| 摘要 |
PURPOSE:To reduce the size of a choke coil and to improve the efficiency of a power source by increasing an oscillating frequency when an output current decreases lower than a reference current. CONSTITUTION:After the ripple component of a DC input applied to between input terminals 10A and 10B is removed by a capacitor 12, the input is applied through a switching transistor 14 to the primary coil 16P of a transformer 16. A switching signal is applied from a switching controller 18 to the base of the transistor 14, which is controlled at the ratio of conducting range to the nonconducting range in the direction for suppressing the variation in the output voltage of the power source. A frequency controller 52 switches the oscillating frequency of a reference oscillator of the controller 18 in respose to the both end voltage of a resistor 54 for detecting the current. |
