CIRCUIT FOR SUPPLYING REGULATED POWER UPON DEMAND

• US 3,787,757 A
• Filed: 02/05/1973
• Issued: 01/22/1974
• Est. Priority Date: 02/05/1973
• Status: Expired due to Term

• Current Assignee: Abel Ching Nam Sheng
• Original Assignee: Abel Ching Nam Sheng
• Inventors: Sheng, Abel Ching Nam
• Primary Examiner(s): Pellinen, A. D.
• Application Number:
  US05/329,618
• Time in Patent Office: 351 Days
• Field of Search: 58/23BA,28R,33 307/297 318/128,132 320/54 323/1,4,16,19,22T
• US Class Current: 323/275
• CPC Class Codes: G05F 1/56 using semiconductor devices in series with the load as final control devices G05F1/461 takes precedence
• CPC Class Codes: Y10S 323/901 Starting circuits

Abstract

A load circuit requires regulated power during relatively short, relatively widely spaced, time intervals. In the absence of a demand for power, a control circuit drawing infinitesimal quiescent current inactivates a regulator circuit connected to the load circuit. When there is a demand for regulated power, the regulator circuit senses this demand and turns on and the control circuit senses a flow of current to the load circuit and in response thereto, locks the regulator in its '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' condition.

Claims

1. For use with a load circuit having a pair of input terminals which, during some periods of operation, are electrically connected, and during others are electrically open, a supply circuit comprising:

first and second output terminals, the first for connection to one terminal of a voltage source whose other terminal is for connection to a point of reference voltage, said first output terminal also for connection to one of said input terminals and said second output terminal for connection to the other of said input terminals;

a control circuit connected between said first output terminal and said point of reference voltage, and responsive to the current flowing from said second output terminal for producing a disabling control voltage in response to the absence of a flow of current from said second output terminal and for producing a maintaining control voltage in response to the presence oF such a flow of current; and

a regulator circuit for producing a relatively constant output voltage over a relatively wide range of variation of the voltage produced by said voltage source, when said regulator circuit is in its operating condition, said regulator circuit coupled to and controlled by said control circuit, responsive to the presence of a voltage at said second output terminal for switching from a disabled to an operating condition and responsive to said maintaining voltage produced by said control circuit for being held in said operating condition, said regulator circuit coupled between said output terminals and said point of reference voltage for maintaining a substantially constant voltage difference between said output terminals when said regulator circuit is in its operating condition.

2. For use with a load circuit having a pair of input terminals which, during some periods of operation, are electrically connected, and during others are electrically open, a supply circuit comprising:

first and second output terminals, the first for connection to one terminal of a voltage source whose other terminal is for connection to a point of reference voltage, said first output terminal also for connection to one of said input terminals and said second output terminal for connection to the other of said input terminals;

a control circuit connected between said first output terminal and said point of reference voltage, and responsive to the current flowing from said second output terminal, for producing a disabling control voltage in response to the absence of a flow of current from said second output terminal and for producing a maintaining control voltage in response to the presence of such a flow of current, said control circuit comprising a voltage divider, which includes diode means, said voltage divider connected between said first output terminal and said point of reference voltage for establishing a bias voltage, and an operational amplifier including a current source referenced to this bias voltage for producing a current at a relatively low level, a pair of transistors connected to conduct the current from said source, and means causing one of said transistors to conduct substantially all of said current; and

a regulator circuit coupled to and controlled by said control circuit, responsive to the presence of a voltage at said second output terminal for switching from a disabled to an operating condition and responsive to said maintaining voltage produced by said control circuit for being held in said operating condition, said regulator circuit coupled between said output terminals and said point of reference voltage for maintaining a substantially constant voltage difference between said output terminals when said regulator circuit is in its operating condition.

3. A supply circuit as set forth in claim 24, wherein the portion of said control circuit responsive to the presence of a flow of current from said second output terminal comprises means for switching the state of said operational amplifier for causing the other transistor of said operational amplifier to conduct substantially all of said current.

