Cover photo
Benson Leung
Works at Google
12,293 followers|9,999,373 views


Benson Leung

Shared publicly  - 
+GTrusted has posted an edit to their previous post, and consider this my retraction as well. The OnePlus 3 supports USB Host and Type-C DRP, but a setting must be changed to enable. Despite it not being a storage option, a user has to go to the storage and usb settings to turn this on.

Thanks for everyone who helped get to the bottom of this.
Martin Lawliet's profile photoDeepak n.r.'s profile photoJuha Uotila's profile photo
It's always nice that people decide to bash a company just because it's THE Company.

Politely check all the settings before posting shit next time thanks 
Add a comment...

Benson Leung

Shared publicly  - 
A few people have asked me how +Monoprice's new Palette Series holds up. If you recall, I reviewed two of Monoprice's other cables and found them to be good.

I'm preparing my reviews, but the sneak preview is that Monoprice's cables are not flawless, and some of the adapters on this list are flat out banned by the spec, yet Monoprice produced them anyway (see if you can guess which one).

Should have something ready to post in a few days.

Meng Shen Lim's profile photoScott Miller's profile photoCandy Sandy's profile photoSean Hennessy's profile photo
+Cory Wilson With me, it was definitely the fact that Monoprice was the first computer cable website I ever visited. Prior to finding Monoprice, I would stroll through Best Buy or Circuit City in despair, thinking, "Well, I wanted an ethernet cord, but I guess some things in life you just can't afford..."
Add a comment...

Benson Leung

Shared publicly  - 
Awesome! The HP Chromebook 13 G1 works well with +Belkin's new #USBC  car charger for 9V charging.

#USB   #TypeC  
How the Belkin USB-C Car Charger + Cable Powers the HP Chromebook 13 G1 Via USB Power Delivery
How the Belkin USB-C Car Charger + Cable Powers the HP Chromebook 13 G1 Via USB Power Delivery
View original post
Matthew J Wronkiewicz's profile photoBenson Leung's profile photo
+Matthew J Wronkiewicz It's definitely an anomaly, since the conditions where those multiple SRCCAPs are sent are at initial connect, not while there is a change in load on the charger. I've not done a detailed reading of the PD spec to corroborate if sending another set of SRCCAP violates the spec as GTrusted says.

To my knowledge, that behavior doesn't cause any problems with any devices I've tried. The sink just looks at the list of PDOs again and sends another request.
Add a comment...

Benson Leung

Shared publicly  - 
+GTrusted has done a series of posts on the new +HP Chromebook 13 G1! I worked on this laptop on the +Google Chrome OS Kernel team, and it's one of my favorite new Chromebooks!

Codename "Chell" the Chromebook 13 is an +Intel Skylake-Y based design with USB Type-C and USB PD based charging system, capable of 45W.

It also supports DisplayPort Alternate mode and USB 3.1 Gen 1 SuperSpeed data!

So far, +GTrusted has done a few reviews to show how well it works with +Anker, +LG Electronics, and Lacie chargers and display-docks, and external hard drives!

#USBC   #USB   #TypeC  
Find or add products which are compatible or not working with the Chromebook 13 G1 by HP
Nick Stam's profile photoBenjamin Cobb's profile photoBenson Leung's profile photoBill Anderson's profile photo
No touchscreen. A year ago a wouldn't have cared...
Add a comment...

Benson Leung

Shared publicly  - 
+Nathan K.​ has done another charger review. This one checks off more boxes for good Type-C behavior but it's a tad bulky and only supplies 2.4A shared out of the other two ports.

Nice work with the analysis Nathan!

My fourth (and possibly final) #USB #TypeC analysis finally found a "decent" charger: Monoprice Obsidian Series 3-Port USB Wall Charger with USB-C.
tl;dr: Safe USB-C 3A charger. Well engineered. However, both Type-A ports SHARE 2.4A.

(Please see this post for what has had chilling effects on my testing for USB-C compliance and safety:)

I finally found a charger that has proper USB-C detection and current supply. I was able to charge my N6P at a full 3A. I was even able to pull the full 27W it is rated for at 80% efficiency. That's pretty good!

