| 摘要 |
PURPOSE:To suppress the occurrence of input current distortion and rush currents and, at the same time, to make control easier by operating a voltage drop chopper for suppressing the occurrence of rush current at the time of making power supply and a voltage boost/drop chopper for improving input current distortion in a steady state. CONSTITUTION:A smoothing DC power source circuit suppresses the occurrence of a rush current after making power supply by operating a voltage drop chopper and improves input current distortion by operating a voltage boost/drop chopper. The switching between the choppers is automatically performed on the basis of the relation between the magnitudes of an input voltage Vin and the DC voltage Vdc of a capacitor C1. Therefore, the circuit configuration of the circuit does not become complicated and the size and cost of the circuit can be reduced. In addition, since the voltage drop chopper is used for suppressing rush currents and, when a transistor Q2 is turned on, an input current flows while charging the capacitor C1, the current of an inductor L2 gently rises. Therefore, the turning off time of the transistor Q2 can be shortened and the control of the transistor Q2 becomes easier. |
