| 摘要 |
PROBLEM TO BE SOLVED: To detect failures in each switching element, using a simple structure, and to improve reliability by providing a resistor in the middle of a bridge circuit. SOLUTION: In a motor drive circuit 10, a resistor 24 for reference voltages, having a large resistance and voltage detection sections 25 and 30, are provided. Also, the voltage in middle wiring 15, when all FETs 11-14 are open, is stored at a storage section 19 in advance as a reference voltage VS. Then, when the motor drive circuit 10 is to be operated, a voltage VM of the middle wiring 15 is compared with a reference voltage VS by an MPU 18, while the FETs 11-14 are open, thus detecting short-circuiting of the FETs. Also, by successively closing only one FET among the FETs 11-14, disconnection in the FET can be detected. As a result, by allowing a small current to flow to the electric motor 4, failures in each FET can be detected. |
