The Secret World of USB Charging

There’s a whole set of USB charging specs you’ve probably never heard of because big-battery smartphones, tablets and 2:1’s demand shorter charge times.

Editor’s note: this particular blog posting is sponsored by Pericom Semiconductor.  

$5 chargers useNow that you can buy $5 USB chargers everywhere (mains- and cigarette lighter-powered), it’s tempting to think of them like LED flashlights: cheap commodity throw-aways. And you would’ve been right…until now.

My recent purchase of an Asus T100 Transformer Windows 8.1/Intel Atom 2:1 tablet hybrid forced me to dig into USB charging (Figure).

My own Asus T100 Transformer Book has a “unique” USB charging profile.  (Courtesy: Asus.)

My own Asus T100 Transformer Book has a “unique” USB charging profile.
(Courtesy: Asus.)

This device is fabulous with its convenient micro USB charging port with OTG support. No bulky wall wart to lug around. But it refuses to charge normally from any charger+cable except for the (too short) one that came with it.

My plethora of USB chargers, adapters, powered hubs and more will only trickle charge the T100 and take tens of hours. And it’s not just the device’s 2.0A current requirement, either. There’s something more going on.

Just Say “Charge it!”

The USB Innovators Forum (USB-IF) has a whole power delivery strategy with goals as shown below. Simply stated, USB is now flexible enough to provide the right amount of power to either end of the USB cable.

The USB Power Delivery goals solidify USB as the charger of choice for digital devices. (Courtesy: www.usb.org )

The USB Power Delivery goals solidify USB as the charger of choice for digital devices. (Courtesy: www.usb.org )

There’s even a USB Battery Charging (UBC) compliance specification called “BC1.2” to make sure devices follow the rules. Some of the new power profiles are shown below:

Table 1: USB Implementers Forum (USB-IF) Battery Charging specifications (from their 1.2 compliance plan document October 2011).

Table 1: USB Implementers Forum (USB-IF) Battery Charging specifications (from their 1.2 compliance plan document October 2011).

The reason for UBC is that newer devices like Apple’s iPad, Samsung’s Galaxy S5 and Galaxy Tab devices–and quite possibly my Asus T100 2:1–consume more current and sometimes have the ability to source power to the host device. UBC flexibly delivers the right amount of power and can avoid charger waste.

Communications protocols between the battery’s MCU and the charger’s MCU know how to properly charge a 3000mAh to 10,000mAh battery. Battery chemistry matters, too. As does watching out for heat and thermal runaway; some USB charger ICs take these factors into account.

Apple, ever the trend-setter (and master of bespoke specifications) created their own proprietary fast charging profiles called Apple 1A, 2A and now 2.4A. The Chinese telecom industry has created their own called YD/T1591-2009. Other suppliers of high-volume devices have or are working on bespoke charging profiles.

Fast, proper rate charging from Apple, Samsung and others is essential as harried consumers increasingly rely on mobile devices more than laptops. Refer to my complaint above RE: my Asus T100.

Who has time to wait overnight?!

USB Devices Available

Pericom Semiconductor, who is sponsoring this particular blog posting, has been an innovator in USB charging devices since 2007. With a growing assurance list of charge-compatible consumer products, the company has a broad portfolio of USB ICs.

Take the automotive-grade PI5USB8000Q, for instance. Designed for the digital car, this fast charger supports all of the USB-IF BC modes per BC1.2, Apple 1A and 2A, and the Chinese telecom standard. The IC powers down when there’s no load to save the car’s own battery, and can automatically detect the communication language to enable the proper charging profile (Figure). Pretty cool, eh?

The USB-IF’s CDP and SDP charging profiles require communication between the USB charger and the downstream port (PD) device being charged. Refer to Table 1 for details. (Courtesy: Pericom Semiconductor.)

The USB-IF’s CDP and SDP charging profiles require communication between the USB charger and the downstream port (PD) device being charged. Refer to Table 1 for details. (Courtesy: Pericom Semiconductor.)

As For My Asus 2:1?

Sadly, I can’t figure out how the T100 “talks” with its charger, or if there’s something special about its micro USB cable. So I’m stuck.

But if you’re designing a USB charger, a USB device, or just powering one, Pericom’s got you covered. That’s a secret to get all charged up about.

Intel’s Atom Roadmap Makes Smartphone Headway

After being blasted by users and pundits over the lack of “low power” in the Atom product line, new architecture and design wins show Intel’s making progress.

