| 摘要 |
PURPOSE:To prevent the breakdown at turning off, by providing the restriction means of re-application voltage giving the back bias between the emitter and collector of transistor or the drain and source. CONSTITUTION:The power supply 1, load 2, power transistor 3, branch diode 4, and base driving circuit 20 constitute the power transistor switch unit, and the means of re-application voltage restriction 200 is inserted between the emitter and collector of the transistor 3. That is, the diode 12 and the series circuit of diode 13, capacitor 14 and inductance 15 are connected in parallel with the emitter and collector of the transistor. Further, the thyristor 16 being the auxiliary switch to increase the turn-off ability to the turn-on ability, or the transistor 16' is connected in parallel with the series circuit of the capacitor 14 and inductance 15. Thus, the switching can be made by the allowable breakdown limit at turning-on of the transistor 3 and the auxiliary switch 16. |
