LTolledo
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Re: Powering my RPi projects using buck converters

Sat Mar 07, 2020 6:33 am

buck coverter top board v3.0 finished and now testing:
on RPi3A+
buck converter top board v3.0 testing on RPi3Ap.jpg
buck converter top board v3.0 testing on RPi3Ap.jpg (192.9 KiB) Viewed 1463 times

and on the "newly discounted" RPi4B-2G (the one I won the argument with the finance manager) ;)
buck converter top board v3.0 testing on RPi4B-2G.jpg
buck converter top board v3.0 testing on RPi4B-2G.jpg (180.78 KiB) Viewed 1463 times

47uf chip aluminum electrolytic capacitor added (seen beside the fan).
no USB HDD were plugged during the test... but I doubt it will change things if I did.
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pi-anazazi
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Re: Powering my RPi projects using buck converters

Sat Mar 07, 2020 11:04 am

Thanks for clarification! Looks nice!

Just for the record: I used the 12V/4.17A with the white cables (photo 3 posts above) to power an old raspi 2 with 2 old 2.5" HDDs (!, not SSDs this time), without getting undervoltage warnings.

Although the max USB-current was elevated, I got some problems with starting both HDDs on first boot, but a reboot brought both of them online without errors in dmesg. So this power supply should be good for my remote NAS with 2 SSDs... :-D
Kind regards

anazazi

Zwartoog
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Re: Powering my RPi projects using buck converters

Sun Mar 08, 2020 5:38 pm

karrika wrote:
Fri Mar 06, 2020 11:37 am
These buck converters look very familiar.

There is one problem in using them. They create a lot of high frequency noise on the 5V power line. I have never been able to use these converter with the 7" official touch screen. The display image looks ok. But the touch screen part refuses to work. Adding extra filtering after the converter does not help either.

I have tried these with multiple Pi's and multiple 7" Official screens.

In any case I rather use the official PSU as it produces clean power.
Do you have an idea if this is inherent to buck-converters, or due to the small size of the components on these boards? When I build a buck-converter from bare components, each component is much larger than on those boards. Only the coil is already near the size of such all-in-one boards. Just wondering what impact the size of the components have on the HF noise.

My plan for now is to use a buck converter for the large voltage drop, followed by a low dropout linear regulator for a smooth supply voltage.

LTolledo
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Re: Powering my RPi projects using buck converters

Mon Mar 09, 2020 12:11 pm

getting an LDO Linear Regulator with a current rating of over 2.5A for powering an RPi is very hard....

I did tried once to power my RPi3B using an old school design PSU with linear regulators, and large capacitors..... you wouldn't like the size of the heatsink it needs.....
...and I was supplying 9v, to drop it to 5.05v....... and still getting the lightning icon on the RPi3B with Jessie Pixel Desktop

the setup was bulky....generates lots heat (good for the winter days though).... and quite frankly..... impractical....... thus abandoned
I still have the with me......just on storage....

still want to do the LDO way?
lets see what you can do....
"Don't come to me with 'issues' for I don't know how to deal with those
Come to me with 'problems' and I'll help you find solutions"

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LTolledo
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Re: Powering my RPi projects using buck converters

Sat Jun 13, 2020 12:27 pm

updating my lineup of buck converter top boards:
RPi buck power module v5.0.jpg
RPi buck power module v5.0.jpg (161.05 KiB) Viewed 1262 times
RPi buck power module v5.0 view2.jpg
RPi buck power module v5.0 view2.jpg (190.36 KiB) Viewed 1262 times
"Don't come to me with 'issues' for I don't know how to deal with those
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hary
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Re: Powering my RPi projects using buck converters

Sun Jul 19, 2020 8:15 am

Hi there.

I've been using some of these LM2596 buck converter to successfully power a lot of my offgrid appliances.
But concerning a RPi3 and RPi4, I have been facing quite some problem like unexplained random reboot, corrupted SD card.
Recently, it's been terrible as it seemed to be so inconsistent but finally completely impossible to boot up the pi.
I was using an USB C cable to power the Pi4.
On the Pi4, I've never seen the "low power signal" on the screen, neither dmesg displayed any warning about power.
But reading all the post here, I decided to replace the LM2596 buck converter with a spare one with 5.1V output voltage with short wires directly soldered on TP1 and TP7 as said in one of the previous post.

And .... since then, everything seems to have come back god to normal !
Defective LM2596 or too long USB C cable ? I'd need to investigate more on that.
But it's very strange as it's been workig ok for several month with that USB C cable.

