Research And Design On High Voltage Switching DC-DC Buck Converters

With the progress of electronic power technology,high-voltage electronic equipment and people's social life are getting closer.Especially in recent years,along with the scale of 5G newsletter,industrial vehicle electrification and industrial 4.0 upgrade,the market has put forward high pressure,high intelligence for power management technology.In response to these needs,this paper designed a high-voltage synchronous step-down switching power supply chip.In this paper,the DC-DC switching power supply technology is researched and analyzed.The basic working principle of the step-down DC-DC converter and the system modulation mode of the DC-DC converter are introduced.Based on the switching network average model method,the small signal transmission equation of the step-down DC-DC converter is derived,and the BUCK converter is modeled and simulated based on the PSPICE environment.After comparing the advantages and disadvantages of various system modulation modes,the final choice of peak current control type PWM/PSM modulation scheme with fixed working frequency,convenient external clock synchronization,high loop bandwidth and high system conversion efficiency in the full load range is selected.An improved slope compensation strategy is designed,which fundamentally solves the limitation of the slope compensation to the maximum load capacity of the system output.By analyzing the small signal of the inner loop of the current,it is found that the BUCK system becomes a single-pole system under the action of the inner loop of the current.Then,the overall architecture of the synchronous rectification BUCK control chip is designed.Next,the circuit design and simulation verification results of several important circuit modules are given in this paper.The simulation results of each functional module meet the requirements of the system.Based on the 0.35um BCD process,the high-voltage step-down switching power supply chip designed in this paper.The chip layout is designed by virtuoso software.Finally,the chip with the parasitic parameters is post simulated.The simulation results show that the function and performance of the chip have reached the design expectations.The system output voltage is stable,the linear regulation rate and load regulation rate are good,the system conversion efficiency is up to 93%,and the system conversion efficiency can reach 88%under light load 50mA load condition.