| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply circuit whose output voltage is gradually increased since the power supply is closed, avoid a capacitive mode in a transient unstable state from the time of power supply closing to a steady state and reduce a stress applied to a switching device. SOLUTION: An input current harmonic is suppressed by an inverter circuit INV, a rush current at the time of power supply closing is suppressed by a step-down chopper circuit POW which is a power supply circuit and a switching device Q2 is shared by the inverter circuit INV and the step-down chopper circuit POW. A resistor R3 and a switching device Q3 is connected in series to a smoothing capacitor C1 and a control unit 1b which controls the switching devices Q1-Q3 is provided to avoid a capacitive mode in a transient unstable state from the time of power supply closing to a steady state. |
