在芯片可调低电压带隙基准源设计

Adjustable low-voltage bandgap reference on chip

为高速双模预分频器提供所需的稳定的参考电平,提出了一种基于带隙基准核的在芯片可调低电压带隙基准源电路设计方法,通过在双极型晶体管的附近并联少量电阻,获得数值可调的、常温下具有零温度系数的低电压基准。讨论了运放的反馈环路、失调电压以及开环增益等各项因素对基准电压精度的影响,并给出了相关的分析公式。设计采用0.18μm数模混合CMOS工艺。仿真结果表明,电路的电源抑制比(PSRR)为-48dB,-40℃^+125℃温度变化范围内的温漂系数为8.3×10-6/℃。电路综合性能良好,能满足低温漂、高精度的设计要求。

With the development of CMOS process and wide application of low-voltage bandgap reference, the low-voltage bandgap reference design based on CMOS process has great practical significance.An ad-j ustable low-voltage bandgap reference based on bandgap core was presented in this paper,and an adj usta-ble output voltage with zero temperature coefficient at room temperature needed by the high speed dual-modulus divider could be realized by paralleling minimum number of resistors next to the bipolar tran-sistor.In addition,some influencing factors such as feedback loop,offset voltage and open-loop gain of OPA were discussed,and correlative analysis formulas given.The circuit is fabricated in 0.18μm standard CMOS process and simulation results show that the power supply rejection ratio （PSRR）is -48 dB,and that the temperature coefficient is 8.3×10-6/℃ in the temperature range from-40 ℃ to＋125 ℃.Above data demonstrate that the circuit gains good comprehensive performance including low- temperature drift,high- precision and so on which can meet the demands of system design completely.