| 摘要 |
PURPOSE:To protect an overcurrent effectively by controlling a resistance for current detection connected to the collector of a transistor (TR) for output, and detecting the current flowing through this resistance and controlling the base current of an initial-stage Darlington-connected transistor (TR). CONSTITUTION:A PNPTR5 is off until the terminal voltage across a resistance R10 rises up to some value, and when a large current flows from an output terminal B, the TRTR5 turns on. Then, the base of an NPNTRTR6 rises in level above that of a resistance R20 and the TRTR6 turns on. Consequently, the base current of an NPNTRTR3 decreases and the amount of conduction of the NPNTRTR1 is controlled accordingly. Consequently, the potential difference between an input and an output is reduced. |
