Re: [time-nuts] For those that insist on using switching power supplies

[Florian Teply]

Am Thu, 13 Oct 2016 17:57:02 -0500
schrieb "Graham / KE9H" :

> Actually, if they have the "CE" stamp on the product, then they have
> very specific radio interference limits that they must test and meet.
> It must have been tested, certified, and the certification package
> available for inspection.
> 
Umm, I guess most of us wish it was actually like that. Strictly
speaking, the CE sign legally is no more than a statement by the
manufacturer that he believes this very product conforms to the
applicable rules ans regulations. This does not imply any testing by
itself. It's more of an self assessment, which could also be based on
gut feeling and customer requirements ("must have CE sign").

Testing is not required to carry the CE mark. Yes, of course, the CE
mark implies that the product meets various requirements, out of which
some can only be guaranteed through testing, but this is often
overlooked.

> Whether they actually met it, then pulled the interference supression
> parts off the board as a "cost reduction" as is common in no-name
> computer power supplies, or whether it never met it to begin with, is
> for you to speculate.  Some suppliers will explain to you that "CE"
> means China Export, not that it meets the consolidated European
> safety and electrical rules.

The more honest scumbags will just claim this very device was not
intended to be sold outside of China and they don't have the logistics
to produce enclosures with different labeling.

How much of this is considered close to truth depends on those who do
consider. As long as all those smallish shops in Shenzhen are not
faced by prosecution, this won't change, and China does not seem keen
on changing this.

Best regards,
Florian
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Re: [time-nuts] For those that insist on using switching power supplies

[Adrian Godwin]

I would add a DC blocker for the input to the spectrum analyser.


On Fri, Oct 14, 2016 at 7:59 PM, Hal Murray  wrote:

>
> time-nuts@febo.com said:
> >> Nick, thanks for your detailed reply.  Would you happen to have a photo
> of
> >> the "spring looking things?"  I am not entirely sure I have one of those
> >> included with the kit that came with the scope.
>
> > I don’t have a picture, but the Internet does: http://i.stack.imgur.com/
> > PSo3N.jpg
>
> The other tool to add to your collection is coax and a soldering iron.  I
> make them in pairs by starting with a BNC-BNC jumper and cutting it in
> half.
> The thin (high-loss) coax is easier to work with and the loss over a few
> feet
> probably won't be a big deal.
>
> --
> These are my opinions.  I hate spam.
>
>
>
>
> ___
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> To unsubscribe, go to https://www.febo.com/cgi-bin/
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Re: [time-nuts] For those that insist on using switching power supplies

[Scott Stobbe]

A basic DSO has maybe 300 uVrms noise over 100 MHz bandwidth, which is a
spectral noise floor of 30 nV/rtHz (assuming a brick-wall filter), if your
DUT is quieter than that you can always add an LNA.

On Fri, Oct 14, 2016 at 2:59 PM, Chris Albertson 
wrote:

> On Fri, Oct 14, 2016 at 11:00 AM, Cube Central 
> wrote:
> > How would one go about testing power supplies and seeing how noisy they
> are?  I have the standard suite of tools, an oscilloscope and a little
> (dangerous) know-how.  I am just not sure what to look for or how to safely
> hook it up to test.
> >
>
> You'd ned a spectrum analyser.You could assemble one from parts
> that are used for Software Radios.   A USB TV tunnel dongle and a
> computer and a good mixer and clean oscillator.   With hat you'd be
> able to characterize noise from DC to about 900MHz
>
> Those with more money than time would just spend the bucks to buy an SA
>
> Those who don't need numbers would just look at the DC on a scope and
> "eye ball it" and say "wow that is noisy" or "wow that looks clean"
>
> In all cases you'd want to put a realistic load on the power supply.
>  But what is that? I bet if varies a lot.
>
> And like I wrote before it may not even matter as phones don't
> directly use the 5 volt DC that these chargers produce.
> --
>
> Chris Albertson
> Redondo Beach, California
> ___
> time-nuts mailing list -- time-nuts@febo.com
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Re: [time-nuts] For those that insist on using switching power supplies

[Hal Murray]

time-nuts@febo.com said:
>> Nick, thanks for your detailed reply.  Would you happen to have a photo of
>> the "spring looking things?"  I am not entirely sure I have one of those
>> included with the kit that came with the scope.

> I don’t have a picture, but the Internet does: http://i.stack.imgur.com/
> PSo3N.jpg 

The other tool to add to your collection is coax and a soldering iron.  I 
make them in pairs by starting with a BNC-BNC jumper and cutting it in half.  
The thin (high-loss) coax is easier to work with and the loss over a few feet 
probably won't be a big deal.

