A UPS circuit, comprising: a rectifier for converting a received alternating current into a direct current; an output (T out ) configured to be coupled to a load; an inverter comprising a plurality of inversion phase legs (PL21, PL22, PL23) coupled to the inverter and configured to be coupled to the output (T out ) via respective first inductors (L inv ) for inverting a direct current output from the rectifier into an alternating current at the output (T out ); a neutral line (N); a failure detection device (D) for detecting a failure of any of the plurality of inversion phase legs (PL21, PL22, PL23); a redundant inversion phase leg (PL2a) having an input connected to the rectifier and configured to be coupled to the output (T out ) via a second inductor (L N ); and a control device for connecting the redundant inversion phase leg (PL2a) to the neutral line (N) via the second inductor (L N ) when the failure detection device indicates no failure of any of the plurality of inversion phase legs (PL21, PL22, PL23), and for receiving a signal sent by the failure detection device indicating a failure of one of the plurality of inversion phase legs (PL21, PL22, PL23), deactivating the failed one of the plurality of inversion phase legs (PL21, PL22, PL23) and disconnecting the redundant inversion phase leg (PL2a) and the second inductor (L N ) from the neutral line (N) based on the received signal, and replacing the deactivated inversion phase leg and its associated first inductor (L inv ) with the redundant inversion phase leg (PL2a) and the second inductor (L N ) without deactivating others of the plurality of phase inversion legs (PL21, PL22, PL23). a rectifier for converting a received alternating current into a direct current; an output (T out ) configured to be coupled to a load; an inverter comprising a plurality of inversion phase legs (PL21, PL22, PL23) coupled to the inverter and configured to be coupled to the output (T out ) via respective first inductors (L inv ) for inverting a direct current output from the rectifier into an alternating current at the output (T out ); a neutral line (N); a failure detection device (D) for detecting a failure of any of the plurality of inversion phase legs (PL21, PL22, PL23); a redundant inversion phase leg (PL2a) having an input connected to the rectifier and configured to be coupled to the output (T out ) via a second inductor (L N ); and a control device for connecting the redundant inversion phase leg (PL2a) to the neutral line (N) via the second inductor (L N ) when the failure detection device indicates no failure of any of the plurality of inversion phase legs (PL21, PL22, PL23), and for receiving a signal sent by the failure detection device indicating a failure of one of the plurality of inversion phase legs (PL21, PL22, PL23), deactivating the failed one of the plurality of inversion phase legs (PL21, PL22, PL23) and disconnecting the redundant inversion phase leg (PL2a) and the second inductor (L N ) from the neutral line (N) based on the received signal, and replacing the deactivated inversion phase leg and its associated first inductor (L inv ) with the redundant inversion phase leg (PL2a) and the second inductor (L N ) without deactivating others of the plurality of phase inversion legs (PL21, PL22, PL23). <EOS>