The Design Of PWM Switching Power Supply Based On Current-model Control

Research of switching power supply with the rapid development of electronicproducts and a great deal of attention, become a core part of electrical equipment,experienced a linear regulator to the development of its leap of switching regulator.With rapid development of microelectronics technology and semiconductortechnology, high integration, strong functions of high frequency integrated circuitswidely.The3.3V-1.8V conversion design in this article’s current mode PWM buckDC-DC switching power supply is to ensure the stability of deuterium light sources.Complete Visible Spectrophotometers including a light source, a monochrome device,sample cell, detector, amplifier circuit and results show the six part, deuterium lampas light source visible spectrophotometer, and its important role in the system as awhole. Spectrophotometer for light source requirement is: using wavelengths withinthe continuous spectrum of the light intensity is large enough, has a good stability.Only sufficient light intensity, and it is good to get the accurate analysis of thestability of the data. Deuterium lamps work stability affects the stability andperformance of the system as a whole. As deuterium-deuterium lamp lamp powersupply must be able to make to sustained and stable work, and meet the requirementsof the entire instrument miniaturization. From the viewpoint of comparison betweenlinear and switching power, switching power supply with small size, light weight, andhigh efficiency, stability as well as good, meeting the needs of design.This article introduces the DC-DC converter of various closed-loop negativefeedback topology and modulation, analyze the pros and cons of PWM/PFMmodulation, expounded the PWM pulse width modulation principle of voltage and current mode control mode, dynamically change based on their response speed andharmonic compensation circuit design for ease of comparison of their advantages anddisadvantages, and make your selection. Simultaneous analysis of the continuousconduction mode in system performance, stability, and introduces the synchronousrectification techniques and error amplifier frequency compensation methods, andfocus on the evaluation of ⅱ-type error amplifier circuit to improve promotion.Multism software is used in this article on each module and the whole circuitsimulation. Simulation results indicate that performance meet circuit requirements foreach module, when input voltage DC-DC converters between2.8V-4.5V changes,stable output voltage to maintain the1.8V, the output voltage ripple less than20mV,output rated load current360mA; between180mA360mA when the load changes,have good load regulation system. Under the rated load, system efficiency can beachieved by more than90%. Chip indicators meet the design requirements, achievingthe desired objectives.