ELECTRIC POWER STEERING CONTROL DEVICE

PROBLEM TO BE SOLVED: To provide an electric power steering control device capable of preventing a driver from feeling uncomfortable and uneasy even when a motor drive circuit is failed without increasing the size or cost. SOLUTION: The electric power steering control device comprises a main motor drive circuit 20 which has switches S21-S24 between a power source 5 and itself and between a motor 4 and itself, and generates the motor driving current based on the current control value E to be output from an MCU 10, and a sub motor drive circuit 31 which has switches S31-S34 between the power source 5 and itself and between the motor 4 and itself, and generates the motor driving current smaller than that of the main motor drive circuit 20. The motor current detected by a main current detection circuit 22 is monitored by the MCU 10, and if it is determined from an abnormal value of the motor current that the main motor drive circuit 20 is failed, the switches S21-S24 are opened, the switches S31-S34 are closed and the motor 4 is driven by the sub motor drive circuit 31. COPYRIGHT: (C)2008,JPO&INPIT