艺偏差的敏感性,根据蒙特卡洛仿真结果,专门设计了熔丝修调电路,以保证电路的输出结果具有较高工艺稳定性。该电路在CSMC 0.18μm CMOS工艺平台进行了流片验证,芯片面积为0.0025 mm^(2)。结果表明该芯片在室温时能够稳定输出475.5 mV电压,在-40~125℃内,温度系数达到1.8×10^(-6)/℃,在10 kHz时电源抑制比达到-68.7 dB。

A voltage reference chip with low-temperature coefficient was designed based on the characteristic of the zero temperature coefficient(ZTC)specific operating point of the MOSFET working in the saturation region.Based on the advantage of the feature that the temperature coefficient of the ZTC operating point was close to zero,and supplemented by a high order curvature compensation circuit,an output voltage with extremely low-temperature coefficient was realized.In addition,in view of the sensitivity of the ZTC operating point to process deviation and according to the Monte Carlo simulation results,the fuse trimming circuit was specially designed to ensure a high process stability of the output result of the circuit.The proposed circuit was fabricated and verified with the CSMC 0.18μm CMOS process platform,and the chip area is 0.0025 mm^(2).The results show that the chip can stably output 475.5 mV voltage at room temperature,the temperature coefficient reaches 1.8×10^(-6)/℃within-40-125℃,and the power supply rejection ratio reaches-68.7 dB at 10 kHz.