Concentric servo voltage regulator utilizing an inner servo loop and an outer servo loop

• US 5,485,077 A
• Filed: 08/09/1993
• Issued: 01/16/1996
• Est. Priority Date: 08/09/1993
• Status: Expired due to Term

• Current Assignee: Aphex, LLC
• Original Assignee: Aphex Systems, Ltd. (RØDE Microphones)
• Inventors: Werrbach, Donn
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): HAN, YOUNGHUIE JESSICA
• Application Number:
  US08/103,522
• Time in Patent Office: 890 Days
• Field of Search: 323/273, 323/274, 323/275, 323/280, 323/281, 323/282, 323/284, 323/285, 323/286, 363/79, 363/21, 363/23, 363/25, 363/97
• US Class Current: 323/286
• CPC Class Codes: G05F 1/565 sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor G05F1/563 takes precedence

Abstract

The present invention is a concentric servo method and apparatus using two servo loops to control and stabilize the output of an electronic voltage regulator. An inner and outer servo loop are employed. The inner servo loop resembles the control loop of a conventional voltage regulator while the outer servo loop controls the sense threshold of the inner servo loop. The outer servo loop senses the voltage delivered to an external load resistance and controls the sense threshold of the inner servo loop to compensate for the voltage loss which may occur between the regulator output and the actual load resistance. The inner loop retains its high speed to regulate out any input voltage irregularities such as ripple and noise. The present invention gives better stability than conventional remote sensing voltage regulator circuits.

Claims

1. A concentric servo voltage regulator comprising:

a. a voltage adjustor having a supply input for receiving a supply voltage, a voltage output for providing a controlled output voltage through a power distribution path to a load, and a control input responsive to a control signal for controlling the level of the output voltage as a function of the control signal;

b. an inner servo loop for generating the control signal for said voltage adjustor and having a sense input coupled to said voltage adjustor output, a first reference input, and a control signal output coupled to said voltage adjustor control input, where the inner servo loop establishes said voltage adjustor output level as a function of the first reference input;

c. an outer servo loop for generating a variable first reference voltage for said inner servo loop and having a voltage sense input coupled directly to the load for sensing an actual load voltage, a second reference input coupled to a reference voltage source, and a control signal output coupled to said first reference input of said inner servo loop, where the outer servo loop maintains control over said inner servo loop;

d. said outer servo loop including a logical comparator for comparing said actual load voltage with said reference voltage source and providing a logical high or low error output when said actual voltage is higher or lower than said reference voltage source, where said error output from said logical comparator is filtered to form said variable first reference voltage by a loop filter; and

e. whereby said outer servo loop senses the actual regulated voltage on said load and maintains control over said inner servo loop forcing said inner servo loop to cause said voltage adjustor to adjust and compensate for any voltage losses in said power distribution path, and thereby regulate the actual voltage on said load to the desired level.

2. The invention as defined in claim 1 wherein said inner servo loop further comprises an inner servo loop comparator for comparing a sample of said output voltage of said voltage adjustor and said sense input of said inner servo loop.

3. A concentric servo voltage regulator comprising:

a. a voltage adjustor having an input and an output for outputting a regulated output voltage to a load, the voltage adjustor being responsive to a control signal;

b. an inner servo loop having means for providing said control signal to said voltage adjustor, the inner servo loop including an inner servo loop comparator having means for comparing an inner servo loop reference voltage with a variable sense threshold from a variable attenuator, and generating said control signal when the variable sense threshold is inconsistent with the inner servo loop reference voltage, and the variable attenuator receiving a first sense voltage that is a sample of said regulated output voltage, and being responsive to a variable servo signal; and

c. an outer servo loop having means for providing said variable servo signal to said attenuator, the outer servo loop including an outer servo loop comparator having means for comparing a second sense voltage that is a sample of an actual voltage on said load with a reference voltage, and generating said variable servo signal when the second sense voltage is inconsistent with the reference voltage;

d. whereby said outer servo loop can sense the actual voltage on said load and provide said variable servo signal to said inner servo loop, so that said control signal produced by said inner servo loop can cause said voltage adjustor to adjust and compensate any fluctuation in said output voltage, and thereby provide a desirable actual voltage on said load.

