US3825776A - Switchable current generator - Google Patents

Switchable current generator Download PDF

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Publication number
US3825776A
US3825776A US00314866A US31486672A US3825776A US 3825776 A US3825776 A US 3825776A US 00314866 A US00314866 A US 00314866A US 31486672 A US31486672 A US 31486672A US 3825776 A US3825776 A US 3825776A
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United States
Prior art keywords
current
node
terminal
input
diode
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Expired - Lifetime
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US00314866A
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English (en)
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C Jacquart
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International Business Machines Corp
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International Business Machines Corp
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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
    • G05F3/22—Regulating voltage or current wherein the variable is DC using uncontrolled devices with non-linear characteristics being semiconductor devices using diode- transistor combinations wherein the transistors are of the bipolar type only

Definitions

  • FIG. 1 A first figure.
  • I ual current source if the desired SWITCHABLE CURRENT GENERATOR BACKGROUND OF THE INVENTION 7 I Prior, art devices for Supplying null Currents essentially comprised a,+l current source and a -I current source in combination with a diode bridge.
  • the oppositepolarity currentlsources are respectively connected toione'of the two apexes of the diode bridge for 'defining first and second diagonals'thereof and oneof the sources is also connected to a'control signal source while the otherapex of the diode bridge provides an output terminal.
  • one'of the H or sources supplies a current to the output terminal of thecircuit.
  • Another object of the present invention is to provide a current generator capable of furnishing precise amplitude values of current, +I and I, dependent only I upon a resistive value.
  • Another object of the present invention is to provide a current generatorwhich is readily implementable into integrated circuit-form'since'the overall circuit does not require precisely balanced-individual current sources.
  • the objectsof the present invention are obtained by base of a transistor T1 whose emitter and collector iterminals are "connected to thea'node-of a diode'Dl and to a +V voltage source, respectively.
  • the cathode of diode D1 is connected to a current sink schematically represented by CS1 which itself is connected to a voltage source -V.
  • the current sink CS1 draws a current Io. from a node .M which isconnected between the anode. terminals of;a pair of diodes D2 and D3.
  • the anode terminal of diode D3 is connected to a node M.
  • Diodes D2 and D3 provide a biasing circuit for node M.
  • the node M is connected to the upper terminal of a'resistive element R and to the anode terminal of diode D4.
  • the cathode terminal of D4 is'con- .nected-to the output terminal S of the current generator.
  • the output terminal S is connected to thecathode terminal of diodeDS and its anode terminal is con- .nected to node N and to the lower terminalof resistor R.
  • the node N) is connected to the cathode of diode D6 and its anode is connected to node N andto the anode of diode D7.
  • FIGS. 1, 2 and ,3 schematically illustrate the identical current generator circuitwith differing directional cur-.
  • the output terminal S is maintained at a fixed-potential arbitrarily selected to be equal to Vo/Z for purposes of the preferred embodiment.
  • Any suitable voltage source such as a resistor bridge (not shown) is capable of providing the precise value of voltage Vo/2.
  • the current generator of the present invention provides either a positive or negative valued current. of identical amplitude or a null current according to the input signals applied'to terminals A1 and A2.
  • FIG. 1 in order to illustrate the operation of the curre nt generatona down signal-is applied at-both input terminals Al .and A2.
  • I transistor T1 isnon-conducting and, ,thus, diode D1 is also nonconducting. Accordingly, cur'rentylo is drawn by the current sink CS1 from node M.
  • the value of this current is derived from the (10 1) current flowing to node N by means of the conducting diode D2 and also from the current I- also flowing to node N by means of conducting diode D3,;
  • diode D2 in a conductive state, its anodeis at approximately ground potential and, thus, its cathode ter minal is at a potential -VD in accordance with the above equation.
  • Diode D3 is also conductive and, therefore, its cathode terminal isalso at a potential of -"VD while its anode terminal is at approximately ground or zero potential, again in accordance with the above equation and, thus, node M is also at ground potential.
  • the" cathode terminal of diode D4 connected to output terminal S is at a potential level Vo/2 or in a reverse bias state and, thus, diode D4 is non-conducting.
  • current I circulates through diode D3 and, thus, necessarily through resistor R.
  • terminal A2 With terminal A2 also at a low or down level, the diode D8 is conducting and, thus, current I is supplied by the current source CS2 down towards terminal A2 through diode D8.
  • node N is at a low or down level which differs from the low level applied to terminal AZ by a value equal to the voltage drop across diode D8. Since the cathode of diode D7 is at a potential value of V0 and its anode is at a down node N is at a potential level'equal to Vo/2 VD.
