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US3536986A - Low level costant current source - Google Patents

Low level costant current source Download PDF

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Publication number
US3536986A
US3536986A US784758A US3536986DA US3536986A US 3536986 A US3536986 A US 3536986A US 784758 A US784758 A US 784758A US 3536986D A US3536986D A US 3536986DA US 3536986 A US3536986 A US 3536986A
Authority
US
United States
Prior art keywords
transistor
terminal
current source
low level
costant
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.)
Expired - Lifetime
Application number
US784758A
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English (en)
Inventor
David Eric Perlman
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.)
Eastman Kodak Co
Original Assignee
Eastman Kodak Co
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 Eastman Kodak Co filed Critical Eastman Kodak Co
Application granted granted Critical
Publication of US3536986A publication Critical patent/US3536986A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F3/00—Non-retroactive systems for regulating electric variables by using an uncontrolled element, or an uncontrolled combination of elements, such element or such combination having self-regulating properties
    • G05F3/02—Regulating voltage or current
    • G05F3/08—Regulating voltage or current wherein the variable is DC
    • G05F3/10—Regulating voltage or current wherein the variable is DC using uncontrolled devices with non-linear characteristics
    • G05F3/16—Regulating voltage or current wherein the variable is DC using uncontrolled devices with non-linear characteristics being semiconductor devices
    • G05F3/20—Regulating voltage or current wherein the variable is DC using uncontrolled devices with non-linear characteristics being semiconductor devices using diode- transistor combinations
    • G05F3/30—Regulators using the difference between the base-emitter voltages of two bipolar transistors operating at different current densities

Definitions

  • This invention relates to constant current sources and more particularly to constant current sources which are adaptable for supplying currents on the order of less than one microampere.
  • the above and other objects of the invention are attained by providing a stage of amplification to increase the flow of current through the feedback resistance so that the amount of current flowing through the feedback resistance is enough so that the feedback resistance can be of a much lower value in order to provide the same voltage drop with a low resistance value that previously was available in the prior art only with a high resistance value.
  • the sole figure shows a schematic diagram of one embodiment of a constant current source according to the invention.
  • a unidirectional current device such as NPN transistor Q
  • the control or base terminal 1 of transistor Q is electrically connected to the collector terminal 2 of transistor Q so that transistor Q operates substantially as a diode.
  • the emitter terminal of transistor Q is electrically connected to common terminal 4 which is grounded.
  • the collector of transistor Q is connected through resistor 3 to the positive terminal of a voltage source S.
  • the collector terminal of transistor Q is connected to the control terminal of a unidirectional current control device such as the base of "ice NPN transistor Q
  • a unidirectional current control device such as the base of "ice NPN transistor Q
  • the collector terminal 6 of transistor Q is coupled to the control termnial of a unidirectional current control device such as the base terminal 7 of PNP transistor Q
  • the emitter terminal of transistor Q is coupled to the constant current output terminal I while the collector terminal 9 of transistor Q is coupled to the control terminal of a unidirectional current control device such as the base terminal 10 of NPN transistor Q
  • the emitter terminal 11 of transistor Q and the emitter terminal 12 of transistor Q are coupled together to resistor 5.
  • the collector terminal 13 of transistor Q is also coupled to the positive terminal of the voltage source.
  • the current which flows at output terminal I is constant since, if there is any tendency for the output current to increase, the base current of transistor Q will tend to increase thus increasing the voltage drop across resistor 5 which elfectively lowers the base voltage on transistor Q which in turn decreases the base current of transistor Q therefore bringing the output current back to its constant value.
  • circuit has been described as being particularly efficacious when manufactured as a monolithic integrated circuit since it can be easily and inexpensively fabricated as such. However, it is at once apparent that the circuit could be fabricated using discrete components in order to provide a high accuracy constant current source.
  • a constant current source adapted to be energized by a voltage source, said current source comprising:
  • said input terminal being coupled to the control electrode of said first device and to said common terminal through said fourth device;
  • a constant current source as in claim 1 which is v fabricated as an integrated circuit. J D MILLER Pnmary Exammer 4.

