How does mobile phone fast charging work?

This video explains the technology behind fast charging in mobile phones, from early phones with linear chargers to the most advanced high power Direct-Charge-Divide/2 systems. We discuss different battery types, special charging systems like Qualcomm’s Quick-Charge QC2.0/3.0 and the new USB-C Power Delivery charging systems, covering Direct Charge and Direct Charge-Divide/2 systems that can deliver charging powers up to 45W without overheating.

We hook up oscilloscope and USB-PD analysers to different smartphones like Galaxy Note 10+ to examine their charging behaviour in detail. We will also tell you about next generation smartphone charging technology like Direct Charge-Divide/4 and dual cell battery systems.

Read more about Richtek’s ‘’Fast charging and USB PD’’ :

Related Richtek products:
RT9467: 5A Switching charger (high current switching charger application)

RT1716: USB-PD 3.0 Power delivery controller (sink side)

RT9471: 3A Switching charger (medium current switching charger application)

Some handy measurement tools that were used in this video: RIDEN TC66 and XYZ studio ZY1271 USB power monitors; Total Phase USB-PD protocol analyser.

music "The Stratosphere" by Adam Vitovsky

[ewicky]

I don't normally comment on videos, but this one deserves more than a thumbs up. Well done sir!

[Imrooot]

I never thought that charging could be so complex. Thank you for the great video.

[Maximus-tqny]

This was absolutely fantastic! I've seen so many "tip-of-the-iceberg" videos on things like USB-C PD but this goes into much more detail. Everything is explained in a way that makes sense. Nonetheless, I'll probably have to watch this one a few more times to catch all of the information that was packed in. You have earned yourself a sub, Sir!

[Infectiond]

Way more than I bargained for.

This is extremely good information. Keep it up!

[Boz]

just what i needed to know. everything about charging. impressive video

[whatmust]

This is a deep down technical level in deep detail. He certainly knows his subject and this is what i am looking for. All the other one are general consumer grade scratches the surface. 99.99% of consumers do not care or know about something they use every day use and charge their cell phone. That means wrong purchase for the wrong purpose and wasteful. No wonder Walmart shelves have ton of these confusing cables, usb adapters. Knowledge is

[engineerkohat]

Wonderful explanation with great equipment use. Awesome.

[niklas]

Never heard of this channel, but saw a middle-aged man with a mustache in front of some oscilloscopes and power supplies and immediately knew, i will get exactly the detailed information I was looking for :D

[two_number_nines]

This is the gold standard of the "how does X work".

[zakit]

If I spend months searching for such quality content for free I’ll simply get to nowhere. Thank you very much for the brilliant & clean effort you have kindly shared with us, respect.

[bharatshetty]

Amazing!!!
Many thanks for sharing all the different types of chargers, their specs and the internal design.
Being an electronics engineer myself I found it more than enlightening, can't thank you more for painstakingly putting up the graphics in such a lovely way and make it look as simple as it did.
Best wishes for your future presentations.

[MatthewWalker]

That RT9759 is insane... "capacitive divider" is not exactly what I'd expect it to be called (no AC signals here). Found the spec sheet, got some clues, and it's more of a double charge-pump that actually uses the battery as a voltage source!

Just considering the top half, it first configures the mosfets to use the battery plus the VBUS (which, recall, is externally maintained at twice the battery voltage) to charge the capacitor to VBUS/2==V_battery, then the mosfets are reconfigured to discharge the capacitor into the battery, and repeat. The bottom half is just a duplicate used presumably to ensure smooth operation.

[peterruppert]

Way more info than I bargained for but I'm thankful for it! Awesome video! I had no idea these phone charging systems were so intuitive!

[phonerepairteam]

We service mobile phones professionally and your video has helped us a lot to detect problems and malfunctions associated with charging on modern smartphones. Thank you very much for such a detailed explanation and we look forward to new content.

[nikolaisafronov]

okay. where is the button to donate? It IS a crime to not support such quality videos!

[tj]

This is a brilliant video I never knew there was so much that went into charging a device. Fascinating stuff.

[iggysixx]

This is the most in-depth, easy to understand, high quality video on charging that I've ever come across.

I love that you are able to explain so comprehensively, while not diving into technical terms (even with the circuit diagrams, and the oscilloscope). That is the sign of true understanding and expertise.

Also, thank you for explaining the differences between 'old' charging methods and the new ones, without skipping explenation of the old.
I like to repair things, but that could be anything from power tools, .to a variety of smartphones, to old cellular phones.
So the gap in my understanding of the differences in charging vs battery chemistry is only becoming more and more apparent as technology develops..

I found an oscilloscope a while back (in the trash - it works fine. From the late 70s I think).
I have been meaning to use it to dig into electronics a bit more.

Your video really shows the value of it, and I am freshly motivated to start digging in

[Patrick-nvxd]

Excellent, informative video. Thanks.

[jasonmiller]

Incredibly well done video. Great organization, instrument use, and pacing. Amazing!

[tabaghdissar]

That's the best video I have watched on power delivery. Everything is detailed and even non engineers can understand the concept