-- 
These are my opinions.  I hate spam.



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Re: [time-nuts] For those that insist on using switching power supplies

[Chris Albertson]

On Fri, Oct 14, 2016 at 11:00 AM, Cube Central  wrote:
> How would one go about testing power supplies and seeing how noisy they are?  
> I have the standard suite of tools, an oscilloscope and a little (dangerous) 
> know-how.  I am just not sure what to look for or how to safely hook it up to 
> test.
>

You'd ned a spectrum analyser.You could assemble one from parts
that are used for Software Radios.   A USB TV tunnel dongle and a
computer and a good mixer and clean oscillator.   With hat you'd be
able to characterize noise from DC to about 900MHz

Those with more money than time would just spend the bucks to buy an SA

Those who don't need numbers would just look at the DC on a scope and
"eye ball it" and say "wow that is noisy" or "wow that looks clean"

In all cases you'd want to put a realistic load on the power supply.
 But what is that? I bet if varies a lot.

And like I wrote before it may not even matter as phones don't
directly use the 5 volt DC that these chargers produce.
-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] For those that insist on using switching power supplies

[Nick Sayer via time-nuts]

> On Oct 14, 2016, at 11:34 AM, Cube Central  wrote:
> 
> Nick, thanks for your detailed reply.  Would you happen to have a photo of 
> the "spring looking things?"  I am not entirely sure I have one of those 
> included with the kit that came with the scope.

I don’t have a picture, but the Internet does: 
http://i.stack.imgur.com/PSo3N.jpg

> What size of capacitor would you suggest?

Well, I use mostly 0805 MLCCs on my boards, not counting the occasional polymer 
or electrolytic.

> I happen to have the exact same dummy load that you do.  I have added on a 
> fan for higher current/longer use.
> 
> Thanks for the help, I look forward to trying out some of the measurements 
> that I've seen posted elsewhere ( such as this link: 
> http://www.righto.com/2012/10/a-dozen-usb-chargers-in-lab-apple-is.html ) 
> 
> Cheers!
> 
>   -Randal R.
>   (at CubeCentral)
> 
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Nick Sayer 
> via time-nuts
> Sent: Friday, 14 October, 2016 12:17
> To: Discussion of precise time and frequency measurement 
> Subject: Re: [time-nuts] For those that insist on using switching power 
> supplies
> 
> Set your scope for AC coupling. Set your scope probe for 1x rather than 10x. 
> Use the absolutely shortest scope grounding you can. That’s what those spring 
> looking things that came with it are for. I typically use the spring gizmo 
> and probe on an SMD cap. The ground wire with an alligator clip will just 
> pick up far more noise than you’ll be measuring. This is how I was able to 
> measure the noise and ripple of the SC189Z switcher feeding the OCXO in my 
> GPSDO. I got measurements of ~4 mV P-P that way. Be careful you don’t get the 
> probe and ground reversed - your scope won’t likely have an isolated ground 
> from your DUT and that would therefore be bad.
> 
> You’re going to want to check the supply’s performance under load. For that, 
> you’ll may want to get yourself a dummy load. I got one from Tindie for 
> testing my Pi Power design: 
> https://www.tindie.com/products/arachnidlabs/reload-2/
> 
> 
> 
>> On Oct 14, 2016, at 11:00 AM, Cube Central  wrote:
>> 
>> How would one go about testing power supplies and seeing how noisy they are? 
>>  I have the standard suite of tools, an oscilloscope and a little 
>> (dangerous) know-how.  I am just not sure what to look for or how to safely 
>> hook it up to test.
>> 
>> Thanks in advance for any tips!  
>> 
>>  -Randal R.
>>  (at CubeCentral)
>> 
>> -Original Message-
>> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Chris 
>> Albertson
>> Sent: Friday, 14 October, 2016 02:29
>> To: Discussion of precise time and frequency measurement 
>> 
>> Subject: Re: [time-nuts] For those that insist on using switching 
>> power supplies
>> 
>> On Thu, Oct 13, 2016 at 6:05 AM, Van Horn, David 
>>  wrote:
>>> To be fair here, phone chargers have almost no requirement to be quiet 
>>> other than conducted and radiated emissions limits.
>>> It's charging a battery.
>> 
>> Not only that but,  the 5 volts comping out of the larger is almost 
>> certainly the input to another DC/DC power supply and NOT used directly.
>> You can't charge a Lithium battery with the 5 volts the charger outputs.
>> 
>> If you don't know about LiPo batteries, they need a constant current power 
>> source and then as they get close to charged the charger switches to 
>> constant voltage (VERY roughly) at about 4V per cell.
>> 
>> I have a project right here on my desk as I type.  I'm using the output of a 
>> generic USB hub.  The circuit is  a cap from 5V to GND and
>> then a low dropout regulator to get 3.3 volts.I don't care to much
>> if there is huge ripple on the 5.0 volts coming in as long as it stays above 
>> the LDO limit.
>> 
>> Also it looks like they tested the USB chargers with no load.  A typical 
>> load might have a say, 0.01uf cap to short the noise to ground.  So in use 
>> the power might be better?
>> 
>> It was no surprise the counterfeit chargers were horrible.  The 
>> manufacturers are by definition of "counterfeit" being dishonest slim balls. 
>> Why would he care about anything other then that he can fool
>> some people into buying his product.   There are third party chargers
>> that are not trying to copy a well known brand, these are usually much 
>> better
>> 
>> 
>> --
>> 
>> Chris Albertson
>> Redondo Beach, California
>> ___
>> time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to 
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>> 
>> ___
>> time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to 
>> 

