| 摘要 |
PURPOSE:To prevent a corrective voltage from being added excessively by shortening storage time and to realize high performance by controlling the bias voltage of a driving transformer corresponding to the reduction quantity of a high output voltage. CONSTITUTION:The high output voltage is always detected by a high voltage detecting means 21, and when the reduction of the high output voltage occurs, a pulse width control circuit 3 generates a driving pulse with pulse width in accordance with the reduction quantity of the high output voltage i.e., the driving pulse with pulse width increasing according to the increment of the reduction quantity, and it is added on an output transistor TR 27 via the driving transformer 25. The TR 27 is turned on only when the pulse width shows that of a driving pulse signal, and the corrective voltage is generated via an addition pulse voltage generated at an addition voltage generating means 9, and the corrective voltage is added on a flyback transformer 2, thereby, the reduction quantity of the high output voltage can be corrected. When such corrective operation is performed, a source voltage control circuit 26 controls the bias voltage of the transformer 25 corresponding to the reduction quantity of the high output voltage. |
