LLC converter is no good for you....your spec is vin = 3-4.2v, vout = 3.2v and iout = 1A.
No way is LLC any good for you...too many components.
Resonant converters ONLY reduce switching losses...and you dont have much switching loss.
Not only that, but LLC converters dont do well as current sources , and a led driver needs a current source....but admitteldy it could have components added to make it workable..its just not worth it.
LLC also needs a transformer.......and that'll make your circuit too big..........unless you design your own core which will cost a fortune......or use an integrated transformer, but that would be a custom build and cost a bomb
For 3w of led light from 3.5V input, no way an LLC converter.
Does your tutor know what an LLC converter is?
Ask him this question........if an half bridge LLC is operated at the upper resonant frequency with a 1:1 transformer...and a vin of 100V, then what is vout?...the answer, without needing calcs, is 50V (minus any diode drops)...ask him this...if he doesnt know the answer, then bin him.
Seriously, LLC?.......What sort of output do you want...split coil and two diodes, or full bridge rectifier?....ridiculous.............if you must have resonant, then why not a resonant non isolated converter.
BTW, do you need isolation......?