Pipe dream or on a pipe near you soon?

Intensifying competition, ongoing price erosion and the challenge of product differentiation are all features of today’s utility meter market. Behind the meter cover, a separate battle rages over semiconductor platforms. Will general purpose or ‘systemon- chip’ devices win, and how far away is the industry from a truly ‘single chip’ meter solution?

Figure 1 single chip meter

2007 will mark a critical inflection point in the global electricity meter market. For the first time in the industry’s history, more static (electronic) meters will ship than mechanical meters. IMS Research, in its latest analysis of the global market for utility meters, AMR systems and related electronic components, estimates that by 2007, around 111 million units of electricity meters will be shipped, of which 57% will be based on electronic technology (Figure 1).

This is one indicator of how much the electricity industry has transformed from a predominantly government run institution 10 years ago, to the largely liberalised and deregulated market that exists today. Today’s increasingly privatised utilities are now run as commercial enterprises and are accountable for winning customers and maximising profit. Demand for enhanced service options for customers (e.g. multiple tariffs), better resource control for utilities (e.g. demand side management, fraud detection, prepayment), and features that help reduce service costs (e.g. AMR) have created a natural transition to electronic metering technology, a trend which is set to continue in the electricity sector.

In contrast, trends towards electronic metering have been slower in other utility sectors. Around 15% of gas meters had some built-in electronics in 2005 (mainly due to prepayment and safety features), whilst less than 5% of water meters used electronics. Adoption of electronic meters in the heating services industry is well over 50%, but globally units of these products are much smaller than for the other utilities.

The commoditisation of the static meter has been most pronounced in the electricity meter market. Developments in electricity meter design, automated manufacturing processes, increased competition, and market pricing pressure have resulted in falling average unit prices to the point where many static electricity meters are now available for the same price (or lower) than a mechanical equivalent.

Commoditisation has also resulted in electricity meters becoming low margin products, which in turn has led to cost implications regarding meter design, the level of functionality that can be built into a given model, and the resulting choice of semiconductor and electronic components.

A typical static utility meter comprises six main system components:

  • Analogue front-end – converts the ‘real world’ measurement signals into digital information. Some signal conditioning and pre-processing may also take place at this stage.
  • Main processor – represents the meter ‘brain’ and is responsible for obtaining measurement data, calculating consumption, handling data storage, managing external communications and controlling the overall system.
  • Battery – in non-mains connected systems, such as water meters, gas meters and heat meters, the battery acts as the main power source, typically necessitating a fairly large, high capacity lithium cell. In the case of electricity meters, which are powered off the mains, the battery generally only supports the real-time clock in the event of mains failure. It may also enable the meter to ‘wake up’ for reading or to detect fraud when the power is down. Smaller coin-cells, ½ and ¾ AA sized batteries are common, again using lithium technology for stable performance over an extended life.
  • Display and display driver – LCD or stepper motor-based display and driver circuits for visualising the meter reading.
  • Non-volatile memory – for data storage. This system component is increasingly being integrated into the main processor.
  • Power supply – in high-end meters such as multiphase commercial and industrial electricity meters, this is often a dedicated power supply module. In smaller residential meters, IC-based voltage regulators or small linear power supplies are used. In static meters where the battery is the primary power source (i.e. water, gas, heat meters, etc.) there is typically no power supply, but there may be some basic voltage regulation.

In some high-end meters, or meters with a bespoke measurement technology, the analogue front-end can represent a substantial portion of the overall cost. However, generally, the main processor and battery are the most expensive components in a basic utility meter (i.e. a meter without AMR). Combined, the battery and processor account for over 70% of the total component bill of materials (BOM). Hence semiconductor manufacturers specifically targeting the metering application tend to focus on solutions incorporating the main processor in order to gain a share of the largest proportion of the electronics content.

In developing utility meters, there are five major problems for designers that have implications on the electronic components used. Specifically:

  • Meter competition is fierce and cost is almost always a concern.
  • Each utility customer has slightly different feature requirements.
  • Each major geographic territory has different meter standards and product quality requirements.
  • Utility customers remain unsure when and in which AMR technology to invest.
  • There remains a lack of choice of semiconductor components that are designed specifically for utility meters.

With different utility customers requiring different product features, it is very difficult for a meter manufacturer to make a competitively priced ‘one-design-fits-all’ meter. Furthermore, with vastly different meter quality and price expectations between markets in the West and in Asia, flexibility in the design of the basic meter is essential.

