Serial signal injection using capacitive and transformer couplings for power line communications

• US 7,286,026 B2
• Filed: 09/02/2004
• Issued: 10/23/2007
• Est. Priority Date: 09/02/2004
• Status: Expired due to Fees

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies ECBU IP Singapore Pte Limited (Broadcom, Inc.)
• Inventors: Law, Robinson Peng Seng
• Primary Examiner(s): Lee; Benny
• Assistant Examiner(s): Glenn; Kimberly E
• Application Number:
  US10/934,263
• Publication Number:
  US 20060044076A1
• Time in Patent Office: 1,146 Days
• Field of Search: 333/124, 333/24.R, 333/24.C, 333/32
• US Class Current: 333/124
• CPC Class Codes: H04B 2203/5491 using filtering and bypassing
• CPC Class Codes: H04B 3/56 Circuits for coupling, blocking, or by-passing of signals

Abstract

A coupling network has a first power line interface port and a power line modem interface configured to be coupled to a power line modem transceiver. An inductor-capacitor circuit coupled to the power line modem interface has a low-impedance resonant frequency at a signal frequency of the power line modem transceiver. An inductor having a corner frequency between the signal frequency and the power line frequency has a first end and a second end. The first end of the inductor is connected to the inductor-capacitor circuit and a second end of the inductor is coupled to an alternating current ground coupled to the transceiver ground. The inductor couples the first power line interface port to a power supply interface port.

Claims

1. A coupling network comprising:

a first power line interface port for connecting said network to a power line that carries a power signal characterized by a power line frequency;

a power line modem interface configured to be coupled to a power line modem transceiver that receives a signal characterized by a signal frequency;

an inductor-capacitor circuit coupled to the power line modem interface and having a low-impedance resonant frequency of the power line modem transceiver;

an alternating current ground coupled to a transceiver ground;

an inductor having a corner frequency between the signal frequency and the power line frequency, and having a first end and a second end, the first end of the inductor being connected to the inductor-capacitor circuit and the second end of the inductor being coupled to the alternating current ground; and

a power supply interface port coupled to the first power line interface port through the inductor.

2. The coupling network of claim 1 wherein the inductor is a winding of a transformer.

3. The coupling network of claim 1 wherein the first end of the inductor is connected to the first power line interface port.

4. The coupling network of claim 1 wherein the first end of the inductor is connected to the power supply interface port.

5. The coupling network of claim 1 further comprising a capacitor coupled to the first power line interface port and to a second power line interface port.

6. The coupling network of claim 5 wherein the capacitor has an impedance less than about 20 ohms at a signal frequency of the coupling network.

7. The coupling network of claim 5 wherein the capacitor has an impedance less than about 12 ohms at a signal frequency of the coupling network.

8. The coupling network of claim 5 wherein the capacitor has an impedance not greater than about 6 ohms at a signal frequency of the coupling network.

9. The coupling network of claim 5 further comprising a first power line lead connected to the second power line interface port.

10. The coupling network of claim 9 further comprising a second power line lead connected to the power supply interface port;

and

a power supply connected to the first power line lead and to the second power line lead.

11. The coupling network of claim 9 wherein the power supply is a linear power supply.

12. The coupling network of claim 9 wherein the power supply is a switching power supply.

13. The coupling network of claim 12 wherein a transformer operates in conjunction with the capacitor to form an EMI filter.

14. The coupling network of claim 1 further comprising the power line modem transceiver.