Re: [time-nuts] For those that insist on using switching power supplies

[Scott Stobbe]

It is also wise to measure the noise floor of the test setup as fully
connected as possible. For one of those usb charger cubes, you can use a
power bar with a power switch (which will only switch the hot line on/off,
earth and neutral are permanently connected, one would hope). You will see
a lot of other noise sources before you even power up your DUT.

On Fri, Oct 14, 2016 at 2:16 PM, Nick Sayer via time-nuts <
time-nuts@febo.com> wrote:

> Set your scope for AC coupling. Set your scope probe for 1x rather than
> 10x. Use the absolutely shortest scope grounding you can. That’s what those
> spring looking things that came with it are for. I typically use the spring
> gizmo and probe on an SMD cap. The ground wire with an alligator clip will
> just pick up far more noise than you’ll be measuring. This is how I was
> able to measure the noise and ripple of the SC189Z switcher feeding the
> OCXO in my GPSDO. I got measurements of ~4 mV P-P that way. Be careful you
> don’t get the probe and ground reversed - your scope won’t likely have an
> isolated ground from your DUT and that would therefore be bad.
>
> You’re going to want to check the supply’s performance under load. For
> that, you’ll may want to get yourself a dummy load. I got one from Tindie
> for testing my Pi Power design: https://www.tindie.com/
> products/arachnidlabs/reload-2/
>
>
>
> > On Oct 14, 2016, at 11:00 AM, Cube Central 
> wrote:
> >
> > How would one go about testing power supplies and seeing how noisy they
> are?  I have the standard suite of tools, an oscilloscope and a little
> (dangerous) know-how.  I am just not sure what to look for or how to safely
> hook it up to test.
> >
> > Thanks in advance for any tips!
> >
> >   -Randal R.
> >   (at CubeCentral)
> >
> > -Original Message-
> > From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Chris
> Albertson
> > Sent: Friday, 14 October, 2016 02:29
> > To: Discussion of precise time and frequency measurement <
> time-nuts@febo.com>
> > Subject: Re: [time-nuts] For those that insist on using switching power
> supplies
> >
> > On Thu, Oct 13, 2016 at 6:05 AM, Van Horn, David  backcountryaccess.com> wrote:
> >> To be fair here, phone chargers have almost no requirement to be quiet
> other than conducted and radiated emissions limits.
> >> It's charging a battery.
> >
> > Not only that but,  the 5 volts comping out of the larger is almost
> certainly the input to another DC/DC power supply and NOT used directly.
> > You can't charge a Lithium battery with the 5 volts the charger outputs.
> >
> > If you don't know about LiPo batteries, they need a constant current
> power source and then as they get close to charged the charger switches to
> constant voltage (VERY roughly) at about 4V per cell.
> >
> > I have a project right here on my desk as I type.  I'm using the output
> of a generic USB hub.  The circuit is  a cap from 5V to GND and
> > then a low dropout regulator to get 3.3 volts.I don't care to much
> > if there is huge ripple on the 5.0 volts coming in as long as it stays
> above the LDO limit.
> >
> > Also it looks like they tested the USB chargers with no load.  A typical
> load might have a say, 0.01uf cap to short the noise to ground.  So in use
> the power might be better?
> >
> > It was no surprise the counterfeit chargers were horrible.  The
> manufacturers are by definition of "counterfeit" being dishonest slim
> balls. Why would he care about anything other then that he can fool
> > some people into buying his product.   There are third party chargers
> > that are not trying to copy a well known brand, these are usually much
> better
> >
> >
> > --
> >
> > Chris Albertson
> > Redondo Beach, California
> > ___
> > time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > and follow the instructions there.
> >
> > ___
> > time-nuts mailing list -- time-nuts@febo.com
> > To unsubscribe, go to https://www.febo.com/cgi-bin/
> mailman/listinfo/time-nuts
> > and follow the instructions there.
>
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> To unsubscribe, go to https://www.febo.com/cgi-bin/
> mailman/listinfo/time-nuts
> and follow the instructions there.
>
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Re: [time-nuts] For those that insist on using switching power supplies