One weird note, unfortunately. This charger appears to be a USB-C 3A charger and USB-A 2.4A charger (with two outlets) smushed into a single housing. If you are charging two Apple devices, they will charge at half speed if at all. Thankfully, I only needed a USB-C charger with "a" USB-A backup port, so I can simply use this to charge one USB-C device and one USB-A.

Another interesting thing about this charger I'd like to mention is rather silly: its size. This thing is beefy. Some of that space might be being used for thermal dissipation or proper circuit designs. The 80% efficiency lends support to that supposition.

If you ever see a charger that claims more wattage than a first-party charger, but it is smaller, and cheaper, RUN AWAY! They usually don't support either (a) the thermal design characteristics or (b) they use simplified, cheaper, smaller power circuits. Those types of designs lack safety, and when they overload they can take out your device.

However, larger doesn't necessarily mean better! (There is a minimum size for a certain safe circuit, but no maximum.)

 Do you remember back when people weighed PSUs to guess the quality/quantity of electrical components, and in turn to determine PSU quality? Let's hope USB-C charger manufacturers don't start putting lead weights in them, or making them big like 80's insertable shoulderpads.

.... wait, too late. Darnit.
Anyone want to review that crazy thing for me? I'll get my hammer pants.

10 comments on original post
Shan Dissanayake's profile photoNathan K.'s profile photo
+Shan Dissanayake​​ I'm afraid not. I would like to focus on the good, consistent brands as opposed to the "value" ones.

If a good brand has an issue, they'll try to fix it. (Like +Tron Smart​​ . They made a mistake with their chargers, but are trying to correct it.) Shady brands will just change the silk-screening on the charger, move on, and keep selling it. So reviewing them is like playing whack a mole, meaningless.
Add a comment...

Benson Leung

Shared publicly  - 
+Nathan K. has done a great job doing some analysis of a +Tronsmart USB Type-C charger. What he found was not promising.

This charger is out of spec, according to Nathan. Don't buy it.

My second #USB   #TypeC analysis is a product I had high hopes for, that were dashed: the Tronsmart 33W Dual USB Wall Charger with Quick Charge 3.0 [Model W2PTU].
tl;dr: Bad charger. Vbus hot, single Rp bridged CC. Do not buy.
(Reposted due to album error.)

Note: I lack advanced LCR equipment or QC 3.0 devices compared to professionals, so I can only examine the basics of this adapter. However as evidenced in the above Amazon review, this shows examples of "bad behavior".

This charger is the third iteration by Tronsmart. Previous models place QC 3.0 on the USB-C port, which is a violation of USB-C specs. Other models supply 2.4A, when the standards call for 1.5A or 3.0A. (2.4A would only be possible through Apple-esque D+/D- manipulation in addition to a 1.5A CC Rp resistor... legal, but silly.)

I had hoped this was the One Charger To Rule Them All (N6P/N5X) and In the Darkness Bind Them (G5/HTC10, at least via a "legal" A-to-C cable.) 2 out of 3 isn't bad, right? Charger legal, Cable legal, Phone... not so much. Sadly, this is not the "Goldilocks" charger you are looking for.

5 comments on original post
Nathan K.'s profile photoTanner Suttie's profile photo
+Nathan K. Nice :) Well I will keep an eye on your G+ profile for your findings
Add a comment...
Have him in circles
12,293 people
Pete Patron's profile photo
Ken Clay's profile photo
Manoel Brasil Barbosa's profile photo
Walter Murphy's profile photo
Preetam Shetty's profile photo
Cezary Andraka's profile photo
Alex Burr's profile photo
christine feliciano's profile photo
Emanuele Zampieri's profile photo

Benson Leung

Shared publicly  - 
EDIT: +GTrusted has followed up on their post, and it looks like they were mistaken. The 3 does have proper DRP support and USB Host support, but it's hidden under a menu under storage options (even for non-storage cases like USB headphones).

Thanks for the corrections everyone!


Ridiculous. Just ridiculous. After a full year of selling a non-compliant Type-C phone, +OnePlus follows up with their OnePlus3 that ALSO doesn't support USB host in the correct way according to the Type-C spec. The OnePlus 2 shipped with a noncompliant cable, and their "otg" mode was noncompliant such that official C device adapters would not work, and so is the OnePlus 3, apparently.

