| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a motor-driven power steering device to improve reliability on a steering feeling during the occurrence of an FET trouble without increasing the number of components. SOLUTION: This power steering device comprises a bridge circuit 1 formed so that FET 11-14 are arranged between source terminals A and B such so that every two FET are arranged in series and two trains are arranged in parallel to each other. Output terminals C and D are arranged between the FET 11-14, an electric motor 3 connected between the output terminals C and D and assisting a steering force by an operational force, a control circuit 2 to vary the energization state of the electric motor 3 by controlling each of the FET 11-14, and detecting means 15 and 16 to detect a short-circuit trouble of each of the FET 11-14. The control circuit 2 switch the FET 13, connected in series to the FET 11, into an ON-state, and the FET 12 and 14, connected in parallel, into an OFF-state, for example, in a case of the short-circuit trouble of the FET 11 being detected and disconnects the FET 11 brought into a short- circuit trouble.</p> |
