802.11 to the nth Degree

Posted on January 26, 2012 by John Donovan

It seems like every major wireless protocol is coming out with a variant that can make it under the low-power limbo bar. Bluetooth has spawned Bluetooth Low Energy and ZigBee now has a low-power healthcare profile. Not to be outdone, the Wi-Fi Alliance developed 802.11n to be a high-speed, lower power alternative to 802.11a/b/g, and it’s been rapidly adopted. Recently even lower-power versions of 802.11n chips have been coming on the market. But the Big Kahuna is 802.11ac, for which first silicon is just starting to appear.

Operating in the 5 GHz band, 802.11ac chips will

  • have 2-4x the bandwidth of 802.11n (80 and 160 MHz channels vs. 40 MHz for 11n);
  • achieve a data throughput of up to 1 GBbit/s—~10x better than 11g and about 3x better than 11n for 2- and 3-stream implementations;
  • support multi-user MIMO with up to 8 data streams (vs. 4 in 11n);
  • support up to 256-QAM vs. 64-QAM in 11n;
  • theoretically result in a considerably better power profile than 11n.

The “theoretically” hinges on the fact that the 802.11ac specification is yet to be ratified. The Initial Technical Specification Draft 0.1 was confirmed by IEEE 802.11 TGac on January 20, 2011. The specification isn’t expected to be finalized until mid-year at the earliest, at which point the Wi-Fi Alliance expects to ratify it, though IEEE ratification will take longer.

Are We There Yet?

That hasn’t stopped a rush to market with ‘pre-ac’ silicon, exactly the same thing that happened before the 802.11n specification was ratified. Last time the first out of the chute was Broadcom, whose ‘pre-n’ 802.11 chips hit the market well before the warring camps in the IEEE working group had ironed out their differences.

At CES earlier this month Broadcom announced that it is sampling 802.11ac silicon—the BCM43xx family, which it refers to as ’5G WiFi’—though it is yet to announce a date for full production. Early adopters of Broadcom’s 11n chips took a big chance but came out unscathed. Will they be as lucky this time? According to Michael Hurlston, Broadcom’s senior vice president of Broadcom’s Home and Wireless Networking business unit, ”I’m confident that any changes to the spec beyond this point and before final ratification will be window dressing, and relatively small.” History, hype, or hope? Only time will tell. Still, having pulled it off before—and pushing a lot of chips, as it were, onto the table—it would be foolish to bet against Broadcom.

Also joining the ‘pre-ac’ race is Redpine Networks, currently sampling its Quali-Fi™ 802.11ac chip. The Quali-Fi product is accompanied by Redpine’s software framework that includes an access point, Wi-Fi certified client and Redpine’s Wi-Fi Direct™ functionality. Redpine CEO Venkat Matella tells Low-Power Design that modules with 801.11ac chipsets will be available late this year or early 2013.

I’d be very surprised if Qualcomm/Atheros and Samsung—who co-chair the IEEE 11ac Task Group—as well as committee members Cisco, Intel, LG, Marvell, Mediatek, and others—didn’t announce 11ac chips shortly after the specification is ratified—if not before.

With even once power-hungry Wi-Fi now joining the low-power race, low-power wireless is no longer just a trend, it’s mainstream. We may not be ‘there yet’—and never will be, since the goal is one you can only approach asymptotically—but silicon vendors are making an impressive amount of incremental progress. Stay tuned for more exciting developments.

 

Posted in RF/Wireless, semiconductors | Tagged , | Leave a comment

Bluetooth Goes Ultra-Low-Power

Posted on January 2, 2012 by John Donovan

There’s hardly a cell phone on the planet that doesn’t have a Bluetooth transceiver for connecting to a wireless headset. Most new PCs now incorporate Bluetooth chips for the same purpose, letting you type while you talk or listen. Many, if not most new cars, have Bluetooth to let you talk hands free while driving. However, while that’s all well and good, there is a wide range of applications for which Bluetooth isn’t appropriate – or at least it wasn’t until now.

Bluetooth is a connection-oriented protocol designed to handle continuous streaming of data at relatively high speeds, making it well-suited to connecting wireless headsets to cell phones. While attempting to remain low power, most changes to the Bluetooth specification have concentrated on boosting the data rate. The basic rate (BR) enables synchronous and asynchronous connections at up to 720 kbps. Bluetooth Version 2.0 (2004) added an extended data rate (EDR) of 3 Mbps (in practice more like 2.1 Mbps). Bluetooth 3.0 (2009) added a high-speed (HS) data capability of up to 24 Mbps by using an alternative MAC/PHY (AMP) that communicates over a co-located 802.11 link. Despite some clever engineering, the quest for higher speed necessarily resulted in higher power consumption.

