| 摘要 |
PURPOSE:To improve the resolution of on/off ratio by presetting plural kinds of on/off ratio of each period within plural predetermined periods so as to change the average on/off ratio over plural periods. CONSTITUTION:A reference clock pulse from an oscillator 1 provided with an oscillating element 1a is frequency-divided at a frequency divider 2, processed by a soft timer 3, outputted as a control signal and the load is controlled. In making a control frequency fc constant, i.e. a period T of the control signal, and the on/off ratio dk is controlled variably with the average value over a period KT being k times the period T, then K-kind of average on/off ratio dk is controlled variably to the given control frequency fc. |
