Tool/software:
In my circuit, FPWM mode is selected by default (mode pin connected directly to RT), when probed at the sw node, i could see duty cycle only varying at fixed switching frequency, when no load is connected. I have attached the oscilloscope image. I used the cursor to check the frequency of the given image, everywhere it was the same, only duty cycle was varied.
But in the datasheet it is mentioned as , when FPWM mode is selected at no load conditions, spread spectrum is active and should be visible. My set frequency is 2.2MHz and accordingly i should see the spread spectrum from 2.2MHz to 2.552MHz (16% from the set frequency - from datasheet - is it correct?)
Could you please let me know on the above issue?
