Research And Design Of High Efficiency BUCK Converter Based On COT Control

Nowadays, China’s economy has entered a stage of rapid development, the power electronics industry began to rise. The rise of power electronics industry originated from the increasing demand for power electronic equipment, electronic products have been popular in the crowd, PCs, smart watches, smart wrist and other electronic products have entered people’s lives, and are closely related to people’s lives, and bring our daily life great convenience and fun. These electronic devices need a stable power supply,switching power supply because of its small size, high efficiency, low power consumption and other advantages are widely used, BUCK DC-DC converter as an important member of the switching power supply chip, the DC voltage can be Step-down. At present, the demand for low power consumption, high efficiency and high frequency of electronic products has accelerated the development of power management chips. In this paper, the efficiency and power consumption of a BUCK converter based on COT control are studied and analyzed.This thesis designs a BUCK converter with high conversion efficiency based on COT control. The BUCK converter has the characteristics of fast transient response,high precision and high efficiency. The load current can reach 10A and the output voltage is adjustable (0.675V-3.3 V), the input voltage range is wide (4.5-26V), can meet the various types of memory supply needs, widely used. In the case of medium load and heavy load, the system works in CCM mode; in the case of light load, the system works in DCM mode; in the case of ultra-light load, the system automatically switches to sleep mode (sleep mode), in sleep mode, The system turns off the chip’s unnecessary analog circuitry to minimize static power consumption. The system is capable of maintaining high efficiency over a full load range of up to 98% efficiency。In this thesis, the classification and development trend of DC-DC converters are introduced. Then, the working principle of the converter based on COT control is analyzed in detail. Then, the main performance indexes of the system are designed and researched, and the sleep mode is designed to improve the system efficiency under ultra-light load. Based on the 0.18μm BCD process, the chip reference voltage circuit,the upper and lower power tube drive module, the zero crossing sampling circuit and the zero - crossing comparator are simulated and verified. The simulation of the sub -module is carried out, and the whole circuit is simulated by using Specter and H-spice simulation software. Simulation results show that high efficiency buck conversion can be achieved.