I spent a day trying to find a proper slope compensation resistor + current feedback resistor combination for LM3478 "simple switcher" from National. The datasheet description on that is vague, the WEBENCH tool at national.com is freaking useless. I can't model it in Spice since it is not clear how exactly the damn thing is supposed to work.
The basic question is: what should be the slope compensation resistor value R if the intended duty cycle of the switch is D and the frequency is F? Everything else can be easily derived once this question is answered.
I finally got it by trial and error. However do you know of any appnote or guide which clarifies this question?
Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
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