| 摘要 |
PURPOSE:To increase the regulating range of an output voltage by adding a transistor member for bias to a saturable reactor to move the hysteresis loop of a core to an apparently high side. CONSTITUTION:A pulse signal of the prescribed frequency is applied to the base of a main switch element 3 to operate switching, the voltage induced at the secondary winding N2 of a main transformer 2 is controlled by a saturable reactor 4 to the prescribed voltage and output. This control is performed by inputting the detection signal Vs of an output voltage V0 to a controller 12 formed of an error amplifier, and flowing a reset current through a control switch element 10. In this case, the reactor 4 is formed by providing a permanent magnet at part of the core on which a coil is wound as a magnetic bias. Thus, since the remaining magnetic flux density of the core is disposed apparently at the position of Br', the initial magnetic flux density of the core can be regulated between the saturated magnetic flux density and Br', to increase the control range of the output voltage V0. |
