| 摘要 |
PURPOSE:To contrive the elongation of back-up time by a method wherein the connection of capacitors in a network, consisting of three sets of capacitors, two sets of switches and one piece of diode, which are connected between a rectifier and a DC/DC converter, is switched. CONSTITUTION:When a predetermined voltage from an AC power source 9 is impressed normally, a switch 6 is put ON and another switch 8 is put OFF in a control circuit, not shown in a diagram, to charge first-third capacitors 2-4 to a predetermined voltage (V1). When the AC power source is interrupted instantaneously, the capacitors 2-4 are discharged through a DC/DC converter 10 to back up. When the voltage Vl is reduced toward a predetermined voltage (V2) after a predetermined time, the switch 6 is put OFF in the control circuit, not shown in the diagram, to out the capacitor 3 off. When a predetermined time has elapsed further and the voltages of the capacitors 2, 4 become very near to the voltage V2, the switch 8 is put ON through the control circuit, not shown in the diagram, to connect the capacitors 2, 4 in series and combine the voltages to increase it. According to this method, a back-up time may be elongated remarkably and the reliability of the power source device may be improved. |
