A TKO is awarded when one fighter is under extreme duress either from one punch or many and the officials feel he can't or shouldn't continue so they stop the fight. You don't have to be knocked down or even woozy, you can simply not be defending yourself well, not punching back, and getting hit hard.
Brashear vs Macintyre stands out as a standing TKO where Steve lands a vicious rib or kidney shot that buckled Brash and the linesmen jumped in and stopped it to protect him from further damage. Orr vs Scott cold also be a TKO.
Belak vs Brashear is a TKO and was damn near a KO, Brash needed help off the ice and had this lazed, goofy look.
There is no such thing as a knockdown win, it's simply a win that included one hockey guy knocking down the other hockey guy. Dribble, dribble.
It's really easy to figure out but so many guys complicate it with draw/edge/kd or draw possible edge, stuff like that.
Incidentally, KO is knocked out. Even for a few seconds.
Hope that helps.