| 摘要 |
PROBLEM TO BE SOLVED: To meet specifications for voltage accuracy without interrupting any output and reduce the capacitance of an input capacitor if an instantaneous interruption occurs in a multiple output power circuit. SOLUTION: A power circuit is connected with a first output circuit 11 of high voltage and low accuracy and a second output circuit 13 of low voltage and high accuracy. Ordinarily, the output voltage of the first output circuit 11 is detected through a photo diode 15, and PWM(Pulse Width Modulation) control is exercised by a switching regulator 19 to control the first output circuit 11 to a constant voltage. Since the output circuit 13 is at a low voltage at this time, it is controlled to a constant voltage. If an AC input 1 is instantaneously interrupted and the voltage of an input capacitor 5 drops, an ACILOW detection circuit 21 detects that and causes an instantaneous interruption countermeasure circuit 23 to operate and transmit a signal for reducing the voltage of the first output circuit 11 to the switching regulator 19. As a result, the voltage of the first output circuit 11 is forcedly dropped to reduce the discharge energy of the input capacitor 5, and the energy contributes to stabilization of the voltage of the second output circuit 13. |
