| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a low-voltage-failure detection circuit of a power supply unit that can achieve miniaturization and cost reduction. <P>SOLUTION: This circuit is provided with a first output terminal OUT1 from which the highest potential is outputted, a third output terminal GND from which the lowest potential is outputted, and a second output terminal OUT2 from which an intermediate potential is outputted. Also, it is provided with a first circuit of R2, ZD1, and R1 connected between the first and third output terminals to decide a first drop detection reference potential, which becomes a reference for detecting the drop of the highest potential, and a series circuit consisting of a second circuit of R3 and ZD4, an alarm signal output means PC1, and a potential-drop detection means Q1 connected between the second and third output terminals. The second circuit stops a current flow if the intermediate potential drops below a second drop detection reference potential. A potential-drop detection means stops the current flow if the highest potential drops below the first drop detection reference potential. The alarm signal output means outputs an alarm signal according to the presence of the current flow. <P>COPYRIGHT: (C)2008,JPO&INPIT |
