| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a small-sized magnetic amplifier capable of reducing a loss without complicating a circuit scale configuration. <P>SOLUTION: When a saturable reactor L1 is turned off, a current flows in an auxiliary coil N2 by commutation operation. At this time, although a transistor Tr is in an off state, the current of the auxiliary coil N2 flows into a parasitic capacitance of the transistor Tr via a rectifier diode D3 to raise a gate potential of the transistor Tr. As a result, the transistor Tr is turned on, and a current I flows in a drain of the transistor Tr, thereby, a source potential of the transistor Tr is raised by a resistance R3 connected to a source of the transistor Tr when a drain current flows. On the other hand, the gate potential of the transistor Tr is held to a Zener voltage by a Zener diode Zd connected to a gate of the transistor Tr. Accordingly, the rise in the source potential reduces a gate-source voltage Vgs of the transistor Tr to turn off the transistor Tr and reduce the drain current. <P>COPYRIGHT: (C)2012,JPO&INPIT |
