Research And Design Of Efficiency And Current Buck DC-DC Converter

With the increasing material and cultural demands,people have higher and higher requirements for the comprehensive performance of electronic products,which also promotes the development of the semiconductor industry.Power supply,as the heart of electronic product,has also been put forward higher requirements such as high conversion efficiency,low cost,high-speed transient response and so on.In recent years,the high-performance DC-DC switching power supply has been become a research hotspot and research difficulty.In this article,a step-down DC-DC switching power supply is designed.And this Buck DC-DC switching power supply has the advantages of high conversion efficiency in a wide load range,fast transient response and a large load current of 10 A.The research design mainly focuses on several key parameters such as high efficiency,fast transient response,large load current and stability.After a comprehensive analysis of the conversion efficiency of the system,a synchronous rectification method,current modulation circuit and control of the dead time are proposed to improve the conversion efficiency of the switching power supply.In order to improve the transient response speed of the chip,the COT constant-time conduction control mode is adopted.And the mode is developed from the hysteresis mode,which has the advantages of simple structure,fast transient response and high conversion efficiency.The maximum load current refers to the maximum current through the load when the system can operate normally in the CCM working state.Due to the trend of low voltage and high current,the DC-DC switching power supply is gradually increasing the load current.In order to increase the load current,there are mainly the following two measures: improving the area of the power tube and integrating the power tube.Stability is one of the most important performances of each semiconductor chip circuit.In this article,a comprehensive system stability analysis is performed for the system and an improved stability scheme is proposed.In order to stabilize the output voltage ripple,an inductor current injection technique is used in this article.And the simulation results achieve the design goals.Based on a 0.35μm high voltage of 24 V BCD process design,the step-down DC-DC converter has an input voltage range of 4.5V-16 V,an output voltage range of 0.8V-13 V and a continuous output current of 10 A.And the peak value of the converter conversion efficiency of the Buck DC-DC converter is 96%,which achieves high conversion efficiency in the wide load range.And load transient and linear transient response can recover steady-state values in about one cycle.The system simulation results show that all parameters achieve the design requirements.