Bluetooth Low Energy, in contrast, was designed from the beginning to be an ultra-low-power (ULP) protocol to service short range wireless devices that may need to run for months or even years on a single coin cell battery. Introduced in Bluetooth Version 4.0 (2010), Bluetooth Low Energy uses a simple stack that enables asynchronous communication with low-power devices, such as wireless sensors that send low volumes of data at infrequent intervals. Connections can be established quickly and released as soon as the data exchange is complete, minimizing PA on time and thus power consumption. Continued

Posted in Wireless | Tagged | Leave a comment

Synopsys Buys Magma—But Will the Marriage Last?

Posted on December 2, 2011 by John Donovan

By John Donovan

Synopsys yesterday (11/30/2011) announced that it has signed a definitive agreement to buy Magma Design Automation for $507 million, the largest acquisition in the EDA industry in many years. The acquisition will strengthen Synopsys’ position in both analog and digital EDA tools, at the same time removing a struggling competitor with whom it’s had a less than friendly relationship.

On the financial side Magma represents an easy acquisition for cash-rich Synopsys and an unexpectedly good exit strategy for Magma. Synopsys has agreed to acquire Magma for $7.35 per share in cash, a 27.8% premium over the $5.75 at which LAVA was trading on the NASDAQ the day before the acquisition was announced (it immediately jumped to $7.09 after the announcement). For Q1 of this year Magma reported a GAAP net loss of $(0.1) million, or $(0.00) per share, compared to a net loss of $(3.3) million, or $(0.06) per share for the year-ago first quarter—a slow crawl back from a bad year but hardly enough to keep up with giants Synopsys, Mentor, and Cadence, all of whom are experiencing healthy growth. Needless to say Magma’s Board of Directors unanimously approved the merger.

On the analysts call announcing the merger Synopsys CEO Aart de Geus was upbeat about the synergies between the companies, highlighting the acquisition as an opportunity to expand their R&D talent pool. John Chilton, senior vice president of marketing and strategic development at Synopsys, underscored de Geus’ point, adding, “We really are getting more requests for more technology. Deep-submicron CMOS is very complex in terms of materials, the number of transistor and the parasitics. Tools have to do more.”

The question of overlapping tools loomed large and will remain a matter of speculation until the deal closes in the middle of next year. Chilton said Synopsys would not discontinue any Magma products at the time of the deal closing, though analysis of how to integrate them into Synopsys’ product lines will clearly be front and center for the next several months.

While de Geus said on the call that Synopsys was not motivated by Magma’s strength in any one particular product area, readers are permitted to take that with a grain of salt. Magma’s FineSim Pro simulator for analog/mixed-signal SoCs has reportedly been gaining key accounts that had previously been using Synopsys HSPICE simulator for RF and analog design, which hasn’t really taken off. On the digital side Magma doesn’t offer logic simulation—much to its detriment—but in Talus and Titan they do have a very capable tool flow from RTL synthesis right through silicon implementation, with Talus’ timing analysis capability being especially attractive to Synopsys. Magma’s yield management tools will also be a plus, though Synopsys isn’t lacking there.

According to Gary Smith, chief analyst at Gary Smith EDA, “It’s a great deal for Synopsys,” not to mention Magma. Also according to Smith, FineSim and Talus fill important gaps in Synopsys’ product offerings, “making them whole.” Over the next few years the Magma acquisition should prove to be quite successful for Synopsys. Over time Smith foresees possible problems integrating both Magma’s tools and its engineers. On the tools side, Magma’s data-driven development paradigm differs considerably from Synopsys’, raising the question of whether their tools, however synergistic, can indeed be integrated; if not, which ones survive and which ones receive an End of Life notice? And will the engineers at Magma, arguably not enamored of Synopsys during their long-running legal battle, stay on after the deal closes, or will they cash out and start their own companies? Smith agrees with de Geus that the engineers are the crown jewel of the acquisition. Keeping them happy and on board will be key to the merger’s long term success.

How all this will shake out remains to be seen. Will Mentor or Cadence respond quickly by acquiring one of the dozens of small, capable EDA companies to fill gaps in their own tool flows (probably)? Will Rajeev wind up in an office next to Aart (<1% chance), or will he take the money and start a new company (>90% chance)? Only time will tell. The one certainty is that the big three EDA companies will continue their acquisition binge, becoming stronger and more capable while at the same time providing a happy landing for some intrepid entrepreneurs.

