| 摘要 |
PURPOSE:To switch a second switching element from ON to OFF by turning off a first switching element with an ON signal input prevention means when a main current becomes smaller than a specific value while the first switching means is ON. CONSTITUTION:When the main current of a transistor 10 becomes smaller than a specific value, namely closer to 0, an ON signal input prevention means consisting of a transistor 9, diodes 12, 13, 15, and 18 and resistors 34-36 turns off the transistor 10. Therefore, a capacitor 6 charged to almost power supply voltage starts to discharge, thus inverting the voltage of a diode 19, turning off a transistor 8, and turning on a transistor 7 and hence positively switching the transistor 7 from OFF to ON. |
