Design Of LDO Based On Curvature Compensation Reference And Closed-loop Stability

The power supply of electronic devices,whether DC or AC,they will change within a certain range during the power supply process.In this case,the integrity of the power supply will be affected.The low dropout regulator can suppress the stability change of some analog circuits caused by voltage fluctuation.The performance of the bandgap reference circuit of the traditional LDO is poor,which cannot meet the requirements of some high-precision circuits.Therefore,it is of important to study the LDO based on curvature compensation reference and closed-loop stability.Based on the analysis of the working conditions and properties of LDO at home and abroad,this paper designs a LDO based on curvature compensation reference and closed-loop stability.The circuit compensates the higher order term of V_BEin BJT through the subthreshold characteristic of MOSFET,and achieves the effect of curvature compensation.The bandgap reference circuit provides a stable input voltage to the LDO,while the source follower and adaptive bias circuit increase the response speed and closed-loop stability of the LDO.This paper first introduces the development of LDO,then analyzes the advanced LDO at domestic and foreign and introduces its functions.Next,based on the basic theory of LDO,analyze the advantages of the LDO designed in this paper and the traditional LDO,design the specific module of LDO introduced in this paper.The LDO is built and simulated,and simulation results are recorded.Finally,layout of LDO is designed.Based on the SMIC 0.13?m process,and use Cadence to build and simulate the circuit.Then simulate the curvature compensation bandgap reference and LDO.The simulation results show that the temperature drift coefficient of the bandgap circuit is8.11ppm/°C,the input voltage is 3V?5V,the output voltage is 2.8V,the linear adjustment rate is 0.22%,the load regulation rate is 0.19%,the leakage voltage is28m V,the loop gain of the circuit is 75d B under light load,with a phase margin of42°,and the loop gain of the circuit is 60d B under heavy load,with a phase margin of 64°,the power supply rejection ratio can be maintained from 60d B to 90d B at low frequencies,and is not lower than 40d B at high frequencies.The output reliability of the bandgap reference circuit and LDO is well.After the pre-simulation is completed,the layout of the circuit is designed.The post-layout simulation of this circuit is basically the same as the previous simulation,and the effective area is about 124?m*155?m.The designed circuit meets the design requirements.The circuit designed in this paper has better temperature compensation characteristics,faster response speed,and higher stability.