[Cube Central]

Nick, thanks for your detailed reply.  Would you happen to have a photo of the 
"spring looking things?"  I am not entirely sure I have one of those included 
with the kit that came with the scope.
What size of capacitor would you suggest?
I happen to have the exact same dummy load that you do.  I have added on a fan 
for higher current/longer use.

Thanks for the help, I look forward to trying out some of the measurements that 
I've seen posted elsewhere ( such as this link: 
http://www.righto.com/2012/10/a-dozen-usb-chargers-in-lab-apple-is.html ) 

Cheers!

-Randal R.
(at CubeCentral)

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Nick Sayer via 
time-nuts
Sent: Friday, 14 October, 2016 12:17
To: Discussion of precise time and frequency measurement 
Subject: Re: [time-nuts] For those that insist on using switching power supplies

Set your scope for AC coupling. Set your scope probe for 1x rather than 10x. 
Use the absolutely shortest scope grounding you can. That’s what those spring 
looking things that came with it are for. I typically use the spring gizmo and 
probe on an SMD cap. The ground wire with an alligator clip will just pick up 
far more noise than you’ll be measuring. This is how I was able to measure the 
noise and ripple of the SC189Z switcher feeding the OCXO in my GPSDO. I got 
measurements of ~4 mV P-P that way. Be careful you don’t get the probe and 
ground reversed - your scope won’t likely have an isolated ground from your DUT 
and that would therefore be bad.

You’re going to want to check the supply’s performance under load. For that, 
you’ll may want to get yourself a dummy load. I got one from Tindie for testing 
my Pi Power design: https://www.tindie.com/products/arachnidlabs/reload-2/



> On Oct 14, 2016, at 11:00 AM, Cube Central  wrote:
> 
> How would one go about testing power supplies and seeing how noisy they are?  
> I have the standard suite of tools, an oscilloscope and a little (dangerous) 
> know-how.  I am just not sure what to look for or how to safely hook it up to 
> test.
> 
> Thanks in advance for any tips!  
> 
>   -Randal R.
>   (at CubeCentral)
> 
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Chris 
> Albertson
> Sent: Friday, 14 October, 2016 02:29
> To: Discussion of precise time and frequency measurement 
> 
> Subject: Re: [time-nuts] For those that insist on using switching 
> power supplies
> 
> On Thu, Oct 13, 2016 at 6:05 AM, Van Horn, David 
>  wrote:
>> To be fair here, phone chargers have almost no requirement to be quiet other 
>> than conducted and radiated emissions limits.
>> It's charging a battery.
> 
> Not only that but,  the 5 volts comping out of the larger is almost certainly 
> the input to another DC/DC power supply and NOT used directly.
> You can't charge a Lithium battery with the 5 volts the charger outputs.
> 
> If you don't know about LiPo batteries, they need a constant current power 
> source and then as they get close to charged the charger switches to constant 
> voltage (VERY roughly) at about 4V per cell.
> 
> I have a project right here on my desk as I type.  I'm using the output of a 
> generic USB hub.  The circuit is  a cap from 5V to GND and
> then a low dropout regulator to get 3.3 volts.I don't care to much
> if there is huge ripple on the 5.0 volts coming in as long as it stays above 
> the LDO limit.
> 
> Also it looks like they tested the USB chargers with no load.  A typical load 
> might have a say, 0.01uf cap to short the noise to ground.  So in use the 
> power might be better?
> 
> It was no surprise the counterfeit chargers were horrible.  The manufacturers 
> are by definition of "counterfeit" being dishonest slim balls. Why would he 
> care about anything other then that he can fool
> some people into buying his product.   There are third party chargers
> that are not trying to copy a well known brand, these are usually much 
> better
> 
> 
> --
> 
> Chris Albertson
> Redondo Beach, California
> ___
> time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 
> ___
> time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.

