The PLC module supports solar technologies with modulation, adjustable frequencies, and built-in protections for stable, efficient functionality.
Power Line Communication (PLC) is increasingly utilized across various end-equipment applications. A notable use case is in grid applications, where devices exchange necessary data using power cables as transmission lines, thus the term Power Line Communication. Data transmission is facilitated by modulating signals at higher frequency bands, typically in the kHz and MHz ranges, onto the power line. TIDA-010935, a reference design from Texas Instruments (TI), demonstrates a straightforward PLC method, employing an On-Off-Keying modulator combined with a line driver and passive filtering to enable data transmission over a Universal Asynchronous Receiver Transmitter (UART) interface.
The applications for this design encompass a variety of solar power technologies, including micro inverters, string inverters, solar power optimizers, and central inverters. It is an affordable, adaptable PLC module tailored for solar applications. The design can be powered directly from a solar panel or an auxiliary power source via screw terminals. It features built-in current limit and reverse polarity protections. The design allows for the selection of multiple carrier frequencies, ranging from 125 kHz to 5 MHz, enabling engineers to bypass interference from the switching frequencies of string inverters that might affect the carrier frequency of the THVD8000. Additionally, the BIAS setting of the THS6222 line driver can be adjusted to enhance power efficiency.
The design includes four selectable modulating frequencies: 125 kHz, 500 kHz, 2 MHz, and 5 MHz. It features built-in current limit protection and reverse polarity protection using TI eFuse technology. The design uses the same communication line for receiving and transmitting, optimizing space. Through the BoosterPack Plug-in Module, it is compatible with multiple microcontroller families, including MSPM0 and the C2000.
The signal generated by the MCU is transmitted over UART to a modulator. A line driver is then required to amplify the signal sufficiently for transmission onto the power line. A discrete filter isolates the necessary band from the incoming spectrum, providing the THVD8000 with the appropriate signal for demodulation.
An RS-485 transceiver equipped with On-Off-Keying (OOK) modulation for power line communication. It features an integrated modulator and demodulator, selectable via the MODE pin. OOK modulation provides immunity to data polarity, simplifying this device’s implementation and usage.
A differential line driver amplifier uses a current feedback architecture crafted using Texas Instruments’ high-speed silicon-germanium process. The device is designed for broadband, high-speed, power line communications applications, particularly those needing high linearity while managing heavy line loads.
The microcontrollers feature highly integrated, ultra-low-power 32-bit MCUs based on the enhanced Arm Cortex-M0+ core platform. Operating at frequencies up to 80 MHz, these cost-effective MCUs are designed to offer high-performance analogue peripheral integration. They support a wide temperature range from –40°C to 125°C and operate with supply voltages from 1.62 V to 3.6 V.
TI has tested this reference design. It comes with a bill of materials (BOM), schematics, assembly drawing, printed circuit board (PCB) layout, and more. The company’s website has additional data about the reference design. To read more about this reference design, click here.