 

Posted in Uncategorized | Leave a comment

Electric Flight—the Ultimate Energy Efficiency Challenge

Posted on November 30, 2011 by John Donovan

If you think electric cars are impressive, how about an electric 747? On a smaller scale, that flight of fancy just became a reality.

Last month in Santa Rosa, CA, an electric-powered 4-seat light plane won the NASA/Google Green Flight Challenge by flying over 200 miles non-stop at over 100 MPH while achieving 403.5 passenger miles per gallon (mpg) using the equivalent of less than one gallon of gasoline. Compare that to the Chevy Volt—the current state of the art in electric (land-based) vehicles—which gets the equivalent of 112 mpg in all-electric mode while driving slowly over flat roads. And even with the benefit of wheels and a 435 lb. battery, the Volt can only keep that up for 35 miles, at which point it reverts to its gas engine, which gets 37 mpg.

The winner of the $1.65 million prize was Team Pipistrel from Penn State, flying a Taurus G4 manufactured in Slovenia. The G4 is a four-seat, twin engine plane with a wingspan of 69’2” and weighing 2,490 lb, slightly less than a Volkswagen Beetle. The two 145 KW (194 HP) motors can drive Pipistrel to about 114 mph, so it won the Challenge race running almost flat out.

Detailed data on the custom-built G4 is hard to come by, but not for the production model Taurus Electro G2. The body is a composite of epoxy resin, fiberglass, carbon fibers and Kevlar in a honeycomb structure. The motor is a high-performance synchronous 3-phase outrunner with permanent magnets, delivering 40 kW on takeoff and 30 kW continuous. The best glide ratio is 1:41, which really qualifies it as a powered glider. To put it in perspective, the typical glide ratio for a two-seat general aviation plane is about 1:10. Aside from getting unimpressive mileage, you really don’t want to run out of gas while flying your Piper Cub. Or in a 747 for that matter.

Electric gliders have been around for a while. The first commercial one was the AE-1 Silent, which first flew in 1997. Weighing a mere 430 lb., the AE-1 is easily powered by its 13 kW (17 Hp) electric motor, which in turn works from a 4.1 kW/77 lb. Li-Ion battery. If you’re so inclined the AE-1 is FAA certified as an ultralight aircraft and it’s still being produced.

More high powered is the Antares 20E from Lange Aviation GmbH, in production since 2004. The 20E is powered by a 42 kW (52 hp) BLDC electric motor weighing 64 lb. Energy storage consists of 72 Li-Ion cells each rated at 44 Ah at 3.7V, for a combined capacity of 12 kWh @ 266V. With a wingspan of 65 ft. and weighing in at 1,455 lb, this is a serious airplane—though still a one seater. The 20E can self launch and climb to 3,300 ft. in four minutes and climb to 10,000 ft., where it can fly for 1.5 hours. Assuming you’ve covered 93 miles at that point and a maximum glide ratio of 1:56 (!), the maximum range then becomes (93+(2×56))=205 miles.

Now let’s figure the mileage for just the powered portion of the flight. Assuming your flight fully depleted the 12 kWh batteries, that works out to 12 kWh/93 miles or 12.9 kWh/100 miles. Using the same formula the EPA applied to the Chevy Volt—where 36 kWh/100 miles = 93 mpg-e—the Antares comes in 2.8x better at 260 mpg equivalent! That’s a pretty energy efficient way to travel.

In an interesting twist Lange is now producing the Antares DLR-H2, which is powered by hydrogen fuel cells, with the tanks slung in pods under the wings. The actual motive force is a 42 kW BLDC motor. The 130 lb. fuel cells can generate 20 kW continuously, twice the 10 kW required for level flight. The DLR-H2 can attain a height of 12,000 ft and has a top speed of 105 mph and a range of 1,240 miles.

Using solar cells to recharge your batteries while in flight can greatly extend your range. In 1990 the solar powered plane Sunseeker flew across the U.S. powered by a 250W array of thin-film solar cells. Since solar cells obviously don’t work at night, it took two weeks to accomplish this task.

The first solar powered plane to complete a 24 hour flight was Solar Impulse. Claiming to have “the wingspan of an Airbus [208 ft.]…the weight of a family car [3,500 lb.]…and the power of a scooter [40 hp],” its designers plan to fly it around the world in 2012. The solar cells on the wings of Solar Impulse cover 650 sq. ft. and can generate 6 kW (8.2 hp), which is stored in Li-Ion cells during the night. All things being equal, this should be enough to keep the 1.6 ton plane aloft day and night while traveling at just over 40 mph.

