Hello guys,
So I recently built a split rail power supply using TPS560430 fixed frequency switcher and a coupled inductor following the topology as shown below. (TPS560430 doesn't require a catch diode)

I designed it to output +6V -6V. The result I got was an uneven split from the ground. Like +9V -3V. More positive than negative.
If I load + and - terminals the split starts improving. And, across the + and - terminals the switcher IC regulates the output of 12V perfectly.
If I increase the input voltage to the IC the split starts getting worse (uneven).
Is there anything I can do to get close to even split without loading the power supply?
Thank you.