  • the current loops for the application of up or high signals being applied to both input terminals A1 and A2 is illustrated in FIG. 2.
  • terminal A1 With terminal A1 at an up level, transistor T1 is conducting and,thus, diode D1 is also conducting.
  • the potential node M is equal to the up level which is represented by the base to emitter voltage. drop of transistor T1 minus the diode .drop or -Vbe VD; During this condition, the diodes D2 and D3 are non-conducting. Accordingly, current is drawn by the current sink CS1 and is applied by the combination of the voltage source +V through transistor T1 and diode D1.
  • diode D8 With terminal A2 at a high level, diode D8 is nonconductive and, thus, current lo suppliedby current source CS2 splits and flows through conducting diodes a l current. With diode D7in a conductive state, the
  • V0/2 VD/R lt' is thus seen that in both instances the amplitudes of the +1 current and the l'current supplied by the current generatorcircuit of the present invention are identical. Since the voltage value V0 is fixed, the value of these amplitudes is controlled solely by the value of resistor R which can be implementedin many forms, either monolithically, or as a discrete element if it is desired to provide a variable switchable current generator.
  • transistors T1 and diodes D1 are non-conducting and, thus, current lo drawn by the current sink CS1 is directed away from or supplied by node M.
  • node M is at a zero or null point. Since the cathode of diode D2 is at a potential level Vo/2 and its anode is at a lower potential, it is reverse biased or non-conducting.
  • diode D8 With terminal A2 at an up or high level, diode D8 is non-conductive and current Io issupplied by current source CS2 and flows through conducting diodes D6 and D7. With diodes D6 and D7 conductive, the potential at node N is at a potential value V0. With the cathode terminal of diode D5 at potential V0 and its anode at potential Vo/2, it is non-conductive. With both diodes D4 and D5 in a non-conductive state, no current is supplied to the output terminal of the current generator. As the current generating circuit is symmetrical, a null current can also be obtained by applying a high or up level to terminal Al and a low or down level to terminal A2. Briefly,the following table illustrates the various conditions of the output current at terminal S for various high and low control signals being applied to input terminals A1 and A2, for example, as binary values l and zero, respectively.
  • the circuit means controlling the circulation or current path constituted by current 10 drawn'by the current sink CS1, which includes transistor T1 and 'diode D1 and the circuit means for controlling the current loop or circulation of current Io supplied by the current'source CS2 and including diode D8 perform the same function and, thus, it is within the scope of the present invention to interchange these means.
  • transistor T1 and diode D1 can be replaced by a diode by connecting the anode of the diode to terminal Al and the cathode of the diode to node M.
  • diode D8 can be replaced by a transistor and a diode connected in series with the transistor collector being connected to the -V voltage source and its base terminal being connected to the terminal A2, and the anode of the diode being connected to node N.
  • Resistor R can also be replaced by any suitable resistive element in a monolithic implementation and even could be implemented by using the internal resistance of a transistor element.
  • diodes DI-D8 can be replaced by a transistor having its collector-to-base junction shorted.
  • a switchable current generator comprising:
  • first and second iode conducting means conspect to said output terminal through said seconddiode conducting means, 1 t t v D. said input terminals being responsive to third 'input signals for providing a null current,
  • said first circuit means comprising a first biasing means connected to said first node for rendering said first diode conducting means non-conductive,
  • A a third diode conducting means connected between said first reference potential meansv connectedbetween said first reference potential and a third node common to the said current sink and to .said first input switching terminal for'passing current from said first reference potentialtowards'said third node, and
  • a switchablecurrent generator as in claim v V A. said first circuit means further comprises a first transistor having its collector connected to a second voltage source'and a baseterminal connected to said first input switching terminal for receiving said first input signals, and B. a fifth diode conducting means connected between said emitter of said first transistor and said third node for passing current from said emitter terminal of said first transistor toward said third node, said first transistor being selectively switched in response to said first inputsignals. 4.
  • a current generator as in claim 2 wherein: A. said 'firstcircuit means further comprises a sixth diode conducting element connected between said.
  • said second biasing means includes:
  • a seventh diode conducting means connected between a second reference potential and a fourth node common to said current source and to said second input switching terminal for passing current from said fourth node towards said second reference potential
  • B. an eighth diode conducting means connected between said second and fourth nodes for passing current from said fourth node to said second node.

