JPS56165457A - Call current supply circuit - Google Patents

Call current supply circuit

Info

Publication number
JPS56165457A
JPS56165457A JP6874580A JP6874580A JPS56165457A JP S56165457 A JPS56165457 A JP S56165457A JP 6874580 A JP6874580 A JP 6874580A JP 6874580 A JP6874580 A JP 6874580A JP S56165457 A JPS56165457 A JP S56165457A
Authority
JP
Japan
Prior art keywords
current
load
slowly
currents
couplers
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
JP6874580A
Other languages
Japanese (ja)
Inventor
Kanji Mukai
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
Original Assignee
NEC 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 Electric Co Ltd filed Critical NEC Corp
Priority to JP6874580A priority Critical patent/JPS56165457A/en
Publication of JPS56165457A publication Critical patent/JPS56165457A/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
    • H04M19/02—Current supply arrangements for telephone systems providing ringing current or supervisory tones, e.g. dialling tone or busy tone

Abstract

PURPOSE:To realize a gentle supply/cut-off of the call current, by connecting a variable resistance element capable of a current control between an operational amplifier and a transistor connected between a telephone circuit and a power source and controlling the element with a variable current source. CONSTITUTION:The input currents of photocouplers 17 and 18 are increased slowly from zero by a variable current source, and accordingly the base currents of transistors 9 and 10 are increased slowly. Thus the DC current to be supplied to a load connected to telephone circuit terminals 1 and 2 increases slowly. The input currents of the photocouplers 17 and 18 reach a certain value, the output currents of these couplers are saturated. Then the DC current which is decided by the load resistance is supplied to the load. On the contrary, the input currents of the couplers 17 and 18 are decreased slowly from a sufficiently large value, and accordingly the DC current to be supplied the load decreases slowly. Then the current flowing to the load is reduced to zero when the input currents of the couplers 17 and 18 become zero.
JP6874580A 1980-05-23 1980-05-23 Call current supply circuit Pending JPS56165457A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP6874580A JPS56165457A (en) 1980-05-23 1980-05-23 Call current supply circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP6874580A JPS56165457A (en) 1980-05-23 1980-05-23 Call current supply circuit

Publications (1)

Publication Number Publication Date
JPS56165457A true JPS56165457A (en) 1981-12-19

Family

ID=13382616

Family Applications (1)

Application Number Title Priority Date Filing Date
JP6874580A Pending JPS56165457A (en) 1980-05-23 1980-05-23 Call current supply circuit

Country Status (1)

Country Link
JP (1) JPS56165457A (en)

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