LM5156: Boost converter 40V to 160V with LM5156EVM

Tool/software:

Hello,

I want to design a 50W boost converter to have a 160V output voltage with an input voltage :9-30V (12V typ).

I evaluate two cascaded boost converter instead of a flyback converter with the LM5156 controller.  I use 2 LM5156EVM-BST boards which I  updated following my specification.

My first boost converter (12V to 40V) works fine but the inductor temperature of the second boost converter is more than 100°C!

The specification of the second boost converter is : 

Input voltage = 40V, Output voltage: 160V/ current: 0,3A,  Switching frequency : 1MHz.

I want that the LM5156 controller works in current mode at the start up mode because there is a large output capacitor so I need to limit the input current to 1,5A (see the current Sense and Slope Compensation of the LM5155_56_Quickstart_Calculator attached file). LM5155_56_Quickstart_Calculator_for_Boost_Converter_Design_V1_1_1_Second cascaded boost 1MHz.xlsx

So the updated bom of the LM5156EVM-BST is

The efficiency the 2nd boot converter is about 82% and like I said the inductor temperature is more than 100°C. what can I do to improve this design ? 

Also, as the output voltage is 160V, the inductor's voltage is 120V, but most ot the inductor have a max operating voltage about 60-80V so I think there is a risk for insulation breakdown. What do you recommend about the operating voltage of the coil ?

Thanks,

Jerome