摘要 |
PROBLEM TO BE SOLVED: To solve a matter that an extra precharge circuit is required for detecting the fact that the voltage in the downstream of a relay is sticking to the GND potential in order to detect a short mode failure of a transistor before a relay is turned on, and a resistive short mode failure may be undetectable even if a precharge circuit is prepared. SOLUTION: A relay having two contacts of normal open and normal close is employed, a discharge circuit is arranged at a connection place on the normal close side being connected with a motor drive circuit when the relay is turned off, and a capacitor in the downstream of the relay is connected automatically with the discharge circuit when the relay is turned off. COPYRIGHT: (C)2009,JPO&INPIT |