| 摘要 |
PURPOSE:To prevent the malfunction of a load circuit by performing comparison between two reference voltage levels through a comparator and using this comparison output to drive a switching transistor. CONSTITUTION:The output V0 of a comparator 1 is set at a low level in case the power supply voltages VCC1 and VCC2 are normal and abnormal respectively (VB>VD). Thus a transistor TR Q4 is turned off and the voltage V1 is set at a high level to turn off a TR Q6. While the voltage VC is set less than a reference level when the voltages VCC1 and VCC2 are abnormal and normal respectively. Thus a TR Q2 and a TR Q3 are turned off and on together with the TR Q4 turned off respectively. A TR Q5 is turned on when the TR Q4 is turned off and the TR Q6 is turned off. Thus the actions of both load circuits L1 and L2 are cut off.
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