| 摘要 |
PURPOSE:To obtain a power source deciding signal completely corresponding output voltage by detecting the output of a differential amplifier stabilizing the output voltage of an electric power converting part and generating the power source deciding signal. CONSTITUTION:When a switch 2 is turned on, the reference voltage of the differential amplifier 22 is turned to a steady value, but the output voltage EO is delayed at its rise. In order to ascend the output voltage EO of the differential amplifier 22 because the output voltage EO is lower than the set value, the output Va of the differential amplifier 22 is saturated, and when the output voltage EO reaches the set voltage, the output Va of the differential amplifier 22 is suddenly changed, exceeds the reference voltage of a comparison detector 17 and reaches the prescribed voltage value. The comparison detector 17 detects the output Va of the differential amplifier 22 operated as described above and sends a power source deciding signal S delayed by T1 by an one-way delay circuit 25. When the switch 2 is off, the power source deciding signal does not stop until the output voltage EO is reduced even if input AC is instantaneously interrupted. |