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Re: [time-nuts] For those that insist on using switching power supplies

[Bob Camp]

Hi

A spectrum analyzer and some sort of active load are generally the two pieces 
of gear I reach for
first when testing supplies. You need an analyzer that will cover the entire 
“range of interest” for 
the supply or possibly multiple analyzers if that turns out to be 0.1 Hz to 6 
GHz. Since noise changes
with load, whatever you do needs to be repeated at various output levels on the 
supply. 

Bob

> On Oct 14, 2016, at 2:00 PM, Cube Central  wrote:
> 
> How would one go about testing power supplies and seeing how noisy they are?  
> I have the standard suite of tools, an oscilloscope and a little (dangerous) 
> know-how.  I am just not sure what to look for or how to safely hook it up to 
> test.
> 
> Thanks in advance for any tips!  
> 
>   -Randal R.
>   (at CubeCentral)
> 
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Chris 
> Albertson
> Sent: Friday, 14 October, 2016 02:29
> To: Discussion of precise time and frequency measurement 
> Subject: Re: [time-nuts] For those that insist on using switching power 
> supplies
> 
> On Thu, Oct 13, 2016 at 6:05 AM, Van Horn, David 
>  wrote:
>> To be fair here, phone chargers have almost no requirement to be quiet other 
>> than conducted and radiated emissions limits.
>> It's charging a battery.
> 
> Not only that but,  the 5 volts comping out of the larger is almost certainly 
> the input to another DC/DC power supply and NOT used directly.
> You can't charge a Lithium battery with the 5 volts the charger outputs.
> 
> If you don't know about LiPo batteries, they need a constant current power 
> source and then as they get close to charged the charger switches to constant 
> voltage (VERY roughly) at about 4V per cell.
> 
> I have a project right here on my desk as I type.  I'm using the output of a 
> generic USB hub.  The circuit is  a cap from 5V to GND and
> then a low dropout regulator to get 3.3 volts.I don't care to much
> if there is huge ripple on the 5.0 volts coming in as long as it stays above 
> the LDO limit.
> 
> Also it looks like they tested the USB chargers with no load.  A typical load 
> might have a say, 0.01uf cap to short the noise to ground.  So in use the 
> power might be better?
> 
> It was no surprise the counterfeit chargers were horrible.  The manufacturers 
> are by definition of "counterfeit" being dishonest slim balls. Why would he 
> care about anything other then that he can fool
> some people into buying his product.   There are third party chargers
> that are not trying to copy a well known brand, these are usually much better
> 
> 
> -- 
> 
> Chris Albertson
> Redondo Beach, California
> ___
> time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 
> ___
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.

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and follow the instructions there.

Re: [time-nuts] For those that insist on using switching power supplies

[Nick Sayer via time-nuts]

Set your scope for AC coupling. Set your scope probe for 1x rather than 10x. 
Use the absolutely shortest scope grounding you can. That’s what those spring 
looking things that came with it are for. I typically use the spring gizmo and 
probe on an SMD cap. The ground wire with an alligator clip will just pick up 
far more noise than you’ll be measuring. This is how I was able to measure the 
noise and ripple of the SC189Z switcher feeding the OCXO in my GPSDO. I got 
measurements of ~4 mV P-P that way. Be careful you don’t get the probe and 
ground reversed - your scope won’t likely have an isolated ground from your DUT 
and that would therefore be bad.

You’re going to want to check the supply’s performance under load. For that, 
you’ll may want to get yourself a dummy load. I got one from Tindie for testing 
my Pi Power design: https://www.tindie.com/products/arachnidlabs/reload-2/



