NOVELTY - The converter (1) has a primary side (2) and a secondary side (3) connected with a high-voltage transmission system and a low-voltage transmission system, respectively. The secondary side comprises a short circuit protection device (18) that comprises two parallel-connected current doublers (5, 6), where each current doubler comprises secondary coils (7, 8) and two parallel-connected throttles (12-15) i.e. choke coils. The throttles are connected in series to short-circuit fuses (S1-S4), and the secondary side comprises a circuit board for formation of a planar transformer.    USE - Direct current (DC) static converter for connecting a high-voltage transmission system and a low-voltage transmission system i.e. on-board electrical system, of a power supply system of an electric power providing device that is utilized for supplying electric power to a high voltage load and a high tension generator such as electrical prime mover i.e. electrically driven compressor of fuel cell system, of a motor car (all claimed).    ADVANTAGE - The short circuit protection device comprises the two parallel-connected current doublers, where each current doubler comprises the secondary coils and the two parallel-connected throttles that are connected in series to the short-circuit fuses, so that ideal balancing of the throttles is enabled, thus enabling flow of low utilizable current through the short-circuit fuses in a normal state and flow of high short circuit current through the short-circuit fuses in an event of an error, and hence avoiding false signal initiations with a high utilizable current while enabling safe triggering of the short-circuit fuses in case of short circuit. The throttles are designed as the choke coils, thus manufacturing the throttles in a simple and inexpensive manner.    DETAILED DESCRIPTION - The short-circuit fuses are designed as fuse wire bridges. An INDEPENDENT CLAIM is also included for an electric power providing device.    DESCRIPTION OF DRAWING(S) - The drawing shows a simplified circuit diagram of a DC static converter.    Short-circuit fuses (S1-S4)    Dc static converter (1)    Primary side (2)    Secondary side (3)    Parallel-connected current doublers (5, 6)    Secondary coils (7, 8)    Parallel-connected throttles (12-15)    Short circuit protection device (18)