| 摘要 |
PROBLEM TO BE SOLVED: To prevent a controller from being damaged by an abnormality arising in a power circuit for a controller, and a circuit to be controlled from operating in no-control state. SOLUTION: When an output from a power circuit 140 for a controller comes to an overvoltage, a voltage signal from a comparator 37 is switched to an "H" level whereby a second LED41 emits light, and a second light-receiving TR 43 is turned on. As a result, by having a current signal with a variable pulse width supplied to the base terminal of a TR15 from a PWM control circuit 13 bypass the second light-receiving TR43, the switching action of the TR15 is turned into a compulsively stopped state. This state is kept until the level of the voltage signal from the comparator 37 is switched to an "L" level by the resolution of a trouble, etc. which has occurred in a power circuit 140 for a controller. COPYRIGHT: (C)2004,JPO&NCIPI
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