They will play AS Roma for a spot in the final of Europe's third-tier competition.
The 21-year-old Fofana, who recently returned from a serious leg injury, showed excellent pace and broke up several dangerous PSV attacks in the second half.
"The togetherness of the boys is unbelievable," Maddison said. "For example, Wesley Fofana is fasting at the minute - he's not eating or drinking anything all day and he puts in a performance like that.
"He's stopping all the counter-attacks by sprinting. That epitomises what we are about in terms of courage."
Leicester manager Brendan Rodgers was happy with the response of his players in the second half.
"We're a team that's young in terms of European football. We come to PSV Eindhoven with a great history in winning the European Cup in 1988. For us, we're so young in it," Rodgers said.
"These are great experiences for us, we showed great personality and I'm so happy for the players and it's the first semi-final in our history."
