JPS5585142A - Semiconductor fail safe logic circuit - Google Patents

Semiconductor fail safe logic circuit

Info

Publication number
JPS5585142A
JPS5585142A JP15754978A JP15754978A JPS5585142A JP S5585142 A JPS5585142 A JP S5585142A JP 15754978 A JP15754978 A JP 15754978A JP 15754978 A JP15754978 A JP 15754978A JP S5585142 A JPS5585142 A JP S5585142A
Authority
JP
Japan
Prior art keywords
constant current
photo
voltage
circuit
fail safe
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP15754978A
Other languages
Japanese (ja)
Inventor
Yoshiaki Koga
Koichi Mizuno
Yoshie Niwa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to JP15754978A priority Critical patent/JPS5585142A/en
Publication of JPS5585142A publication Critical patent/JPS5585142A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K19/00—Logic circuits, i.e. having at least two inputs acting on one output; Inverting circuits
    • H03K19/007—Fail-safe circuits

Landscapes

  • Logic Circuits (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Computing Systems (AREA)
  • General Engineering & Computer Science (AREA)
  • Mathematical Physics (AREA)

Abstract

PURPOSE:To obtain the logic circuit having fail safe function by combining the current constant circuit of step type constant current characteristics and the photo coupler, through the use of breakdown phenomenon of junction type FET and constant current diode used. CONSTITUTION:The constant current circuit having step type constant current characteristics using the breakdown phenomenon of FET is constituted with junction type FET's 5, 6, resistors 7, 8, and constant current diodes 9, 11. The constant current circuit controls the current flowing to the light emitting diodes 13, 14 of the photo couplers 10, 12. Further, when the voltage within specific range is fed to the input terminals 1, 2 and 3, 4, stable point is made within active region of the photo transistors 17, 19. When either of photo transistor 17 or 19 does not take stable point within active region, the voltage at the output terminal 18 is closed to the voltage at the power supply terminals 15, 20, allowing to obtain normal output even if one failure is taken place.
JP15754978A 1978-12-22 1978-12-22 Semiconductor fail safe logic circuit Pending JPS5585142A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP15754978A JPS5585142A (en) 1978-12-22 1978-12-22 Semiconductor fail safe logic circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP15754978A JPS5585142A (en) 1978-12-22 1978-12-22 Semiconductor fail safe logic circuit

Publications (1)

Publication Number Publication Date
JPS5585142A true JPS5585142A (en) 1980-06-26

Family

ID=15652102

Family Applications (1)

Application Number Title Priority Date Filing Date
JP15754978A Pending JPS5585142A (en) 1978-12-22 1978-12-22 Semiconductor fail safe logic circuit

Country Status (1)

Country Link
JP (1) JPS5585142A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2579041A1 (en) * 1985-03-13 1986-09-19 Jeumont Schneider LOGIC CIRCUIT GENERATING A MAXIMUM DETERMINED OUTPUT DIRECT CURRENT
JPS6439119A (en) * 1987-08-04 1989-02-09 Nec Corp Logical operation circuit
JPH0275507U (en) * 1988-11-29 1990-06-08

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2579041A1 (en) * 1985-03-13 1986-09-19 Jeumont Schneider LOGIC CIRCUIT GENERATING A MAXIMUM DETERMINED OUTPUT DIRECT CURRENT
JPS6439119A (en) * 1987-08-04 1989-02-09 Nec Corp Logical operation circuit
JPH0275507U (en) * 1988-11-29 1990-06-08

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