Error correction for powerline communication modem interface

• US 9,280,405 B2
• Filed: 03/15/2013
• Issued: 03/08/2016
• Est. Priority Date: 11/07/2012
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Magin, Gregory Allen, Corral, Celestino Anastasio
• Primary Examiner(s): Rizk, Sam
• Assistant Examiner(s): KABIR, ENAMUL MD
• Application Number:
  US13/841,997
• Publication Number:
  US 20140129892A1
• Time in Patent Office: 1,089 Days
• US Class Current: 1/1
• CPC Class Codes: G06F 11/0706 the processing taking place on a specific hardware platform or in a specific software environment
• CPC Class Codes: H04B 2203/542 using zero crossing information
• CPC Class Codes: H04B 2203/5491 using filtering and bypassing
• CPC Class Codes: H04B 3/542 the information being in digital form
• CPC Class Codes: H04B 3/56 Circuits for coupling, blocking, or by-passing of signals

Abstract

A powerline communication (PLC) power supply and modem interface can be implemented using a power supply processing unit coupled with a PLC modem unit. The power supply processing unit generates a composite PLC signal comprising a PLC signal and a DC power signal modulated with a zero cross signal (all determined from an AC powerline signal). High-powered components of the PLC modem unit can cause signal distortion in the zero cross signal component of the composite PLC signal making it difficult to extract zero cross information. An error correction unit can be implemented at the PLC modem unit to minimize the signal distortion and generate a zero cross signal with little or no error. The PLC modem unit also extracts the PLC signal and the DC power signal from the composite PLC signal, and processes the PLC signal using the zero cross information extracted from the corrected zero cross signal.

Claims

1. A powerline communication (PLC) device comprising:

an error correction unit configured to;

receive an input AC line cycle signal and a voltage drop superimposed on the input AC line cycle signal;

generate an initial correction signal comprising the voltage drop based, at least in part, on the input AC line cycle signal;

generate an error correction signal that comprises a voltage pulse that corresponds to the voltage drop based, at least in part, on the initial correction signal; and

generate a corrected AC line cycle signal based, at least in part, on the error correction signal and a sample of the input AC line cycle signal.

2. The PLC device of claim 1, further comprising a zero cross detector configured to extract an AC zero cross signal from the corrected AC line cycle signal.

3. The PLC device of claim 1, wherein the error correction unit comprises an operational amplifier configured to generate the error correction signal.

4. The PLC device of claim 3, wherein the operational amplifier is configured in a differential input mode and an inverted amplifier output mode.

5. The PLC device of claim 1, wherein the voltage drop superimposed on the input AC line cycle signal represents signal distortion from dynamic loading effects associated with the input AC line cycle signal.

6. The PLC device of claim 1, wherein,

an amplitude of the voltage pulse of the error correction signal approximately equals an amplitude of the corresponding voltage drop of the input AC line cycle signal, and a polarity of the voltage pulse of the error correction signal is opposite to a polarity of the corresponding voltage drop of the input AC line cycle signal.

7. The PLC device of claim 1, wherein the error correction unit comprises a summing unit configured to combine the error correction signal with the sample of the input AC line cycle signal to minimize an amplitude of the voltage drop.

8. The PLC device of claim 1, further comprising an operational amplifier configured to operate as a band pass filter and an amplifier, wherein the operational amplifier generates the corrected AC line cycle signal.

9. A powerline modem comprising:

a biasing unit configured to;

extract a powerline communication (PLC) signal from a composite PLC signal received at the powerline modem, and

extract a DC power signal modulated with an AC zero cross signal from the composite PLC signal;

an error correction unit configured to;

process the AC zero cross signal to reduce signal distortion associated with the powerline modem; and

a zero cross detector configured to;

receive the processed AC zero cross signal from the error correction unit, and

extract zero cross information from the processed AC zero cross signal.

10. The powerline modem of claim 9, wherein the error correction unit is further configured to:

generate an error correction signal from the AC zero cross signal; and

generate the processed AC zero cross signal based, at least in part, on the error correction signal and a sample of the AC zero cross signal.

11. The powerline modem of claim 9, wherein the error correction unit is further configured to:

generate an initial correction signal comprising a voltage drop superimposed on the AC zero cross signal, wherein the voltage drop is representative of the signal distortion from dynamic loading effects associated with the powerline modem; and

generate an error correction signal based, at least in part, on the initial correction signal.

12. The powerline modem of claim 11, wherein

the error correction signal comprises a voltage pulse that corresponds to the voltage drop superimposed on the AC zero cross signal, an amplitude of the voltage pulse of the error correction signal approximately equals an amplitude of the corresponding voltage drop of the AC zero cross signal, and a polarity of the voltage pulse of the error correction signal is opposite to a polarity of the corresponding voltage drop of the AC zero cross signal.

13. The powerline modem of claim 9, wherein the zero cross detector is further configured to:

generate the zero cross information representing timing of zero crossings of the composite PLC signal based, at least in part, on sampling the processed AC zero cross signal.

