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Patent Searching and Data


Title:
BREAKING DETECTION CIRCUIT
Document Type and Number:
Japanese Patent JPH0526911
Kind Code:
A
Abstract:

PURPOSE: To detect that the current is cut off, by a method wherein a current flows through a diode when one power source is cut off, three transistors connected to the diode in series turn ON and the current detected by a current detecting means increases.

CONSTITUTION: When a switch SW1 is opened, a power supply from a first power source VA to an internal circuit 10 is interrupted and the power supply is made from a second power source VB to the circuit 10 through a diode 1. By a current flowing through the diode 1, the voltage of the diode 1 lowers, a base voltage of a transistor 2 becomes lower than an emitter voltage and the transistor 2 turns ON. Thereby both transistors 3 and 4 turn ON, a current flows from a third power source VD to a current detecting resistor 5, a voltage of a breaking detecting terminal 6 turns to be of 'L' level and a signal of detection of the breaking of the power source VA appears at the terminal 6. Since the power is supplied to the circuit 10 through the diode 1 in the state wherein the power source VA is cut off, the circuit 10 is not put in non- operation.


Inventors:
AIDA TORU
NAKANO TOSHIYA
Application Number:
JP18457891A
Publication Date:
February 05, 1993
Filing Date:
July 24, 1991
Export Citation:
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Assignee:
MITSUBISHI ELECTRIC ENG
MITSUBISHI ELECTRIC CORP
International Classes:
G01R19/165; H02H11/00; (IPC1-7): G01R19/165; H02H11/00
Attorney, Agent or Firm:
大岩 増雄 (外2名)