Even electric commercial airliners are in the works. In Europe EADS, Airbus’ parent company, has proposed the VoltAir ducted fan engine that would power commercial airliners. To achieve the energy density required to move such a massive aircraft, the VoltAir motor would be constructed of high-temperature superconducting (HTS) materials, cooled by liquid nitrogen. HTS motors are expected to reach power densities of 7-8 kW/kg, comparable to 7 kW/kg for today’s turboshaft engines. The batteries will still be Li-Ion, which EADS hopes will become more efficient, or Li-Air should it become commercially viable by then.

Coming to an Airport Near You

While electric flight is both fun and interesting—especially to engineers—it may impact you sooner than you think. Every major city and most smaller ones have general aviation airports. The Taurus G2 and numerous others like it would make quiet, inexpensive air taxis practical. Not only are the planes inexpensive—about the cost of a high-end car—they’re extremely inexpensive to operate, highly reliable, quiet, and essentially non-polluting. Instead of fighting the traffic between New York and Boston or San Jose and Sacramento you would be able to hop a quick, cheap flight there and gaze smugly down at the congestion below.

So there you have it. Electric boats and cars—been there, done that. Stay tuned for electric aircraft. You hopefully won’t have to stay tuned for long, and it will be worth the wait.

Posted in Clean energy, Electric flight, Energy Efficiency | Leave a comment

Hands On: Evaluation Kit Eases Lighting Design Starts

Posted on October 28, 2011 by John Donovan

CY3267 dev kitNormally you order an evaluation kit to check out whether a particular microcontroller seems appropriate for a design you have in mind; if everything seems OK, you then order a more costly development kit to prototype your design. Cypress’ CY3267 PowerPSoC Lighting Evaluation Kit manages to cross that line, enabling a quick out-of-the-box evaluation within a few minutes but including a full suite of tools, circuits, and programmable components to enable developing some sophisticated lighting control systems.

The CY3267 PowerPSoC kit includes a main board built around a CY8CLED04D PowerPSoC MCU in a floating load buck topology. The PSoC core drives four 1A internal MOSFETs that power a 10W 4-channel RGBA LED mounted on a separate daughter card sitting atop a large heatsink. A power supply, USB cable, LED diffuser, an assortment of jumpers, and a MiniProg programming connector complete the kit.

Within five minutes of opening the package I was able to connect the daughter card to the main board; connect the main board to my computer; power up both boards; and cycle through the different colors in the LED array using the two Capsense buttons. Five minutes later I had installed the Intelligent Lighting Control application included on the kit CD and could experiment with basic lighting control.

Figure 1

Figure 1: Intelligent Lighting Control GUI

The Intelligent Lighting Control application (Figure 1) works with the default firmware to demonstrate 4-channel color mixing. From the CIE Color Selection tab you can click on any point on the color gamut and watch the LED array output that color. You can set the intensity by moving the Requested Luminous Flex slider. You can also set the white intensity by moving the Color Temperature Control slider (up to 4000K).

Clicking on the Direct LED Control tab you can move each of the four sliders to select the intensity of the red, green, blue, and amber LEDs. More…

 

Posted in Lighting, Microcontrollers, semiconductors | Tagged | Leave a comment

Storing Volts

Posted on September 27, 2011 by John Donovan

While electric vehicles have been around since the late 19th century, they only became practical with the development of energy storage systems that sport a lot better horsepower-to-weight ratio than bulky lead acid batteries.

By the mid-90’s automakers had pretty much given up on being able to go very far on batteries alone, which led Toyota to introduce the Prius—the first commercial hybrid—in Japan in 1997. In EV mode the Prius is powered by a sealed 38-module 6.5 Ah/274V NiMH battery pack weighing 53.3 kg. That works out to 1.78 kWh total capacity. According to the EPA’s formula, one gallon of gasoline is equivalent to 33.7 kWh—almost 20x what the Prius’ battery alone can deliver. So it’s hardly surprising that the Prius relies primarily on its internal combustion engine for propulsion.

Volt battery packThe Chevrolet Volt features a much larger battery with a considerably higher energy density than the Prius. The Volt uses a 16 kWh (197 kg) manganese spinel lithium-polymer prismatic battery pack, which alone can power the Volt for 35 miles (56 km). The Volt’s lithium-ion battery is 2.5x larger in terms of energy density than the Prius’ NiMH battery (.0812 vs. .0319 kWh/kg). Considering that the energy density of NiMH is under 2x that of NiMH—140-300 Wh/liter for NiMH vs. 250-620 Wh/liter for lithium ion—that’s well on the high side of what you would expect.