4. A supply circuit as set forth in claim 3 wherein the portion of said control circuit for producing a maintaining control voltage comprises means responsive to current flow through said other transistor for producing an output voltage.

5. For use with a load circuit having a pair of input terminals which, during some periods of operation, are electrically connected, and during others are electrically open, a supply circuit comprising:

first and second output terminals, the first for connection to one terminal of a voltage source whose other terminal is for connection to a point of reference voltage, said first output terminal also for connection to one of said input terminals and said second output terminal for connection to the other of said input terminals;

a control circuit connected between said first output terminal and said poiNt of reference voltage, and responsive to the current flowing from said second output terminal, for producing a disabling control voltage in response to the absence of a flow of current from said second output terminal and for producing a maintaining control voltage in response to the presence of such a flow of current; and

a regulator circuit coupled to and controlled by said control circuit, responsive to the presence of a voltage at said second output terminal for switching from a disabled to an operating condition and responsive to said maintaining voltage produced by said control circuit for being held in said operating condition, said regulator circuit coupled between said output terminals and said point of reference voltage for maintaining a substantially constant voltage difference between said output terminals when said regulator circuit is in its operating condition, said regulator circuit comprising;

an operational amplifier connected between said first output terminal and said point of reference voltage, said amplifier including a current source and first and second transistors for conducting the current from said source;

a reference voltage circuit connected between said first output terminal and said point of reference voltage, including means responsive to current flow through said reference voltage circuit for establishing a bias level for said current source, means responsive to said current flow for establishing a voltage level on the control electrode of the first transistor, and a normally off third transistor for preventing the flow of current through said reference voltage circuit; and

a starting circuit comprising means responsive to a voltage at said second output terminal for turning on said normally off transistor, said second output terminal being connected also to the control electrode of the second transistor of said operational amplifier.

6. A supply circuit as set forth in claim 25, further including current control means coupled between said point of reference voltage and the control electrode of said second transistor and controlled by said operational amplifier.

7. A supply circuit as set forth in claim 6, further including means responsive to the flow of current through said current control means for controlling said control circuit.

8. A supply circuit as set forth in claim 7, further including a connection from said control circuit to said control electrode of said normally off transistor of said reference voltage circuit.

9. A circuit for supplying regulated power to a load circuit which demands power for relatively short, relatively widely spaced intervals comprising, in combination:

a control circuit coupled to said load circuit drawing relatively little current in the absence of a demand for power for producing a disabling signal in the absence of such demand and for producing a maintaining signal in the presence of such demand; and

a regulator circuit coupled to said control circuit and manitained disabled by said disabling signal in the absence of a demand for power, and coupled to said load circuit and responsive to a demand for power, for being placed in an operative condition, to thereby regulate the power applied to said load circuit, said control circuit supplying said maintaining signal to said regulator circuit for maintaining it in its operative condition in response to said demand for power, said regulator circuit comprising connections for a voltage source, means responsive to the voltage provided at said connections by said voltage source for producing a relatively fixed reference voltage level at a fraction of the value of said source voltage, and means including a voltage comparison circuit for producing an output voltage at this relatively fixed level over a relatively wide range of variation of said source voltage.

10. A circuit as set forth in claim 9 in which said means for producing a relatively fixed reference voltage level comprises reference voltage establishing means conneCted essentially in series with switch means, said switch means being responsive to said disabling signal for opening to thereby prevent the production of said fixed reference voltage level and being responsive to said maintaining signal for being held in a closed condition to thereby prevent the production of said fixed reference voltage level and being responsive to said maintaining signal for being held in a closed condition to thereby permit the production of said fixed reference voltage level.

11. A circuit as set forth in claim 10 wherein said switch means comprises a transistor having a control electrode and a conduction path, said conduction path connected essentially in series with said reference voltage establishing means, and said control electrode being connected to receive said disabling and maintaining signals.

