SLLA590 May   2022 THVD8000 , THVD8010

 

  1.   Abstract
  2.   Trademarks
  3. 1Introduction
  4. 2THVD80x0 Devices Theory of Operation and Limitations of Use
    1. 2.1 Overview and Similarities between Standard RS-485 Transceivers and THVD80xo Devices
    2. 2.2 Differences between Standard RS-485 Transceivers and THVD8000/8010
    3. 2.3 Standard Approach to Using THVD80xo Devices to Communicate over Power Lines
    4. 2.4 Drawbacks to Standard Approach with Higher Voltage Systems
  5. 3Integration of Line Driver with THVD80x0 Devices to Drive Low Impedance Loads
    1. 3.1 Overcoming Drive Strength Requirement with A Line Driver Amplifier
    2. 3.2 Modification to Typical System Signal Chain Path Through Integration of Line Driver
  6. 4High Voltage Interface and Communication Interface Power Supply
    1. 4.1 Line Driver Output and Input RX signal Protection Circuit
    2. 4.2 High-Voltage Interface
    3. 4.3 Receive Path Optional Bandpass
  7. 5System Level View and Relation to Higher Voltage Implementations
    1. 5.1 Powering the Powerline Communication System
    2. 5.2 System Overview with Selected Test Results
    3. 5.3 Changes to Design for Higher Voltage AC or DC Applications
  8. 6Summary
  9. 7References

6 Summary

The THVD8000 and THVD8010 are excellent devices when trying to communicate over a power line. Lower voltage systems (< ~30 V) with line to ground impedance’s of 375 Ω benefit from the standard approach outlined in both the THVD8000 and THVD8010 data sheets as well as the THVD8000 design guide. Higher-voltage systems with line to ground impedance’s of less than 375Ω can benefit from the implementations detailed in this application note. To integrate the THVD8000/THVD8010 into a higher voltage and/or lower impedance systems modifications to the standard approach must be made. By utilizing a line driver such as the THS6222 in addition to the THVD8000 and THVD8010 to transmit RS-485 data; lines with less than 375 Ω to ground can be used as a transmission medium. With the addition of a protection circuit with a robust high-voltage interface not only can lines with less than 375 Ω be driven, but the high voltage signal pathway is isolated away from the communication circuit allowing for communication over the powerlines of any voltage if the interface can block and or filter out the high voltage signal. The THVD8000 and THVD8010 devices are excellent parts for transmitting RS-485 data over power lines and with a few modifications can be expanded to fit in most power line communication-based applications.