TINA/Spice/LM5116: Some issue of the LM5116

Tool/software: TINA-TI or Spice Models

Hi,

We used LM5116 in a synchronous buck controller and the solution is similar as TI evaluation board LM5116-12EVAL, the parameter as below: input voltage is 30-60VDC, output voltage is 12VDC,

Peak current is 5A and the work current is 2-3A;

Now we have some issue for LM5116:

1.We can't change the PWM duty cycle whether it is no-load or full load;

2.Our circuit efficiency is lower than 90% if it is no-load(the reference is 99%), what is the right efficiency?

3.If we increase of the L1 from 10uH to 22uH, the efficiency is increased larger than 90%.

The schematic diagram as attachment for your evaluating, thanks.