Hi
Well, a typical buck converter with current mode control has a PWM controller referenced to output ground, a current sense transformer to bring down the current sense signal and a pulse transformer to level shift the gate signal.
Another approach is the one from Fairchild with an integrated solution riding on the switch node:
To be independant on single source parts, I would like to do the same with the standard PWM controllers like the SG3524, UC1843 etc as shown in the scematics below:
I haven't build it yet, but do any of you have experiences with this? Ofcourse I need to make a seperate plane connected to the SW (switch) node below the entire PWM controller circuit to combat leakage currents by the parasitic capacitances/dV/dt.
Anything more to look out for?
Thanks
Klaus