Digital error signal comparator

• US 9,660,540 B2
• Filed: 11/05/2012
• Issued: 05/23/2017
• Est. Priority Date: 11/05/2012
• Status: Active Grant

• Current Assignee: Flextronics America LLC (Flextronics International Limited)
• Original Assignee: Flextronics America LLC (Flextronics International Limited)
• Inventors: Telefus, Jr., Mark
• Primary Examiner(s): Berhane, Adolf
• Application Number:
  US13/669,229
• Publication Number:
  US 20140125305A1
• Time in Patent Office: 1,660 Days
• Field of Search: 323241, 323283, 323322, 363 2101, 363 95, 363971, 363 23, 363 17
• CPC Class Codes: H02M 3/33515 with digital control
• CPC Class Codes: H02M 3/33523 with galvanic isolation between input and output of both the power stage and the feedback loop

Abstract

A digital error feedback system, method and device adjusts the output voltage of a power converter. The digital error feedback system uses a digital comparator and one or more digital signal generators to generate and compare a digital signal corresponding to the output voltage to a reference digital signal in order to determine the current amount of error in the output voltage. The error is then able to be compensated for using a control signal generated based on the determined error.

Claims

1. A digital error feedback system comprising:

a power supply for supplying an input power;

a power converter coupled with the power supply, wherein the power converter produces an output voltage on a load using the input power;

a digital-to-analog converter (DAC) coupled to the power converter;

a first digital signal generator that generates a digital reference signal; and

a digital comparator coupled with the first digital signal generator and the DAC, wherein, based on the digital reference signal and a frequency of a digital feedback signal representing the output voltage, the digital comparator produces a digitally compared control signal that is received by the DAC and converted to an analog signal, and further wherein the DAC transmits the analog signal to the power converter such that the digitally compared control signal, as converted to the analog signal, causes the power converter to adjust the output voltage.

2. The system of claim 1, further comprising a second digital signal generator coupled with the power converter and the digital comparator, wherein the second digital generator detects the output voltage and generates the digital feedback signal based on the detected output voltage level.

3. The system of claim 2, wherein the digital comparator produces the digitally controlled control signal by determining the difference in frequency between the digital reference signal and the digital feedback signal and adjusting the digitally compared control signal based on the determined difference.

4. The system of claim 1, wherein the power converter comprises a controller and the digital feedback signal is based on a pulse width modulated converter signal output by the controller in order to produce the output voltage on the load.

5. The system of claim 4, wherein the digital comparator produces the digitally compared control signal by determining a number of cycles of the digital reference signal that occur during each high pulse of the digital feedback signal and adjusting the digitally compared control signal based on the determined number of cycles per high pulse.

6. The system of claim 3, wherein the frequency of the digital reference signal is associated with a desired voltage that is required by the load.

7. The system of claim 6, wherein the first digital signal generator enables the frequency of the digital reference signal to be adjusted.

8. The system of claim 1, wherein the first digital signal generator and the digital comparator are a part of a separate integrated circuit that is coupled with the power converter.

9. The system of claim 1, wherein the power converter, the first digital signal generator and the digital comparator are a part of a single integrated circuit.

10. A digital error feedback device comprising:

a power converter coupled with a power supply, wherein the power converter produces an output voltage on a load using input power provided by the power supply;

a digital-to-analog converter (DAC) coupled to the power converter;

a first digital signal generator that generates a digital reference signal; and

a digital comparator coupled with the first digital signal generator and the DAC, wherein, based on the digital reference signal and a frequency of a digital feedback signal representing the output voltage, the digital comparator produces a digitally compared control signal that is received by the DAC and converted to an analog signal, and further wherein the DAC transmits the analog signal to the power converter such that the digitally compared control signal, as converted to the analog signal, causes the power converter to adjust the output voltage.

11. The device of claim 10, further comprising a second digital signal generator coupled with the power converter and the digital comparator, wherein the second digital generator detects the output voltage and generates the digital feedback signal based on the detected output voltage level.

12. The device of claim 11, wherein the digital comparator produces the digitally compared control signal by determining the difference in frequency between the digital reference signal and the digital feedback signal and adjusting the digitally compared control signal based on the determined difference.

13. The device of claim 10, wherein the power converter comprises a controller and the digital feedback signal is based on a pulse width modulated converter signal output by the controller in order to produce the output voltage on the load.

14. The device of claim 13, wherein the digital comparator produces the digitally compared control signal by determining a number of cycles of the digital reference signal that occur during each high pulse of the digital feedback signal and adjusting the digitally compared control signal based on the determined number of cycles per high pulse.

15. The device of claim 12, wherein the frequency of the digital reference signal is associated with a desired voltage that is required by the load.

16. The device of claim 15, wherein the first digital signal generator enables the frequency of the digital reference signal to be adjusted.

17. The device of claim 10, wherein the first digital signal generator and the digital comparator are a part of a separate integrated circuit that is coupled with the power converter.

18. The device of claim 10, wherein the power converter, the first digital signal generator and the digital comparator are a part of a single integrated circuit.

19. A method of adjusting the output voltage of a power converter using digital error feedback, the method comprising:

producing an output voltage on a load with a power converter using the input power of a power source;

generating a digital reference signal with a first digital signal generator;

receiving the digital reference signal and a digital feedback signal representing the output voltage with a digital comparator;

producing a digitally compared control signal with the digital comparator;

forwarding the digitally compared control signal from the digital comparator to a digital to analog converter; and

converting the digitally compared control signal to an analog signal with the digital to analog converter such that the digitally compared control signal, as converted to the analog signal, causes the power converter to adjust the output voltage, wherein the digitally compared control signal is based on the digital reference signal and a frequency of the digital feedback signal.

20. The method of claim 19, further comprising detecting the output voltage and generating the digital feedback signal with a second digital signal generator based on the detected output voltage level.

21. The method of claim 20, wherein producing the digitally compared control signal comprises determining the difference in frequency between the digital reference signal and the digital feedback signal and adjusting the digitally compared control signal based on the determined difference.

22. The method of claim 19, further comprising outputting a pulse width modulated converter signal with a controller of the power converter in order to produce the output voltage on the load, wherein the digital feedback signal is based on the pulse width modulated converter signal.

23. The method of claim 22, wherein producing the digitally compared control signal comprises determining a number of cycles of the digital reference signal that occur during each high pulse of the digital feedback signal and adjusting the digitally compared control signal based on the determined number of cycles per high pulse.

24. The method of claim 21, further comprising associating a frequency of the digital reference signal with a desired voltage that is required by the load.

25. The method of claim 24, wherein the associating comprises adjusting the frequency of the digital reference signal with the first digital signal generator.

26. The method of claim 19, wherein the first digital signal generator and the digital comparator are a part of a separate integrated circuit that is coupled with the power converter.

27. The method of claim 19, wherein the power converter, the first digital signal generator and the digital comparator are a part of a single integrated circuit.