For a similar reason, AMR electronics are usually partitioned separately from the basic meter functionality. The integration of any single AMR technology typically adds well over 100% to the basic meter BOM. For example, a relatively simple single-phase residential meter today has an electronic component BOM of roughly $3 to $5. Meter designers typically do not want to get involved in developing communications chip sets and hence tend to buy in AMR sub-system components where possible.

Figure 2single chip meter

Engineers at two of the world’s biggest meter manufacturers quoted figures of over $7 for the additional cost of components to upgrade a basic meter to fixed line modem AMR and almost $30 for integrating a cellular modem. Power line communications (PLC) chip sets are available at much lower cost, around $3 or less (no doubt one factor behind why PLC is the highest penetration AMR technology in electricity metering).

However, even a $3 add-on to the cost of a low cost, low margin product means that this feature can’t usually be integrated as standard across a full meter product range. On top of accommodating variable product features and AMR requirements is a more generic problem for meter designers – the lack of semiconductor ICs and subsystem components specifically designed for the utility meter industry. The vast majority of electronic utility meters have been designed, up to now, using a general purpose microcontroller platform as the main processor.

General purpose devices allow system modifications without the need for complete redesign and allow a range of meters to be developed on a single platform. There is also a number of general purpose products on the market tailored with the typical memory and some peripheral devices required in metering. However, they generally leave meter designers with the ongoing problem that systems are not optimised to individual designs.

With price pressure a constant problem in the market, engineers are constantly struggling with how to balance the system partitioning in such a way as to maximise the available resources on the processor whilst minimising cost.

For example, a major industrial electricity meter manufacturer indicated to IMS Research that the types of modem ICs currently available are significantly over specified for a metering application. As a result, it was looking at utilising some of the modem’s memory and processor overhead to remove cost from the basic meter. The small amount of billing data transmitted from utility meters requires only a fraction of the performance of the latest high-end communications chip sets.

Unfortunately, it is a function of the semiconductor industry that older IC technology (perfectly suited for metering) does not continue to fall in price indefinitely owing to the direct relationship between silicon area and cost. Newer communications ICs based on smaller process geometry ultimately become cheaper, but result in increasingly overspecified performance for the metering application. So what are the alternatives to the general purpose platform?

FPGA

For flexible hardware design, and the ability to rework systems quickly and embed specific standard functions with no up-front non-recurring expenses (NREs), the field programmable gate array (FPGA) offers one readily available solution towards achieving a single chip meter. However, although these have come down significantly in price over the last five years, they remain several times more expensive than ICs currently used in meters, rely on the meter designer to implement every aspect of the system, and are power hungry.

ASIC

Application specific integrated circuits (ASICs) offer absolute system optimisation, low unit cost in volume and low power consumption. Using a mixed signal ASIC it is theoretically possible to combine all of the electronics of a specific meter design into a single, highly optimised IC. However, as discussed previously, flexibility in electricity meter design is critical. Furthermore, the up-front NREs associated with ASIC development are often too high (above $1million) with sales of any single meter design rarely reaching sufficient volumes to amortise these costs.

ASSP

In the middle ground between general purpose devices and ASICs lie application specific standard products (ASSPs). These are, by definition, ICs designed for one specific application but are sufficiently standardised to appeal to many different customers. IMS Research’s latest analysis predicts substantial growth in the ASSP market (Figure 2).

 The majority of metering ASSPs in the market to date have been targeted at electricity meters, owing to the large size of opportunity this sector offers. The extent to which they have penetrated meter designs has varied considerably by geographic region. In the West, manufacturers entrenched in the general purpose design route have been slow adopters. Ongoing concerns over design flexibility and being tied to one IC vendor have limited take-up.

In the Far East, and particularly China, the situation has been the reverse. For example, the ‘One House One Meter’ programmes conducted in China around ten years ago faced a critical problem – the existing mechanical meter factories could not ramp-up production sufficiently to service demand. As a result, many new electronics assembly companies entered the market that had little or no previous meter design experience, but wanted to cash in on this new opportunity.

An inrush of low specification static meter products swamped the Chinese market, many based on a simple stepper motor design, providing a cheap way to achieve a meter whose data would not be lost and could still be read in the regular brownouts that affect the region. The ASSP played an important role, offering manufacturers a fast and simple route to developing a fully functional electricity meter with little prior industry experience.

