Parallel voltage regulator

• US 6,078,168 A
• Filed: 12/16/1997
• Issued: 06/20/2000
• Est. Priority Date: 12/17/1996
• Status: Expired due to Term

• Current Assignee: SGS-Thomson Microelectronics (STMicroelectronics NV)
• Original Assignee: SGS-Thomson Microelectronics (STMicroelectronics NV)
• Inventors: Paolo, Migliavacca
• Primary Examiner(s): Berhane, Adolf Deneke
• Assistant Examiner(s): Patel, Rajnikant B.
• Application Number:
  US08/991,317
• Time in Patent Office: 917 Days
• Field of Search: 323/226, 323/316, 323/907, 323/280, 323/269, 323/281, 327/538
• US Class Current: 323/226
• CPC Class Codes: G05F 1/613 using semiconductor devices in parallel with the load as final control devices G05F1/461 takes precedence
• CPC Class Codes: G05F 3/225 producing a current or voltage as a predetermined function of the temperature

Abstract

The present invention relates to a voltage regulator for connection in parallel to a load, including a circuitry for generating a temperature-stable reference voltage; a controllable circuit for branching a portion of a current meant for the load; a circuit for regulating the branched current according to the current absorbed by the load; and a circuit for controlling a regulation circuit supply current with the current branched by the branching means.

Claims

1. A voltage regulator for connection in parallel to a load, including:

a means for generating a temperature-stable reference voltage;

a controllable means for branching a portion of a current meant for the load; and

a regulation means for regulating the branched current according to the current absorbed by the load,

and including

a means for controlling a supply current of the regulation means with the current branched by the branching means.

2. The regulator of claim 1, wherein the control means includes:

a means for copying a control current of the branching means; and

a means for reinjecting the copied current, assigned with a positive factor, into the supply current of the regulation means.

3. The regulator of claim 2, wherein the copying means is formed of a first bipolar transistor connected as a current mirror on an input transistor of the branching means receiving the control current.

4. The regulator of claim 2, wherein the regulation means is formed of a differential stage, on a branch of which the control current of the branching means is taken, the differential stage being supplied by a source of constant current, a correction current proportional to the control current being added to the constant current issued by the current source.

5. The regulator of claim 4, wherein the reinjection means is formed of a second bipolar transistor, connected as a diode and in series with the first transistor, and of a third bipolar transistor, connected as a current mirror on the second transistor and in parallel on the current source.

6. The regulator of claim 5, wherein the current mirror comprising the reinjection means has a factor greater than or equal to one.

7. The regulator of claim 1, wherein the means for generating the reference voltage includes a differential stage, an output of which forms a differential input of the regulation means, and a differential input of which receives a voltage proportional to a variation of the reference voltage.

8. The regulator of claim 1, wherein the branching means includes a branching transistor connected in parallel with the load, this transistor being controlled by an assembly for amplifying the control current issued by the regulation means.

9. A differential stage receiving a supply current and, as an input, a differential control voltage and providing an output current taken on a branch of the differential stage, and including a means for controlling the supply current of the differential stage with the output current of this stage,

wherein the control means includes a means for adding a correction current to a current issued by a current source to form the supply current, the correction current being obtained by copying and amplifying of the output current of the differential stage.

10. A voltage regulator comprising:

a reference circuit for establishing a reference voltage;

a differential output stage for providing voltage signals for the reference circuit;

a branching stage for branching a portion of a current meant for a load;

and a control circuit coupled to the differential output stage and for controlling a supply current of the differential output stage and in accordance with the current branched by said branching stage.

11. A voltage regulator according to claim 10, wherein said reference circuit establishes a temperature-stable reference voltage.

12. A voltage regulator according to claim 10, where said differential output stage includes a circuit regulating branched current according to the current absorbed by the load.

13. A voltage regulator according to claim 10, wherein said control circuit includes a circuit for copying a control current of the branching stage.

14. A voltage regulator according to claim 13, wherein said control circuit further includes a circuit for reinjecting the copied current, assigned with a positive factor, into the supply current of the differential output stage.

15. A volt age regulator according to claim 14, wherein the copying circuit if formed of a first bipolar transistor connected as a current mirror on an input transistor of the branching stage receiving the control current.

16. A voltage regulator according to claim 10, wherein the differential output stage comprises a differential stage, on a branch of which the control current of the branching stage is taken.

17. A voltage regulator according to claim 16, wherein said differential stage is supplied by a source of constant current, a correction current proportional to the control being added to the constant issued by the current source.

18. A voltage regulator according to claim 17, wherein said control circuit includes a first transistor and a second transistor said second transistor being a bipolar transistor connected as a diode and in series with said first transistor.

19. A voltage regulator according to claim 18, further including a third bipolar transistor connected as current mirror on the second transistor and at parallel with the current source.

20. A voltage regulator according to claim 19, wherein the current mirror has a factor greater than or equal to 1.

21. A voltage regulator according to claim 10, wherein said reference circuit for generating the reference voltage includes a differential stage, on output of which forms a differential input of the differential output stage.

22. A voltage regulator according to claim 21, wherein said differential stage comprises a pair of light conductivity transistors.

23. A voltage regulator according to claim 22 and further including a current source in series with said differential stage.

24. A voltage regulator according to claim 10, wherein said branching stage includes a branching transistor connected in parallel with the load.

25. A voltage regulator according to claim 24, wherein said branching transistor is controlled by an assembly for amplifying the control current provided by the differential output stage.

26. A voltage regulator according to claim 10, further including a first current source associated with said differential output stage and a second current source associated with said reference circuit.

27. A voltage regulator according to claim 10, wherein said branch stage comprises first and second bipolar transistors interconnected in series.

28. A voltage regulator according to claim 27, further including an amplifying assembly coupled between said first and second bipolar transistors.

29. A voltage regulator according to claim 28, further including a current source coupled to one of said pair of bipolar transistors.