Intel EVP Dadi Permutter revealing early convertible tablet computer at IDF2012.

Intel EVP Dadi Permutter revealing early convertible tablet computer at IDF2012.

A 10-second Google search on “Intel AND smartphone” reveals endless pundit comments on how Intel hasn’t been winning enough in the low power, smartphone and tablet markets.  Business publications wax endlessly on the need for Intel’s new CEO Brian Krzanich to make major changes in company strategy, direction, and executive management in order to decisively win in the portable market. Indications are that Krzanich is shaking things up, and pronto.

Forecasts by IDC (June 2013) and reported by CNET.com (http://news.cnet.com/8301-1035_3-57588471-94/shipments-of-smartphones-tablets-and-oh-yes-pcs-to-top-1.7b/) peg the PC+smartphone+tablet TAM at 1.7B units by 2014, of which 82 percent (1.4B units, $500M USD) are low power tablets and smart phones. And until recently, I’ve counted only six or so public wins for Intel devices in this market (all based upon the Atom Medfield SoC with Saltwell ISA I wrote about at IDF 2012). Not nearly enough for the company to remain the market leader while capitalizing on its world-leading tri-gate 3D fab technology.

Behold the Atom, Again

Fortunately, things are starting to change quickly. In June, Samsung announced that the Galaxy Tab 3 10.1-inch SKU would be powered by Intel’s Z2560 “Clover Trail+” Atom SoC running at 1.2GHz.  According to PC Magazine, “it’ll be the first Intel Android device released in the U.S.” (http://www.pcmag.com/article2/0,2817,2420726,00.asp)and it complements other Galaxy Tab 3 offerings with competing processors. The 7-inch SKU uses a dual-core Marvell chip running Android 4.1, while the 8-inch SKU uses Samsung’s own Exynos dual-core Cortex-A9 ARM chip running Android 4.2. The Atom Z2560 also runs Android 4.2 on the 10.1-incher. Too bad Intel couldn’t have won all three sockets, especially since Intel’s previous lack of LTE cellular support has been solved by the company’s new XMM 7160 4G LTE chip, and supplemented by new GPS/GNSS silicon and IP from Intel’s ST-Ericsson navigation chip acquisition.

The Z2560 Samsung chose is one of three “Clover Trail+” platform SKUs (Z2760, Z2580, Z2560) formerly known merely as “Cloverview” when the dual-core, Saltwell-based, 32-nm Atom SoCs were leaked in Fall 2012. The Intel alphabet soup starts getting confusing because the Atom roadmap looks like rush hour traffic feeding out of Boston’s Sumner tunnel. It’s being pushed into netbooks (for maybe another quarter or two); value laptops and convertible tablets as standalone CPUs; smartphones and tablets as SoCs; and soon into the data center to compete against ARM’s onslaught there, too.

Clover Trail+ replaces Intel’s Medfield smartphone offering and was announced at February’s MWC 2013. According to Anandtech.com (thank you, guys!) Intel’s aforementioned design wins with Atom used the 32nm Medfield SoC for smartphones. Clover Trail is still at 32nm using the Saltwell microarchitecture but has targeted Windows 8 tablets, while Clover Trail+ targets only smartphones and non-Windows Tablets. That explains the Samsung Galaxy Tab 3 10.1-inch design win. The datasheet for Clover Trail+ is here, and shows a dual-core SoC with multiple video CODECs, integrated 2D/3D graphics, on-board crypto, multiple multimedia engines such as Intel Smart Sound, and it’s optimized for Android and presumably, Intel/Samsung’s very own HTML5-based Tizen OS (Figure 1).

Figure 1: Intel Clover Trail+ block diagram used in the Atom Z2580, Z2560, and Z2520 smartphone SoCs. This is 32nm geometry based upon the Saltwell microarchitecture and replaces the previous Medfield single core SoC. (Courtesy: Intel.)

Figure 1: Intel Clover Trail+ block diagram used in the Atom Z2580, Z2560, and Z2520 smartphone SoCs. This is 32nm geometry based upon the Saltwell microarchitecture and replaces the previous Medfield single core SoC. (Courtesy: Intel.)

I was unable to find meaningful power consumption numbers for Clover Trail+, but it’s 32nm geometry compares favorably to ARM’s Cortex-A15 28nm geometry so Intel should be in the ballpark (vs Medfield’s 45nm). Still, the market wonders if Intel finally has the chops to compete. At least it’s getting much, much closer–especially once the on-board graphics performance gets factored into the picture compared to ARM’s lack thereof (for now).

