Qualcomm Quick Charge 3.0 Coming To Numerous Snapdragon SoCs

[Lucian Armasu]

Qualcomm announced Quick Charge 3.0, its third-generation fast charging technology, which can charge four times faster compared to conventional charging and will be supported by the Snapdragon 430, 617, 618, 620 and 820 SoCs.

Qualcomm Quick Charge 3.0 Coming To Numerous Snapdragon SoCs : Read more

 

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Great. Most mobile devices these days have non-replaceable lithium batteries. High density rechargeable batteries do not age gracefully when subjected to heavy charge and discharge currents and now they introduce improved technology to help you ruin your non-user-serviceable batteries even faster if you choose to use it.

If you aren't in a hurry to top off your phone, tablet, nettop or whatever (ex.: charging overnight) and want to maximize your battery's useful life, slow-charge whenever you can.

 

[targetdrone]

Quick charge is the solution to a problem that shouldn't exist. I can easily charge a couple of spare batteries for my Note II overnight then swap them out as needed if needed.

 

[hst101rox]

[InvalidError]Great. Most mobile devices these days have non-replaceable lithium batteries. High density rechargeable batteries do not age gracefully when subjected to heavy charge and discharge currents and now they introduce improved technology to help you ruin your non-user-serviceable batteries even faster if you choose to use it.

If you aren't in a hurry to top off your phone, tablet, nettop or whatever (ex.: charging overnight) and want to maximize your battery's useful life, slow-charge whenever you can.

Hello CPU Genius!
And a bigger wall wart than you may want! 3-4 amps for a smart phone? 6 amps for a tablet? I doubt there will be an option to charge slower if not in a hurry unfortunately, like you can in an electric car for instance. Unless, you use a small output charger. I assume Quick charge 3.0 requires a smart AC adapter so the phone/tablet can communicate with the AC adapter on it's capabilities. Otherwise it could burn it out with the load.
Interesting the efficiency is improved by 38%, but power dissipation reduced by 45%? Shouldn't those 2 values be the same? Unless 'improved' and 'reduced' messes with the ratio.

 

[InvalidError]

I doubt there will be an option to charge slower if not in a hurry unfortunately

Of course there is: that thing still needs to be compatible with regular USB ports, just plug in a regular dumb 500-2100mA 5V USB power adapter instead of a QuickCharge one, done.

As for power efficiency vs losses, they are two slightly different and closely related calculations. Since they are comparing the old model with the new, the proportions in which efficiency (Pout / Pin) and losses (Pin - Pout) improve are not necessarily the same and you get different relative improvements.

 

[hst101rox]

I doubt there will be an option to charge slower if not in a hurry unfortunately

Of course there is: that thing still needs to be compatible with regular USB ports, just plug in a regular dumb 500-2100mA 5V USB power adapter instead of a QuickCharge one, done.

I wonder how large the genuine wall warts will be to enable the quick charging. Maybe not too big if they can increase the efficiency of AC-DC charging beyond 'Efficiency Level V' and it would be nice if smart phones/tablets had an option to stop charging the battery when it reaches ~80% charge, like what my HP laptop can do to lengthen the lifespan of the battery when you don't need the full capacity.

 

[InvalidError]

I wonder how large the genuine wall warts will be to enable the quick charging.

Most of the efficiency gain comes from simply requiring lower current to deliver the same amount of power at higher voltages: 20W at 5V requires 4A of current and if your total wiring (transformer winding + USB cable) has 0.25 ohm of resistance, you would be wasting 4W in the wiring. The same 20W at 20V only requires 1A of current and wastes only 0.25W in wiring.

Trade some of the gains on wiring losses for a higher switching frequency so you can reuse the same-sized transformer core (higher core losses) to push the extra power and you should be able to squeeze a 20V/20W power adapter in the same form factor while still achieving improved overall efficiency.

 

[hst101rox]

I wonder how large the genuine wall warts will be to enable the quick charging.

Most of the efficiency gain comes from simply requiring lower current to deliver the same amount of power at higher voltages: 20W at 5V requires 4A of current and if your total wiring (transformer winding + USB cable) has 0.25 ohm of resistance, you would be wasting 4W in the wiring. The same 20W at 20V only requires 1A of current and wastes only 0.25W in wiring.

Trade some of the gains on wiring losses for a higher switching frequency so you can reuse the same-sized transformer core (higher core losses) to push the extra power and you should be able to squeeze a 20V/20W power adapter in the same form factor while still achieving improved overall efficiency.

Sorry for the late reply. To pick your brain some more; You are saying that you can increase efficiency of the power supply by increasing the output voltage so there is less line loss? Guess that's how they'll reduce the power dissipation mostly. Increasing the switching frequency reduces efficiency but keeps the component (Inductors, capacitor and MOSFETs and the transformer?) size down? I know you mentioned transformer size with switching frequency increase but not the other hardware. Who knows if they’ll go that route. Or maybe they’ll just let the AC adapter run hotter so they won’t have the components increase in size much, which begs the question, what has to increase in size for more power output and why? It isn’t necessarily because of increased heat, because there is more heat with higher switching frequencies, yet smaller components size of certain types of components.
I think I usually see a regular looking transistor (flyback transistor?) in these switching AC adapters and also MOSFETs but I could be wrong. The regular transistor takes up most of the space/weight.
In the mobile device, would it be less efficient to convert 20V down to the ~4-5V that the device runs at/charges the battery at versus 5V to 4-5V? More heat loss, more volume needed in the device for the voltage regulators or would it be about the same? Probably same volume, just a different voltage regulator chip, and possible increase in heat dissipation in stepping down the voltage more, isn't much against the increased efficiency of the AC adapter.
And what other tricks might they use? From the February 2013 article ‘Qualcomm Reveals Quick Charge, Powers Devices 40% Faster‘, user named ‘saturnus’ at the bottom of the comments say that already uses pulsed current to help the battery take a faster charge (and I suppose all switching power supplies delivers PWM to the device and hence to the battery unless filtered out).

 

[InvalidError]

In the mobile device, would it be less efficient to convert 20V down to the ~4-5V that the device runs at/charges the battery at versus 5V to 4-5V? More heat loss, more volume needed in the device for the voltage regulators or would it be about the same?

A lithium battery requires 4-4.3V charging voltage, so the mobile device already has a step-down converter/charger to take the 5V from the power adapter or USB port down to whatever voltage or current the battery or the rest of the device needs. The only change from that end is re-designing that PWM to work across the 4-22V range instead of 4-6V.

On the semiconductor side, power semiconductors rated for 50V are microscopically bigger than ones rated for 10V so higher voltage has negligible impact on size and cost. For current though, the junction size is usually directly related to current. Re-designing the intermediate voltage supply to increase it from 5V to 20V does not only improve efficiency, it also reduces costs.

 

[Robert Dunlop]

I love Quick Charge 2.0 so l can't wait to feel the power!