I read the Christophe Basso APEC 2011 seminar, about this figure I have one question.

1.) Why RLED,max need to below this equation(Red line), what happen if RLED above this equation(Red line)

[![enter image description here](https://i.stack.imgur.com/JbXJc.png)](https://i.stack.imgur.com/JbXJc.png)