How do MBP USB-C/TB ports stack to iPhone/iPad chargers?

[aevan]

I am curious, and I can't seem to find the info - when you plug in your iPhone or iPad in your Mac, it gets charged. It's hard for me to estimate how fast this is (I usually leave them overnight anyway) but I'm curious. Is it closer to those old 5W chargers or to the new 20W ones. I'm talking about USB-C/TB Macs.

Thanks.

 

[joevt]

According to https://en.wikipedia.org/wiki/USB:
USB-C should be able to do 15W.
USB 3.0 Type A should be able to do 4.5W.
USB 2.0 Type A should be able to do 2.5W.

There are different Battery Charging (USB BC) and Power Delivery (USB PD) and Quick Charge (QC) specs (and some others?) that allow for more power but I don't think Mac USB ports have any of those beyond the above limits? And I don't know what types of charging the iPhone/iPad devices can use - I think Apple has there own spec?
https://en.wikipedia.org/wiki/USB_hardware#USB_Battery_Charging
https://en.wikipedia.org/wiki/USB_hardware#USB_Power_Delivery
https://en.wikipedia.org/wiki/Quick_Charge
https://support.apple.com/en-us/HT210133
https://www.pcmag.com/how-to/what-is-fast-charging
https://www.digitaltrends.com/mobile/how-does-fast-charging-work/
https://www.androidauthority.com/fast-charging-explained-2-889780/
https://www.howtogeek.com/670644/what-is-fast-charging-and-how-does-it-work/

A USB port needs to be able to convey to a USB device how much power it can deliver (voltage and current) using one of those specs. The USB device and USB port will negotiate. The USB device will not use more current than has been negotiated, otherwise damage can occur to the source if the source is not sufficiently protected. The USB source will not use voltage greater than negotiated, otherwise damage to the USB device can occur if the USB device is not sufficiently protected.
https://support.apple.com/en-us/HT210133
https://support.apple.com/en-ca/guide/iphone/iph8c1e31583/ios
https://support.apple.com/en-ca/HT208137
https://www.zmi.com/blogs/blog/on-apples-new-18w-usb-pd-wall-charger-model-a1695

There are USB power delivery analyzers (expensive) and power measuring devices (inexpensive). They don't all work with all possible voltages and currents and all transmission speeds (they should at least do 10 Gbps; some may be limited to 5 Gbps or 480 Mb/s; probably none will do 20 Gbps required for Thunderbolt) and I don't know if they interfere with any of the charging specs.
https://www.aikencolon.com/best-usb-testers/
https://www.amazon.com/usb-power-meter/s?k=usb+power+meter
http://www.chargerlab.com/a-comparison-of-the-chargerlab-power-z-usb-testers-v5-0/
https://www.totalphase.com/products/usb-power-delivery-analyzer/
https://www.cypress.com/documentation/development-kitsboards/cy4500-ez-pd-protocol-analyzer

 

[aevan]

According to https://en.wikipedia.org/wiki/USB:
USB-C should be able to do 15W.
USB 3.0 Type A should be able to do 4.5W.
USB 2.0 Type A should be able to do 2.5W.

There are different Battery Charging (USB BC) and Power Delivery (USB PD) and Quick Charge (QC) specs (and some others?) that allow for more power but I don't think Mac USB ports have any of those beyond the above limits? And I don't know what types of charging the iPhone/iPad devices can use - I think Apple has there own spec?
https://en.wikipedia.org/wiki/USB_hardware#USB_Battery_Charging
https://en.wikipedia.org/wiki/USB_hardware#USB_Power_Delivery
https://en.wikipedia.org/wiki/Quick_Charge
https://support.apple.com/en-us/HT210133
https://www.pcmag.com/how-to/what-is-fast-charging
https://www.digitaltrends.com/mobile/how-does-fast-charging-work/
https://www.androidauthority.com/fast-charging-explained-2-889780/
https://www.howtogeek.com/670644/what-is-fast-charging-and-how-does-it-work/

A USB port needs to be able to convey to a USB device how much power it can deliver (voltage and current) using one of those specs. The USB device and USB port will negotiate. The USB device will not use more current than has been negotiated, otherwise damage can occur to the source if the source is not sufficiently protected. The USB source will not use voltage greater than negotiated, otherwise damage to the USB device can occur if the USB device is not sufficiently protected.
https://support.apple.com/en-us/HT210133
https://support.apple.com/en-ca/guide/iphone/iph8c1e31583/ios
https://support.apple.com/en-ca/HT208137
https://www.zmi.com/blogs/blog/on-apples-new-18w-usb-pd-wall-charger-model-a1695

