#### wholx

##### Member level 4

**dc/dc compensation network**

hi,

i am confused about the relation between the switching freq and the bandwidth of the overall feedback converter. i read in a doc that the bandwidth should be 3 times smaller that the switching freq, how is that?

i made a circuit and found the output voltage of the error opamp doesnt look like a constant value until i increase the switching freq to a much higher value. the original design is Fsw = 100KHz so i made the bandwidth as 33KHz with a phase margin = 75degree. finally i need a Fsw=5MHz to get the constant Verramp. anyone can tell me what happened to my design? did i mistaken the constraint to the bandwidth by the the switching freq?

Added after 1 hours 42 minutes:

i see that if we wanna reduce the output ripple, we can increase the output capacitance or the switching frequency. i wanna know if there is a max value of switching frequency that the converter can work on?