Research And Design Of An Alterable-Frequency Converter Chip

LCD (Liquid Crystal Display) is the research center and magistral technologe of information display field because of its legerity, portability, low power consuming and easily integratied. With the widely utilization of LCD in portable devices, the rapid process actuates constantly the advancement of the technique of switching power supply. As the application field expanded, the demand on high efficiency, high reliability and high power density becomes the new design challenge to switching power supply IC.Based on the in-deep study of the interrelated technique of the DC-DC boost converters, a design scheme of the switching regulator of current-mode PWM boost converters operating at a alterable frequency of 640kHz or 1.2MHz is presented. According to the application demands a specification is put forward, the working principles of the converter are also explained. By consideration the key factors of the circuit design the structure of the converter is defined, then the design procedure of some primary function blocks are presented, with the simulation by Cadence Spectre. Lastly, a typical application circuit is introduced, based on which the whole chip simulation is achieved.The higher efficiency and high power density is the most important design guidelines for DC-DC switching regulators, all the time. In this thesis a pithy circuit design style is introduced, that insures the converter obtains the higher efficiency and the industry's high power density with the circuit functions fully achieved.The design is implemented base on the 0.5μm BCD technologies, with the fully system-level simulations. The results indicate that the controller has a fast transient response with small output ripple coefficient less than 0.417%, upstanding load regulation less than 1% and quite fine efficiency up to 90% in typical application. The high power density can be achieved by using high efficiency.