| 摘要 |
PURPOSE:To prevent a capacitor voltage from unbalancing at a light load time by detecting the unbalance state of the capacitor voltage for dividing an input DC voltage, and controlling a dummy load circuit connected between output terminals. CONSTITUTION:Two one-element DC/DC converters CV1, CV2 in which the primary sides are connected in series, and the secondary sides are connected in parallel convert AC voltages by pulse-width-modulating the DC voltage divided by capacitors C1, D2 in which input DC voltages Vin are connected in series, rectified, smoothed, and supplied to a load L. In this case a dummy load circuit 3 is connected between output terminals 21 and 22 connected with the load L, and a circuit 4 for detecting the unbalance state of the capacitors C1, C2 is provided. Thus, when the load L becomes light so that the capacitor voltage becomes unbalanced, a difference occurs at the secondary winding voltages e1, e2, and when it becomes the prescribed value or higher, the load circuit 3 is driven. Thus, the load is increased apparently to operate to balance the unbalanced state. |
