Proving the Business Case for the Internet of Things

STM chipset pushes PLC for smarter energy

Steve Rogerson
October 10, 2017

Swiss semiconductor company ST Microelectronics says it is powering the global shift to smarter energy consumption and management with its modular power-line communications (PLC) modem chipset.
The chipset should provide more flexibility to manufacturers of utility meters, smart-grid nodes, streetlamps, and home and industrial controllers. Three smart-meter manufacturers are already designing products based on this platform.
The chipset consolidates protocol handling to package and adapt data so they can be transmitted and line driving for sending over mains wires. It enables users to implement PLC cost-effectively, either as part of new designs or as the core of an add-on module on older devices.
For markets with specific regulatory requirements, the chipset acts as an external communications module that interfaces with either the existing or a new metering or controlling device. In addition, flexible programmability allows multiple product variants to share a common hardware foundation, and permits software updating in the field to lower cost of ownership.
“STM has been serving the leading smart-meter manufacturers since the roll-out of the first generation of digital meters, with more than 60 million chipsets deployed in homes and buildings across Europe, China and the Americas,” said Domenico Arrigo, general manager of STM’s industrial and power conversion division. “Building on the lessons from this first phase, next-generation metering and other IoT programmes across the world have new design requirements, to which our new chipset is the best answer: flexible and cost-effective PLC connectivity with full programmability to enable simpler global deployment in support of the different PLC standards.”
The two-chip set comprises the ST8500 programmable PLC engine and STLD1 line-driver.
The ST8500 is a system-on-chip (SoC) IC containing a quad-core DSP for real-time protocol processing, and an Arm Cortex-M4F core for upper-layer processing and system management. Each has its own code and data SRAM on-chip, and a dedicated set of peripherals focused on smart-energy applications is provided, including an AES cryptographic engine. The analogue front end (AFE) for connecting to the STLD1 line driver is also integrated.
The ST8500 consumes less than 100mW in receive mode, ensuring low-power performance in line with the latest specifications to reduce the grid load imposed by new smart meters. The STLD1 line driver communicates reliably, even across noisy cables and with low impedance, with high-drive capability and high linearity over an output range of 18V in single-ended or 36V in differential mode. 
The chipset is supplied with certified G3-PLC and Prime power-line protocol stacks and complies with Cenelec, FCC and ARIB frequency-band regulations.
The chipset is in production and available. The ST8500 SoC is packaged as a 7 by 7 by 1mm QFN56, and the STLD1 is a 4 by 4 by 1mm QFN24.