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RPI 4 USB-C supply

Posted: Mon Sep 09, 2019 11:41 am
by brasta78
Hi,

Ok I heard about RPI 4 problems implementing USB-C spec but for me is other related question - I have DELL USB-C power supply https://www.dell.com/en-ie/work/shop/de ... ccessories that can provide 20V/9V/5V and I don't understand can I plug and test RPI which require 5V? Ampers more than enough - 30W/5V = 6A

Re: RPI 4 USB-C supply

Posted: Mon Sep 09, 2019 12:09 pm
by bjtheone
USB C issue is that the 4B does not have the appropriate resistor to fully implement the USB C "device type" part of the spec. Due to this smart chargers, that can supply greater than 5V don't know what it wants. Unfortunately various vendors have tacked their own fast charging extensions on and may or may not be fully spec compliant.

In theory a fully compliant USB C multi voltage smart charger should just not charge the Pi. I have not heard of a charger that supplies an over voltage that would harm the Pi but it could happen. I have heard of smart chargers that don't work with the 4B and I believe that at least some Dell chargers do not work.

Re: RPI 4 USB-C supply

Posted: Mon Sep 09, 2019 1:32 pm
by jamesh
brasta78 wrote:
Mon Sep 09, 2019 11:41 am
Hi,

Ok I heard about RPI 4 problems implementing USB-C spec but for me is other related question - I have DELL USB-C power supply https://www.dell.com/en-ie/work/shop/de ... ccessories that can provide 20V/9V/5V and I don't understand can I plug and test RPI which require 5V? Ampers more than enough - 30W/5V = 6A
My Dell USB power supply does not work with the Pi4. Just use the official power supply, it's cheap and works.

This problem with certain high end power supplies will be sorted out in a later board revision.

Re: RPI 4 USB-C supply

Posted: Mon Sep 09, 2019 1:47 pm
by W. H. Heydt
bjtheone wrote:
Mon Sep 09, 2019 12:09 pm
In theory a fully compliant USB C multi voltage smart charger should just not charge the Pi...
Nitpick...
A Pi requires a "power supply unit" (PSU), not a "charger". There are no power storage devices on a Pi, and--therefore--nothing to charge. (Yes, there are small capacitors, but the charge they hold isn't intended to and won't power the Pi.)
/Nitpick

Re: RPI 4 USB-C supply

Posted: Mon Sep 09, 2019 2:21 pm
by fruitoftheloom
brasta78 wrote:
Mon Sep 09, 2019 11:41 am
Hi,

Ok I heard about RPI 4 problems implementing USB-C spec but for me is other related question - I have DELL USB-C power supply https://www.dell.com/en-ie/work/shop/de ... ccessories that can provide 20V/9V/5V and I don't understand can I plug and test RPI which require 5V? Ampers more than enough - 30W/5V = 6A

Just buy the Official Power Supply it was chosen to give quality at an affordable price:

https://www.raspberrypi.org/products/ty ... er-supply/

Re: RPI 4 USB-C supply

Posted: Mon Sep 09, 2019 3:51 pm
by brasta78
check results with my DELL USB-C AC adapter - red light is on and green is flashing but on 2 different monitors and TV didn't show any boot screen... The same with my other USB-C 6V adapter from soldering iron. Voltage on Pin 2 and 4 is 5V.
Should I try to flash EEPROM? But my green light is flashing...

Re: RPI 4 USB-C supply

Posted: Mon Sep 09, 2019 4:08 pm
by W. H. Heydt
brasta78 wrote:
Mon Sep 09, 2019 3:51 pm
check results with my DELL USB-C AC adapter - red light is on and green is flashing but on 2 different monitors and TV didn't show any boot screen... The same with my other USB-C 6V adapter from soldering iron. Voltage on Pin 2 and 4 is 5V.
Should I try to flash EEPROM? But my green light is flashing...
No. You should get an official RPF PSU and try with that.

Re: RPI 4 USB-C supply

Posted: Mon Sep 09, 2019 4:36 pm
by drgeoff
brasta78 wrote:
Mon Sep 09, 2019 3:51 pm
check results with my DELL USB-C AC adapter - red light is on and green is flashing but on 2 different monitors and TV didn't show any boot screen... The same with my other USB-C 6V adapter from soldering iron. Voltage on Pin 2 and 4 is 5V.
Should I try to flash EEPROM? But my green light is flashing...
Do you realise that without a bootable OS on an inserted micro-SD card you have no prospect of seeing anything on the screen other than a "No signal" or equivalent message generated by the monitor itself?