14. An apparatus comprising:

a power supply processing unit configured to;

generate a DC power signal from an AC powerline signal received from a powerline communication (PLC) network;

determine an AC zero cross signal associated with the AC powerline signal;

determine a modulated DC power signal by modulating the AC zero cross signal onto the DC power signal;

extract a PLC signal from the AC powerline signal;

generate a composite PLC signal comprising the PLC signal and the modulated DC power signal; and

a powerline modem configured to;

extract the PLC signal and the modulated DC power signal from the composite PLC signal received from the power supply processing unit;

extract the AC zero cross signal from the modulated DC power signal;

process the AC zero cross signal to reduce signal distortion associated with the powerline modem; and

process the PLC signal based, at least in part, on zero cross information determined from the processed AC zero cross signal.

15. The apparatus of claim 14, wherein the power supply processing unit is coupled to the powerline modem via a two-wire connector.

16. The apparatus of claim 14, wherein the power supply processing unit is coupled to the powerline modem via a multi-wire connector.

17. The apparatus of claim 14, wherein the power supply processing unit comprises:

a rectifier configured to generate a rectified signal comprising a DC power component and a superimposed AC ripple component;

a transformer configured to generate a low voltage rectified signal by stepping down the rectified signal; and

a filter configured to generate the DC power signal and minimize the superimposed AC ripple component by filtering the low voltage rectified signal.

18. The apparatus of claim 17, wherein the power supply processing unit further comprises:

a powerline sampling unit configured to generate the AC zero cross signal based, at least in part, on a sample of the AC powerline signal.

19. The apparatus of claim 18, wherein the power supply processing unit further comprises:

an output sampling unit configured to provide a sample of the modulated DC power signal as feedback to a summing unit of the power supply processing unit;

the summing unit configured to generate a feedback signal based, at least in part, on the AC zero cross signal received from the powerline sampling unit and the sample of the modulated DC power signal; and

a voltage regulator configured to;

maintain stability of the DC power signal based, at least in part, on the feedback signal; and

couple the feedback signal with the rectified signal to modulate the AC zero cross signal onto the DC power signal.

20. The apparatus of claim 19, wherein the voltage regulator comprises:

a switch mode controller configured to;

generate an error signal based, at least in part, on a difference between the sample of the DC power signal and a threshold DC signal;

generate a switching waveform based, at least in part, on the error signal; and

apply the switching waveform to a switching device associated with the power supply processing unit to control an amplitude of DC power signal.

21. The apparatus of claim 20, wherein the switch mode controller comprises a comparator coupled with a pulse width modulator,

wherein the switch mode controller is configured to:

receive the sample of the DC power signal and the AC zero cross signal from the output sampling unit;

compare the sample of the DC power signal against the threshold DC signal;

generate the error signal at a first voltage level in response to determining that the DC power signal exceeds the threshold DC signal;

generate the error signal at a second voltage level in response to determining that the DC power signal is at or below the threshold DC signal; and

provide the error signal to the pulse width modulator; and

wherein the pulse width modulator is configured to;

generate the switching waveform based, at least in part, on the error signal; and

apply the switching waveform to the switching device to control the amplitude of DC power signal.

22. The apparatus of claim 14, wherein the power supply processing unit comprises a biasing unit configured to:

generate the composite PLC signal by coupling the PLC signal with the modulated DC power signal; and

provide the composite PLC signal to a corresponding biasing unit associated with the powerline modem.

23. The apparatus of claim 14, wherein the powerline modem comprises a biasing unit configured to generate the PLC signal by removing the modulated DC power signal from the composite PLC signal.

24. The apparatus of claim 14, wherein the powerline modem further comprises:

an error correction unit configured to;

generate an error correction signal comprising a voltage pulse that corresponds to a voltage drop superimposed on the AC zero cross signal; and

generate the processed AC zero cross signal with reduced signal distortion based, at least in part, on filtering and amplifying a combination of the error correction signal and a sample of the AC zero cross signal.

25. The apparatus of claim 24, wherein an amplitude of the voltage pulse of the error correction signal approximately equals an amplitude of the corresponding voltage drop of the AC zero cross signal, and a polarity of the voltage pulse of the error correction signal is opposite to a polarity of the corresponding voltage drop of the AC zero cross signal.

26. The apparatus of claim 14, wherein the powerline modem further comprises a zero cross detector configured to:

determine the zero cross information that is representative of timing of zero crossings of the AC powerline signal by sampling the processed AC zero cross signal.

27. A method comprising:

receiving, at a powerline communication (PLC) device via a PLC network, an input AC line cycle signal and a voltage drop superimposed on the input AC line cycle signal;

generating an initial correction signal comprising the voltage drop based, at least in part, on the input AC line cycle signal;

generating an error correction signal that comprises a voltage pulse that corresponds to the voltage drop based, at least in part, on the initial correction signal; and

generating a corrected AC line cycle signal based, at least in part, on the error correction signal and a sample of the input AC line cycle signal.

28. The method of claim 27, further comprising extracting zero cross information associated with the input AC line cycle signal from the corrected AC line cycle signal.

29. The method of claim 27, wherein

an amplitude of the voltage pulse of the error correction signal approximately equals an amplitude of the corresponding voltage drop of the input AC line cycle signal, and a polarity of the voltage pulse of the error correction signal is opposite to a polarity of the corresponding voltage drop of the input AC line cycle signal.

30. The method of claim 27, further comprising summing the error correction signal with the sample of the input AC line cycle signal to minimize an amplitude of the voltage drop.