Silvermont and Bay Trail and…Many More Too Hard to Remember

But Intel knows they’ve got more work to do to compete against Qualcomm’s home-grown Krait ARM-based ISA, some nVidia offerings, and Samsung’s own in-house designs. Atom will soon be moving to 22nm and the next microarchitecture is called Silvermont. Intel is finally putting power curves up on the screen, and at product launch I’m hopeful there will be actual Watt numbers shown, too.

For example, Intel is showing off Silvermont’s “industry-leading performance-per-Watt efficiency” (Figure 2). Press data from Intel says the architecture will offer 3x peak performance, or 5x lower power compared to the Clover Trail+ Saltwell microarchitecture. More code names to track: the quad-core Bay Trail SoC for 2013 holiday tablets; Merrifield with increased performance and battery life; and finally Avoton that provides 64-bit energy efficiency for micro servers and boasts ECC, Intel VT and possibly vPro and other security features. Avoton will go head-to-head with ARM in the data center where Intel can’t afford to lose any ground.

Figure 2: The 22nm Atom microarchitecture called Silvermont will appear in Bay Trail, Avoton and other future Atom SoCs from "Device to Data Center", says Intel. (Courtesy: Intel.)

Figure 2: The 22nm Atom microarchitecture called Silvermont will appear in Bay Trail, Avoton and other future Atom SoCs from “Device to Data Center”, says Intel. (Courtesy: Intel.)

Oh Yeah? Who’s Faster Now?

As Intel steps up its game because it has to win or else, the competition is not sitting still. ARM licensees have begun shipping big.LITTLE SoCs, and the company has announced new graphics, DSP, and mid-range cores. (Read Jeff Bier and BDTi’s excellent recent ARM roadmap overview here.)

A recent report by ABI Research (June 2013) tantalized (or more appropriately galvanized) the embedded and smartphone markets with the headline “Intel Apps Processor Outperforms NVIDA, Qualcomm, Samsung”. In comparison tests, ABI Research VP of engineering Jim Mielke noted that that Intel Atom Z2580  ”not only outperformed the competition in performance but it did so with up to half the current drain.”

The embedded market didn’t necessarily agree with the results, and UBM Tech/EETimes published extensive readers’ comments with colorful opinions.  On a more objective note, Qualcomm launched its own salvo as we went to press, predicting “you’ll see a whole bunch of tablets based upon the Snapdragon 800 in the market this year,” said Raj Talluri, SVP at Qualcomm, as reported by Bloomberg Businessweek.

Qualcomm  has made its Snapdragon product line more user-friendly and appears to be readying the line for general embedded market sales in Snapdragon 200, 400, 600, and “premium” 800 SKU versions. The company has made available development tools (mydragonboard.org/dev-tools) and is selling COM-like Dragonboard modules through partners such as Intrinsyc.

Intel Still Inside

It’s looking like a sure thing that Intel will finally have competitive silicon to challenge ARM-based SoCs in the market that really matters: mobile, portable, and handheld. 22nm Atom offerings are getting power-competitive, and the game will change to an overall system integration and software efficiency exercise.

Intel has for the past five years been emphasizing a holistic all-system view of power and performance. Their work with Microsoft has wrung out inefficiencies in Windows and capitalizes on microarchitecture advantages in desktop Ivy Bridge and Haswell CPUs. Security is becoming important in all markets, and Intel is already there with built-in hardware, firmware, and software (through McAfee and Wind River) advantages. So too has the company radically improved graphics performance in Haswell and Clover Trail+ Atom SoCs…maybe not to the level of AMD’s APUs, but absolutely competitive with most ARM-based competitors.

And finally, Intel has hedged its bets in Android and HTML5. They are on record as writing more Android code (for and with Google) than any other company, and they’ve migrated past MeeGo failures to the might-be-successful HTML5-based Tizen OS which Samsung is using in select handsets.

As I’ve said many times, Intel may be slow to get it…but it’s never good to bet against them in the long run. We’ll have to see how this plays out.

PCI-SIG “nificant” Changes Brewing in Mobile

PCI-SIG Developers Conference, June 25, 2013, Santa Clara, CA

Of five significant PCI Express announcements made at this week’s PCI-SIG Developers Conference, two are aimed at mobile embedded.

