基于运放弱失配机制的快速启动和稳定的PTAT电流源设计

Rapid start-up and fast stabilization PTAT current reference based on weak mismatch mechanism of operational amplifier

为了解决传统PTAT电流源在启动过程中响应速度过长和收敛速度过慢等问题,提出了一种新型快速启动和稳定PTAT电流源.基于高可靠双极结构,引入了一种具有弱失配机制的运算放大器结构,利用局部负反馈以及共享负载电容等方法,在优化芯片面积的同时,大大加快电路的启动速度和环路收敛稳定速度.电路性能在上电启动、稳定收敛和工作模式三方面均有大幅度的提升.结果表明,在标准UMC 180 nm CMOS工艺下,电賂可实现-40℃到85℃的宽温工作范围,2.5-5 V宽摆幅工作电压,104.26μA的平均电流,实现4μs的启动速度以及108 dB的高PSRR抑制比特性,在对启动与收敛速度要求较高的系统芯片中有良好的应用前景.

In order to solve the problems of long response speed and slow convergence speed of traditional PTAT current source during startup,a new PTAT current source with fast startup and stability is proposed.Based on the highly reliable bipolar structure,an operational amplifier structure with weak mismatch mechanism is introduced.By using local negative feedback and shared load capacitance,the chip area is optimized,and at the same time,the circuit startup speed and loop convergence stability speed are greatly accelerated.The circuit performance has been greatly improved in three aspects:power-on start-up,stable convergence and working mode.The results show that under the standard UMC 180 nm CMOS process,the circuit can achieve a wide temperature range of-40 C to 85℃,a wide swing voltage of 2.5-5 V,an average current of 104.26μA,a startup speed of 4μs and a high PSRR rejection ratio of 108 dB.It has a good application prospect in system chips with high requirements for startup and convergence speed.