The legacy of these low cost products can still be seen today in China. However, in line with the rest of the world, Chinese utilities are looking for more advanced features such as AMR, fraud detection and prepayment. As a result, more complex LCD readout meters are increasingly being adopted in the region. ASSPs are forecast to continue to increase in popularity over general purpose devices as AMR and meter standards begin to settle and as further investment goes into improving ASSP specifications and their feature set.

Some of the multinational semiconductor companies addressing the growing meter ASSP market include Analog Devices Inc. (ADI), Cirrus Logic, Microchip, STMicroelectronics and Teridian Semiconductor. ADI and Teridian Semiconductor are two of the most recent companies to announce new families of ASSPs providing a meter system-on-chip (SoC) solution. ADI’s new family of single-phase electricity meter SoCs, the ADE7100 and ADE7500 integrate a high performance analogue frontend and include a comprehensive set of built-in pre-designed features specifically for metering that typically are not found on general purpose devices. For example, during some metering tampering events, the ground is disconnected but the current is still able to flow through the load.

However, the meter doesn’t have a ground to establish a traditional power supply. ADI’s solution can be powered from a current transformer and continue measuring an accurate RMS current. Another feature is the attention to detail that has been taken over the LCD drive. To overcome the problem of a poor LCD contrast ratio in cold environments, the LCD driver features a charge pump which converts the system voltage of 3.3 V up to 5 V. This feature is dynamically adjusted relative to temperature so as not to waste battery power. This charge pump also allows for a DC offset at least one tenth the size of an alternative resistor ladder design in order to mitigate long term chemical degradation of the LCD. When asked to describe how ADI has approached the meter market and the key benefits of ASSPs compared to alternative solutions, Paul Daigle, ADI’s SoC business development manager commented “Success is derived by focusing on a niche. By choosing a reasonably large market segment, focusing on the specific needs of that niche, and satisfying the needs exceptionally well, ADI leverages its established core competency to improve the solutions that our customers have access to. The ADE7169 is an excellent example of this. It is a true SoC with integrated energy measurement, programmable MCU, memory, LCD drivers, battery management, temperature sensor, and real-time clock.

It was defined for open market appeal in functionality and ease of designing an EMC robust meter.” In June 2006 Teridian introduced its 71M6521 family of meter SoCs. A key feature of the product is Teridian’s novel Single Converter TechnologyTM. Unlike traditional static meter designs that have separate A/D converters for each phase of voltage and current, the Teridian product multiplexes the input signals into a single high resolution converter. Steve McClure, VP marketing at Teridian commented: “Our highly integrated SoC family for residential meters allows our customers to design their metering product line based on a single IC platform, with the associated benefits of using the same programming model, code reuse and similar board layout between designs, helping reduce R&D costs.

This also accelerates customers’ time to market, with programmability to meet the varying requirements of different utilities across the globe. In addition, the precision and measurement flexibility of the Single Converter TechnologyTM offers an optimum solution spanning accuracy and feature requirements for single and polyphase applications.” With ASSP products now widely available integrating all the basic electricity meter functions, the remaining issue is whether these ICs will expand to encompass AMR as well.

Both ADI and Teridian thought it unlikely that an ASSP solution integrating both the metering hardware and a range of programmable AMR options would become available in the near term due to cost. However, neither ruled out that selected AMR options would become available built into future product families.

Summary In summary, the ‘basic’ ASSP single chip electricity meter is already here and has been fighting a platform battle with general purpose devices for several years. In the other major utility meter sectors, gas and water, uptake of SoCs has been limited, mainly because these static meter markets have not developed sufficiently to attract investment from ASSP developers. Although electricity meter designs vary depending on the requirements of different utility customers, the basic measurement functionality of the meter is becoming increasingly standardised, leaving utility meter manufacturers having to differentiate their products based on more advanced features.

The next platform battle between ASSPs and general purpose devices will most likely be over AMR territory, as this is increasingly the key differentiator between utility meter products. In the near term it appears that AMR will remain partitioned from the basic meter and therefore a true ‘single chip’ solution in metering still looks some way off. The IMS Research report

The Global Market for Semiconductors & Components in Utility Meters & AMR Systems is available to order directly from the Metering International online shop at www.metering.com