Abstract:

This application note for the MIC38C43 provides a design tool for the project engineer. This note also provides a template for future projects: the user need only scale the appropriate sections. Designing an off-line discontinuous flyback power supply for the first time can become overwhelming. The task involves many disciplines of electrical engineering-magnetics, filter, feedback, layout, and thermal issues to name a few. The design procedure can be broken down into two parts. The reader starts with (1) an in-depth, block-by-block theory of operation and follows with (2) a step-by-step practical example. This example includes specifying the major components, including the magnetics. The schematic, PCB layout, electrical waveforms, and a bill of materials are also included.