From PCI to PCI Express to Gen3 speeds, the PCI-SIG is one industry consortium that lets no grass grow for long. As the embedded, enterprise and server industries roll out PCIe Gen3 and 40G/100G Ethernet, the PCI-SIG and its key constituents like Cadence, Synopsis, LeCroy and others are readying for another speed doubling to 16 GT/s (giga transfers/second) by 2015. The PCIe 4.0 next step evolves bandwidth to 16Gb/s or a whopping 64 GB/s (big “B”) total lane bandwidth in x16 width. PCIe 4.0 Rev 0.5 will be available Q1 2014 with Rev 0.9 targeted for Q1 2015.

Table of major PCI-SIG announcements at Developers Conference 2013

Table of major PCI-SIG announcements at Developers Conference 2013

Yet as “SIG-nificant” as this announcement is, PCI-SIG president Al Yanes said it’s only one of five major news items. The others include: a PCIe 3.1 specification that consolidates a series of ECNs in the areas of power, performance and functionality; PCIe Outside the Box which uses a 1-3 meter “really cheap” copper cable called PCIe OCuLink with an 8G bit rate; plus two embedded and mobile announcements that I’m particularly enthused about. Refer to the table for a snapshot.

New M.2 Specification

The new M.2 specification is a small, mobile embedded form factor designed to replace the previous “Mini PCI” in Mini Card and Half Mini Card sizes. The newer, as-yet-publicly-unreleased M.2 card will be smaller in size and volume but is intended to provide scalable PCIe performance to allow designers to tune SWaP and I/O requirements. PCI-SIG marketing workgroup chair Ramin Neshati told me that M.2 is part of the PCI-SIG’s increased focus on mobile.

The scalable M.2 card is designed as an I/O plug in for Bluetooth, Wi-Fi, WAN/cellular, SSD and other connectivity in platforms including ultrabook, tablet, and “maybe even smartphone,” said Neshati. At Rev 0.7 now, Rev 0.9 will be released soon and the final (Rev 1.0?) spec will become public by Q4 2013.

PCI-SIG M.2 card form factor

The PCI-SIG’s impending M.2 form factor is designed for mobile embedded ultrabooks, tablets, and possibly smartphones. The card will have a scalable PCIe interface and is designed for Wi-Fi, Bluetooth, cellular, SSD and more. (Courtesy: PCI-SIG.)

Mobile PCIe (M-PCIe)

Seeing the momentum in mobile and the interest in a PCIe on-board interconnect lead the PCI-SIG to work with the MIPI Alliance and create Mobile PCI Express: M-PCIe. The specification is now available to PCI-SIG members and creates an “adapted PCIe architecture” bridge between regular PCIe and MIPI M-PHY.

The Mobile PCI Express (M-PCIe) specification targets mobile embedded devices like smartphones to provide high-speed, on-board PCIe connectivity. (Courtesy: PCI-SIG.)

The Mobile PCI Express (M-PCIe) specification targets mobile embedded devices like smartphones to provide high-speed, on-board PCIe connectivity. (Courtesy: PCI-SIG.)

Using the MIPI M-PHY physical layer allows smartphone and mobile designers to stick with one consistent user interface across multiple platforms, including already-existing OS drivers. PCIe support is “baked into Windows, iOS, Android,” and others, says PCI-SIG’s Neshati.  PCI Express also has a major advantage when it comes to interoperability testing, which runs from the protocol stack all the way down to the electrical interfaces. Taken collectively, PCIe brings huge functionality and compliance benefits to the mobile space.

M-PCIe supports MIPI’s Gear 1 (1.25-1.45 Gbps), Gear 2 (2.5-2.9 Gbps) and Gear 3 (5.0-5.8 Gbps) speeds. As well, the M-PCIe spec provides power optimization for short channel mobile platforms, primarily aimed at WWAN front end radios, modem IP blocks, and possibly replacing MIPI’s own universal file storage UFS mass storage interface (administered by JEDEC).

M-PCIe by the PCI-SIG can be used in multiple high speed paths in a smartphone mobile device. (Courtesy: PCI-SIG and MIPI Alliance.)

M-PCIe by the PCI-SIG can be used in multiple high speed paths in a smartphone mobile device. (Courtesy: PCI-SIG and MIPI Alliance.)

PCI Express Ready for More

More information on these five announcements will be rolling out soon. But it’s clear that the PCI-SIG sees mobile and embedded as the next target areas for PCI Express in the post-PC era, while still not abandoning the standard’s bread and butter in PCs and high-end/high-performance servers.

