Research Of Flyback DC-DC Circuit

With the increase of the portable electronic products, the demand of micropower, high-efficiency and small DC-DC converter has been enhanced. Therefore, DC-DC converter has a very great potential in the markets, with a good future. With rapidly growing demand in high-frequency digital modularization power supply system, it's significative to study on high-frequency digital switching mode power supply.Firstly, this thesis discusses the fundamental and computation method of isolation DC-DC converter circuit. Then, it introduces the characteristic and basic design method of different topology in flyback circuit's development. The third chapter gives the detailed steady-state analysis and design method, and this circuit can reduce the switching loss of power MOSFET effectively. The fourth chapter gives a design course of this circuit and operates the closeloop simulation by one-cycle control method. The one cycle-control method is a kind of method which can be implemented by numeric method. This thesis also presents the design and implementation of a single-end flyback converter circuit with openloop control. The openloop control circuit includes a signal source circuit which makes up of a single chip micyoco AT89S52 and a logic inverter 74LS06, and an electric insulated circuit which makes up of a high speed optical coupler 6N136 and a application specific drive chip of power MOSFET IR2110.This thesis proves that the active-clamp ZVZCS flyback DC-DC converter circuit can reduce switching loss of switching mode power supply effectively base on theory analysis and simulation. The single-end flyback experiment board used the control side of the DSP digital power supply system.