| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply changeover unit controlled by sampling a coil voltage, high in stability and reliability. SOLUTION: The power supply changeover unit controlled by sampling the coil voltage includes an input electrical path 1, a transformer T, and an output electrical path 2. The input electrical path 1 has: a switch part 11; a controller 12 performing a switch part control operation; and a coil voltage sampling device 13. The coil voltage sampling device 13 measures a minus primary coil voltage where the voltage falls quickly, and outputs an input voltage value having an effect on the controller 12. The transformer T has: a primary coil N1 and a primary coil N2 which are joined to the switch part 11 and the coil voltage sampling device 13 respectively; and a secondary coil N3. The output electrical path 2 is joined to the secondary coil N3 of the transformer T, and has an output terminal Vout. Thus, the coil voltage sampling device 13 measures a setting reference point voltage of the primary coil of the transformer T, and the controller 12 can perform application control. COPYRIGHT: (C)2009,JPO&INPIT
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