Design And Research Of DC-DC Converter With High-efficiency, Wide-input, And Multiple-separation Power Rail

The update of electronic products range from low-power devices such as smart phones and smart wristbands to large-capacity devices such as drones and balance cars is so fast.Power management chips as an essential part of these electronic products,its innovation and upgrade become more and more important.As an important part of the power chip,the DC-DC converter has been widely used in current electronic products with its advantages of high efficiency,high load carrying capacity,and good transient response,which can satisfy consumer’s requirement such as life time of the product,load and stability,so DC-DC converters gradually began to dominate the market.This thesis follows the trend of development and research hot spots of switching power supplies,and combines previous research results to design a Buck-type DC-DC converter with high efficiency,wide input,and multiple-separation power rails.In recent years,drones and other high-power products have developed rapidly.The input voltage range of traditional low-voltage chip is too small to meet the input voltage requirements of such products.In order to increase the input voltage range,we put forward a design scheme of multiple-separation power rails.The input voltage range can reach 3V-20 V,and the maximum load current is 8A,which meets the application requirements of different types of electronic products.Firstly,based on the three basic topology structures of DC-DC converters,the principle of PWM and PFM modulation methods are analyzed,and the advantages and disadvantages of the two modulation methods in different application environments are combined to put forward a new structure of PWM/PFM automatic switching.This structure chooses the modulation way according to the load size,which can reduce the power consumption,improve the chip,s efficiency;Then explain the working principle of the LDO circuit,key sub-module of the system.The circuit design analysis and the simulation results were explained.Finally,the loop of the whole circuit was modeled and analyzed for loop stability and load transient transient response,output voltage accuracy,conversion efficiency,and startup.The overall performance of the process is verified by simulation to ensure that the designed circuit works well.Based on 0.35 um BCD process,a Buck-type DC-DC converter with high-efficiency,wide-input and multiple-separation power rail is designed.The Cadence EDA integrated circuit design tool under the LINUX operating system is used to build the system circuit.The Spectre simulation tool is used to verify the circuit.Simulation results show that thechip achieves a maximum efficiency of 97% at a load current of 2.5A and a minimum of83% at full load.The output voltage ripple is only 3mV at a switching frequency of750 KHz,and the load current can reach 8A.Satisfy the requirements of the design index on product efficiency,accuracy,load capacity and other aspects.