There are USB power delivery analyzers (expensive) and power measuring devices (inexpensive). They don't all work with all possible voltages and currents and all transmission speeds (they should at least do 10 Gbps; some may be limited to 5 Gbps or 480 Mb/s; probably none will do 20 Gbps required for Thunderbolt) and I don't know if they interfere with any of the charging specs.
https://www.aikencolon.com/best-usb-testers/
https://www.amazon.com/usb-power-meter/s?k=usb+power+meter
http://www.chargerlab.com/a-comparison-of-the-chargerlab-power-z-usb-testers-v5-0/
https://www.totalphase.com/products/usb-power-delivery-analyzer/
https://www.cypress.com/documentation/development-kitsboards/cy4500-ez-pd-protocol-analyzer

Thank you very much for the detailed answer!

 

[PBG4 Dude]

My iPhone and iPad charge more slowly when connected to my 15” MBP than they do if I connect them directly to my MBP’s power supply.

 

[joevt]

I used one of those USB testers (the KJ-KayJI 2 in 1 Type C USB Tester) on my Mac mini 2018. Below are some results for my iPad Air ME898C/A
In the USB tab of System Information.app, it shows numbers for Extra Operating Current and Sleep Current. Generally Sleep Current means there's an extra 500mA (from Current Available) that can be added to Extra Operating Current while the computer is sleeping?

Type A: 4.83V 1.83A-1.92A 8.8W-9.3W
Extra Operating Current: 1.6A
Sleep Current: 2.1A

USB-C: 4.95V 1.75A 8.63W
Extra Operating Current: 1.9A
Sleep Current: 2.4A

Apple 10W power adapter is identified as Apple Fast/PD (2.7V D+, 2V D- which should indicate Apple iPad 2.1A current charging mode)
5.04V 2.05A 10.31W

This means Apple does allow more than the base power from type A ports. Of course, connecting an iPad to a Mac means D+ and D- are being used for USB 2.0 data - so they cannot indicate an Apple Fast/PD charging capability. It must be using a different spec for delivering the extra current.

When I connect the iPad Air to a USB 3.0 type A hub that isn't connected to the computer, it's limited to 5V 0.07A 0.36W - basically no charging happens until the hub is plugged into the Mac mini 2018. Then it does 5.1V 0.46A 2.33W but the iPad Air says "Not Charging" because that is too low. The USB tab says there's 0 Extra Operating Current (500mA for Sleep current).
I connect the iPad Air to the other port of the hub, then it says 4.86V 1.45A 7.03W but the numbers in the USB tab don't change (still says 500mA current available/required/sleep). The hub is part of my XV273K display. Nothing in the display's manual says one port has different charging capability compared to the other ports...

As for USB-C, I only have a type A to lightning cable. I don't know if a type-C to lightning cable can allow faster charging than what I got with a USB-C to type A adapter in the above USB-C test.

 

[joevt]

the KJ-KayJI 2 in 1 Type C USB Tester

If you get one of these - there is plastic on each side to peel off.

 

[joevt]

I have another charger in the house (not Apple) which appears to support the Apple 2.4A current charging mode:
5.06V 2.36A 11.93W. That mode is supposed to be indicated by D+ and D- at 2.4V but I see 2.56V - does that mean the charger is indicating support for a faster charging mode but my iPad Air only supports the 12W mode? Probably not. For Apple, 12W is the highest for type A. For 18W, you need to go to USB-C.

https://support.apple.com/en-us/HT210133
https://www.ti.com/lit/ds/symlink/tps2543.pdf
https://www.ti.com/lit/ds/symlink/bq25886.pdf
https://electronics.stackexchange.c...ort-controller-divider-mode-and-bc-compliancy
https://e2e.ti.com/support/power-ma...ment-forum/295853/tps2513a-apple-charge-modes

I have a battery charger that has two type A ports, with different charging speeds. I didn't know they were different speeds. I see now that the fast port has two tiny lightning bolt icons and the slow port has only one tiny lightning bolt icon (they look like dents in the plastic of the battery charger next to the ports).
5.08V 2.04A 10.33W (D+ 2.7V, D- 2.07V) (Apple 10W mode)
5.11V 0.94A 4.8W (D+ 1V, D- 1V) (not an Apple mode; normal USB 3.0 type A power?)