Running a Pi3, I had also some problem and finally ended up with a "directly soldered wire fashion" on the Pi, but at that time, it was easy to diagnose a weak power supply as the lighting icon was showing up quite often in the right upper corner as the warning in the dmesg output.

I wonder if this can also be related to another problem I had : On HDMI, the screen was sometime blue, then back to normal, sometimes completely loosing HDMI signal needing a "sudo reboot" from ssh, sometime a hard reboot as no ssh command was even possible.

Hope this can help.

LTolledo
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Re: Powering my RPi projects using buck converters

Sun Jul 19, 2020 1:18 pm

Hi there hary!

glad you have your buck converter powering problem sorted out.
all of my RPi desktops and NAS are now powered using buck converters (12v source), most of the configurations as shown within this topic.
even the "lowly" MP1584EN based buck converters are capable of powering the RPi4B-4B (this desktop am using now)

regarding the HDMI trouble you have,
better make a different topic for that.
"Don't come to me with 'issues' for I don't know how to deal with those
Come to me with 'problems' and I'll help you find solutions"

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hary
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Re: Powering my RPi projects using buck converters

Sun Jul 19, 2020 2:58 pm

LTolledo wrote:
I mentioned the blue HDMI
screen because it seemed to have also disappeared since the swap and wire soldered instead of the USB C cable !

Again, the strange point is that I never noticed the "low voltage icon" nor any warning in the dmesg output when facing these problem.

One guy on this thread said the LM2596 was possibly failling after a while ! Didn't you face any such problem ? Never, never, never ?

I might give a try with the mp1584en as it is smaller than the LM2596 based model !

drgeoff
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Re: Powering my RPi projects using buck converters

Sun Jul 19, 2020 4:34 pm

It is well known that SMD electrolytics like those in the buck converter boards in LTolledo's photos are extremely prone to failure. Loss of capacitance and increased ESR. They are not suitable for the level of ripple current encountered in switch mode converters delivering the current that RPis require. Expect problems sooner or later with such modules.
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hary
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Re: Powering my RPi projects using buck converters

Sun Jul 19, 2020 8:51 pm

drgeoff wrote:
Sun Jul 19, 2020 4:34 pm
It is well known that SMD electrolytics like those in the buck converter boards in LTolledo's photos are extremely prone to failure. Loss of capacitance and increased ESR. They are not suitable for the level of ripple current encountered in switch mode converters delivering the current that RPis require. Expect problems sooner or later with such modules.
Good to know.
But LTolledo didn't seem to face such problem anytime !
As these small buck converter are very usefull, can we fix them by replacing the failling capacitor with a proper one ?
If yes, which one should we choose ?

LTolledo
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Re: Powering my RPi projects using buck converters

Sun Jul 19, 2020 9:34 pm

after over a year of use of the buck converters (both types), am still to experience any trouble....
maybe after 5 years.... who knows..... :D

my DAC-Amp is also powering my RPi4B-8G thru its built in buck converter....with SMD capacitors
drgeoff wrote: It is well known that SMD electrolytics like those in the buck converter boards.....

can you provide links to substantiate this "claim", specifically about SMD electrolytics....
hary wrote: can we fix them by replacing the failling capacitor with a proper one ?
If yes, which one should we choose ?
if it does happen, I can replace those with standard (non SMD) Rubicon 105 types.
"Don't come to me with 'issues' for I don't know how to deal with those
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drgeoff
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Re: Powering my RPi projects using buck converters

Sun Jul 19, 2020 10:48 pm

I can't point to any definitive sources but ask anyone who routinely repairs by fault finding to component level on equipment using SMD electrolytics.

Regarding ripple current, see http://www.farnell.com/datasheets/1676921.pdf for a reputable brand (Panasonic) of SMD electrolytics. Note that these are specifically touted as "low impedance". Page 3 gives the ripple current for the 100uF 50 volt item as 350mA and the 220uF 35 volt item as 600mA. Those doesn't stack up well against the couple of Amps that a RPi3B or 4B can be drawing.
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emma1997
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Re: Powering my RPi projects using buck converters

Mon Jul 20, 2020 7:28 pm

hary wrote:
Sun Jul 19, 2020 8:51 pm
drgeoff wrote:
Sun Jul 19, 2020 4:34 pm
It is well known that SMD electrolytics like those in the buck converter boards in LTolledo's photos are extremely prone to failure. Loss of capacitance and increased ESR.
But LTolledo didn't seem to face such problem anytime !
As these small buck converter are very usefull, can we fix them by replacing the failling capacitor with a proper one ? If yes, which one should we choose ?
Out of several dozen LM2596 type like LTolledo's used personally and many more used by others about 10% failed with Pi3 and Pi4. In a few cases they just didn't seem to provide enough current but in others it was that cap falling or knocked off. Less than 1% fail with XL4015 type for only a few pennies more.