They simply haven't learned how to build a phone properly.

Thanks +GTrusted for the scoop.

Folks, avoid OnePlus's phones if you want a phone that actually works with peripherals in the growing USB Type-C ecosystem like thumbdrives, for goodness sake.

Dexter Morelli's profile photoBenson Leung's profile photoNathaniel Watkins's profile photoJosh Smith's profile photo
+Nathaniel Watkins I agree overall but they could have checked with some other users. Agree it could be handled in a more user friendly way and I'll make the suggestion to the OnePlus guys. 
Add a comment...

Benson Leung

Shared publicly  - 
+Neil Brown has posted the first part in a series on about #USB  Battery Charging and the Linux kernel.

It's a good read, though he steers away from talking specifically about USB Type-C, it's a good explainer about how Battery Charging 1.2 (BC1.2) works.
Benson Leung's profile photoMike Wallace (MikeWallaceDev)'s profile photoKlisk Midori's profile photokaran pandhre's profile photo
Hello ,Benson,

I saw your reviews on amazon and found them really helpful. You are doing a great job. Well, I'm confused and I think only you can help me. I'm using Nexus 5X and I'm in search of power bank and a perfect cable for it. So far I was thinking of getting Oneplus's cord for charging with MI's 20k power bank. But after reading your reviews I don't think it's a good idea. So can you help me with this, Which power bank and cable shoud I buy without damaging my phone?

Thanks in advance. :)

Add a comment...

Benson Leung

Shared publicly  - 
The International Electrotechnical Commission (IEC) has formally adopted #USB   #TypeC , USB Power Delivery, and USB 3.1 as international standards for high-speed data delivery and device charging.

I particularly liked this part of this press release :
In addition, widespread adoption of the resulting International Standards will help to reduce the encroachment of poorly designed or manufactured aftermarket substitutes which may affect the operation of electronic devices in compliance with regulatory requirements.

Here's hoping that's true... A lot of noncompliance out there still.

Benson Leung's profile photoandy o's profile photo
andy o
+Benson Leung btw, has Monoprice sent you the new Palette cables? I suspect they're not in spec for IR drop, and they even advertise the C-C cables as only capable of 2.4A probably because of that. They charge slower than the Google and previous Monoprice cables, and even an Anker one which is thinner and more flexible. And they have no problem using your name on that page prominently praising their (previous) C-A cables, which seems a bit skeevy to me.
Add a comment...

Benson Leung

Shared publicly  - 
My fellow consumer watchdog +Matthew Garrett's profile.

Watch for his reviews before you click Buy on IoT devices like smarbulbs and smart outlets.
I'm a software developer working on internet security, especially on Internet of Things devices. I've reverse engineered a range of things to integrate them into my home network, and in the process found security bugs that always get reported to the manufacturer. If I say something's insecure, ...
Benson Leung's profile photoRod Moore's profile photo
+Jason Howell​ did you know you could follow a profile on Amazon?
Add a comment...

Benson Leung

Shared publicly  - 
Props to +Matthew Garrett for reviewing with a close eye on security a number of IoT devices on Amazon. Looks like this random Chinese manufacturer pulled their product after Matt left them a review exposing their terribly weak security.

Great work! It's so great to see others take to consumer sites like Amazon to clean up ecosystems!
Scott Hirschman's profile photo
Add a comment...

Benson Leung

Shared publicly  - 
+Nathan K. explains why some cut rate chargers may be problematic with newer and more advanced Type-C cables.

#USB #typeC #Usbc
WHY is it bad for-C to use a single resistor on both CC lines?
tl;dr: Because it will make your active/e-marked cables fail to charge. And your device think it is a headphone jack. You could also potentially blow your DAC or charging circuit.

(Note: corrections, comments, or clarifications are welcomed.)

Recently I posted a critical review of a charger that bridged CC pins and used only one Rp resistor. The manufacturer stated it was for "compatibility" with non-compliant devices. Benson explained this is bad, but people may not understand HOW serious this matter is. Cue this post.

(You can follow along with the pictures below using a basic understanding of circuits. Or memes.)

