| 摘要 |
PROBLEM TO BE SOLVED: To provide a failure diagnosis circuit for diagnosing the failure of each switching element of a bridge circuit, without rotating a motor. SOLUTION: Pull-up pull-down terminals P+ and P1 and monitor terminals T+ and T- are connected to both input terminals M+ and M- of a motor 3, respectively. The pull-up/down terminals P+ and P- selectively take two states, namely a pull-up state for supplying a voltage of 5 V for diagnosing failure to resistors R+ and R- and a pull-down state for supplying a ground potential of 0 V to the motor input terminals M+ and M- via the resistors R+ and R-, respectively. A failure diagnosis circuit 1 switches the two states of the pull-up/down terminals P+ and P- and at the same time switches one element out of switching elements Q1-Q4, monitors the potential changes in the monitor terminals T+ and T-, corresponding to each combination between the above state switching and the switching of the above switching elements and makes diagnosis on the failure of the switched switching elements. |
