| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching DC power unit which is arranged, so that a rectifying circuit may not become a simple capacitor input in the case that excessive voltage is generated in the output of an active filter, and that an excessive peak current may not flow against the constant input current, in a switching DC power unit using a step-up active filter. SOLUTION: This power unit is equipped with a rectifying circuit DB1 which rectifies AC input voltage, a step-up chopper active filter 7 which has rectified pulse voltage inputted and outputs DC voltage, a DC-DC converter 8 which converts the DC voltage into specified DC voltage, a control circuit 9 which controls the switching element of the active filter 7, a control circuit 11 which controls the switching element of the DC-DC converter 8, a voltage detecting circuit 10 which generates an overvoltage detection signal to stop the oscillation of the control circuit 9 when it has detected the overvoltage by detecting the output voltage of the active filter 7, and an oscillation stop signal generating circuit 14 which stops the oscillation of the control circuit 11 by detecting the overvoltage detection signal. |