In the first image, I show how things "should" work. Two separate Rp resistors. By varying Rp you change the voltage on the CC line, vRd-USB. The charger and device sense this voltage to find each other. The device also learns how much current it is allowed to pull. (This is where Benson's crusade began!)

In the second image, I show what happens when you start cutting corners and "things go bad". Some manufacturers -- saving $0.001 by omitting a resistor ( ) -- use a single Rp and bridge the CC pins instead.

This is a violation of Section "Initially, a Source exposes independent Rp terminations on its CC1 and CC2 pins, and a Sink exposes independent Rd terminations on its CC1 and CC2 pins"

If using an e-marked/active cable (as will be mandatory soon),  there is an Ra pulldown on the second CC pin inside the cable. With an illegal charger there are now two paths to ground. You now have something called a "voltage divider" merging both CC pins. The formulas get a bit messy, but you can simplify the circuit. The resulting vRd-USB makes no sense to the device. It may charge slowly, not at all, or behave erratically.

First-rate [e-marked] cables like's Thunderbolt 3/USB-PD line won't even work with this kind of spec-violation!

(StarTech, if you are reading this, please consider joining Benson Leung in calling out non-compliant USB-C products. Manufacturers violating spec will make you and your well-engineered cables look bad. I can guarantee in the future, someone will post "Why isn't my ___ charging at full speed with my $40 StarTech cable? It works fine with my cheap [non e-marked] cable.")

In the third picture, I show how a non-compliant charger may even cause an active/e-marked cable to appear as a "Audio Adapter Accessory"...  in other words, a headphone jack! If the partner device is "DRP" capable, it may misinterpret the CC bridging as the presence of Ra on both pins. This is a unique alternate mode that repurposes the USB D+/D- pins to output analog audio signals from the phone's DAC. (There is already one phone on the market that lacks a 3.5mm audio jack, with more coming.)

You may have read about how Benson is loudly warning Qualcomm QC is illegal on USB-C. This is one reason why. QC 3.0 modulates the voltages on... you guessed it... the USB D+/D- lines to change the voltage delivered to the phone. QC had to do this on USB-A since there were only 4 wires. But USB-C has [2 pins/1 wire]¹ dedicated to negotiating voltage, and [at minimum 5 wires/11 pins]¹. (Apple chargers have D+/D- signaling too, but is merely the charger telling the phone it MAY take extra current. Not instructing the charger to jack up the voltage.)

The possibility exists -- however remote -- that an [illegal] QC-over-USB-C charger, with an [illegal] bridged CC pin, with a [GOOD] active cable, and [GOOD] phone, will result in the phone being fried.

(Disclaimer: this is a worst-case-scenario, based on my best understanding. I may have erred in a calculation -- darnit Jim I'm a MechE not an EE -- but it is my humble attempt at explaining how this one flaw [bridged CC pins] can blow up bigtime. I'll explore other "illegal" scenarios in other posts.)

¹: Thank you to Benson for pointing out the bare minimums! Please see "Table 3-11 USB 2.0 Type-C Standard Cable Assembly Wiring" for details.

#USB   #TypeC   #USBC
13 comments on original post
Matthew Foley's profile photoBenson Leung's profile photoPaul Milovanov's profile photoNathan K.'s profile photo
+Paul Milovanov The term "USB-C" includes both the Connector and the Communications protocols. Thunderbolt 3 uses a proprietary controller and "alternate mode" protocol called "Alpine Ridge". (Even pricing of the IC is proprietary.) It is fancy, I'll give it that, but completely separate development by Intel. (Keep in mind Thunderbolt 1/2 were failures because of how proprietary they were.)

I don't think it's right to suggest it includes better quality control. I'm helping someone with an Asus G501VW-FY081T where the Thunderbolt 3 port only works one way round! So while neat, Thunderbolt 3 has its own quirks.