If the red LED is on and not blinking or going out, then the USB-C issue with the RPI's power input is not the immediate problem.

Re: RPI 4 USB-C supply

Posted: Wed Sep 11, 2019 2:50 pm
by brasta78
so guys all of you who forced me to buy original Raspberry power supply are owing me 10€ :) because my 2 owned USB-C AC adapters appears also working and @drgeoff was right - problem was with SD card

Re: RPI 4 USB-C supply

Posted: Wed Sep 11, 2019 3:05 pm
by jamesh
brasta78 wrote:
Wed Sep 11, 2019 2:50 pm
so guys all of you who forced me to buy original Raspberry power supply are owing me 10€ :) because my 2 owned USB-C AC adapters appears also working and @drgeoff was right - problem was with SD card
In our defence, the thread title is about power supplies...!!!

Re: RPI 4 USB-C supply

Posted: Wed Sep 11, 2019 3:12 pm
by brasta78
that board is alive with non branded power supply it was clear from my test results:
red light is on and green is flashing

Re: RPI 4 USB-C supply

Posted: Wed Sep 11, 2019 3:19 pm
by jamesh
brasta78 wrote:
Wed Sep 11, 2019 3:12 pm
that board is alive with non branded power supply it was clear from my test results:
red light is on and green is flashing
At that stage it's not possible to tell if the supply is supplying enough power though. The firmware need to be loaded to get any reports, and I suspect at that point its wasn't.

Re: RPI 4 USB-C supply

Posted: Wed Sep 11, 2019 3:28 pm
by brasta78
jamesh wrote:
Wed Sep 11, 2019 3:19 pm
At that stage it's not possible to tell if the supply is supplying enough power though. The firmware need to be loaded to get any reports, and I suspect at that point its wasn't.
jamesh, you know that Dell AC adapter 30W more than enough;)

Re: RPI 4 USB-C supply

Posted: Wed Sep 11, 2019 5:00 pm
by Burngate
Don't, whatever you do, argue with Jamesh.
He's an engineer, he's a moderator, but more to the point, he's all-powerful

If you argue, he makes life difficult for the rest of us

Re: RPI 4 USB-C supply

Posted: Wed Sep 11, 2019 5:57 pm
by davidcoton
Burngate wrote:
Wed Sep 11, 2019 5:00 pm
Jamesh... he's all-powerful
Is "all-powerful" more than 30W? :lol:

Re: RPI 4 USB-C supply

Posted: Wed Sep 11, 2019 5:59 pm
by HawaiianPi
brasta78 wrote:
Wed Sep 11, 2019 3:28 pm
jamesh, you know that Dell AC adapter 30W more than enough;)
Actually, no, we don't. Battery chargers may not have the precise voltage regulation needed to run a Pi computer. In fact, some battery charging algorithms require voltage variation (constant current charging), while Pi computers need a stable 5V over varying loads. So while a charger may also act as a power supply for a battery powered device, it's not not necessarily up to the task of powering a computer directly.

Re: RPI 4 USB-C supply

Posted: Wed Sep 11, 2019 7:56 pm
by jamesh
brasta78 wrote:
Wed Sep 11, 2019 3:28 pm
jamesh wrote:
Wed Sep 11, 2019 3:19 pm
At that stage it's not possible to tell if the supply is supplying enough power though. The firmware need to be loaded to get any reports, and I suspect at that point its wasn't.
jamesh, you know that Dell AC adapter 30W more than enough;)
If that is indeed what it will supply, but that requires negotiation with the board, which is not supported on the Pi.

Not only that, but when I tried a Dell USB-C power supply from my dock, it didn't work at all...

I'm not all powerful, that's Liz.

Re: RPI 4 USB-C supply

Posted: Wed Sep 11, 2019 8:21 pm
by wildfire
jamesh wrote:
Wed Sep 11, 2019 7:56 pm
I'm not all powerful, that's Liz.
:lol: :lol: :lol: :lol: :lol:

James, Eben may be having a word with you tomorrow.

Re: RPI 4 USB-C supply

Posted: Wed Sep 11, 2019 8:28 pm
by jamesh
wildfire wrote:
Wed Sep 11, 2019 8:21 pm
jamesh wrote:
Wed Sep 11, 2019 7:56 pm
I'm not all powerful, that's Liz.
:lol: :lol: :lol: :lol: :lol:

James, Eben may be having a word with you tomorrow.
Only if Liz tells him to.

