Research And Design Of An Ultra-low Power Low-dropout Regulator

With the booming of electronic and communication technology,portable electronic devices have been popularized and power management has received widespread attention.By researching the power management market and its developing trends,it can be found that Low Dropout Regulator(LDO),as an important member in the market of power management,has been widely applied for its simple structure,small size,high Power Supply Rejection Ratio(PSRR),excellent stability,low noise,low power consumption,highly integrated Power Management Unit(PMU)and other characteristics.At present,the demand for miniaturized electronic products has changed the research direction of LDO from large load current to high integration and low power consumption.The design of high-performance LDO has become the hot spot in integrated circuit field.The main contents of this thesis are:(1)The key issues in the design of ultra-low power LDO were studied,including the improvement of system stability and transient response,and the Miller compensation scheme was improved to improve the system stability;Meanwhile,adaptive bias current technology is used to improve the load transient response performance and realize low power consumption in standby state by reducing bias current.The compromise between low power consumption and fast transient response is solved.(2)For the low power consumption design in this thesis,firstly adopt adaptive bias current technology to provide low bias current for the operational amplifier and reduce the quiescent current in the standby state;secondly,the design optimization of the main functional modules is carried out,and a depletion and enhancement voltage reference source is proposed for ultra-low power circuit design;finally,a current monitoring module is added to the over-temperature protection circuit to reduce the power consumption of the over-temperature protection circuit in the standby state.The low power consumption design is realized.(3)For the high-precision design in this thesis,firstly the fuse trimming network is used to repair and adjust the reference voltage to obtain a high-precision reference output voltage;secondly,the LDO output voltage with high precision is obtained through the design of high gain operational amplifier.The high-precision design is realized.The chip test results showed that the proposed LDO output voltage was stable at 1.2V to 3.6V when its supply was set to be from 2.2V to 5.5V.The temperature drift coefficient is 25.7ppm/℃ in the operating temperature range from-40℃ to 125℃,and the accuracy can reach ±1%.The dropout voltage was 218 m V at a maximum output current of 150 m A.The linear regulation was 0.022%/V,the load regulation was 3m V,the quiescent current below 485 n A.The power supply rejection ratio was 81.4d B at 100 Hz,and 57.76 d B at 1KHz.The noise was 96.7μVrms.While ensuring the stability of the LDO,compared with the same type of design at home and abroad,the design achieves an excessive power consumption from μA and even m A to n A,reducing at least three orders of magnitude.± 1% is the highest level of accuary in this field,and the overall performance of LDO is excellent.The designed circuit was validated by the results of the chip test.