Dual Transformer Communication Interface

• US 20090315700A1
• Filed: 06/23/2008
• Published: 12/24/2009
• Est. Priority Date: 07/25/2006
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Hurwitz, Jonathan Ephriam David, Rocamora, David Gimenez
• Granted Patent: US 9,705,562 B2
• Time in Patent Office: Days
• US Class Current: 340/538
• CPC Class Codes: H04B 2203/5483 using coupling circuits
• CPC Class Codes: H04B 3/54 Systems for transmission via power distribution lines
• CPC Class Codes: H04B 3/56 Circuits for coupling, blocking, or by-passing of signals

Abstract

A power line communication device comprises a plurality of transformers in series. These transformers are used to increase the voltage of a digitally encoded signal in a stepwise fashion prior to being coupled into a power line. While a transmit path includes at least a first transformer and a second transformer in series, a receive path may include only one of these two transformers. For example a receive path may include only the first transformer, or include the first transformer and a third transformer. The net ratio of voltage increase and decrease may be different in the transmit and receive paths.

Claims

1. A system comprising:

a first signal source configured to generate a first data encoded signal;

a first transformer configured to receive the first data encoded signal at a primary winding, and having a primary to secondary winding ratio that is greater than one; and

a second transformer in series with the first transformer, configured to receive an output of the first transformer at a primary winding of the second transformer, configured to provide an output signal including the first data to an alternating current power line, and having a primary to secondary winding that is greater than one.

2. The system of claim 1, further comprising a signal conditioner configured to pass the data encoded signal and block a frequency at which power is conveyed through the power line.

3. The system of claim 1, further comprising a signal conditioner configured to pass the data encoded signal and attenuate a frequency at which unwanted signals are conveyed.

4. The system of claim 1, further comprising a signal conditioner disposed between the first transformer and the second transformer.

5. The system of claim 1, further including a first signal conditioner and a second signal conditioner configured to pass the data encoded signal, and further including a third signal conditioner configured to pass a second data encoded signal received from the power line, wherein the first signal conditioner is further configured to pass the second data encoded signal, and the second signal conditioner is further configured to not pass the second data encoded signal.

6. The system of claim 1, further comprising a first signal conditioner impedance matched to the first transformer and a second signal conditioner impedance matched to the second transformer.

7. The system of claim 1, further including a signal receiving circuit configured to receive a second data encoded signal and to decode the data, wherein a signal path of the received signal includes the power line and the second transformer but not the first transformer.

8. The system of claim 1, further including a signal receiving circuit configured to receive a second data encoded signal and to decode the second signal, wherein a signal path of the received second signal includes the second transformer and the first transformer.

9. The system of claim 1, further including a second signal source configured to generate a second data encoded signal within a frequency range that is different than a frequency range of the first data encoded signal, wherein a signal path of the second data encoded signal includes the second transformer but not the first transformer.

10. The system of claim 1, wherein at least part of the first data encoded signal is at frequency between 1.8 MHz and 30 MHz.

11. The system of claim 1, wherein the first transformer includes a primary to secondary winding ratio between approximately 1:

1.5 and 1;

3.

12. The system of claim 1, wherein the first signal source is configured to generate the first data encoded signal at a peak-to-peak voltage of between approximately 2 and 8 volts.

13. The system of claim 1, wherein the output of the first signal source comprises a CMOS (complementary metal oxide semiconductor) circuit and the output of the second transformer is at least 4 volts peak-to-peak.

14. The system of claim 1, further comprising a line driver powered by the same supply voltage as the first signal source, the line driver being configured to drive first data encoded signal.

15. The system of claim 1, wherein the first signal source includes a plurality of line drivers configured to generate additive signals.

16. The system of claim 1, wherein the first signal source includes a plurality of line drivers configured to drive interdependent signals.

17. A system comprising:

a transmit path between a signal source and a power line, the transmit path comprising at least a first transformer and a second transformer in series; and

a receive path between the power line and a signal receiver, the receive path comprising at least the second transformer but not the first transformer, the signal source and signal receiver being included in the same communication interface.

18. The system of claim 17 wherein the transmit path further comprises a first signal conditioner impedance matched to the first transformer, and a second signal conditioner impedance matched to the second transformer.

19. The system of claim 17, wherein the second signal conditioner is included in the receive path.

20. The system of claim 17, wherein the receive path further comprises a third transformer in series with the second transformer.

21. The system of claim 17, wherein the second transformer is a multi-tap transformer.

22. A method of communicating a signal, the method comprising:

generating a first digitally encoded signal;

passing the first digitally encoded signal through a first transformer;

passing the first digitally encoded signal through a second transformer in series with the first transformer; and

coupling the first digitally encoded signal into an AC power line.

23. A method of communicating a signal, the method comprising:

receiving a first digitally encoded signal from an AC power line;

passing the first digitally encoded signal through a first transformer;

conditioning the first digitally encoded signal to separate frequencies of the AC power from frequencies of the first digital encoding;

passing the first digitally encoded signal through a second transformer in series with the first transformer; and

decoding the first digitally encoded signal.

24. The method of claim 23, further comprising, in response to the first digitally encoded signal,

generating a second digitally encoded signal;

passing the second digitally encoded signal through a third transformer;

passing the first digitally encoded signal through the first transformer in series with the third transformer; and

coupling the first digitally encoded signal into the AC power line.