A fix for dangerus USB 3.0 cables is now here...and its not elegant - Page 1
Forum section: electronics / projects

author: Berni
author_rank: Super Contributor
timestamp: April 13, 2016, 10:27:40 am
content: As you may have seen, devices that use USB 3.0 ports for charging can get fried by using a cheep WonHunLo USB cable to charge it. But have no fear the bofins that write the USB 3.0 standards have updated the standard with a solution for this.http://www.theverge.com/2016/4/12/11416624/usb-c-authentication-fried-laptopBasically they are going to go the Apple route and add authentication chips in to the connectors so that a device can check if this is a genuine cable that has been certified by them.This also means that if the device manufacturers decide to push out this software update that even the original USB cable provided with the device will stop working, rendering the device unable to change until you go to the store and buy a proper new fangled certificated USB cable. Or is it an evil plan to squeeze money out of USB cable manufacturers.What do you guys think of this fix?

author: ElektroQuark
author_rank: Unknown
timestamp: April 13, 2016, 10:59:43 am
content: I think freedom will be a note in books in a few years.

author: Rerouter
author_rank: Super Contributor
timestamp: April 13, 2016, 11:04:09 am
content: I've gone searching, but am left wondering how a cable, not a charger, but a piece of wire can damage it? if its hard shorting positive and negative, the device should have a form of protection, if its data to either, the transceivers should be rated to handle it,If someone could help fill me in how its doing damage it would be appreciated,Edit:Ok i went and found that its somehow related to the cable telling the maximum charging current, that still doesn't make too much sense to me,

author: sleemanj
author_rank: Super Contributor
timestamp: April 13, 2016, 12:39:11 pm
content: Complete bullshit imho.The guy that busted his chromebook had a reverse wired cable, the fact the chromebook failed with reverse polarity, irrevocably, is just poor design of the chromebook if you ask me. Sure it shouldn't happen that a cable is reverse polarity, but it is forseeable and something a 5c mosfet can protect against.As for a cable asking for more current, even if that is the case, a device sourcing current, be it a charger or a laptop, should surely have some inherent current limit to protect itself, by, you know, NOT trying togive more current than it was designed to.

author: rrinker
author_rank: Super Contributor
timestamp: April 13, 2016, 01:00:06 pm
content: Though what about the MacBook one, where the computer DID shut off the port to protect itself but still wasn't working 100% afterwards?Anyway, 2 days after the chipped cables come out, the chip will be counterfeited and Wun Hung Lo will be back in business making dodgy cables, except instead of 50 cents they'll cost 60 cents.

author: Rerouter
author_rank: Super Contributor
timestamp: April 13, 2016, 01:30:42 pm
content: I wouldn't say a computer would shut off to protect its port, sounds more like that mac book had a supply rail shorted and went into brownout reset, or tripped the supply,Again this shows product engineers are falling behind the idiots of the world, and better idiots have once again triumphed, (Note in this case shame on the whole debarkle)

author: nctnico
author_rank: Super Contributor
timestamp: April 13, 2016, 01:45:04 pm
content: Quote from: Rerouter on April 13, 2016, 01:30:42 pmI tend to agree. After reading some articles this seems to be a design problem in the devices with the USB ports (too little protection) rather than wrong cables. IMHO a USB port should be designed in a way that is can deal with any situation within the voltage ranges usually present on a USB interface.

author: borjam
author_rank: Unknown
timestamp: April 13, 2016, 02:14:36 pm
content: Quote from: nctnico on April 13, 2016, 01:45:04 pmSo History always repeats itself. Firewire was a really cool interface, but I've known several cases of blown ports due to connectors plugged in the wrong position. And the connector itself was quite prone to reverse insertion. Sigh.

author: tszaboo
author_rank: Super Contributor
timestamp: April 13, 2016, 02:23:21 pm
content: It is just the next proof that the USB specifications are written by morons and programmers who never used computers in their life.

author: Maxlor
author_rank: Frequent Contributor
timestamp: April 13, 2016, 02:53:40 pm
content: The real fix for dangerous USB 3 cables is everyone switching to Type C ports.The whole issue with cables exist only with cables that convert between Type C and Type A/B ports, because those cables are not actually not cables (i.e. a bunch of wires going to contacts on a connector) but adapters, converting between a Type C and Type A/B connection. But why do we need adapters?Type C doesn't just have more and faster signals, the current-carrying capacity has also been significantly upgraded. In order to still allow cheap power supplies, they've designed it such that the type of power delivery you'd expect from a phone charger can happen without digital communication, by the old method of adding different resistor values for different supply capabilities. Those resistors are added to the control signals of the connection.Now, if you have a Type-C to Type-C cable, the device (i.e. your phone) sees the resistor in the charger, and knows how much current to draw. However, if your charger has a Type A port instead, there are no pins for the control signals to connect to! So we need an adapter from Type C to type A, that does something semi-smart with the unconnected signals, like connect the resistor that would be in the charger itself, if it had a Type C port. And because it's convenient, let's combine the cable and the adapter into a single thing, and call it C->A cable.What the manufacturers first did, and what many chinese manufacturers still do, is not think hard enough about which resistor to add. They figure, let's make the cable as high-performance as possible and support 3A charging, and indicate that by adding that famed 10k resistor! The problem with that is, the adapter here doesn't make a statement about how much current the cable supports, but about how much the charger supports. And most of the type, 3A is out of spec for a charger with a Type A port. The right thing to do is being conservative about what charger can do, and add a 56k resistor which indicates 1.5A max current.As I said, it's a temporary issue. Once everything's switched over to Type C on both sides of a connection, cables are as dumb and simple and ever, and it's the charger itself that is able to express how much current it can supply.

