高精度低噪声基准电压源的设计

Design of a High-precision Low-noise Bandgap Voltage Reference

利用反向带隙电压原理,采用基于CMOS阈值电压的自偏置共源共栅电流镜技术,设计了一种低压低噪声基准电压源。该电压基准源没有外加滤波电容的情况下,通过双极型晶体管大的输出阻抗特性,实现了更低的噪声输出,提高了输出电压的精度。Hspice仿真结果表明,在0.95V电源电压下,输出基准电压为233.9mV,温度系数为7.6×10-6/°C,30Hz频率下输出频带噪声谱线密度是15nV/Hz。在0.9～2.0V的电源电压范围内,室温下基准电压的变化为1.7mV。流片后的测试结果验证了所设计的基准电压源能工作于较低电源电压,输出基准电压的温度系数小,噪声与功耗低。

A new low-voltage low-noise voltage reference independent of temperature is presented by employing the reverse bandgap voltage principle （RBVP） and based on subthreshold MOSFETs. Without the use of a large external filtering capacitor the topology has a low-noise output due to the large output impedance of bipolar transistor. Hspice results show that the nominal output is 233.9 mV, the temperature coefficient is 7.6×10-6/℃ for 0.95 V supply voltage and the output noise spectral density of 15 nV/√Hz at 30 Hz can be obtained. The reference voltage variation is 1.7 mV for supply voltage from 0.9 V to 2.0 V at room temperature. The chip measurement demonstrates the proposed voltage reference circuit may operate with a supply voltage as low as 1 V and has lower noise, temperature coefficient and power dissipation.