12. A circuit as set forth in claim 11, further including means responsive to said demand for power connected to said control electrode, for initially placing said conduction path in a low impedance condition in response to said demand for power.

13. A circuit as set forth in claim 10, wherein said reference voltage establishing means comprises diode means.

14. A circuit for supplying power to a load circuit which includes a normally open switch comprising, in combination:

a first output terminal connectable to said load circuit to which one terminal of an operating voltage source may be connected;

a high impedance circuit connected between that terminal and a reference terminal to which the other terminal of said operating voltage circuit may be connected, said high impedance circuit for producing a turn off voltage when said switch is open and responsive to current flow through said switch, when said switch is closed, for producing a maintaining voltage;

a regulator circuit, responsive to the voltage produced by said high impedance circuit, connected between said first output terminal and said reference terminal for producing a relatively constant output voltage when turned on, over a relatively wide range of values of the voltage produced by said operating voltage source;

a second output terminal connectable to said load circuit; and

means responsive to the presence of a voltage at that second terminal for turning on said regulator circuit and for concurrently changing the condition of said high impedance circuit causing it to produce said maintaining voltage, whereby said regulator circuit maintains said second output terminal at a given voltage relative to the voltage at said first output terminal.

15. In combination:

a first operational amplifier including a current source, and first and second current paths connected in parallel between said source and a point of reference potential, said second path including a diode;

a second operational amplifier including a current source, and a pair of current paths connected in parallel between said source and said point of reference potential, each such path including the conduction path of an amplifier and each amplifier including a control electrode; and

a transistor having base, emitter and collector electrodes, connected at its collector electrode to one of said control electrodes of said second operational amplifier and having its emitter-base junction connected across said diode.

16. In the combination as set forth in claim 11, said first operational amplifier including means for quiescently causing the current from its source to flow substantially entirely into said first path, and further including means for changing the state of said first operational amplifier comprising means for shifting said current flow into said second path.

17. In the combination as set forth in claim 15, further including a control current path connected at one terminal to said collector electrode and having a second terminal for connection to an operating voltage source.

18. In the combination as set forth in claim 17, further including reference voltage establishing means in said control current path for placing said collector electrode of said transistor at a voltage level differing by a fixed amount from that of said operating voltage source.

19. In the combination as set forth in claim 18, said reference voltage establishing means comprising a pair of diodes connected in series in the forward direction, and further including a connection from the point in said series circuit between the two diodes to said current source of said second operational amplifier for establishing the level at which current flows in said second operational amplifier.

20. In combination:

a first operational amplifier including a current source, and first and second current paths connected in parallel between said source and a point of reference potential, said second path including a diode connected at one electrode to said point of reference potential;

a second operational amplifier including a current source, and a pair of current paths connected in parallel between said source and said point of reference potential, each such path including the conduction path of an amplifier and each amplifier including a control electrode; and

a transistor having base emitter and collector electrodes, connected at its collector electrode to one of said control electrodes of said second operational amplifier and at its emitter electrode to said point of reference potential, and the base-emitter junction of said transistor connected across said diode.

21. In the combination as set forth in claim 20, said first and second current paths of said first operational amplifier each comprising the emitter-to-collector path of a respective one of two transistors, the two emitters connected to one another and to said current source of said first operational amplifier, one collector connected through said diode to said point of reference potential and said other collector connected to said point of reference potential.

22. In the combination as set forth in claim 21, said two transistors of said first operational amplifier each having a base electrode, further including resistor means connecting said base electrodes, means connected to one of said base electrodes for quiescently biasing both transistors in the forward direction, and said transistors having geometries such that when they are equally forward biased, the one connected to said diode conducts none of the current supplied by the current source of said first operational amplifier and the other transistor conducts substantially all of this current.

