| 摘要 |
PURPOSE:To enhance the safety of a car air conditioner by always setting the output of an operational amplifier which produces a control signal to a transistor which supplies a motor current to a low level at the time when a malfunction such as a motor lock or the like occurs. CONSTITUTION:When a main switch 3 and an air conditioner switch 4 are closed, an operational amplifier OP1 outputs a high level signal, causing a transistor Tr1 to be conducted ON, thereby supplying a current to a motor 5. On the other hand, an operational amplifier OP2 outputs a low level signal when the motor 5 is operating normally. Accordingly, a transistor Tr2 is in OFF state. Since the output of the amplifier OP2 becomes high level at the time of malfunction such as a motor lock, causing the transistor Tr2 to be conducted ON. Therefore, the output of the amplifier OP1 becomes low level, thereby performing the transistor Tr1 to become OFF. |
