I am trying to design a buck converter using an LM2576HV (Vref: 1.23 V) and a digital potentiometer (input: 48 V, output: 0 to 48 V, Imax= 3 A).
The digital potentiometer with the highest supply voltage I could find works with 36 V. So I can only get 1.23-36 V at the output of the buck converter.
I am thinking of using a linear regulator like a TPS7A4101 that converts 48 V to 36 V to be able to supply the potentiometer, then using an op-amp to be able to increase the digital potentiometer output from 36 to 48 V. In this way, the output will be 1.65-48 V.
Would this be the right approach or should I go a different way? I have doubts about whether I can get enough current from the op-amp output.
Also I can't get 0 V at the output because of the reference voltage of the LM2576HV. How can I reduce the minimum voltage at the output from 1.65 to 0 V?