> On Oct 14, 2016, at 11:00 AM, Cube Central  wrote:
> 
> How would one go about testing power supplies and seeing how noisy they are?  
> I have the standard suite of tools, an oscilloscope and a little (dangerous) 
> know-how.  I am just not sure what to look for or how to safely hook it up to 
> test.
> 
> Thanks in advance for any tips!  
> 
>   -Randal R.
>   (at CubeCentral)
> 
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Chris 
> Albertson
> Sent: Friday, 14 October, 2016 02:29
> To: Discussion of precise time and frequency measurement 
> Subject: Re: [time-nuts] For those that insist on using switching power 
> supplies
> 
> On Thu, Oct 13, 2016 at 6:05 AM, Van Horn, David 
>  wrote:
>> To be fair here, phone chargers have almost no requirement to be quiet other 
>> than conducted and radiated emissions limits.
>> It's charging a battery.
> 
> Not only that but,  the 5 volts comping out of the larger is almost certainly 
> the input to another DC/DC power supply and NOT used directly.
> You can't charge a Lithium battery with the 5 volts the charger outputs.
> 
> If you don't know about LiPo batteries, they need a constant current power 
> source and then as they get close to charged the charger switches to constant 
> voltage (VERY roughly) at about 4V per cell.
> 
> I have a project right here on my desk as I type.  I'm using the output of a 
> generic USB hub.  The circuit is  a cap from 5V to GND and
> then a low dropout regulator to get 3.3 volts.I don't care to much
> if there is huge ripple on the 5.0 volts coming in as long as it stays above 
> the LDO limit.
> 
> Also it looks like they tested the USB chargers with no load.  A typical load 
> might have a say, 0.01uf cap to short the noise to ground.  So in use the 
> power might be better?
> 
> It was no surprise the counterfeit chargers were horrible.  The manufacturers 
> are by definition of "counterfeit" being dishonest slim balls. Why would he 
> care about anything other then that he can fool
> some people into buying his product.   There are third party chargers
> that are not trying to copy a well known brand, these are usually much better
> 
> 
> -- 
> 
> Chris Albertson
> Redondo Beach, California
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Re: [time-nuts] For those that insist on using switching power supplies

[Cube Central]

How would one go about testing power supplies and seeing how noisy they are?  I 
have the standard suite of tools, an oscilloscope and a little (dangerous) 
know-how.  I am just not sure what to look for or how to safely hook it up to 
test.

Thanks in advance for any tips!  

-Randal R.
(at CubeCentral)

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Chris Albertson
Sent: Friday, 14 October, 2016 02:29
To: Discussion of precise time and frequency measurement 
Subject: Re: [time-nuts] For those that insist on using switching power supplies

On Thu, Oct 13, 2016 at 6:05 AM, Van Horn, David 
 wrote:
> To be fair here, phone chargers have almost no requirement to be quiet other 
> than conducted and radiated emissions limits.
> It's charging a battery.

Not only that but,  the 5 volts comping out of the larger is almost certainly 
the input to another DC/DC power supply and NOT used directly.
You can't charge a Lithium battery with the 5 volts the charger outputs.

If you don't know about LiPo batteries, they need a constant current power 
source and then as they get close to charged the charger switches to constant 
voltage (VERY roughly) at about 4V per cell.

I have a project right here on my desk as I type.  I'm using the output of a 
generic USB hub.  The circuit is  a cap from 5V to GND and
then a low dropout regulator to get 3.3 volts.I don't care to much
if there is huge ripple on the 5.0 volts coming in as long as it stays above 
the LDO limit.

Also it looks like they tested the USB chargers with no load.  A typical load 
might have a say, 0.01uf cap to short the noise to ground.  So in use the power 
might be better?

It was no surprise the counterfeit chargers were horrible.  The manufacturers 
are by definition of "counterfeit" being dishonest slim balls. Why would he 
care about anything other then that he can fool
some people into buying his product.   There are third party chargers
that are not trying to copy a well known brand, these are usually much better


-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] For those that insist on using switching power supplies

[Chris Albertson]

On Thu, Oct 13, 2016 at 6:05 AM, Van Horn, David
 wrote:
> To be fair here, phone chargers have almost no requirement to be quiet other 
> than conducted and radiated emissions limits.
> It's charging a battery.

Not only that but,  the 5 volts comping out of the larger is almost
certainly the input to another DC/DC power supply and NOT used
directly.
You can't charge a Lithium battery with the 5 volts the charger outputs.

If you don't know about LiPo batteries, they need a constant current
power source and then as they get close to charged the charger
switches to constant voltage (VERY roughly) at about 4V per cell.

I have a project right here on my desk as I type.  I'm using the
output of a generic USB hub.  The circuit is  a cap from 5V to GND and
then a low dropout regulator to get 3.3 volts.I don't care to much
if there is huge ripple on the 5.0 volts coming in as long as it stays
above the LDO limit.

Also it looks like they tested the USB chargers with no load.  A
typical load might have a say, 0.01uf cap to short the noise to
ground.  So in use the power might be better?

It was no surprise the counterfeit chargers were horrible.  The
manufacturers are by definition of "counterfeit" being dishonest slim
balls. Why would he care about anything other then that he can fool
some people into buying his product.   There are third party chargers
that are not trying to copy a well known brand, these are usually much
better


-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] For those that insist on using switching power supplies

[Hal Murray]

> Whether they actually met it, then pulled the interference supression parts
> off the board as a "cost reduction" as is common in no-name computer power
> supplies, or whether it never met it to begin with, is for you to speculate.

