SLLA573 May   2022 THVD8000

 

  1.   Trademarks
  2. 1Introduction
  3. 2Tests and Setup
    1. 2.1 Test 1: 4-Node Star Network Test
    2. 2.2 Test 2: 4-Node Terminated Star Network Test
    3. 2.3 Test 3: 4-Node Loaded and Terminated Star Network Test
    4. 2.4 Test 4: 4-Node Loaded and Terminated Star Network Test with Line Driver
  4. 3Summary

1 Introduction

THVD8000 and THVD8010 are transceivers for power line communication (PLC) applications. The built-in on-off key (OOK) modulation and demodulation cells enable communication data to be transmitted over a decoupling capacitor on power cables. The detailed discussion about system design is documented in the THVD800 Design Guide application note. These two devices utilize RS-485 physical layer signaling to achieve good common-mode immunity for long distance communication.

Like the RS-485 systems, daisy chain is the preferred topology for this power line communication system with termination at the two furthest ends. Without termination, open ends could generate reflections and create signal integrity issues. In some low data rate applications, the signal might have enough time to settle within one bit width. However, designers might find it is hard to apply THVD8000 and THVD8010 in other network topologies than the daisy chain. In this application note, some techniques are proposed as potential solutions for different bus topologies, and lab measurement data is presented for discussion.