Search patents by E. Miyata in USPTO for more details.

I had a nagging feeling that I'd disremembered the circuit
Miyata developed and tried to look it up. Must be an IEEE
paper since there's no patent in his name that I can find.

But these patents may help: 6936803 and 6884977

This paper seems to describe a circuit close to that oven converter.
http://yakimov.homeftp.net/banditko/...ticles%20from%
20ieeexplore/01217760.pdf