A guide to simplifying switch-mode power supply design

In secondary-side regulated flyback converter designs, feedback from the secondary side needs to be passed to the primary side, while allowing both sides to remain electrically isolated from each other for safety reasons. While optocouplers perform this task well, they are expensive, slow, and their life is limited to around 10 years because of the LEDs they incorporate. 

In this week's Engineers' Insight, Philip Lechner takes a look at how feedback circuitry can be integrated into switcher ICs in order to reduce cost, complexity, and space requirements in switch-mode power supplies