| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a motor driver surely backing up a bridge circuit when a switching element of the bridge circuit for motor drive fails and configured at low cost. <P>SOLUTION: Two drive systems are constituted by connecting two switching elements Q in parallel with each of arms A1, A2, B1, and B2 of the bridge circuit 45. Then, the motor driver switches the output destination of a PWMM control signal alternately during usual motor drive control. The drive systems are switched when the current value of an electric motor 15 becomes zero, so as to protect the switching element Q. Moreover, in using a switching element smaller in current capacity than a main switching element Qm as a sub switching element Qs, the output of the PWM control signal to the sub switching element Qs is inhibited when the current value of the electric motor 15 reaches a reference value or more. <P>COPYRIGHT: (C)2008,JPO&INPIT |
