Design Of A High Efficiency Buck DC/DC Converter With Wide Input Voltage

With the development of electronic information technology, small, portable and wearable electronic equipments are becoming increasingly popular in people’s daily life. These electronic devices have various functions and their volume are becoming smaller and smaller. This makes the battery life become a big challenge. The power management IC can not only improve the utilization rate of electric energy, but also provide a very stable supply voltage. So, developing a small volume and high efficiency power management IC is an inevitable market trend at this time.At the same time,in some specific occasions, the power management IC is required to work in a wide input voltage range, so that the chip can be used in more areas. But when the input voltage is in high level, the quiescent power loss will increase。So itis not a small problem to ensure the high efficiency of the chip when it works in a wide input voltage range.Based on bipolar technology, I design a high efficiency BUCK DC/DC converter with large load current(peak current is 3A) andwide input voltage range(5.5V~60V). Its switching frequency is 500 KHZ.It has an integrated power switch transistor with a low resistor(0.1Ω).It can reach to a high efficiency more than 85% in typical application. In order to reduce the static power consumption of the driver circuit and switch transistor, a circuit without switch off current is used to drive the power switching transistor. And in order to improve the efficiency of light load high input voltage, the output of the chip is used to provide the current to the internal module. Thus, the wide input voltage range is guaranteed. The chip is mainly used in portable computer, industrial and automotive electronics and distributed power supply.At first, this article introduces the current situation and development about the switch power management technology at home and abroad and analyzes several structures and basic fundamentals of DC/DC converter. Then, this paper analyzes the power loss of the BUCK DC/DC converter.So we can reveal several efficiency loss factors and converter efficiency loss mechanism.According to the analysis results, some methods to reduce the power loss are proposed. Then, based on the theory ofBUCK DC/DC converter, this paper designs and simulates a high efficiency BUCK DC/DC converter circuit with wide input voltage rangon system level and module level. Finally, this article designsa peripheral circuit and simulate s the whole circuit with the peripheral circuit. The results show that, the chip can work stably and efficiently in the input voltage range of 5.5V~60V.The whole work and some problems are summarized and some clear future directions are given in the end.