As for resistor signaling, it is there so you can make really simple chargers. A 10kR resistor to 5V with a captive cable is the bare minimum of circuitry. If you do want a chip, these exists that do exactly what you describe (USB-PD):
Add a comment...
Benson's Collections
Have him in circles
12,293 people
Pete Patron's profile photo
Ken Clay's profile photo
Manoel Brasil Barbosa's profile photo
Walter Murphy's profile photo
Preetam Shetty's profile photo
Cezary Andraka's profile photo
Alex Burr's profile photo
christine feliciano's profile photo
Emanuele Zampieri's profile photo
Software Engineer
  • Google
    Software Engineer, 2010 - present
    Linux kernel developer on the Chrome OS team.
  • Marvell Technology Group
    Software Engineer, 2006 - 2010
  • Intel Corporation
    Software Engineer, 2005 - 2006
Fixer of Bugs.
Bragging rights
Power Porkchop!
Basic Information
Benson Leung's +1's are the things they like, agree with, or want to recommend.
USB 3.1 Cables - Type C -

USB 3.1 Cables - Type C Monoprice, Inc. (DBA. specializes in the wholesale distribution of world class cable assemblies for h

IEC Formally Adopts USB Type-C™, USB Power Delivery and USB 3.1 Specific...

The IEC and USB Implementers Forum today announced that IEC has formally adopted the latest USB-IF specifications for high-speed data delive

USB charging, part 1: requirements []

USB, the Universal Serial Bus, was primarily designed to transfer data to and from peripherals, with a secondary function of providing power

Recommended for Chromebook 13 G1 by HP

Find or add products which are compatible or not working with the Chromebook 13 G1 by HP Profile For Matthew Garrett

I'm a software developer working on internet security, especially on Internet of Things devices. I've reverse engineered a range of things t Matthew Garrett's review of AuYou Wi-Fi Switch, Timing Wirel...

Find helpful customer reviews and review ratings for AuYou Wi-Fi Switch, Timing Wireless Smart Outlet Socket, Turn On/Off Electronics Power

Sign in - Google Accounts

One account. All of Google. Sign in with your Google Account. Enter your email. Need help? Sign in with a different account Create account. Benson Leung's review of USB Type C, SingBel Hi-Speed USB 3....

Find helpful customer reviews and review ratings for USB Type C, SingBel Hi-Speed USB 3.1 Type C to USB Type A Male Cable Black. For New Mac

Belkin USB-C Car Charger + Cable- The World’s First Car Charger with Pow...

Belkin USB-C Car Charger + Cable- The World’s First Car Charger with Power Delivery Goes the Distance

Arms Technica and the tale of the Nonda Zus Kevlar cable

It’s probably a strong cable, but it failed to survive a live-fire exercise.

GTrusted - Discover Products, Check Compatibility, Share Your Experience

Social Media for Products. Use the World’s Largest Product Compatibility Database to Get Product Recommendations and Share User Experiences.

LG G5 Supports USB Power Delivery In Addition to Qualcomm Quick Charge 3...

LG G5 Supports USB Power Delivery In Addition to Qualcomm Quick Charge 3.0 over USB Type-C

Using USB Type-C on hobyist projects | scorpia

The new Type-C USB connector is the latest addition to the USB connector standards. It offers reversible plugs, direction independent cables Benson Leung's review of USB Type C Cable, OKPOW Hi-speed Go...

Find helpful customer reviews and review ratings for USB Type C Cable, OKPOW Hi-speed Gold Plated Nylon Braided USB Type C to Type A (USB-C

HP and Google made this thin, all-metal Chromebook

Here's the first Chromebook in a while that's worth paying attention to: the HP Chromebook 13. It's a thin, all-metal machine with surprisin Benson Leung's review of USB Type C Car Charger,Tronsmart 33...

Find helpful customer reviews and review ratings for USB Type C Car Charger,Tronsmart 33W Dual USB Car Charger with Quick Charge 3.0 Technol Benson Leung's review of Lemeng USB 3.0 (Type-A) Male to USB...

Find helpful customer reviews and review ratings for Lemeng USB 3.0 (Type-A) Male to USB3.1 (Type-C)Female Gold Plated Connector Converter A Benson Leung's review of Type C, iOrange-E USB C to USB 6.6 ...

Find helpful customer reviews and review ratings for Type C, iOrange-E USB C to USB 6.6 Ft Braided Cable with LED Indicator for Nexus 6P, 5X