The invention relates to a protective device (2) for an electrical circuit (1), including a first fuse (8), a pyroelectric switch (12) connected in parallel with the first fuse and comprising a control area (16), capable of receiving a trigger signal (S), and a power area (18) for the passage of the electric current. The device also comprises a control circuit configured to produce and transmit the trigger signal to the control area. The device includes a second fuse connected in series between a first input conductor (4) and the first fuse and capable of supplying a power supply voltage (V) to the control circuit, which is connected between the second fuse and the control area.