 

Intel Gets Smart with Smartphones

The 15 year anniversary of Intel’s Developers Forum kicked off with a somewhat predictable keynote by Dadi Perlmutter, EVP/GM Intel Architecture Group (Figure 1). We’re so used to Intel hitting it out of the park that the astounding messages bordered on ho-hum: reminding the audience of the pervasiveness of mobile computing; the morphing of the (not-yet-successful) Ultrabook segment into tablets, slates, and convertible variants; Windows8 and touch, gesture, and voice computing; next year’s Haswell 22nm microarchitecture; and a brief mention of future Atom variants. What is 100 percent certain is that Intel’s server (Xeon), desktop and laptop (3rd and soon 4th generation Core) processors will be amazing technology machines that are better than anything available today. And you’ll want one just as soon as they begin shipping in Q12013 because they’ll be cool. Literally.

Figure 1: Intel’s Dadi Perlmutter, EVP/GM Intel Architecture Group opens Day 1 of IDF 2012.

But what was most interesting is what Mr. Perlmutter didn’t say that the whole audience wanted to hear: What’s Intel’s roadmap in low-power, portable devices like smartphones and tablets? He offered only that the “First Wave” of Intel Inside smartphones is now available (Figure 2), with more on the way.

Turns out Intel is like an iceberg with only a bit showing above the waterline. The company merged the Core and Atom design teams this year, emphasizing both the need to focus on low power and SoC solutions, and to solidify the Haswell architecture’s “roadmap-ability” to scale up to server-class performance, while down to low-leakage, high-K power-sipping sleep modes. Five cell phone wins have been announced, all based upon the SoC Atom Z2460 1.6 GHz Medfield platform (Saltwell core): Lenovo, ZTE, Megafon, LAVA and Orange. They all run Android 4.0 Ice Cream Sandwich – one revision behind the latest Jelly Bean – except for the Lava which runs 2.3. According to an Intel spokesperson, all are loosely based upon the company’s Smartphone Reference Design , but the Lava most closely resembles the original Intel specs.

Figure 2: Intel announced five smartphone wins at IDF, all based upon the Medfield Atom SoC and Saltwell core.

The Lava XOLO X900, sold in India, uses the Z2460 with Hyper-threading, has 16 GB of NV storage and 1 GB of RAM, and drives a 4.03-inch screen at 1024 x 600 with Intel’s 400 MHz Media Graphics Accelerator running OpenGL ES 2.0 with OpenVG 1.1 support. Its 1460 mAh battery is on the small side but similar to the iPhone 4s (allegedly 1432 mAh), but “should last 6-8 hours”. The China-destined Lenovo, on the other hand uses the same Atom SoC and graphics chip, but the 4.5-inch screen displays 720p content. The phone uses a 1900 mAh battery.

Figure 3: Who knew Intel made modems? The family – available in multiple form factors – originally came from the 2010 Infineon Wireless acquisition.

The other Intel surprise was their wireless modem family (Figure 3), spawned by the 2010 acquisition of Infineon’s wireless group. The company offers modem ICs, dongles, and cores for integration into their own (future) SoCs. The XMM family has a variety of flavors; all five of the smartphones displayed at IDF use Intel’s XMM 6260 HSPA+ 21 Mbits/s down/5.8 Mbit/s up modem. Designed for 2G/3G networks, multimode “Penta-band” support works with multiple worldwide standards: GSM, GPRS, and EDGE (850/900/1800/1900); and HSPA (850/900/1700/1900/2100). These are mixed signal solutions, combining digital and analog baseband in what Intel calls X-GOLD. No small technical feat.

Intel also has a roadmap strategy for “feature phones” (those candy bar phones popularized by Nokia) for the huge portion of the non-connected world that sees no need for a smartphone. Atom SoCs and modems are available for this slice of the mobile market, too.

So the part of the iceberg floating below the water that is publicly visible – Medfield SoCs and mixed signal 3G modems – is hugely impressive and clearly shows Intel’s commitment to low power mobile devices. And these are only the “First Wave”. Clearly Intel knows how to integrate smartphone peripherals, perform baseband signal processing, accelerate and decode/transcode HD graphics, and make a pretty decent low-power smartphone. With Intel writing the Intel Architecture BSP and native code on Android for Google (one of last year’s IDF announcements), the company is well positioned to smartly get into the smartphone game. The Haswell microarchitecture should ratchet down power by 20 times at the system level, said Permutter. We’re anxious to see it applied to the Atom roadmap in the Silvermont microarchitecture.

It’s about time.