| 摘要 |
PURPOSE:To prevent destruction of an actuator, by turning off a switch means when the output of a supply voltage circuit enters into the short-circuit or open state. CONSTITUTION:When an output 15 of a supply voltage circuit 14 enters into the short-circuit or open state an NPN transistor 32 and a PNP TR 34 are turned off and a PNP TR 35 and an NPN TR 37 are turned off also because an NPN TR 29 is turned on. Consequently, a supply voltage is not inputted to an actuator driving circuit part 4. When an output 16 is short-circuited or opened, a PNP TR 22 and the NPN TR 29 are turned off and the NPN TR 32 or the like is turned off, and therefore, the same operation state is set. When an output 18 is short-circuited or opened, the PNP TR 22 of a detecting circuit 19 is turned off and the NPN TR 29 is turned on, and therefore, a switch circuit part 31 is set to the same operation state. Thus an excessive current does not flow to the actuator to prevent destruction of the actuator.
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