4. The invention as defined in claim 3 wherein said inner servo loop further comprises an inner servo loop filter connected between said inner servo loop comparator and said voltage adjustor.

5. The invention as defined in claim 3 wherein said outer servo loop further comprises an outer servo loop filter connected between said outer servo loop comparator and said inner servo loop comparator.

6. The invention as defined in claim 3 further comprising a fullwave rectifier and an input filter connected to said input of said voltage adjustor.

7. The invention as defined in claim 3 further comprising an output filter connected to said output of said voltage adjustor.

8. A concentric servo voltage regulator comprising:

a. a switchmode voltage adjustor having an inner servo loop, an input and an output for outputting a regulated output voltage to a load;

b. a variable attenuator for providing a variable sense threshold to said inner servo loop of said switchmode voltage adjustor, the variable attenuator receiving a first sense voltage that is a sample of said regulated output voltage, and being responsive to a variable servo signal; and

c. an outer servo loop having means for providing said variable servo signal to said attenuator, the outer servo loop including an outer servo loop comparator having means for comparing a second sense voltage that is a sample of an actual voltage on said load with a reference voltage, and generating said variable servo signal when the second sense voltage is inconsistent with the reference voltage;

d. whereby said outer servo loop can sense the actual voltage on said load and provide said variable servo signal to said attenuator which in turn provides said variable sense threshold to said inner servo loop of said switchmode voltage adjustor and causes it to adjust and compensate any fluctuation in said output voltage, and thereby provide a desirable actual voltage on said load.

9. The invention as defined in claim 8 wherein said inner servo loop further comprises an inner servo loop filter connected between an inner servo loop comparator and said voltage adjustor.

10. The invention as defined in claim 9 wherein said outer servo loop further comprises an outer servo loop filter connected between said outer servo loop comparator and said inner servo loop comparator.

11. The invention as defined in claim 8 further comprising a fullwave rectifier and an input filter connected to said input of said voltage adjustor.

12. The invention as defined in claim 8 further comprising an output filter connected to said output of said voltage adjustor.

13. A concentric servo voltage regulator comprising:

a. voltage adjustor having an input for receiving an unregulated input voltage, an output for outputting a regulated output voltage to a load, and a control terminal for receiving a control signal;

b. an inner servo loop for providing said control signal to said voltage adjustor, the inner servo loop having an inner servo loop comparator and an inner servo loop filter, the inner servo loop comparator having a first input for receiving a first sense voltage that is a sample of said regulated output voltage, a second input for receiving a variable sense threshold, and an output, the inner servo loop comparator generating a logical high or low error signal at its output when the first sense voltage is higher or lower than the variable sense threshold, and the inner servo loop filter connected between the output of the inner servo loop comparator and said control terminal of said voltage adjustor; and

c. an outer servo loop for providing said variable sense threshold to said inner servo loop, the outer servo loop having an outer servo loop comparator and an outer servo loop filter, the outer servo loop comparator having a first input for receiving a second sense voltage that is a sample of an actual voltage on said load, a second input for receiving a reference voltage, and an output, the outer servo loop comparator generating a logical high or low error signal at its output when the second sense voltage is higher or lower than the reference voltage, and the outer servo loop filter connected between the output of the outer servo loop comparator and said second input of said inner servo loop comparator;

d. whereby said outer servo loop can sense the actual voltage on said load and provide said variable sense threshold to said inner servo loop, so that said control signal produced by said inner servo loop can cause said voltage adjustor to adjust and compensate any fluctuation in said output voltage, and thereby provide a desirable actual voltage on said load.

14. The invention as defined in claim 13 further comprising a fullwave rectifier and an input filter connected to said input of said voltage adjustor.

15. The invention as defined in claim 13 further comprising an output filter connected to said output of said voltage adjustor.

16. The invention as defined in claim 13 further comprising an additional filter connected between said first input of said inner servo loop comparator and said first input of said outer ervo loop comparator for preventing interference between said first sense voltage and said second sense voltage.