Re: RPI 4 USB-C supply

Posted: Wed Sep 11, 2019 8:54 pm
by W. H. Heydt
jamesh wrote:
Wed Sep 11, 2019 8:28 pm
wildfire wrote:
Wed Sep 11, 2019 8:21 pm
jamesh wrote:
Wed Sep 11, 2019 7:56 pm
I'm not all powerful, that's Liz.
:lol: :lol: :lol: :lol: :lol:

James, Eben may be having a word with you tomorrow.
Only if Liz tells him to.
I wouldn't wish to get in an argument with either of them. Or with you, for that matter.

Re: RPI 4 USB-C supply

Posted: Wed Sep 11, 2019 9:41 pm
by wildfire
jamesh wrote:
Wed Sep 11, 2019 8:28 pm
Only if Liz tells him to.
:D

Anyway, back on topic...

I don't understand why some people use 3rd party chargers when RPF/RPT (always get them mixed up) provide reasonably cheap power supplies which do as it says on the tin and are supported. I've, hold on... 6 Pi's running here (2 0w's 2 3B+'s & 2 4B4's) all using official PSU's and the only time I've seen the lightning bolt over the last few years was booting from an SSD on a 3B+. A powered USB HUB solved that.

When buying a POWER SUPPLY UNIT for the Raspberry Pi, if it's not official then caveat emptor.

Re: RPI 4 USB-C supply

Posted: Thu Sep 12, 2019 1:39 am
by jcyr
wildfire wrote:
Wed Sep 11, 2019 9:41 pm
jamesh wrote:
Wed Sep 11, 2019 8:28 pm
Only if Liz tells him to.
:D

Anyway, back on topic...

I don't understand why some people use 3rd party chargers when RPF/RPT (always get them mixed up) provide reasonably cheap power supplies which do as it says on the tin and are supported. I've, hold on... 6 Pi's running here (2 0w's 2 3B+'s & 2 4B4's) all using official PSU's and the only time I've seen the lightning bolt over the last few years was booting from an SSD on a 3B+. A powered USB HUB solved that.

When buying a POWER SUPPLY UNIT for the Raspberry Pi, if it's not official then caveat emptor.
Actually the whole point of rigorous standards, such as USB, USB 2.0, USB 3.0, and USB C, is to provide interoperability between vendors. A good thing, no?

Why wouldn't I buy a RFP/RPT power supply for each Pi? Because I've already got plenty of 5V supplies sitting around doing nothing. Many of them, specially the cheaper ones, work fine with the Pi.

Re: RPI 4 USB-C supply

Posted: Thu Sep 12, 2019 5:13 am
by brasta78
wildfire wrote:
Wed Sep 11, 2019 9:41 pm

Anyway, back on topic...

I don't understand why some people use 3rd party chargers when RPF/RPT (always get them mixed up) provide reasonably cheap power supplies which do as it says on the tin and are supported. I've, hold on... 6 Pi's running here (2 0w's 2 3B+'s & 2 4B4's) all using official PSU's and the only time I've seen the lightning bolt over the last few years was booting from an SSD on a 3B+. A powered USB HUB solved that.

When buying a POWER SUPPLY UNIT for the Raspberry Pi, if it's not official then caveat emptor.
same thing i wanted to reply as @jcyr - I've already have 2 USB-C AC adapters and my last thought - stop polluting and save the world :!:

Re: RPI 4 USB-C supply

Posted: Thu Sep 12, 2019 6:29 am
by wildfire
@jcyr @brasta78

As I emphasized in my post, a charger is not the same as a power supply unit, they may look the same and in many cases a charger can replace a PSU but, one has regulated voltage when under load the other does not.

Re: RPI 4 USB-C supply

Posted: Thu Sep 12, 2019 6:54 am
by MisterEd
wildfire wrote:
Wed Sep 11, 2019 9:41 pm
I don't understand why some people use 3rd party chargers when RPF/RPT (always get them mixed up) provide reasonably cheap power supplies which do as it says on the tin and are supported. I've, hold on... 6 Pi's running here (2 0w's 2 3B+'s & 2 4B4's) all using official PSU's and the only time I've seen the lightning bolt over the last few years was booting from an SSD on a 3B+. A powered USB HUB solved that.

When buying a POWER SUPPLY UNIT for the Raspberry Pi, if it's not official then caveat emptor.
Some of the official retailers that sell Pis also sell there own power supplies. For example I have the following:
* CanaKit Raspberry Pi 3 Power Supply (Micro USB) - 2.5A
* CanaKit Raspberry Pi 4 Power Supply (USB-C) - 3.0A
Shouldn't these power supplies also be considered just as safe as buying an official power supply? Can't I assume that these power supplies meet technical requirements RPF has established?