I only watched the first part of the video.

I'm surprised nobody has mentioned it yet, but there are clearance 
requirements on the routing of line power signals vs ground.  The board 
looked like standard digital spacing.


>  Some suppliers will explain to you that "CE" means China 

I expect there are trademark issues.


-- 
These are my opinions.  I hate spam.



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Re: [time-nuts] For those that insist on using switching power supplies

[Scott Stobbe]

Benchtop linear power supplies also share in some deceptive marketing
regarding noise. Some have horrible 1/f noise, others are on par to a
tl431, which isn't too bad. Some will have spurious tones 10's of dB above
the Gaussian noise spectrum. Unfortunately most linear power supplies only
spec a total rms noise over 20 Hz - 20 MHz. Whether that's a flat power
spectrum or a handful of tones, is a test it and see senario.

On Wednesday, 12 October 2016, Pete Lancashire 
wrote:

> Although this link
>
> http://www.righto.com/2012/10/a-dozen-usb-chargers-in-lab-apple-is.html
>
> is about the little Line to 5V USB adapters one sees everywhere now days,
> it does show how crappy the output looks when one gets a 'bargin'
>
> -pete
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Re: [time-nuts] For those that insist on using switching power supplies

[Attila Kinali]

On Thu, 13 Oct 2016 20:07:41 -0500
David  wrote:

> That confusion between the European Economic Area CE and the China
> Export CE is just shrewd.

It's an outright lie
https://en.wikipedia.org/wiki/CE_marking#China_Export

Attila Kinali

-- 
Malek's Law:
Any simple idea will be worded in the most complicated way.
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Re: [time-nuts] For those that insist on using switching power supplies

[David]

Even if they meet the CE or FCC requirements for unintentional
radiators, they can still screw up the short wave bands and more; many
are bad enough that I can see the noise they emit on an oscilloscope
with a shorted probe.  At least in the US, there are a *lot* of cheap
products with switching regulators which cause problems including CFL
and LED lamps and FCC enforcement is poor.

That confusion between the European Economic Area CE and the China
Export CE is just shrewd.

On Thu, 13 Oct 2016 17:57:02 -0500, you wrote:

>Actually, if they have the "CE" stamp on the product, then they have very
>specific radio interference limits that they must test and meet.
>It must have been tested, certified, and the certification package
>available for inspection.
>
>Whether they actually met it, then pulled the interference supression parts
>off the board as a "cost reduction" as is common in no-name computer power
>supplies, or whether it never met it to begin with, is for you to
>speculate.  Some suppliers will explain to you that "CE" means China
>Export, not that it meets the consolidated European safety and electrical
>rules.
>
>--- Graham
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Re: [time-nuts] For those that insist on using switching power supplies

[Alan Melia]

.but can you listen to the radio in the car ??  Many of these things 
will kill other applications like broadband over twisted pair and PLT tv 
extension. Never mind killing you!

Alan
G3NYK
- Original Message - 
From: "Van Horn, David" 
To: "Discussion of precise time and frequency measurement" 


Sent: Thursday, October 13, 2016 2:05 PM
Subject: Re: [time-nuts] For those that insist on using switching power 
supplies



To be fair here, phone chargers have almost no requirement to be quiet 
other than conducted and radiated emissions limits.

It's charging a battery.

As a designer of some fairly quiet SMPS systems, this feels like "look how 
bad a family car this tractor is".


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Re: [time-nuts] For those that insist on using switching power supplies

[Graham / KE9H]

Actually, if they have the "CE" stamp on the product, then they have very
specific radio interference limits that they must test and meet.
It must have been tested, certified, and the certification package
available for inspection.

Whether they actually met it, then pulled the interference supression parts
off the board as a "cost reduction" as is common in no-name computer power
supplies, or whether it never met it to begin with, is for you to
speculate.  Some suppliers will explain to you that "CE" means China
Export, not that it meets the consolidated European safety and electrical
rules.

