There are now so many so-called standards for USB, Thunderbolt and Power Delivery that we have updated our guide – my how it has changed over a year.
USB, Thunderbolt and Power Delivery for dummies covers from USB 1.0 to the new USB-4 and the confusing power delivery (PD), battery charging (BC) and Quick Charging (QC) standards (and they are not the same things).
In preparing the USB, Thunderbolt and Power Delivery for Dummies,
it was not a matter of looking up a Wiki (wish it were) but consolidating USB
standards and battery power standards.
USB-A (and variants) – As USB-A should be on the way out now our best advice is to look for USB-C devices.
USB-C is a little easier. Well, it was more difficult this time due to the new USB-4 standards (not yet seen on any device). And it seems some manufacturers are pushing the standards as well. For example, USB-C can have a PD from 10W to 100W, but it depends on cable ratings!
PD is about using USB-C for data and power delivery
Fast charge is how fast you can fill the tank (Mainly USB-C)
USB, Thunderbolt and Power Delivery for dummies
Note 1Mbps = .125MBps = .001Gbps or .000125GBps.
Note: Half-Duplex (HD) can send or receive data but not at the
same time (think of a single lane bridge where a car has to stop to let another
through), so it achieves about half the speed. Full-Duplex (FD) means it can
send and receive data (two lanes) at the same time only losing a small amount
USB-A only (includes micro-USB and mini-USB connectors and variants).
1.0 – up to 12Mbps (HD) – black keyed port and cable
up to 5 metres
2.0 – 480Mbps (HD tops out at 280Mbps) – ditto
3.0 – 5Gbps (FD tops out at 3.2Gbps) – blue
keyed port and cable to 3 metres
USB-C (3.1 can also use some USB-A blue keyed ports)
3.1 Gen 1 – 5Gbps (FD with the right SuperSpeed cable)
3.1 Gen 2 – 10Gbps (FD with the right SuperSpeed+ cable)
3.2 Gen 1 – 5Gbps
3.2 Gen 2 – 10Gbps
and 3.2 Gen 2 2×2 – 20Gbps
USB-4 (based on Thunderbolt 3)
Gen 2×1 – 10Gbps with USB3.2, DP1.4a and PCIe tunnelling, Host to host OTG transfers
Gen 2×2 – 20Gbps – ditto
and Gen 3×2 – 40Gbps – ditto
Usually, 40Gbps over .5m Thunderbolt certified USB-C
cables but older implementations and longer ‘passive’ cables will see that
reduce to 10 or 20Gbps.
Thunderbolt 2 is 10Gbps FD and 20Gbps HD.
Battery charging (BC) Specification (these are not as ‘standard’ as we would like)
Battery Charging (for USB-A only and relates to ‘dumb’
chargers). It is unwise to plug a higher rated charger into a lower-rated
device as excess power converts into heat. Conversely, you can use a lower-rated
charger, and it takes longer to charge.
In our experience, USB-A chargers come in 5V/.3A (1.5W),
5V/.9A or 1A (4.5-5W), 5V/2A (10A and the limit of micro-USB cables) and 5V/3A (15W
and for USB-C devices).
1.0 is 5V up to 500mAh (2.5W) – there is no intelligence, and the charger should match the device amperage needs, e.g. 5V 300mA (1.5A), 5V/500mA (2.5W).
1.1 is 5V up to 900mA (4.5W) – ditto. Also called USB 3.1 gen 1 over USB-C
1.2 is 5V up to 1.5A (7.5W) – ditto. Also called USB 3.1 gen 2 over USB-C
We have seen a lot of USB-A, 5V/2.4A and 5V/3A (12-15W) chargers and these are outside BC standards – more the PD 1.0 standard below. Do not use these with older USB devices.
Generally, USB-A self-powered (bus-powered) devices (using the USB-A 2.0 host or later) draw 5V and from 100mA-1000mA (.5W to 5W).
Obviously, the BC protocol ran out of ‘steam’, and USB-C PD
came into play.
Power Delivery (PD) over USB-C (applies to USB-C 3.1 or higher)
PD 1.0 (5V/3A/15W) – smartphones and devices USB devices to 15W: This is the most common USB-A to USB-C cables can handle that. If the device does not need the wattage, the charger delivers lower wattage.
US PD is a standard as the charger and device have some
intelligence (called a power contract or handshake) to deliver the right voltage
and amperage. The only catch is that you need a cable rated for the amperage. You
need an EMCA (Electronically Marked Cable Assembly) cable for over 3A. And
power can flow upstream (to the device) and downstream (from the device).
You will hear the term ‘fast charge’ bandied around but, it
is just pouring (flooding) more wattage into the battery. It is safe, but the jury
is out on whether repeated charging shortens battery life.
There are other lower PD standards like 1.5A (12-20V/1.5-3A/18-60W),
3A (12/20V/3-5A (36-60W) and 5A (12-20/5W. 60-100W). We seldom see them.
PD 2.0 introduced the ability to use fixed voltages from
5/9/15/20V and 3 to 5A (15-100W).
But it is not an elegant standard relying on large voltage,
and amperage jumps from say, 20V/3W for the first 30%, dropping to 15W/3A for
the next 20% etc. PD 2.0 tops out at 60W without a special cable.
PD 3.0 is 5V up to 20V and 3A to 5A (15-100W). It is
a more elegant and universal solution because it allows micro-voltage and
amperage steps instead of the fixed voltages. In this way, it can deliver higher
voltages and lower amperages.
USB On-the-Go (OTG) simply means ports that can send
data/power upstream or downstream. USB-C cables are full-duplex; it is the
devices that may be half-duplex.
