Hello Guys,
I have performed the loop test on LM61460(5V out,2MHz) buck solution, the curves are below:
I have two questions for you ,hope you can help.
<1>why the highlighted region’s gain curve is flat and the phase is happened to 180 degree at low frequency? I think no integral element effects at those region, but your datasheet show you have one integral element in the loop. Can you explain that? Or can you show your transfer function of your converter’s compensation stage?
<2> the 0-db crossover frequency is about 100KHz(switching frequency is 2.1MHz,from this perspective, it makes sense),can you confirm that this value is qualified to suppress the parameter variations in feedback elements? Another expression is do you think the high frequency noise in the feedback stage can be effectively decreased squeezed under this condition?
Thanks very much!