Ken Biberaj ain't giving up his name for anyone ... even toy giant Mattel, who he says is overextending its reach in order to monopolize the "Ken" moniker.

We spoke with Biberaj -- who hosts the "Coffee with Ken" podcast -- on "TMZ Live," and we asked him about his current beef with Mattel ... which he says kicked off when he tried to patent the name of his show. Getty

Biberaj says they were preliminarily approved for the trademark ... before Mattel came out of nowhere and objected to Ken and his team for registering the show because they believed anything "Ken" belongs to them. Of course, the most famous Ken in existence has to be the Ken doll -- Barbie's man, who was introduced by Mattel in 1961.

KB is calling BS on the claim ... pointing out hundreds of thousands of dudes in

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