23. In the combination as set forth in claim 21, said pair of current paths of said second operational amplifier comprising the emitter-to-collector paths of two transistors, respectively, the two emitters connected to one another and to said current source of said second operational amplifier, and further including means connecting both collectors to said point of reference potential.

24. In the combination as set forth in claim 23, said control electrodes comprising base electrodes, said second operational amplifier connected at one base electrode to one base electrode of said first operational amplifier and to a point in the circuit at which a voltage to be regulated periodically is present, and said second operational amplifier connected at its other base electrode to a circuit point at which a reference voltage level periodically is present.

25. In the combination as set forth in claim 24, further including a load circuit connected to the point in said circuit at which a voltage to be regulated periodically appears, the current through said load circuit establishing the voltage at said point, and amplifier means connected to and controlled by said second operational amplifier connected between said point in said circuit and a point of reference potential for supplying said current through said load circuit.

26. A circuit for supplying power to a load circuit comprising, in combination:

first, second, third and fourth transistOrs of a first conductivity type and fifth and sixth transistors of a second conductivity type, each of said transistors having a base, an emitter, and a collector electrode;

means for connecting said first and said second transistors in a first emitter coupled amplifier configuration having an input circuit including their base-emitter paths and having an output circuit including the collector-emitter path of said second transistor;

means for connecting said third and said fourth transistors in a second emitter-coupled amplifier configuration having an input circuit including their base-emitter paths and having an output circuit including the collector-emitter path of said fourth transistor;

means for connecting said fifth transistor in a first common-emitter amplifier configuration with its base electrode direct coupled to the output circuit of said first emitter-coupled amplifier and with its collector electrode direct coupled to the input circuit of said second emitter-coupled amplifier configuration;

means for connecting said sixth tranxistor in a second common-emitter amplifier configuration with its base electrode direct coupled to the output circuit of said second emitter coupled amplifier configuration and with its collector electrode direct coupled to said load circuit; and

means for sensing the amount of power applied to said load circuit to provide a control signal direct coupled to said input circuit of said first emitter-coupled amplifier.

27. In the combination set forth in claim 26, means for controlling the combined emitter currents of said third and said fourth transistors in response to collector current of said fifth transistor;

and means providing a path for starting current to the emitter electrodes of said third and said fourth transistors in response to said load circuit coming conductive.

28. A circuit for supplying regulated power at a relatively fixed level to a load circuit which demands power for relatively short, relatively widely spaced intervals in spite of variations in the voltage provided by the voltage source powering said circuit comprising, in combination:

a control circuit coupled to said load circuit drawing relatively little current in the absence of a demand for power for producing a disabling signal in the absence of such demand and for producing a maintaining signal in the presence of such demand, said circuit including voltage divider means for connection across said voltage source and having an impedance in the megohm range, diode means forming part of said voltage divider means for producing a relatively constant output voltage in response to current flow through said voltage divider means, a constant current source responsive to said relatively constant output voltage level for producing a constant current at a relatively low level, a pair of current paths, means for causing said current to flow in one of said paths in the absence of said demand for power and for switching said current into the other of said paths in response to the presence of said demand for power, and means in said other path responsive to the absence of current flow in said other path for producing said disabling signal and responsive to the presence of said current flow for producing said maintaining signal; and

a regulator circuit coupled to said control circuit and maintained disabled by said disabling signal in the absence of a demand for power, and coupled to said load circuit and responsive to a demand for power, for being placed in an operative condition, to thereby regulate the power applied to said load circuit to a relatively constant value, and said control circuit supplying said maintaining signal to said regulator circuit for maintaining it in its operative condition in response to said demand for power.

29. A circuit as set forth in claim 28 wherein said means in said other path responsive to current flow in said other path comprises diode means connected to conduct said current in the forward direction.

30. A circuit as set forth in claim 28 wherein said regulator circuit includes a transistor having a base-emitter junction, said diode means being connected across said base-emitter junction for causing current flow therein in response to a voltage developed across said diode means.