Replacing the missing LM2596 caps with cheapest chinese non-SMD junk fixed it in every case (see pic). I'm not convinced ESR etc is an issue here. Swapping with expensive low impedance versions on the ones with poor current had little effect. More MFDs better but still limited long term benefit.

For commercial designs from scratch I do take care to use proper parts but can't say it really matters in most cases. Inductor size, ground pour, placement, and capacity struck me as more relevant.

PS make sure to glue it down with a touch of 5min epoxy or else...
Attachments
lm2596_new_cap.JPG
lm2596_new_cap.JPG (65.05 KiB) Viewed 895 times

H34dl3ss
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Re: Powering my RPi projects using buck converters

Wed Aug 05, 2020 1:52 pm

Hi,
nice collection of buck converters!
A bit more information regarding types and specs would have been nice if somebody is on a shopping tour. :)
Anyway, I'm thinking of using some of those XL4015 for some of my berries.
Should be no problem for the ones without audiophonic purpose.
For audio purposes I would think that the 180 kHz switching frequency could be an issue.
The distortion on displays is also nasty.

I wonder why there is no PCB with the TPS62133 chip available yet. :?
It has a max switching frequency of 2,5 MHz. Along with the downstream cap it should have almost no noticeable ripple
on the output line. 8-)

LTolledo
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Re: Powering my RPi projects using buck converters

Wed Aug 05, 2020 10:25 pm

the buck converters show in my post are based on

LM2956, the larger modules with blue colored PCBs
MP1584EN, the smaller modules in green colored PCBs.

my Suptronicx X400 v3 DAC-Amp is supplying power to itself and the RPi board using
TI5430 based Wide Input Range, Step-Down Converter, at fixed frequency of 500kHz
https://www.ti.com/lit/ds/symlink/tps54 ... e.com%252F

no problem with the audio quality

also have the XL4015 modules, no plans to deploy it yet.

this RPi4B-4G desktop is being powered by the MP1584EN module:
RPi4B-4G desktop buck power module view1.jpg
RPi4B-4G desktop buck power module view1.jpg (174.55 KiB) Viewed 757 times
"Don't come to me with 'issues' for I don't know how to deal with those
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sora03
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Re: Powering my RPi projects using buck converters

Sun Aug 09, 2020 4:12 am

I am currently powering my RPi 3B+ with a XL4015 set to output 5.25V. I also used the official microUSB cable that I cut from the Official PSU of RPi. I don't want to power it via GPIO pins. Before this XL4015, I tried MP1584 but has issue with cooling them. My room temp is always around 35 deg C. I've never had any problems with XL4015, no undervoltage warnings. I added a large capacitor to the output of the XL4015 it is a 6800 uF electrolytic capacitor. I have not tested whether this causes interference to the audio output of the Pi, as I use it headless and rpitx seems to cause problems to audio because I am using it to send pages to my motorola pager.
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Pi.JPG
XL4015 buck powering Pi 3B+
Pi.JPG (119.15 KiB) Viewed 707 times
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LTolledo
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Re: Powering my RPi projects using buck converters

Sun Aug 09, 2020 10:29 pm

hmmm.... a XL4015 powering a headless RPi4 seems a "little bit overboard" for me... ;)
but if you're happy with it then its OK. :D

I've run this MP1584EN powered RPi4B-2G desktop setup for several hours at an ambient of 32C....
RP4B-2G 2xHDD in USB3 at boot.jpg
RP4B-2G 2xHDD in USB3 at boot.jpg (233.94 KiB) Viewed 669 times
MP1584EN's output voltage set at 5.12v
under-voltage alarms not triggered on the RPi4B-2G, even while accessing media data on 1TB HDD (the bottom one, not the WD), and playing that media on windowed VLC....

not clealy seen on the image are the heatsinks on the MP1584EN module
a heatsink on the MP1584EN chip
and a heatsink on the inductor...
"Don't come to me with 'issues' for I don't know how to deal with those
Come to me with 'problems' and I'll help you find solutions"

Some people be like:
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moriartynz
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Re: Powering my RPi projects using buck converters

Mon Aug 10, 2020 9:53 am

My experience with buck converters is that they are generally ok, but cheaper ones have a lot of ripple. This causes headaches with my overclocked rpi4B machines as they require a rock-solid steady Vin with minimal ripple or they become unstable.