author: Delta
author_rank: Super Contributor
timestamp: April 13, 2016, 04:19:11 pm
content: I've read the article linked, and the Amazon review linked from there, and I'm still not entirely sure what they're saying, as they seem to contradict each other...Are these "dodgy" cables damaging the devices they are charging - as the Amazon review seems to state...or damaging hosts used to charge devices (ie charging a phone from a laptop) - as the article seems to say.How can a device be damaged by trying to draw more power than a charger can provide?andSurely all hosts have current limiting on their USB ports?If the damages was caused by a reversed polarity cable, than that's an out and out F-up by the cable manufacturer, rather than them not following the standard fully.... and is nothing to do with USB, USB3, USB type C connectors or anything, just an old-fashioned screw up.Something's not right here....

author: timb
author_rank: Super Contributor
timestamp: April 13, 2016, 07:28:21 pm
content: Quote from: Delta on April 13, 2016, 04:19:11 pmExactly. And every computer I've ever seen does have current limiting on the USB ports. There's actually chips designed specifically to protect USB ports.Ports on Apple laptops are actually designed to give more current than the standard allows, for charging iPhones and iPads. However, they use a smart port protector that monitors the current (one of the aforementioned chips) and shuts off the port if the device tries to draw too much current. You'll actually see a message pop up in OS X telling you as much. (I believe PCs running Windows do something similar as this is part of the USB standard.)

author: Berni
author_rank: Super Contributor
timestamp: April 13, 2016, 08:41:59 pm
content: Yeah this is pretty much my point. Devices with USB ports should be designed to handle any sort of over current condition and a short between any of the pins since connectors and cables can get damaged. Okay reverse polarity it probably wouldn't need to withstand since it needs the cable to be wired wrong in the first place to cause that.Clearly a decision made by the big bosses that have no clue how USB even works.

author: Ian.M
author_rank: Super Contributor
timestamp: April 13, 2016, 08:48:57 pm
content: At the power levels that USB 3.0 can deliver, there's a good argument for introducing over-temperature protection for ports that can deliver power in excess of 2.5W, in addition to the over-current protection.However adding secure digital signatures to cables smells like back-door protectionism, effectively forming a cartel.

author: langwadt
author_rank: Super Contributor
timestamp: April 13, 2016, 08:49:56 pm
content: Quote from: timb on April 13, 2016, 07:28:21 pmyou would thinks so, but I've accidentally shorted the USB on an Acer aspire (afair) result was instant reset and shutoffas if it basically shorted the main supply

author: timb
author_rank: Super Contributor
timestamp: April 13, 2016, 08:56:00 pm
content: Quote from: langwadt on April 13, 2016, 08:49:56 pmHuh, well there you go. I have seen some $99 desktops without USB protection, so I guess it's not surprising budget laptops cut corners too.My experience has been with higher end PC laptops like Thinkpads and such, which have had the current protection.

author: timb
author_rank: Super Contributor
timestamp: April 13, 2016, 09:06:33 pm
content: Also, there's no need for an authentication chip in the cable with USB-C, as that already *requires* current monitoring *and* two-way negotiation for power delivery:QuoteMore info here.

author: jh15
author_rank: Frequent Contributor
timestamp: April 13, 2016, 09:20:40 pm
content: Another way for "safety problems" to be used as an excuse to limit end user property from being theirs.Can I change my own car oil? No, you need a dealer chipped wrench to remove the drain bolt. Oil is too hazardous for the end user to handle.More fodder for "Defective By Design" and EFF crews.Also, wait for copyright to slime its way in...

author: jeremy
author_rank: Super Contributor
timestamp: April 13, 2016, 10:31:52 pm
content: This article is very confusing. On the one hand, it says that the chips will be used for the device to authenticate the host (ie no chip in the cable), but then it says this detection scheme doesn't work on currently produced cables, implying that the cable indeed will change. Which one is it?The quote from the spec doesn't even mention anything about putting chips in cables: " host systems  confirm the authenticity of a USB device or USB charger, including such product aspects as the descriptors/capabilities and certification status."

