Do you have a scope? Look at the voltage across R353/354. With a scope not a meter. I want to see the waveform.

The waveform is as below:

 

 

Ought to take the FLIR camera and investigate WHAT is heat source, the core or the bobbin. If bobbin - means wire is too thin, or, many cases at high frequency, the heat is caused by Focault, thus must divide wire into litzendrath. Litz wire often solves this problem. For example, 50 kHz allows maximum 0.6 mm wire diameter, but better not overstep the 0.38. Thus make the needed cross section according to 3 A/mm2 (or better 2 A/mm2) with many parallel spiralized branches. If contrary, the core is those heating up while the bobbin is cold, then B(max) is overstepped. Thus must apply the more turns count in the bobbins, and if there is no more place, then apply the bigger hamm.., pardorn core.

 

Ought to take the FLIR camera and investigate WHAT is heat source, the core or the bobbin. If bobbin - means wire is too thin, or, many cases at high frequency, the heat is caused by Focault, thus must divide wire into litzendrath. Litz wire often solves this problem. For example, 50 kHz allows maximum 0.6 mm wire diameter, but better not overstep the 0.38. Thus make the needed cross section according to 3 A/mm2 (or better 2 A/mm2) with many parallel spiralized branches. If contrary, the core is those heating up while the bobbin is cold, then B(max) is overstepped. Thus must apply the more turns count in the bobbins, and if there is no more place, then apply the bigger hamm.., pardorn core.

Do you mean I need change a inductor with better material and better constructure? would you recommend one to me? thanks!

 

@Janis59 was saying that if you want the inductor to run cooler you might have to change the winding or the core.

The winding is already Litz wire, so maybe an inductor with a more suitable core can be found.

But that is the recommended inductor and it seems it is being operated well within its limits.

I am not familiar with your power supply control chip but looking at the current waveform it looks as though the control loop is oscillating. If that is the case you need to adjust the values in the compensation circuit or the current limit section.

Is your gate drive frequency in agreement with the application note?

 

Actually, I had to sugges that before any measures taking ought to take the thermal camera and investigate what is the heated element, bobbin or core. Never happens at both simultaneously.