In addition to having a greater energy density than NiMH—in terms of both weight and volume—lithium-ion batteries also display a much lower self-discharge rate; a greater maximum number of charge/discharge cycles (i.e., they last longer); a more linear discharge rate, which enables more accurate prediction of remaining capacity; and they perform better at low temperatures.

As far as durability goes, both battery types are about the same: NiMH batteries can be discharged and recharged 500-1000 times, with Li-ion batteries being good for 400-1200 cycles. Since replacing an EV battery pack can be a very expensive proposition—currently about $8,000 for the Volt—manufacturers typically guarantee them for an extended period. GM guarantees the Volt’s battery bank for 100,000 miles or eight years.

Not Your Dad’s Li-Ion Battery

Li-ion batteryOK, assuming your Dad had Li-ion batteries, the ones in the Volt are better. The Volt’s battery design is based on technology developed at Argonne National Laboratory. The Lab used x-ray absorption spectroscopy to study new cathode compositions. They came up with a manganese-rich cathode that resulted in a dramatic increase in the battery’s energy storage capacity while at the same time making it less likely to overheat, and therefore safer and easier to maintain. To complete the trifecta, the new cathode material is also cheaper to manufacture.

Even if there isn’t much beyond Li-ion in terms of energy density—unless you’re comfortable with a thorium-based energy source—there’s still room for improvement. According to Khalil Amine, an Argonne senior materials scientist, “Based on our data, the next generation of batteries will last twice as long as current models.” Chances are your car would give out long before your battery does.

Recycling

When your Volt battery bank finally sends you an End of Life notice, what can you do with it? For one thing you could keep it and use it to help recharge your new Volt battery. Or you might rig it to an inverter bank as a backup source of electricity during power outages or at least peak billing times.

If GM gives you a credit for turning in your old battery on a new one, what can they do with it? The EPA claims that rechargeable batteries are not an environmental hazard if they’re not dumped in landfills; European governments aren’t quite so sanguine, since Li-ion isn’t exactly something you’d like to wind up in your water supply. Both the cathode and anode material can be recycled, which is what most jurisdictions require.

In the end the Volt’s energy storage system turns out to be as high-tech as the rest of the car. Considering how much more reliable electric motors are than internal combustion engines, Volt owners could wind up owning their cars for a very long time.

[This article is part of a series on the Chevy Volt for the UBM/Avnet series Drive for Innovation.]

Posted in Automotive, Batteries, Clean energy | 1 Comment

Get on the Drivetrain

Posted on August 30, 2011 by John Donovan

There are a lot of reasons for thinking of buying a hybrid electric car—ecological, economic, political, and just getting cheesed off at seeing all those hybrids with one passenger whiz by you in the Diamond/HOV lane. Besides, admit it—the technology is cool. So just what is the technology inside the Chevrolet Volt?

You Want Gas with That?

Series hybrid vehicleThere are two basic types of hybrid drivetrains: series and parallel. Series hybrids have a gas engine that turns a generator that charges a battery bank that powers an electric motor that powers the car; the engine is not connected to the drivetrain. The Chevy Volt—which GM refers to as “an extended range electric vehicle (EREV)”— is essentially a series hybrid, though with a twist that we’ll describe in a moment.

Parallel hybrid vehicleIn parallel hybrids both the electric motor and the gas engine are connected to the transmission through clutches that enable one or the other to power the vehicle.

Then of course there’s the series/parallel hybrid. In this configuration the two power sources are joined in a planetary gear set that enables either the motor or the engine to power the vehicle, or to share the burden as needs be. Despite being primarily an electric vehicle, the volt actually falls into this category. When you need rapid acceleration, the engine works in parallel with the motor until you let up on the accelerator. Also, the gas engine takes over from the motor when you exceed 70 mph. That’s an appropriate place for the motor – which has its greatest torque at low rpm – to hand control over to the engine, which generates maximum torque at high rpm. Besides, at 80 mph you’ve ceased being an ecopurist and are just in a hurry.

Both the Volt and the Prius are essentially series/parallel hybrids. The main difference is that on the open road the Volt relies more on electrical power and the Prius more on its engine. The Volt as a result has a considerably larger battery bank: 16 kWh for the Volt vs. 5.2 kWh for the Prius. Not surprisingly the Prius has a larger gas engine: a 1.8 liter/98 hp engine vs. the Volt’s 1.4 liter/80 hp engine. OTOH the Volt’s 111 kW (149 hp) electric motor can generate 273 lb-ft of torque, considerably more than the Prius’ 80 hp, 153 lb-ft motor. You might think of the Prius as a gas/electric hybrid and the Volt as an electric/gas hybrid.