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Automation & Control Theory (AREA)
  • Electronic Switches (AREA)
  • Amplifiers (AREA)
  • Control Of Voltage And Current In General (AREA)
  • Control Of Electrical Variables (AREA)
US00314866A 1971-12-21 1972-12-13 Switchable current generator Expired - Lifetime US3825776A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7147851A FR2164545B1 (enrdf_load_stackoverflow) 1971-12-21 1971-12-21

Publications (1)

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US3825776A true US3825776A (en) 1974-07-23

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Application Number Title Priority Date Filing Date
US00314866A Expired - Lifetime US3825776A (en) 1971-12-21 1972-12-13 Switchable current generator

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US (1) US3825776A (enrdf_load_stackoverflow)
JP (1) JPS531033B2 (enrdf_load_stackoverflow)
DE (1) DE2262565C2 (enrdf_load_stackoverflow)
FR (1) FR2164545B1 (enrdf_load_stackoverflow)
GB (1) GB1397828A (enrdf_load_stackoverflow)
IT (1) IT969829B (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4470056A (en) * 1981-12-29 1984-09-04 International Business Machines Corporation Controlling a multi-wire printhead

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SU249804A1 (ru) * Л. В. Венгеровский, А. Вайнштейн , В. А. Дворецкий Двухпозиционный регулятор
US3205377A (en) * 1963-07-10 1965-09-07 Jr Lawrence A Nix Raster linearity correction generator
US3231753A (en) * 1960-09-26 1966-01-25 Burroughs Corp Core memory drive circuit
US3280389A (en) * 1961-08-04 1966-10-18 Siemens Ag Freely expanding pressure mounted semiconductor device
GB1081676A (en) * 1964-02-10 1967-08-31 Mullard Ltd Improvements in or relating to time-bases
US3435256A (en) * 1966-01-17 1969-03-25 Bell Telephone Labor Inc Alternating polarity current driver using cascaded active switching elements
US3480923A (en) * 1965-12-06 1969-11-25 Ibm Memory driving circuit
US3629691A (en) * 1970-07-13 1971-12-21 Rca Corp Current source
US3683270A (en) * 1971-02-22 1972-08-08 Signetics Corp Integrated circuit bilateral current source
US3708695A (en) * 1971-10-19 1973-01-02 Singer Co High speed switch with complementary outputs

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3126488A (en) * 1964-03-24 Current
FR2063496A5 (enrdf_load_stackoverflow) * 1969-10-14 1971-07-09 Ibm France

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SU249804A1 (ru) * Л. В. Венгеровский, А. Вайнштейн , В. А. Дворецкий Двухпозиционный регулятор
US3231753A (en) * 1960-09-26 1966-01-25 Burroughs Corp Core memory drive circuit
US3280389A (en) * 1961-08-04 1966-10-18 Siemens Ag Freely expanding pressure mounted semiconductor device
US3205377A (en) * 1963-07-10 1965-09-07 Jr Lawrence A Nix Raster linearity correction generator
GB1081676A (en) * 1964-02-10 1967-08-31 Mullard Ltd Improvements in or relating to time-bases
US3480923A (en) * 1965-12-06 1969-11-25 Ibm Memory driving circuit
US3435256A (en) * 1966-01-17 1969-03-25 Bell Telephone Labor Inc Alternating polarity current driver using cascaded active switching elements
US3629691A (en) * 1970-07-13 1971-12-21 Rca Corp Current source
US3683270A (en) * 1971-02-22 1972-08-08 Signetics Corp Integrated circuit bilateral current source
US3708695A (en) * 1971-10-19 1973-01-02 Singer Co High speed switch with complementary outputs

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
J. Whittaker, A Simple Current Generator, Nuclear Instrs. and Methods, 39(1966) p. 183, 184. *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4470056A (en) * 1981-12-29 1984-09-04 International Business Machines Corporation Controlling a multi-wire printhead

Also Published As

Publication number Publication date
DE2262565C2 (de) 1983-03-31
FR2164545B1 (enrdf_load_stackoverflow) 1974-06-07
IT969829B (it) 1974-04-10
FR2164545A1 (enrdf_load_stackoverflow) 1973-08-03
DE2262565A1 (de) 1973-06-28
GB1397828A (en) 1975-06-18
JPS531033B2 (enrdf_load_stackoverflow) 1978-01-13
JPS4871559A (enrdf_load_stackoverflow) 1973-09-27

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