| 摘要 |
PURPOSE:To reduce a size and to decrease a generated noise at high voltage inputting time by using a one-element forward type when an input voltage is high and a push-pull type when the input voltage is low. CONSTITUTION:When an input voltage from a primary power source 1 is a predetermined value or higher, the operation of a driver 6 is stopped by a gate circuit 7, a transistor 4 is turned OFF, and a transistor 3 is operated as a one-element forward type. When the input voltage from the source 1 is low, drivers 5, 6 are operated, and the two transistor 3, 4 are operated as a push-pull type. Thus, the peak value of a current flowing to a transformer 3 at normal operation time when the input voltage from the source 1 is high can be reduced.
|