Looking at the table, the Volt has about the same power as my Mazda 3, though it gets >3x better gas mileage—and infinitely more for trips under 35 miles, where it’s purely electric. It’s also a lot quieter and more fun to drive.

Table 1The Train is Leaving the Station

In late 2010 GM formally introduced the Voltec powertrain on which the Volt is based, though its roots go back to 2007. The basic design combines a small gas engine and a large electric motor that drives the vehicle, though they can work smoothly in tandem when it makes sense to do so. The large lithium-ion battery bank is designed to be recharged at home overnight—in 10 hours from a 110 VAC source or 4 hours from 220 VAC.

The table shows the basic specifications for the 2011 Chevy Volt. GM has announced plans to use the Voltec powertrain in other cars, SUVs, and even trucks, bring down the cost by using the platform across a much larger base of vehicles. Expect the Volt specs to scale for SUVs and trucks. Even Porsche is getting into the act, toying with the idea of an electric 911 (though not the Turbo GT2).

Maybe drivers won’t miss the roar of a big engine so much while they’re quietly zipping past yet another filling station advertising gas for $4/gallon.

Note: This article was first posted at http://www.driveforinnovation.com/get-on-the-drivetrain. Please check out the site if you’re at all into electric vehicles and follow Brian Fuller as he pilots the Chevy Volt across America–well, parts of it anyway. –JD

Posted in Automotive, Batteries, Clean energy | Leave a comment

SiliconBlue Rolls Out 40-nm Low-Power FPGAs

Posted on July 12, 2011 by John Donovan

To date winning a cell phone socket has been a bridge too far for FPGA vendors. Xilinx’s CoolRunner CPLDs have been successful there by adding glue logic, but FPGAs have long been too bulky, expensive, and power hungry to get into anything smaller than a military manpack. Startup SiliconBlue intends to change that.

SiliconBlue Technologies has announced that it is sampling its Los Angeles family of low-power FPGAs – the LP series for smart phones and the HX series for tablets. The FPGA fabric routing in the LP series is optimized for low power and in the HX series for speed. Both product lines are based on TSMC’s 40-nm LP CMOS process and achieve, according to SiliconBlue CEO Kapil Shankar, static power of “tens of microwatts for LP and hundreds of microwatts for HX.”

SiliconBlue’s unique contribution is an SRAM-based FPGA fabric that, according to Shankar, “can operate from a 1.0V core and consume 50% less static power and over 50% less dynamic power than 1.8V ‘low-power’ PLD alternatives.” The Los Angeles family tops out at 16,192 logic cells (800K system gates), a good order of magnitude higher than CPLDs, opening up a far wider range of possible applications.

How Did They Do That?

Going to 40 nm certainly helps to reduce dynamic power, since you can drop the core voltage to 1.0V. On the other hand quantum tunneling through very thin gate dielectrics increases leakage current and drains off the charge from SRAM capacitors. SiliconBlue has introduced some ‘secret sauce’ CMOS process improvements and altered the gate geometries to minimize off-state leakage. Their iCE65L04 chip—with 3,520 logic cells or 2,700 equivalent macrocells—draws 26 µA in standby mode.

There are some other interesting tweaks to the usual SRAM FPGA fabric. Instead of constructing LUTs from N-channel transistors, SiliconBlue uses matching N- and P-channel transistors, effectively limiting leakage. The chips use a buffer-free interconnect, dispensing with the usual 4-6 buffers per interconnect. Finally, the routing fabric is designed for minimum leakage, not maximum speed.

Shankar told Low-Power Design that the chips have no static or full shutdown mode, though only the portions of the chip that are actually used are powered up, the rest are shut down; static power is measured at 0 Hz, namely with the clock shut down.

SiliconBlue uses a 2T non-volatile SRAM memory—based on Kilopass’ XPM CMOS NVM process—that avoids the expense of embedded Flash or EEPROM. Traditional floating-gate memories such as EPROM, EEPROM, NOR and NAND Flash as well as SONOS store electrical charges near a transistor gate; at smaller geometries—helped by mobile ion contaminants—those charges can bleed off quickly. SiliconBlue’s Non-Volatile Configuration Memory (NVCM) “uses the controlled electrical change of transistor gate dielectric from insulator to conductor as the basis of the memory.” NVCM blocks are built on the same bulk CMOS die as the programmable fabric, reducing processing costs and die size while adding an ‘instant on’ capability to the chips. The company claims the NVCM blocks take up only 2-5% of the die area and draw 8 µA operating current.

Packaging also targets high-density PCBs. The smallest parts come in a 2.5 x 2.5 mm (0.4 mm pitch) micro plastic BGA package, made possible by using wafer-level chip-scale technology.

