| 摘要 |
<P>PROBLEM TO BE SOLVED: To suppress power supply higher harmonic waves, by realizing the stabilization of current control by maintaining a load output voltage at a constant level, in a power supply device having a power factor improving means. <P>SOLUTION: When a voltage of a load 4 is obtained with a step-up chopper circuit 3 by converting an input power supply 1 into a DC voltage, a power factor is improved, by switching a switching element 3c of the step-up chopper circuit 3 and short circuiting via a step-up chalk coil 3a. A no-load output voltage is detected by a voltage-dividing resistor circuit 12 for detecting a load voltage and an A/D converting means of a control part 13 at its current control. A prescribed ratio value is multiplied to the no-load output voltage. The voltage deviation between the no-load output voltage, to which the prescribed ratio value is multiplied, and the output voltage with a load is calculated. Voltage control, corresponding to an amount of the voltage deviation, is added so as to maintain the no-load output voltage and the output voltage with a load at a prescribed ratio. The output voltage is maintained at a constant level, regardless of the resistance variations of the voltage-dividing resistor circuit 12 and variations of a reference voltage in the A/D conversion means. Consequently, stabilization of the current control can be realized. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
