Design Of An Adjustable, High Precision Low Dropout Linear Regulator

The power management integrated circuit has many advantages, such as high integrity, high performance/price ratio, and high-eficiency power supply etc. Currently many foreign companies still occupy most market of Power management IC.It is very important to study and develop domestic power management IC.A design of LDO voltage regulator is presented in this paper,it has wide input voltage range (2.5V～6V) and many kinds of output voltages, and the LDO voltage regulator posses characteristics of high precision.The basic working principle of LDO Linear Regulator is researched in this paper firstly. Its various indicators are analyzed later.The top circuit is researched,also some functional modules are introduced and analyzed which include bandgap reference,bias circuit.error amplifier, over temperature protection, current limiting circuit, Short-circuit protection circuit and so on.Based on the HHNEC0.35um BCD process,simulated the designed circuits by cadence and Hspice under different voltages,temperatures,models after the completion of the design of the circuits, the results show that the performance of the LDO regulator is excellent,it posses characteristics of high precision.The regulator is good for line regulation,also it is good for load regulation,the line regulation is0.002%/V in typical condition,the load regulation is0.02%/A in typical condition.the maximum output current is300mA,the dropout voltage Vdropout is95mV in typical condition.The layout of the LDO linear regulator is finished after the completion of the design and the simulation of the circuit. The pre-simulation and post-simulation verification are performed for the chip circuit,this enhances the design reliability and fab success.The simulation results show that the characteristics of the chip can meet the specifications.