TPS54386PWPR : Inductor phase margin error with Switcher pro tool

Can you post the loop response plot from your switcherpro design?

Hi John,

Please find the Loop plot.

I think 32 degrees PM is too low. Did you modify any of the component values from what switcherpro initially recommended?

Yes, I adjusted to my circuitry.

I would be inclined to use what switcherpro recommends.

I would probably be inclined to use the components as recommended by the tool. What all did you change?

Hi John,

I have changed the Inductor value, output capacitor values according to my circuit preferences.

Is there any other way to compensate this phase margin without changing the inductor ?

Thanks & Regards,
Nanjunda M

The tPS54386 is an internally compensated voltage mode control device. As such the output inductor and capacitor values and capacitor ESR are chosen to align with the internal compensation for stability. If you are using all ceramic output capacitors, you will need to adjust the compensation with RC network about the feed back resistors. Section 8.3.12.2 in the datasheet details this. Personally, I tend to only use the feed forward capacitor C2 and not use C1 and R3. I am not sure if switcherpro can accommodate those changes, but you can easily model this with the TINA-TI or pspice average models available here:
www.ti.com/.../toolssoftware