author: Berni
author_rank: Super Contributor
timestamp: April 14, 2016, 05:23:34 am
content: Quote from: jeremy on April 13, 2016, 10:31:52 pmWell they say that the devices will be able to tell apart a proper and bad cable by only using a software patch. This means there is no extra protection circuitry in the device to tell it that something went wrong, so they have to do something to the cable. Obviously they putting power electronics in the cable would be bulky and expensive so a lot of cables would skip it. The other way is to have the cable carry some sort of secure ID inside of it that the device can check (Like apple lighting cables do).They do also talk certifying USB devices and chargers, that part does make sense. That is if passing the certification actually requires them to have the protection circuitry to keep the device from blowing up rather than giving them X number of dollars.EDIT: Oh and in the end they talk about only new cables supporting this.

author: Carl_Smith
author_rank: Frequent Contributor
timestamp: April 14, 2016, 05:52:23 am
content: Doesn't the USB type C high power charging use a higher voltage than 5V? Up to 20V I think. Maybe that's happening to devices that didn't ask for it and can't handle more than 5V.Sounds like it might be prudent in the future to design all USB powered devices to not be damaged by up to 20V.As for resetting your PC when shorting USB power -- I worked a decade ago on desktop motherboard design. The USB ports were protected in pairs with a one amp polyswitch resettable fuse. The fuse was connected directly to the 5V supply, no other current control. If you short the 5V to ground, the fuse would trip fast enough to protect the motherboard from damage, but it would usually NOT react fast enough to prevent the 5V from being pulled down low enough to reset the system.

author: Psi
author_rank: Super Contributor
timestamp: April 14, 2016, 07:45:10 am
content: Quote from: Ian.M on April 13, 2016, 08:48:57 pma lot in excess of 2.5W infact, USB 3 can do 100W !

author: Berni
author_rank: Super Contributor
timestamp: April 14, 2016, 07:56:26 am
content: Quote from: Psi on April 14, 2016, 07:45:10 amYup it does do 100W as it was designed to be used for charging laptops and such. However ever since they announced it i was a bit skeptical how safe and reliable that would be over the flimsy cables and connectors.And yes if they can put 20V on it there better be a fancy negotiation sequence to make sure it never gets there on accident or make the specification that all of the devices that use it must survive 20V. Also certainly use some more fancy protection than they currently use. For laptops usually all USB ports are run off a single overcurrent protector IC (Had that chip fail in my laptop out of the blue, didn't even short it. Made all my USB ports non functional until i soldered a new one in)

author: Ian.M
author_rank: Super Contributor
timestamp: April 14, 2016, 09:07:00 am
content: 2.5W through a type A connector has a good track record of reliability and a low risk of damage , even with cruddy connectors. However if you push 5A @20V through a connector of approximately the same size, and it has dirty contacts, if the resulting contact resistance is 1 ohm, you've got 25W dissipation at the connector. Hopefully, the voltage drop will be detected quickly enough for the powered device to command the power source to shut down before the connector is damaged, but the combination of numerous manufacturers and declining software quality in the consumer marketplace does not inspire one to be confident that the protection will be reliable.IMHO over-temperature protection is essential, but non-engineer led standards committees are like the blind men inspecting the elephant, so I woudn't expect such sanity until there has been at least one fatal fire caused by faulty USB 3.0 power delivery . . . .

author: station240
author_rank: Unknown
timestamp: April 14, 2016, 09:50:34 am
content: Perhaps the idea is the miswired cables will fry the chip, due to reversed polarity.The real problem is the monkey see, monkey do method of engineering in some Chinese companies.They look at what someone else has made, go "Oh this is just cable" and make something with no understanding of why the original was made in a certain way.

author: Delta
author_rank: Super Contributor
timestamp: April 14, 2016, 10:32:45 am
content: I really don't like this 100W, 5A @ 20V malarky. It's pushing things too far and forgetting the U in USB - USB delivers 5v, that's it, one of the reasons why USB charging has become so ubiquitous for phones and tablets. Standardise laptop charging? Great idea. Try to do so with bloody USB? Stupid idea.

author: dannyf
author_rank: Super Contributor
timestamp: April 14, 2016, 10:49:05 am
content: "devices that use USB 3.0 ports for charging can get fried by using a cheep WonHunLo USB cable to charge it. But have no fear the bofins that write the USB 3.0 standards have updated the standard with a solution for this."It doesn't surprise me that a poorly designed standard has to be changed to deal with a cable.It does surprise me when there are people stupud enough to think it is the fault of the cable that the standard compliant port was fried.

author: rrinker
author_rank: Super Contributor
timestamp: April 14, 2016, 03:51:04 pm
content: This article from AnandTech explains it better:http://www.anandtech.com/show/10251/usbc-authentication-announcedYou will actually be able to load your own certs. As explained in the article, this is actually pretty cool for places where they need to allow specific USB devices but in general want to block the average user from just plugging in any old virus-laden USB memory stick or external drive and copying all the company data. Definitely not an inelegant or bodged solution.

author: DanielS
author_rank: Frequent Contributor
timestamp: April 14, 2016, 05:35:08 pm
content: Quote from: Ian.M on April 14, 2016, 09:07:00 amThere is no need to tell the host anything, the load can simply reduce its own current limit just like many devices that charge over USB already do when bus voltage is lower than expected.But that won't do anything to protect devices with incomplete input protection from miswired cables, such as how Chromebooks lack reverse polarity protection.