| 摘要 |
PURPOSE: A method for detecting voltage drop using a photocoupler is provided to detect voltage drop using a photocoupler, a resistor, and P12V or N12V of a power supply instead of OP AMP. CONSTITUTION: An anode as the primary side of a photocoupler is connected to P15V through an input resistance. A cathode of the photocoupler is connected to P12V as the reference voltage. A collector as the secondary side of the photocoupler is connected to a data BUS of an ISA BUS through a BUS buffer. An emitter of the photocoupler is connected to a grounding portion. The current is applied from the anode of the photocoupler to the cathode of the photocoupler by the potential difference of 3V between the P15V and the P12V when the P15V is normally outputted. At this time, a transistor of the secondary side is turned on, the current is applied from the collector to the emitter, and an output of the photocoupler becomes LOW. The transistor of the secondary side is turned off when a DC/DC converter is in the abnormal state.
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