While networks based on using the ubiquitous powerline don’t have the glamor or speed of Ethernet or Wi-Fi (to cite just two examples), they’re a hardware- and cost-effective solution for energy management and building a smarter grid. To address their unique interface needs, as well as the multiple protocols in use among utilities and in different countries, Microchip developed the PL360B powerline modem IC. It implements a range of existing and emerging industry-standard Power Line Communication (PLC) protocols, including ITU G.9903 (G3-PLC) and ITU G.9904 (PRIME), as well as CENELEC-, FCC-, and ARIB-compliant applications.
This programmable PLC modem supports narrowband operation in any frequency band up to 500 kHz (Fig. 1). The critical front-end interface includes a programmable gain amplifier (PGA) with automatic gain control (AGC) for analog-to-digital converter operation over a wide dynamic range. The digital-to-analog converters and transmission driver support direct-line driving or external Class-D amplifier driving, along with digital transmission-level control. Furthermore, the device supports two independent transmission branches for the PLC signal.
1. The PL360B IC from Microchip Technologies eases the challenge of implementing a powerline modem, meeting a wide array of multiple industry and regulatory standards.
In addition to the interface, the IC implements a high-performance architecture combining a CPU, specific coprocessors for digital signal processing, and dedicated hardware accelerators for common narrowband PLC tasks. It includes an ARM 32-bit Cortex-M7 core-managing PL360 system comprised of co-processors, hardware accelerators and peripherals, as well as dedicated SRAM memories for code and data.
Then there’s data security, an increasingly important issue, despite (or perhaps as a consequence of) the nature of the powerline media. The PLC360B addresses this with a cryptographic engine and secure boot, and supports AES-128, 192, 256 standards. In addition, the secure-boot feature supports AES-128 CMAC for authentication, and AES-128 CBC for decryption. Security is also enhanced by the availability of fuse-programming control for decryption and authentication with 128-bit keys.
Effective use of ICs such as the PL360B involves numerous hardware and software issues. Not only does the 57-page datasheet provide detailed insight into the IC operation, registers, sequencing, and interconnection, it also shows the functions of the critical coupling block that resides between the IC and the AC mains (Fig. 2). On top of that, Microchip provides modem reference designs (design files, bill of materials, and schematics) for applications such as a complete electricity meter with PLC, a single PLC modem, and a master PLC device in charge of mastering the complete network of PLC nodes.
2. Key to an effective modem is the coupling block, which is the link between the well-behaved and constrained IC environment and the harsh powerline reality.
For those who prefer or need to explore and evaluate, the company also offers an evaluation kit with two evaluation boards and free G3-PLC and PRIME-PLC communications firmware used to establish point-to-point communication. The kit includes PC tools for assessing the performance of the PL360B, including a PHY tester for point-to-point test, a PLC “sniffer” to capture PLC traffic in a deployed network, and a PLC manager to manage the resulting network.
The PL360B requires a single 3.3-V supply voltage for its digital and analog I/O, and incorporates a +1.25-V voltage regulator for its core functions. It comes housed in TQFP-48 and QFN-48 packages, specified for operation over the −40 to +85°C temperature range. The PLC360B IC is priced at $2 each in 10,000-piece lots, while the ATPL360 evaluation kit goes for $500.