--- Graham



On Thu, Oct 13, 2016 at 5:25 PM, Nick Sayer via time-nuts <
time-nuts@febo.com> wrote:

>
> > On Oct 13, 2016, at 6:05 AM, Van Horn, David  backcountryaccess.com> wrote:
> >
> > To be fair here, phone chargers have almost no requirement to be quiet
> other than conducted and radiated emissions limits.
> > It’s charging a battery.
>
> Not quite. They power the device in question *while* they’re charging the
> battery. Now, I’ll admit that powering a phone is a much lower bar than
> powering, say, an audio amplifier, but I’d also say that some of the
> devices on that page were pumping out way more garbage than even any
> digital system should have to put up with.
>
>
> >
> > As a designer of some fairly quiet SMPS systems, this feels like “look
> how bad a family car this tractor is".
>
> Well, there’s some of that, but the worst offenders were counterfeit
> devices that were pumping out unreasonable levels. To your analogy, they
> were the outer shell of a family car with a the engine from an Edsel
> installed in it without a muffler or any emissions controls fed from an
> open bucket of gasoline sitting on the passenger’s seat.
>
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> mailman/listinfo/time-nuts
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>
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Re: [time-nuts] For those that insist on using switching power supplies

[Nick Sayer via time-nuts]

> On Oct 13, 2016, at 6:05 AM, Van Horn, David 
>  wrote:
> 
> To be fair here, phone chargers have almost no requirement to be quiet other 
> than conducted and radiated emissions limits.
> It’s charging a battery.

Not quite. They power the device in question *while* they’re charging the 
battery. Now, I’ll admit that powering a phone is a much lower bar than 
powering, say, an audio amplifier, but I’d also say that some of the devices on 
that page were pumping out way more garbage than even any digital system should 
have to put up with.


> 
> As a designer of some fairly quiet SMPS systems, this feels like “look how 
> bad a family car this tractor is".

Well, there’s some of that, but the worst offenders were counterfeit devices 
that were pumping out unreasonable levels. To your analogy, they were the outer 
shell of a family car with a the engine from an Edsel installed in it without a 
muffler or any emissions controls fed from an open bucket of gasoline sitting 
on the passenger’s seat.

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Re: [time-nuts] For those that insist on using switching power supplies

[Van Horn, David]

To be fair here, phone chargers have almost no requirement to be quiet other 
than conducted and radiated emissions limits.
It's charging a battery.

As a designer of some fairly quiet SMPS systems, this feels like "look how bad 
a family car this tractor is".

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Re: [time-nuts] For those that insist on using switching power supplies

[Bob Stewart]

I've actually got 10 or 12 of those sitting in a box.  I got them because of 
the "grounded" power header.  The units I got used the 3-pin header but only 
had a 2-wire plug.  So, something seemed wrong and I opened it up.  I noticed 
the same thing: that the non-soldered ground pin went nowhere.  But, I demanded 
my money back due to the power cord not being as pictured, and went back to my 
previous supplier of a different power unit.  Since it was from China, it 
wasn't economic to ship them back.  It may be that ebay actually paid for the 
refund, I don't remember.  The build quality was pretty poor, and that figures 
since it had a screw-together clamshell.


Bob

  From: Bryan _ 
 To: Discussion of precise time and frequency measurement  
 Sent: Wednesday, October 12, 2016 3:42 PM
 Subject: Re: [time-nuts] For those that insist on using switching power 
supplies
   
And this one to show how safe and well designed they are.


https://youtu.be/g-NQSNoWlZ4



-=Bryan=-



From: time-nuts  on behalf of Pete Lancashire 

Sent: October 12, 2016 10:58 AM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] For those that insist on using switching power supplies

Although this link

http://www.righto.com/2012/10/a-dozen-usb-chargers-in-lab-apple-is.html
A dozen USB chargers in the lab: Apple is very good, but not quite the 
best
www.righto.com
When you buy a USB charger, how do you know if you're getting a safe, 
high-quality charger for your money? You can't tell from the outside...




is about the little Line to 5V USB adapters one sees everywhere now days,
it does show how crappy the output looks when one gets a 'bargin'

-pete
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postings to ...



and follow the instructions there.
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Re: [time-nuts] For those that insist on using switching power supplies

[Bryan _]

And this one to show how safe and well designed they are.


https://youtu.be/g-NQSNoWlZ4



-=Bryan=-



From: time-nuts  on behalf of Pete Lancashire 

Sent: October 12, 2016 10:58 AM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] For those that insist on using switching power supplies

Although this link

http://www.righto.com/2012/10/a-dozen-usb-chargers-in-lab-apple-is.html
A dozen USB chargers in the lab: Apple is very good, but not quite the 
best
www.righto.com
When you buy a USB charger, how do you know if you're getting a safe, 
high-quality charger for your money? You can't tell from the outside...




is about the little Line to 5V USB adapters one sees everywhere now days,
it does show how crappy the output looks when one gets a 'bargin'

-pete
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