What’s a CMD?

You don’t grab handset sockets selling FPGAs. QuickLogic, for example, doesn’t make (OTP) FPGAs, they make Customer Specific Standard Products (CSSPs), a sort of customizable ASSP. SiliconBlue, for its part, makes Custom Mobile Devices (CMDs). Its mobileFPGA chips are “ready-to-use devices that incorporate custom functionality as well as standard building blocks that are standard to handset applications.” The entire chip is programmable, with Silicon Blue offering 50+ “mobileWARE customizable function blocks” to assist in custom designs. Basically there’s nothing custom about Custom Mobile Devices until you customize them yourself or have SiliconBlue do it for you.

If all of this sounds like a marketing pitch, frankly it is. But with impressive power and density figures, coupled with a lot of cell-phone oriented IP, the company is trying to take their chips where no FPGA has gone before. They push the flexibility, time-to-market, and BOM cost reduction arguments, which are all legitimate; the FPGA camp has been making them since Day One, but they’ve only gained traction as power consumption declined and custom ASICs became a game only the big dogs could play.

Still, LA family devices have some clearly targeted uses. SiliconBlue wants its CMDs to be companion chips to existing mobile chipsets, targeting video and imaging, sensor management, memory management, and port expansion. MobileWARE IP blocks support a wide range of protocols useful on handsets, including SLIMbus, DBI, ECI, MIPI-DBI/DPI, WUXGA, DDR 133, SDIO 3.0, and USB 2.0. Considering the increasingly wide range of sensors found in cell phones, CMDs could find full employment interfacing them with the applications processor.

High-speed, high-definition video is another promising area for low-power FPGAs, whose massively parallel structure makes them a natural for an application where DSPs are starting to run out of steam. For imaging the iCE40 features flexible, cascaded BRAM and extra PLLs to support high-speed LVDS signaling. iCE40 CMDs can stream video at 525 Mbps, enabling HD720p (1280 x 720) at 60 Hz and HD1080p (1920 x 1080) at 30 Hz.

Despite having a low profile in the U.S., SiliconBlue has some major design wins in Asia. Shankar claims the company has shipped 7 million of their 65-nm devices to over 250 customers, including tier one customers like Samsung and Huawei. Their chips are found in 30-40 products to date, including smartphones, cameras, personal media devices, and e-books.

The iCE40LP8K and iCE40HX8K, 8000 logic cell LP-Series and HX-Series devices are available now, with the smallest package starting at $1.99 in high volume. Remaining members of the Los Angeles family are expected to be in full production by Q4 2011.

–John Donovan

Posted in semiconductors | Tagged , | Leave a comment

MEMS Sensors Still Center Stage

Posted on July 2, 2011 by John Donovan

I recently wrote an article for EE Times titled Sensors: More Than MEMS reviewing the recent Sensors Expo in Chicago. That wasn’t meant to diss MEMS sensors, which are where the action still is as a number of sensor vendors reminded me recently. In addition to powering the Wii game console in my son’s bedroom, MEMS sensors find huge markets in consumer, automotive, networking, medical, and industrial applications. Sensors are already pervasive and on their way to being ubiquitous.

For starters take a look at your smart phone: it’s likely to contain as many as a dozen sensors, including an accelerometer, magnetometer, gyroscope, camera, GPS/A-GPS, microphone, pressure sensor, light sensor, capacitive touchscreen, and temperature sensor. And coming soon: proximity sensors so your phone can turn off the screen when you hold it to your ear or wake up when you reach for it; and MEMS-powered pico-projectors for giving impromptu presentations or vacation recaps to a group of people. Not all of these sensors are MEMS based, but many of them are. According to HIS iSuppli the MEMS sensor content in mobile devices will increase five fold in the next two years alone, with revenues for new CE and mobile MEMS devices reaching US$457.3 million in 2011.

There are numerous MEMS sensors in the average automobile, enabling airbags, electronic stability control, tire pressure monitoring, active suspension, and parking and braking systems. MEMS accelerometers are also a key part of forthcoming collision avoidance systems. Again according to iSupply, the automotive market will consume over 700 million MEMS sensors in 2011.

In his recent Digi-Key/EE Times Sensors Virtual Conference keynote, Stéphane Gervais-Ducoret, Freescale’s global marketing director for sensors, detailed some of the interesting applications that suddenly become possible when you bring enough sensors to bear.

Ducoret’s key point is that when you integrate enough different types of sensors into a device you achieve context awareness. Your cell phone might be made aware of all the relevant elements in your immediate environment, including your exact location, elevation, relative motion and direction; the temperature, humidity and noise level; your activity patterns; and your connectivity options.

