The US electoral college is not PR.  It is the result of 50 separate FPTP elections (maybe 48, there are 2 states that do things differently) to elect a slate of "electors" in each state.  The number of electors is roughly proportional to population but is biased to giving more votes to states with smaller populations.  That way, you have a national election, not just a contest run in 7 or so really populous states which is what would happen if the number of electors per state was purely by population.  It is why Hilary, who ran up huge majorities in New York and California, lost overall.