| 摘要 |
PURPOSE:To drive a large load capacitance at high speed without impairing the performance of a bipolar transistor and causing breakdown, by adding an element energized when a reverse bias voltage being applied between the base and the emitter of the bipolar transistor exceeds a prescribed value. CONSTITUTION:When the lowering of the emitter potential of the bipolar transistor 9 is delayed and it becomes larger by Vf than the base potential at the time of switching an output terminal 8 from a high level to a low level, a diode 13 is energized. Therefore, the electric charge of a wire connected to the output terminal 8 is also discharged by a MOS transistor 4 via the diode 13, and the maximum potential in a reverse direction to be applied between the base and the emitter of the bipolar transistor 9 is limited to the Vf, and the bipolar transistor 9 is operated normally without generating the breakdown. Also when the load capacitance of the wire connected to the output terminal 8 is large, since a part of accumulated charge is discharged by the transistor 4 via the diode 13, the change of the output terminal 8 from the high level to the low level can be accelerated.
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