Calvin (and I believe Luther also) uses the term "regeneration" to refer to a process, sometimes almost synonymous with how we use the word "sanctification" today.
Using "regeneration" as a technical reference to the moment-in-time implantation of new life (i.e. the new birth) which results in faith is found specifically in Peter Van Mastricht (1630-1706) and others who followed, a la Jonathan Edwards.