| 摘要 |
PURPOSE:To extend a field of application by connecting the base of a PNP transistor TR to a middle connection point of a diode row and connecting the collector of the PNP TR to the gate of a semiconductor switch through the first diode and making the anode current and the cathode current coincident with each other. CONSTITUTION:A switch 6 is turned on to supply a current from a curret source 5 to a row of dioses 19, 16-18, and 20. Then, all of these diodes are turned on, and conduction voltages are generated between anodes and cathodes of diodes 19 and 20. At this time, conduction voltages of diodes 19 and 20 are set equally, and values of resistances 9 and 10 are set equally, and factors of current amplification of TRs 11 and 12 are set equally, and conduction voltages between bases and emitters of TRs 11 and 12 are set equally, thus making a gate driving current supplied to the switch 1 through a diode 14 and a current drawn out from the cathode through a diode 15 equal to each other. |
