| 摘要 |
In a switching regulator which is operable in response to an input a.c. voltage to produce an output d.c. voltage and which comprises a main transformer having primary and secondary windings for primary and secondary circuits, respectively, the primary circuit is formed by a series connection of the primary winding and a switching transistor selectively turned on and off at a high frequency of, for example, several hundreds of kHz while the secondary circuit comprises a series connection of a saturable reactor, a diode, and an output capacitor connected in parallel to a load. The saturable reactor exhibits high and low impedances when the diode is put into nonconductive and conductive states, respectively, and serves to reduce a switching loss resulting from interception of a voltage and a current. A frequency control circuit is connected between the output capacitor and the switching transistor to put the transistor into the on-state and the off-state at the high frequency with a time interval of the off-state kept unchanged and with a time interval of the on-state varied.
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