17. A concentric servo voltage regulator comprising:

a. a voltage adjustor having an input for receiving an unregulated input voltage, an output for outputting a regulated output voltage to a load, and a control terminal for receiving a control signal;

b. an inner servo loop having means for providing said control signal to said voltage adjustor, the inner servo loop having an inner servo loop comparator, an inner servo loop filter and a variable attenuator, the inner servo loop comparator having a first input for receiving an inner servo loop reference voltage, a second input for receiving a variable sense threshold from the variable attenuator, and an output, the inner servo loop comparator generating a logical high or low error signal at its output when the variable sense threshold is higher or lower than the inner servo loop reference voltage, the inner servo loop filter connected between the output of the inner servo loop comparator and said control terminal of said voltage adjustor, and the variable attenuator receiving a first sense voltage that is a sample of said regulated output voltage, and being responsive to a variable servo signal; and

c. an outer servo loop having means for providing said variable servo signal to said attenuator, the outer servo loop having an outer servo loop comparator and an outer servo loop filter, the outer servo loop comparator having a first input for receiving a second sense voltage that is a sample of an actual voltage on said load, a second input for receiving a reference voltage, and an output, the outer servo loop comparator generating a logical high or low error signal at its output when the second sense voltage is higher or lower than the reference voltage, and the outer servo loop filter connected between the output of the outer servo loop comparator and said second input of said inner servo loop comparator;

d. whereby said outer servo loop can sense the actual voltage on said load and provide said variable servo signal to said inner servo loop, so that said control signal produced by said inner servo loop can cause said voltage adjustor to adjust and compensate any fluctuation in said output voltage, and thereby provide a desirable actual voltage on said load.

18. The invention as defined in claim 17 further comprising a fullwave rectifier and an input filter connected to said input of said voltage adjustor.

19. The invention as defined in claim 17 further comprising an output filter connected to said output of said voltage adjustor.

20. A concentric servo voltage regulator comprising:

a. a switchmode voltage adjustor having an input for receiving an unregulated input voltage, an output for outputting a regulated output voltage to a load, and a sense input for receiving a control signal, the switchmode voltage adjustor further including an inner servo loop for adjusting the output voltage;

b. a variable attenuator for providing a variable sense threshold to said sense input of said switchmode voltage adjustor, the variable attenuator receiving a first sense voltage that is a sample of said regulated output voltage, and being responsive to a variable servo signal; and

c. an outer servo loop having means for providing said variable servo signal to said attenuator, the outer servo loop having an outer servo loop comparator and an outer servo loop filter, the outer servo loop comparator having a first input for receiving a second sense voltage that is a sample of an actual voltage on said lead, a second input for receiving a reference voltage, and an output, the outer servo loop comparator generating a logical high or low error signal at its output when the second sense voltage is higher or lower than the reference voltage, and the outer servo loop filter connected between the output of the outer servo loop comparator and said variable attenuator;

d. whereby said outer servo loop can sense the actual voltage on said lead and provide said variable servo signal to said attenuator which in turn provides said variable sense threshold to said inner servo loop of said switchmode voltage adjustor and causes it to adjust and compensate any fluctuation in said output voltage, and thereby provide a desirable actual voltage on said lead.

21. The invention as defined in claim 20 further comprising a fullwave rectifier and an input filter connected to said input of said voltage adjustor.

22. The invention as defined in claim 20 further comprising an output filter connected to said output of said voltage adjustor.

23. A method of regulating an output voltage of a voltage adjustor having a supply input for receiving a supply voltage, a voltage output for providing a controlled output voltage through a power distribution path to a load, and a control input responsive to a control signal for controlling the level of the output voltage as a function of the control signal, comprising the steps of:

a. providing an inner servo loop for generating the control signal for said voltage adjustor and having a sense input coupled to said voltage adjustor output, a first reference input, and a control signal output coupled to said voltage adjustor control input, where the inner servo loop establishes said voltage adjustor output level as a function of the first reference input;

