JPS55150658A - Current supply circuit - Google Patents

Current supply circuit

Info

Publication number
JPS55150658A
JPS55150658A JP5891779A JP5891779A JPS55150658A JP S55150658 A JPS55150658 A JP S55150658A JP 5891779 A JP5891779 A JP 5891779A JP 5891779 A JP5891779 A JP 5891779A JP S55150658 A JPS55150658 A JP S55150658A
Authority
JP
Japan
Prior art keywords
terminals
supply circuit
power source
current supply
current
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
JP5891779A
Other languages
Japanese (ja)
Inventor
Koichi Hasegawa
Yoshinori Oikawa
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.)
NEC Corp
Nippon Telegraph and Telephone Corp
Original Assignee
NEC Corp
Nippon Telegraph and Telephone Corp
Nippon Electric Co Ltd
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 NEC Corp, Nippon Telegraph and Telephone Corp, Nippon Electric Co Ltd filed Critical NEC Corp
Priority to JP5891779A priority Critical patent/JPS55150658A/en
Publication of JPS55150658A publication Critical patent/JPS55150658A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M19/00—Current supply arrangements for telephone systems
    • H04M19/001—Current supply source at the exchanger providing current to substations
    • H04M19/005—Feeding arrangements without the use of line transformers

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Signal Processing (AREA)
  • Devices For Supply Of Signal Current (AREA)

Abstract

PURPOSE:To improve a characteristic and make a unit small-size by integration, by constituting a current supply circuit by an operational amplifier. CONSTITUTION:Terminals 1 and 2 are connected to the telephone line, and terminals 3 and 4 are connected to the earth and power source -48V respectively. The loop including operational amplifier 19, resistance R21, transistor TR9, and resistance R23 becomes a voltage follower, and input Z of the impednace Z converter dependent upon R13 and follower 15 is high, and output Z is low, and therefore, DC Z between terminals 1 and 3 is determined by R5, 7 and 11. Similarly, DC Z between terminals 2 and 4 is determined by R6, 8 and 12, and the current from the power source is flowed to the DC load between terminals 1 and 2 as a constant- voltage current supply circuit. In respect to a sound band signal, no AC current is flowed to amplifier 19 and TR19, and AC Z between terminals 1 and 3 is looked very high and has no influence upon the frequency of the sound signal transmitted and received through the telephone line. Further, since terminal 3 and the emitter of TR9 have the equal potential for power source noise, noise is not generated between terminals 1 and 2.
JP5891779A 1979-05-14 1979-05-14 Current supply circuit Pending JPS55150658A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP5891779A JPS55150658A (en) 1979-05-14 1979-05-14 Current supply circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP5891779A JPS55150658A (en) 1979-05-14 1979-05-14 Current supply circuit

Publications (1)

Publication Number Publication Date
JPS55150658A true JPS55150658A (en) 1980-11-22

Family

ID=13098167

Family Applications (1)

Application Number Title Priority Date Filing Date
JP5891779A Pending JPS55150658A (en) 1979-05-14 1979-05-14 Current supply circuit

Country Status (1)

Country Link
JP (1) JPS55150658A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4872199A (en) * 1984-12-27 1989-10-03 Fujitsu Limited Battery-feed circuit for exchange

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4872199A (en) * 1984-12-27 1989-10-03 Fujitsu Limited Battery-feed circuit for exchange

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