Modeling and Controller Design of Flyback Converter Operating in DCM for LED Constant Current Drive

Abstract

In power converter, the system model has a significant meaning of the design of the controller and the dynamic characteristics. In this paper, the switching network average method is used to set up the small signal model of flyback circuit, which is operating in discontinuous current mode(DCM). A controller with single zero and single pole is designed based on the small signal model which is set up in this paper. Moreover, the analysis of system stability and dynamic response is proposed. Finally, the system is simulated and verified by a flyback LED constant current drive circuit (220AC input, 0.7A/16W output).