Fast or Quick Charge (QC) for smartphones (note these do not support data transfer like PD)
A quick refresher: Volts x Amps = Watts (OHMS law), 1000 milliamps per Amp (mA), mAh is the total mA the battery can deliver for one hour.
Volts are a lineal measure of voltage. Amps are how fast that
voltage flows into the battery and Watts – well that is the overall volume or charge
ability of V x A. Note its not so much the Voltage that can kill a person but the
Amperage – 10mA can give you a painful shock and 100-200mAh can kill.
There are a few confusing issues like efficiency and loss
due to heat but suffice to say that all smartphone batteries are 3.3V and pouring
in 5V will not hurt them.
One final measurement is smartphone battery capacity in milliamp
hours or mAh. Simply put a 4000mAh battery can deliver 4A for one hour. If your
device had a power draw at idle of say 400mA, then it would drain the battery in
10 hours. Similarly, if you want to charge that battery at 10W (5Vx2A) it would
take 2 hours to fill (but the reality is that lower charging efficiencies make
that even longer).
From 2019 new Google Android smartphones (to comply with Google
Mobile Services) must have a USB Type-C port with full interoperability with
chargers that are compliant with the USB-PD 2.0 specifications. Older micro-USB
is slowing being phased out except those with lower-powered MediaTek SoCs.
Most, if not all QC technology (except OPPO) uses exponential
charging. It floods the battery with the highest volt/amps it will take until
about 50% full then steps down to 9V to 75-80% when the standard 5V/2A kicks
in. This is to prevent battery fires and help preserve battery life.
QC requires a compatible Qualcomm SD SoC and a phone that
has a QC charging circuit. Standards are backwards compatible.
1.0 – 5V/2A (10W)
2.0 – 5/9/12 (18W) for latter SD2XX/4XX/6XX up to SD810
3.0 – dynamic 200mV increments 3.6-20V up to 18W – SD4XX to SD821
4.0 – dynamic 20mV increments 3.6-20V/2.5-3A (27W) – SD6XX, 710 and 835 and PD 2.0 compatible
4+ – for SD670, 845/855. PD 3.0 compatible. Introduces Dual charge paths like OPPO VOOC
OPPO (also known as Dash or Warp Charge (OnePlus) and used in vivo and realme
A proprietary solution requires a special dual-channel ‘green’
insert USB-A cable to work with dual batteries; otherwise, it delivers half the
amperage. You can use QC compatible chargers, but the maximum is PD 2.0 at 10W.
VOOC 2.0: 5V/4A (20W)
SuperVOOC: 5V/4A – Find X
VOOC 3.0: 5V/5A (25W) for OPPO Reno
VOOC 4.0 (not released) is 5V/6A (30W) (also called
Coming 10V/5A (50W)
It is a proprietary solution, but QC 3.0 chargers will give reasonable speed. We note that Huawei SuperCharge batteries run hotter than most during charge.
V 1.0 – 4.5V/5A (22.5W) for P and Mate 10 series
– need purple insert USB-A cable. Also has 5/9V/3A for PD 2.0 compatibility at
V2.0 (4.5-10V at 4/4.5/5 – maximum 40W) for Mate
30/Pro – PD 2.0 charges at 27W
Samsung Adaptive Fast Charge
Since the Note7 issue, Samsung has been ultra-cautious about
battery pedigree (build) and fast charging. In all our tests, Samsung phones
maintain the lowest battery temperature, and we think that is best. Note that
all chargers support similar Qualcomm QC 2.0 or 3.0 standards as the phones can
use Exynos or Qualcomm chips depending on the market.
5/9V and 2A (18W) for its older Galaxy/Note series
phones (QC 2.0)
5/9 and 3/2.77A (25W) plus PD 3.3/5.9/3A and
3.3/11/2.25A (28W) for Galaxy 10 5G (QC 3.0)
5/9/12V and 2/1.67/2.1A for its tablets PD 2.0
The Note10+ can use a special 10V/4.5A (45W)
charger, but if you use QC 3.0 or 4.0 chargers it only charges at 27W.
Motorola’s TurboPOwer is more a marketing term and it basically
QC 2.0 in disguise unless using a MediaTek SoC.
15 is 9/12V and 1.2-1.67A (15W)
25 is 5/9/12 and 2.15-2.85A (25W)
30 is 5V/5.7A (28.5W) – Motorola needs to use
batteries that can handle the Amperage.
MediaTek Pump Express
MediaTek has QC 2.0 compatible charging on some of its
2.0+ is 5-20V in .5V increments 3-4.5A (maximum
15W) – works with Micro-USB cables to 10W
3.0 is 3-6V in 10-20mV increments 5A (25-30W) –
USB-C only and three-stage – Regular, Turbo 1 (, and Turbo 2 (6V/2A/15W) – PD 2.0
GadgetGuy’s take – USB, Thunderbolt and Power Delivery is a whole lot of mumbo jumbo
We put this reference together a year ago because we get so
many claims about fast charging or USB-C PD that we needed to develop a reference,
free from marketing BS.
Boy, has a lot changed. One thing has become evident – power is the lifeblood of any device and the alibility to recharge it quickly is paramount to users.
In fact, we have seen in recent tests where a 5V/3A charger (15W)
meets or beats a so-called fast charger to 100%.
In most cases, there is more marketing hype than reality in
smartphone fast charge claims. Most start by claiming, for example, 50% in just
30 minutes neglecting to tell you that the battery has been flood charged at say
15V/4A (60W) and any more would risk thermal burnout. Fast charge is a three or
even four-stage charge.
Please note that should you find any errors please let me know
– there are a lot of numbers here.