You know a market is hot when multiple IC companies release platforms for the same market nearly simultaneously. Such is the case with Maxim Integrated (sponsor of the Integrated Nation site) and STMicroelectronics (STMicro). Both recently launched system on chips (SoCs) or SoC-based platforms for the smart metering market and other smart grid applications.
Both product lines include significant integration, including analog and mixed signal, to provide more functionality useful in metering and power monitoring applications.
Maxim recently released the Capistrano reference platform for smart meters and other smart grid applications. In its press release, Maxim cited some highlights of the platform, including 0.1 percent accuracy over an 8000:1 current range, an integrated application processor, a dedicated security co-processor, another microcontroller for metering, and a front end with digital signal processing (DSP) for metering. Here's a block diagram of the Maxim platform, including the Zeus SoC.
I reached out to Timery Crawford, corporate communications manager at Maxim, to get a few more details. She told me there are up to seven ADCs, which are “typically targeted for energy consumption measurement, [although] they could be purposed for other measurements.” She also stressed the high level of integration, which includes the ARM M3, a 32-bit RISC processor in the metering section, and a 32-bit DSP core doing raw measurement processing. All of these are part of the Zeus chip. The figure below shows the reference platform, which provides the designs to integrate display, control (such as PLC), communication, and sensors into the complete system.
I asked Crawford to compare this new platform to Maxim's line of metering SoCs, such as the 71M653x series. Basically, the Zeus product takes all the measurement functions integrated in the earlier series and adds the ARM processor, which can run communication stacks, over-the-air software upgrades, plus the security co-processor.
If you follow industrial networked sensors, you know that security has become a big concern. Maxim's new platform seems to be a direct response to industry trends and concerns. In fact, it indicated that the Zeus is the first to integrate so-called elliptic curve encryption methods.
The day after Maxim announced the Capistrano platform, STMicro unveiled the STCOMET10 product line, which it called the “Industry’s First Smart-Meter System-on-Chip.” Michael Markowitz, director of technical media relations for STMicro, referring to the large SOGRID in France, told me the new SoC will be “the core technology for processing and transmission of digital data for the entire grid, becoming the key enabler for smart grid in France.”
This block diagram shows what is included in the STMicro SoC, alongside a photo of the TQFP176 package.
It appears that STMicro is positioning this IC as the first smart meter SoC based on the level of integration, which is extensive. The metering section includes three 24-bit Δ-Σ ADCs, which Markowitz said are suitable for class 0.2 meters (ANSI C12.20-2010 0.2 accuracy class, or 0.2 percent accuracy) or better. The data brief indicates that the analog front end (AFE) has 3.6 kHz bandwidth and delivers <0.1 percent error over a 5,000:1 range. The other AFE can be used for power line communications and includes both the line drivers and the ADCs.
Like the Maxim product, the STCOMET10 includes several processors, with an ARM M4 as the main processor which can run the communication protocol stacks as well. Both designs integrate energy calculations and DSP in hardware and embedded security. STMicro says the STCOMET10 supports AES 128/192/256 encryption. It is interesting to see the crypto featured so visibly in the press releases and literature from both companies. Maxim may be able to claim an edge here, having already adopted elliptic curve encryption methods. In his MOOC on cryptography, Professor Dan Boneh of Stanford University says there is a “slow migration to elliptic curve methods,” though AES256 is considered very strong at present.
Both the Maxim and STMicro designs have high levels of integration, though the STMicro SoC contains more than Maxim's. However, by providing a complete platform reference, Maxim makes it especially easy for designers to use its product. Are you working within the smart energy space? What do you think of these new, highly integrated products?
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