One of my older rpi4B machines was heavily cooked in the early days before the more recent cool-running firmware and I have to actually underclock it when using a noisy buck converter for it to function stably.

It has been some months now since doing readings, but I vaguely recall that the overclocked rpi4s became unstable with a ripple voltage of 160mV (pk-pk) as per oscilloscope reading on the GPIO 5V and ground pins (same pins power was supplied on).

sora03
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Re: Powering my RPi projects using buck converters

Thu Aug 27, 2020 2:01 am

@LTolledo, what power supplies do you use when using those buck converters? Are they all 12V? I currently use laptop chargers as power supply and did not have problems with them, they are powered on 24/7. (19V -> buck converter -> 5.2V)
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LTolledo
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Re: Powering my RPi projects using buck converters

Thu Aug 27, 2020 8:49 am

@sora03
am using 12v wall adapters left over from my Orico 3.5" HDD case adapter, the board of which were used in my NAS projects
viewtopic.php?f=29&t=244224&p=1541272#p1541272
from that 2 projects I gained 4 units of 12v 2A adapters....

Also have 2 x 19.6V laptop adapters, from my dead laptops, but have not tried it yet on my buck converters.... :D
"Don't come to me with 'issues' for I don't know how to deal with those
Come to me with 'problems' and I'll help you find solutions"

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hary
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Re: Powering my RPi projects using buck converters

Thu Sep 03, 2020 6:53 pm

Reading this thread, I've ordered 10 MP1584EN buck converter for different project including RPi4.

It seems to work ok with the RP64 as desktop, but they hardly handle more than 1.5-1.6A max instead of the 3A advertised !

At more amp than 1.6A, I think they become too hot and the security comes into action !

Plus adjusting the right voltage output is quite of a chalenge with the kind of potentiometer they have !

msl
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Re: Powering my RPi projects using buck converters

Thu Sep 03, 2020 7:45 pm

hary wrote:
Thu Sep 03, 2020 6:53 pm
Reading this thread, I've ordered 10 MP1584EN buck converter for different project including RPi4.

It seems to work ok with the RP64 as desktop, but they hardly handle more than 1.5-1.6A max instead of the 3A advertised !

At more amp than 1.6A, I think they become too hot and the security comes into action !

Plus adjusting the right voltage output is quite of a chalenge with the kind of potentiometer they have !
At 10pcs, why don’t you make your own PCB layout and order it assembled?

hary
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Re: Powering my RPi projects using buck converters

Thu Sep 03, 2020 7:58 pm

What would be the point ?

I'm not PCB designer and have no ability in that derection.

Plus, if you look at thet MP1584 datasheet, you must care a lot about the PCB design !

msl
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Re: Powering my RPi projects using buck converters

Thu Sep 03, 2020 8:52 pm

hary wrote:
Thu Sep 03, 2020 7:58 pm
What would be the point ?

I'm not PCB designer and have no ability in that derection.

Plus, if you look at thet MP1584 datasheet, you must care a lot about the PCB design !
Sorry, was reading this thread on the go and thought it’s topic starter getting more and more converters instead of building own custom. Just wondering how much additional effort spent to fit those in place.

LTolledo
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Re: Powering my RPi projects using buck converters

Thu Sep 03, 2020 9:02 pm

hary wrote:
Thu Sep 03, 2020 6:53 pm
It seems to work ok with the RP64 as desktop....
RP64? RockPi64?

it works on this RPi4B-4G desktop (the one am using to write this post)
and I've plugged a 2.5" seagate 2TB HDD (rated 1A) to this desktop, without any ill effects.
as in the image several post above, I've even loaded a RPi4B-2G with 2 units of bus powered 2.5" HDDs
hary wrote: I think they become too hot....
I know it will become hot as current draw increases.... thus the heatsink on the chip and on the inductor.
heatsink installed using thermal glue, not double sided thermal tape.
just touched this RPi4B-4G desktop's MP1584EN's heatsink, doesnt even feel like its getting 35C on an ambient of 26C
I tried using body thermometer, the sensor touching the MP1584EN's heatsink, but reading stays at "L".
hary wrote: Plus adjusting the right voltage output is quite of a challenge with the kind of potentiometer they have
it is quite a challenge, requires precise movement from my shaky hands :mrgreen:
even the LM2956 buck converter module's potentiometer are a challenge as well...
winning the challenge is quite rewarding! :D
"Don't come to me with 'issues' for I don't know how to deal with those
Come to me with 'problems' and I'll help you find solutions"

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