Hi, team.
My customers are considering UCC28722 for a smart meter.
I am considering referring to the following documents.
However, since customers do not want to use auxiliary windings, I would like to regulate the secondary side to 5 V without using auxiliary windings.
※Challenging the proposal by adding DC/DC to the 15V regulation circuit, but it is said that there is no cost merit.
<Reason not want to use auxiliary winding wire>
・Circuit cost is occupied by transformer, because there is price difference of more than twice with and without auxiliary winding.
・There was also a circumstance that was connected to a trouble trying to use a transformer of the auxiliary winding type before.
And, considering a circuit to return to VDD from the secondary side, the secondary side voltage must be higher than UVLO.
For this reason, we consider a discrete charge pump circuit using the switching operation of the following part and think whether it can return to the power supply of the primary side.
※I would like to sell TI's charge pump ICs originally, but I'm thinking of having a desire to reduce the cost to the limit and building it with a discrete configuration.
<Question>
Combine the charge pump circuit with discrete configuration and can return to the power supply of the primary side?
Best regards,
Pokkun