b. providing an outer servo loop for generating a variable first reference voltage to said inner servo loop and having a voltage sense input coupled directly to the load for sensing an actual load voltage, a second reference input coupled to a reference voltage source, and a control signal output coupled to said first reference input of said inner servo loop, where the outer servo loop maintains control over said inner servo loop, the outer servo loop including a logical comparator for comparing the actual load voltage with the reference voltage source and providing a logical high or low error output when the actual voltage is higher or lower than the reference voltage source;

c. providing a loop filter for filtering said error output from said logical comparator to form said variable first reference voltage by a loop filter; and

d. whereby said outer servo loop senses the actual regulated voltage on said load and maintains control over said inner servo loop forcing said inner servo loop to cause said voltage adjustor to adjust and compensate for any voltage losses in said power distribution path, and thereby regulate the actual voltage on said load to the desired level.

24. A method of regulating an output voltage of a voltage regulator, comprising the steps of:

a. providing an inner servo loop which has means for producing a control signal to a voltage adjustor, having an output for outputting a regulated output voltage to a load and means for comparing an inner servo loop reference voltage with a variable sense threshold from a variable attenuator, which receives a first sense voltage that is a sample of said regulated output voltage, and is responsive to a variable servo signal, and means for generating said control signal when the variable sense threshold is inconsistent with the inner servo loop reference voltage;

b. providing an outer servo loop which has means for producing said variable servo signal to said variable attenuator, and means for comparing a second sense voltage that is a sample of an actual voltage on said load with a reference voltage, and means for generating said variable servo signal when the second sense voltage is inconsistent with the reference voltage;

c. whereby said outer servo loop can sense the actual voltage on said load and provide said variable servo signal to said inner servo loop, so that said control signal produced by said inner servo loop can cause said voltage adjustor to adjust and compensate any fluctuation in said output voltage, and thereby provide a desirable actual voltage on said load.

25. A method of regulating an output voltage of a switchmode voltage adjustor having an output for outputting the regulated output voltage to a load and an inner servo loop for adjusting the output voltage, comprising the steps of:

a. providing a variable attenuator which has means for producing a variable sense threshold to said inner servo loop of said switchmode voltage adjustor, where the variable attenuator receives a first sense voltage that is a sample of said regulated output voltage, and is responsive to a variable servo signal; and

b. providing an outer servo loop which has means for producing said variable servo signal to said attenuator, and means for comparing a second sense voltage that is a sample of an actual voltage on said load with a reference voltage, and means for generating said variable servo signal when the second sense voltage is inconsistent with the reference voltage;

c. whereby said outer servo loop can sense the actual voltage on said load and provide said variable servo signal to said attenuator which in turn provides said variable sense threshold to said inner servo loop of said switchmode voltage adjustor and causes it to adjust and compensate any fluctuation in said output voltage, and thereby provide a desirable actual voltage on said load.

26. A concentric servo voltage regulator comprising:

a. a voltage adjustor having an inner servo loop and an output for outputting a regulated output voltage to a load, the inner servo loop sensing the output voltage and adjusting it to a desired level;

b. an attenuator being responsive to a variable servo signal, for receiving a sample of said output voltage and providing a variable sense threshold to said inner servo loop of said voltage adjustor; and

c. an outer servo loop having means for comparing a sample of an actual voltage on said load with a reference voltage, and providing said variable servo signal to said inner servo loop when the actual voltage is inconsistent with the reference voltage;

d. whereby said outer servo loop can sense said actual voltage on said load and provide said variable servo signal to said inner servo loop, so that said inner servo loop can cause said voltage adjustor to adjust and compensate any fluctuation in said output voltage, and thereby provide a desirable actual voltage on said load.

27. The invention as defined in claim 26 wherein said inner servo loop further comprises an inner servo loop comparator for comparing said sample of said output voltage and said variable servo signal.

28. The invention as defined in claim 26 wherein said outer servo loop further comprises an outer servo loop comparator for comparing said sample of said actual voltage and said reference voltage.

29. The invention as defined in claim 28 wherein said outer servo loop further comprises an outer servo loop filter connected between said outer servo loop comparator and said inner servo loop of said voltage adjustor.