Sensors can enable a wide range of localized, highly targeted services. By being able to locate you with a high degree of accuracy—thanks perhaps to a combination of GPS, cell tower and Wi-Fi triangulation—suddenly very detailed location-based services (LBS) become possible. For example, you might be on the second floor of a shopping mall and want to find a music store. Instead of searching for a directory at the far end of a long hall you query your phone, which pops up mall map and walks you to the store. Or perhaps the store puts out an ad to the phones of just those people in the mall—or even just those near the store—advertising its sale of ZZ Top posters (you pass on that one). Of course an application could quickly look you up on Facebook, determine that you were a big Rolling Stones fan, and pitch you on that poster instead. That’s when these things may be getting a bit too intrusive.

Ducoret’s larger point is that adding intelligence to MEMS devices opens up a lot of possibilities for devices and services that weren’t previously available. We used the example of context awareness in a shopping mall, but context awareness is critical in remote patient monitoring, another market where smart embedded MEMS devices are having a dramatic impact.

With silicon vendors now offering a seemingly endless stream of high precision converged sensor devices—so called sensor fusion—if you’re designing an embedded system that needs to be aware of its environment, you’re now only limited not by the silicon but by your imagination.

Think in other categories.

Posted in Sensors | Tagged , | Leave a comment

More than MEMS

Posted on June 23, 2011 by John Donovan

The fact that I spend too much time focusing on consumer electronics was brought home to me vividly last week by a visit to the Sensors Expo 2011 in Chicago. Far from the niche show that I expected, it was swamped by over 4,000 attendees checking out 140 exhibiting companies, making navigating the aisles a good application for GPS, LIDAR, a 3-axis accelerometer and a collision avoidance system.

While the bulk of the $9.7B U.S. sensors market is MEMS-based accelerometers—the not-so-secret sauce empowering the 34 million Wii game consoles sold to date—there were plenty of other sensor technologies on display, including proximity, light, piezo-electric, thermal, pressure, touch, gas, chemical, IR and probably more that I missed. The applications consisted of a wide range of consumer, industrial, medical, environmental and security devices, all of which relied on sensor data for input. If you can’t measure it, you can’t control it—the problem this show addressed.

On with the Show

Instead of rolling out individual products ROHM Semiconductor chose to showcase a number of them at once with its Sensor Race Track, which featured a model Hummer circuiting a track populated with nine different sensors:  3-axis accelerometers, an ambient light sensor, a UV sensor, a Hall Effect sensor, an optical proximity sensor and an inclinometer. All of these inputs fed into a sensor hub and then to a wireless networking module, which in turn presented the data in real time on a large screen.

Digi International used Google Earth to demonstrate its “cloud-based wireless sensor network,” which enables centralized monitoring and control of disparate resources worldwide—from rotating solar panels to tracking trucks to monitoring vending machines—all using wireless sensors nodes connected to the internet.

Some companies such as ROHM, Epson, MEDER and many others displayed numerous individual sensors; others showed products that could integrate data from different sensors—so called sensor fusion. STMicro highlighted its iNEMO inertial measurement unit (IMU) devices, which combine data from various motion sensors with magnetic (compass), barometric/altitude and GPS data to enable location-based services. ST stressed the low-power angle, a theme echoed by TI, Maxim, Microchip, Linear Tech, Analog Devices and most other vendors. The chip companies, by and large, focused on managing the power going to and the data coming from remote sensor devices.

Energy Harvesting

A number of companies focused on extending the useful life of remote sensor nodes by using energy scavenging techniques. Cymbet uses a combination of tiny solar panels backed up by their proprietary thin-film batteries to supplement coin cells in wireless sensor nodes; Microchip and TI, among others, rely on Cymbet’s board to power their energy scavenging kits.

Powercast pulses RF from a central source to top up power in and gather data from remote sensor nodes. The Powercast P2110 receiver is an RF energy harvesting device that converts RF to DC and stores it in a capacitor. The Powercast transmitter can power an array of battery-free receivers throughout a building for industrial monitoring, HVAC and smart-grid applications—all of which resembles a wide-area active RFID system.

Nextreme’s miniature, embedded thermoelectric generators (eTEG) are essentially thin-film thermocouples that fit between a heat source (MCU, PA, etc.) and its heatsink. Converting temperature differences of as little as 5°C into electrical power, the eTEG is designed for powering gas sensors; trickle charging wireless sensors in dark or remote places; and improving fuel efficiency in automobiles.

Posted in Energy scavenging, Sensors, trade shows | Tagged , | Leave a comment