Trifonov earned his first call-up to the
Bulgaria national side in March 2011 for the
Euro 2012 qualifier against
Switzerland and the
friendly match versus
Cyprus, but did not feature in these games. On 22 February 2018, Trifonov joined
Third League club
Spartak Pleven. In June 2018, he moved to
Second League side
Montana.
Later career Missing most of the 2019–20 season due to an injury in the autumn 2019, 35-year old Trifonov decided to retire at the end of the year. In February 2020, he returned to
PFC CSKA Sofia as a youth coach, where he became head coach of the players from 2004 and would also help the U17 team. Beside that, he also signed for
Kostinbrod in March 2020. ==Managerial statistics==