Research And Design Of Picowatt-level Self-biased CMOS Voltage Reference

With the rapid development of Io T,5G and portable devices,the contradiction between high power consumption and insufficient battery power has become increasingly prominent.In some ultra-low power(ULP)applications,such as miniature sensors,wearable devices,RF transceivers,implantable medical devices,and energy harvesting systems,nanowatts or even picowatts of power consumption are required in standby or in working.The voltage reference source is one of the most basic modules that constitute these circuits or systems,so it is of great significance to design an ultra-low power voltage reference source with low design cost,small area,and high performance.This paper analyzes the conduction principle of subthreshold MOS transistors from the physical structure,and discusses the feasibility of designing voltage reference with subthreshold MOS transistors.According to the analysis of the current typical sub-threshold voltage reference circuit,the nanowatt-level voltage reference usually uses a separate bias current generation circuit,resulting in additional power consumption;Picowatt-level voltage references usually use special process devices or use the leakage current of MOS transistors,resulting in poor performance,high cost,and incompatibility.In consideration of the above shortcomings,this paper designs a novel picowatt-level self-biased CMOS voltage reference source circuit based on the 2T-CVR self-bias circuit structure.For the designed voltage reference source.Firstly,the temperature compensation principle,linear adjustment performance and power supply suppression performance of the voltage reference source are derived from the formula.Then,the standard CMOS process was used to simulate the performance of the voltage reference source circuit.The simulation results show that the temperature coefficient is 36.8ppm/?,the linear adjustment rate is 1.289%/V,the low-frequency PSRR is-50d B,and the power consumption is 273.36p W.This voltage reference source not only has a simple structure,small area,and high performance,but can be integrated using a standard CMOS process,and only consumes picowatt power.For improving the performance of the reference circuit.On the basis of the voltage reference source,a start-up circuit,a single-stage operational amplifier circuit and a trimming circuit are added.The start-up circuit can eliminate the degenerate bias point and also reduce the settling time of the reference voltage.The op amp structure can clamp the voltage and improve linear adjustment performance and power supply suppression performance.The trimming circuit can further compensate for changes in the temperature coefficient of the reference voltage caused by process changes and mismatches.The simulation results show that although the increased auxiliary circuit causes the power consumption to increase by110.54p W,the temperature coefficient is improved to 21.3ppm/?,the linear adjustment rate is improved to 0.0145%/V,and the low-frequency PSRR is improved to-69.3d B.The proposed voltage reference source is taped out in the 0.18?m 1.8/5V standard CMOS process and packaged in the form of COB.If Pad is not calculated,its Die area is only 0.0094mm~2.Compared with the few picowatt-level voltage reference sources currently in high-level international journals,the performance indexes of the voltage reference sources proposed in this paper have reached a high level.