| 摘要 |
PURPOSE:To attain high-speed switching by branching a base signal current when a collector potential of a bipolar transistor (TR) is lower than a prescribed potential to prevent oversaturatin of the TR. CONSTITUTION:When a power MOSFET2 is conducted, a bipolar TR1 is conductive. In this case, if a saturated voltage of a diode 3 and a collector-emitter saturated voltage of the TR1 are going to be lowered to the sum between the base-emitter saturated voltage of the TR1 and the saturated voltage of a diode 4, a forward current is branched also to a diode 3, and the forward current of the diode 4 is lowered. Thus, the oversaturation of the TR1 is prevented by distributing properly the voltage of the diodes 3, 4. |
