Patent ID: 8379361

Claim:
A power supply system (S), comprising: a power processor ( 1 ) having a power input ( 2 ) with a nominal input voltage VNin and an AC power output ( 3 ) with a nominal output voltage V Nout and a nominal output current I Nout ; and a power backup circuit ( 6 ) connected in parallel to said power processor ( 1 ) between said power input ( 2 ) and said AC power output ( 3 ) and comprising: a bidirectional switch ( 7 ), and control means ( 12 ) for closing said bidirectional switch ( 7 ) after detecting a short circuit condition downstream of the AC power output ( 3 ); wherein said power backup circuit ( 6 ) also comprises a current limiter ( 9 ) connected in series to said bidirectional switch ( 7 ) to limit the current that can flow through the power backup circuit ( 6 ) to a maximum current which is capable of tripping a breaker ( 4 ) downstream of said power processor ( 1 ) without tripping a breaker ( 8 ) upstream of said power processor ( 1 ) when said bidirectional switch ( 7 ) is closed.