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • Power Engineering (AREA)
  • Nonlinear Science (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Automation & Control Theory (AREA)
  • Control Of Electrical Variables (AREA)
  • Dc-Dc Converters (AREA)
  • Amplifiers (AREA)
US784758A 1968-12-18 1968-12-18 Low level costant current source Expired - Lifetime US3536986A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US78475868A 1968-12-18 1968-12-18

Publications (1)

Publication Number Publication Date
US3536986A true US3536986A (en) 1970-10-27

Family

ID=25133441

Family Applications (1)

Application Number Title Priority Date Filing Date
US784758A Expired - Lifetime US3536986A (en) 1968-12-18 1968-12-18 Low level costant current source

Country Status (4)

Country Link
US (1) US3536986A (de)
DE (1) DE1963341A1 (de)
FR (1) FR2026456A1 (de)
GB (1) GB1289485A (de)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3651347A (en) * 1970-09-28 1972-03-21 Rca Corp Signal translating stage providing direct voltage translation independent of supplied operating potential
US3659121A (en) * 1970-11-16 1972-04-25 Motorola Inc Constant current source
US3775667A (en) * 1973-03-12 1973-11-27 Itt Monolithic integrable series stabilization circuit
US4380728A (en) * 1981-05-19 1983-04-19 General Motors Corporation Circuit for generating a temperature stabilized output signal
US4563632A (en) * 1982-09-30 1986-01-07 Sgs-Ates Componenti Elettronici Spa Monolithically integratable constant-current generating circuit with low supply voltage
US4600876A (en) * 1985-09-23 1986-07-15 Gte Communication Systems Corp. Integrated bootstrap bias circuit
US4680535A (en) * 1985-10-17 1987-07-14 Harris Corporation Stable current source
US20040147558A1 (en) * 2000-11-30 2004-07-29 Anthony Treston Synthesis of 3-amino-thalidomide and its enantiomers

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2135846B (en) * 1983-02-04 1986-03-12 Standard Telephones Cables Ltd Current splitter

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3255402A (en) * 1959-09-25 1966-06-07 Siemens Ag Current control circuits
US3310731A (en) * 1963-01-29 1967-03-21 Rca Corp Voltage reference circuit
US3434038A (en) * 1966-05-27 1969-03-18 Carl W Vette Dc current regulator

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3255402A (en) * 1959-09-25 1966-06-07 Siemens Ag Current control circuits
US3310731A (en) * 1963-01-29 1967-03-21 Rca Corp Voltage reference circuit
US3434038A (en) * 1966-05-27 1969-03-18 Carl W Vette Dc current regulator

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3651347A (en) * 1970-09-28 1972-03-21 Rca Corp Signal translating stage providing direct voltage translation independent of supplied operating potential
US3659121A (en) * 1970-11-16 1972-04-25 Motorola Inc Constant current source
US3775667A (en) * 1973-03-12 1973-11-27 Itt Monolithic integrable series stabilization circuit
US4380728A (en) * 1981-05-19 1983-04-19 General Motors Corporation Circuit for generating a temperature stabilized output signal
US4563632A (en) * 1982-09-30 1986-01-07 Sgs-Ates Componenti Elettronici Spa Monolithically integratable constant-current generating circuit with low supply voltage
US4600876A (en) * 1985-09-23 1986-07-15 Gte Communication Systems Corp. Integrated bootstrap bias circuit
US4680535A (en) * 1985-10-17 1987-07-14 Harris Corporation Stable current source
US20040147558A1 (en) * 2000-11-30 2004-07-29 Anthony Treston Synthesis of 3-amino-thalidomide and its enantiomers

Also Published As

Publication number Publication date
FR2026456A1 (de) 1970-09-18
GB1289485A (de) 1972-09-20
DE1963341A1 (de) 1970-07-02

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