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Title:
NEGATIVE VOLTAGE DETECTING CIRCUIT
Document Type and Number:
Japanese Patent JPS6043906
Kind Code:
A
Abstract:

PURPOSE: To prevent destruction of an output transistor (TR) of an amplifier or a load speaker by detecting an abnormal negative voltage fluctuation of a neutral potential of a full direct couple DC amplifier by means of a small detecting current and interrupting a switch when the current exceeds a prescribed range.

CONSTITUTION: A voltage across a diode 11 placed at a higher potential side in a constant voltage circuit using the forward constant voltage characteristic of two diodes 11 and 12 is divided by resistors 21 and 22, and a base of an NPN TR15 is connected to said voltage dividing point. An emitter and a collector of an input PNP TR16 are connected respectively to an emitter of said TR15 and ground, a diode 13 forming a current mirror circuit is connected between a positive power supply and a collector of the NPN TR15, a collector of other TR14 of the current mirror circuit is used as an output terminal and a base of the input TR16 is used as an input terminal.


Inventors:
ISODA MICHIO
Application Number:
JP1983000152731
Publication Date:
March 08, 1985
Filing Date:
August 22, 1983
Export Citation:
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Assignee:
NIPPON ELECTRIC IC MICROCOMPUT
International Classes:
H03F1/34; H03F1/52; (IPC1-7): H03F1/52



 
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