| 摘要 |
A series voltage regulator includes a protective circuit that detects the collector current from a PBP power transistor and the collector-emitter voltage thereof. Such current and voltage signals are generated, respectively, by an auxiliary PNP transistor having a collector current which is proportional to that of the PNP power transistor, and by a circuit connected between the emitter and the collector of the PNP power transistor. The collector current and collector emitter voltage signals are processed by a circuit which, whenever the current and voltage values are greater than preset maximum values, reduces the PNP power transistor current and maintains it within permissible limits. The protective circuit does not affect the minimum voltage drop between the input and output of the regulator and may be dimensioned so as to use the maximum extent of the S.O.A. of the PNP power transistor.
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