42nd analysis: #USB #TypeC +Anker
PowerPort Speed PD 30w wall charger [Model A2014111].tl;dr: Noncompliant charger. Printed and advertised levels do not match actual capabilities. Inconsistent overload protection.
It may not work on certain laptops and high-power devices.[PDF of Compliance Checklist for Anker A2014111]
(to be posted later, data in images)
Anker released this product just a few days ago. It seems they repeated certain design errors common to their other products.https://plus.google.com/+BensonLeung/posts/71FgNerD8TB
This charger violates [Section 10.2.2 Normative Voltages and Currents] [Table 10-2 Normative Voltages and Currents] of the USB-PD spec. This sates "Table 10-3, Table 10-4, Table 10-5 and Table 10-6 show the Fixed Supply PDOs that shall
be supported for each of the Normative voltages defined in Table 10-2."
Per [Section 220.127.116.11 Shall/Normative]: "Shall and Normative are equivalent keywords indicating a mandatory
requirement. Designers are mandated
to implement all such requirements to ensure interoperability with other compliant Devices."*
Furthermore, Anker misrepresents the capabilities of the charger on marketing materials and text on the charger itself. On the side of the charger and online it even claims: "5v/3a 9v/3a 15v/2a 20v/1.5a". USB D+/D- BC1.2 DCP signaling mandatory. [I advocate "Autodetect" signaling here.]
electronic capabilities of the charger are "5v/3a 9v/3a 14.5v/2a
20v/1.5a". USB D+/D- have Apple 12W signaling. (Attached traffic dumps from a TotalPhase PD-Analyzer and Google/Plugable Twinkie linked.)
This will cause it to silently fail
when used with certain high-power devices and laptops using the 15v rail. I dislike this type of error since users without very expensive test equipment will never know what is happening.
Another ramification of this is certain devices like Chromebooks which prefer "lower voltage for same wattage" will latch on to the higher voltage rail and generate more heat converting voltage than they otherwise should.
15v*2a=30w and 20v*1.5a=30w. The rules were set up so devices which can only accept 20v get 20v (like laptops) -- but flexible ones (like Chromebooks) which accept 15v or 20v can take whatever is most efficient for them to convert. In this case, 15v is more "efficient" and runs cooler.
But because Anker used 14.5v/2a (instead of 2.06a exactly), the Chromebook will see 14.5v*2a=29W and 20v*1.5a=30W, and will pick the inappropriate 20v level. You're probably generating 3-5W of waste heat [and losing that much from charging] as a result. (See my recent disclosure about the Pixel charging behavior for "thermal" notes.)
This appears as if Anker tried to use a workaround to support Apple's proprietary voltage levels. The proper way to do what Anker was trying to attempt would be to offer 5/9/(14.5 optional)/15/(20 optional) and the exact proper amp values, respectively.
This suggests other bugs in the PD controller firmware, which I found.
The IR drop compensation is sawtooth, not linear. This suggests non-optimal design. With the chips already in the charger, it should have been possible to use linear PWM compensation. The PD controller firmware has bugs shared with some chargers, like inappropriate packet header incrementing, and claiming to be "dual role data" when it is not appropriate.
Finally, the overload protections are questionable. Sometimes it shuts off the charger entirely and reboots into 5v. Other times it sags voltage to unsafe levels and holds it there. this caused some issues with my load testers. (Documentation supplied in the form of TotalPhase PD-Analyzer voltage and current logs.)
All in all I'd say this was a VERY close attempt by Anker, but due to questionable issues I can't recommend it. #USBC