| 摘要 |
PURPOSE:To regulate the power supplied to a load without changing frequency, and when the load is a discharge lamp, stably light the discharge lamp a-t the time of deep light control. CONSTITUTION:Switching elements S1, S2 and S3, S4 are connected in series to a DC power source, and an inductor L1, a capacitor C2, and a load Z are connected between contact points of the switching elements S1, S2 and S3, S4. To the ON/OFF timing of the switching elements S1, S2, the ON/OFF timing of the switching elements S3, S4 is varied in the range from the same phase to the phase shifted by 180 deg.. The simultaneous ON period of the switching elements S1, S4 and S2, S3 in the diagonal positions is changed to regulate the power supplied to the load Z without changing the switching frequency. The switching frequency of the switching element S2 is differed from the switching frequencies of the other switching elements to make positive and negative feeding power to a resonance circuit unbalanced, the DC component is supplied to the load Z to prevent the lighting failure or flickering by moving stripes, when the load Z is a discharge lamp, for example, is prevented. |
