hey everybody welcome to another episode
of EE stalk tech as always my name is
Mike Hoffman
I'm Daniel Bogdanoff and today we have
Kenny Johnson you've probably seen Kenny
on our YouTube channel before he came
around during scope month gave us a
great little tip about how to use it
like a ten thousand dollar active probe
to clean out the charging port of your
iPhone that's still to date my favorite
scope date or scope month video with
Kenny - Dr. Kenny and his doctor science
glasses and today we're gonna talk about
power integrity because Kenny is is our
resident power expert so Kenny can you
introduce yourself a little bit tell us
about your background yeah sure you know
but before I got too far though expert
is a loose term it's like calling me a
giant even though I'm just the tallest
pygmy in the tribe right it's every
relative we've had on this podcast says
well you know yeah expert so I've come
to convince myself that experts never
think they're experts okay carry on
sorry yeah so you know I've been working
for this place for like 32 years now and
most of that was in R&D and but I've taken a
couple of trips over into marketing as
poduct line manager and stuff like
that and best part about the job has
been through all those years just
visiting with hundreds or maybe a
thousand different users out there and
helping them solve their problems and
you know my expertise really is more
about like probing and making good
measurements and it's just it's turned
out the last maybe three or four years
when I've been working on this stuff
that people have just really been having
a hard time with what I call the power
consumer there's people out there that
produce the power and then there's the
people that use the power the people
that produce the power you know they're
the ones that you know whether like that
might be the wind farm or the solar farm
or just a coal-fired power plant all the
way up to the plug in the wall and even
from the plug in the wall up to kind of
like that you know this silver can that
your AC to DC power supply inside your
whatever product you've got that's kind
of the power producer the power consumer
guys a guy that's taken then he's
worried about the quality and quantity
of the power that he's using and so I
really started kind of get into this
like I said I don't know four or five
years ago or thereabouts and people were
sweating
chasing the milliamps in the micro amps
and stuff like this around and and so
we're helping to make those measurements
and people kept raising their hand
asking like hey you got something I can
look at the ripple of noise on supplies
and I don't know if as a kid your folks
have already the book Horton Hears a Who
or you saw the story you dad but you
know at some point it's like all these
little people are screaming for help and
then just one more voice gets on there
and then it finally registers it's like
ah it's this little dust back that the
protecting and then like no one can hear
it except for him because he has nine
years yeah and then there's like one
like teenage kid who's like I'm not
gonna yeah yeah yeah yeah I'm so and so
finally there's fear such there's some
threshold of voices where I finally
heard us like oh my gosh we need to do
something for these folks and so that's
when we started making like parallel
probes and things like that you know to
help out with this power integrity so
it's um so for the power integrity it's
you know the rough definition is
something almost esoteric sounding like
the study of the effectiveness of the
conversion and delivery of DC power from
the source to the gates on the IC. I'm
on the edge of my seat right now are you
reading out of one of your textbooks
here's please tell me you wrote one of
these wrote the book uh yeah yeah and I
loosely quoted that so I don't have to
actually name my source that's fine but
really you know folks were just they
were freaking out about like hey I need
to measure the ripple of noise on my
supplies and we didn't really have a
good solution for that so then started
digging in more and more and found out
how much all this stuff is tied together
that what's happened over the years you
guys all familiar with Moore's law right
that every 18 to 24 months we're gonna
double the number of gates on an IC sure
yeah interesting thing about that I read
it I read a guy's paper where he says
you know if Moore's law keeps up for
about the next six hundred years we will
have a computer that is capable of
simulating every atom in the known
universe
ooh Hitchhiker's Guide to the galaxy
style with that article went but anyway
you have a backup right that's the
checkered sky it is so I get the end of
the series too like oh yeah here's the
backup and everything
resumes as if ever oh really again the
anyway so with that what happens is you
know we've been cramming more and more
stuff in there and so you start getting
numb
one more gates packed together and
everything and and we start ending up
with like thermal hotspots you're just
just too much power you know you're
gonna you're gonna fry devices and
everything and so to take care of the
power for those hotspots but also to
extend battery life or just you know how
many how many kilowatts your thing is
using over here out of the wall is we
start dropping voltages and so everybody
starts getting more and more concerned
about this ripple and noise on the
supplies and supplying good clean power
to everything and so that's where we all
started in you know it's um there's
actually when I first got into it I went
out to Amazon and I said okay I need to
read a book right and so I started
checking some books and all the books
that were published I think there was
two at the time maybe three I mean they
literally were just coming out about
three four years ago um so it's been
something that is really exploding for a
long time now the truth be told is that
people have been doing power integrity
measurements the first reference I ever
saw was from some work in like 1930, so people have been like looking
at this it's just that right now it's
become more and more important because
if product functional reliability is
directly proportional to the quality of
the power inside that product and so as
we have a lot more functionality in our
products you whether that's your smart
phone or my cool little you know
exercise wristband kind of thing there's
more and more opportunities for things
to go south and to fail and so that's
why there's this increased focus on this
and the and it's there's a correlation
then or they're kind of tied together
well you know we're supplying a voltage
to these things that they're operating
and they're also consuming current
they're pulling current through there
okay and so you start thinking about
this it's like wow so that's sounding
vaguely familiar to like Ohm's law right
and we're just missing like the the our
where's the R in the whole thing or the impedance
yeah yeah exactly exactly and so if you
think about it like a typical product
it's going to have power and ground
planes and you can want the impedance of
those things to be pretty low so you're
not getting some kind of IR drop across
the ground plane and so I know it's a
gross simplification but it's it's a
pretty easy model to work with is that
the idea coming from some of the the
early pioneers this stuff Istvan Novack
or Ray Ridley guys like that they talk
about these flat impedance power planes
and the idea is you can kind of take
whatever your voltage is you know if
it's a five volt supply or whatever
divided by the the change in current
that you expect you what's your
basically your peak current multiply
that by the tolerance and you end up
with like a target impedance for your
power planes yeah and so if you can you
know maintain a pretty much a flat and
pedis what happens then is you don't get
a whole lot of noise showing up on your
power splice so if you think about it it
goes so you want a flat impedance over
the different current ranges right over
over frequency yeah okay yeah yeah and
so you know if you think about it you
know remember back to like a circuits
101 is that an inductor is open at high
frequency and so we've got these these
power planes and really those are just
big inductors so at some point their
impedance is going to go up and so when
you have things like you're just writing
data out to memory well there's some
pretty fast transients there they're
associated with 0 1 0 1 it actually
takes some some energy to change that
from a 0 to a 1 and you have to draw
some current to do that when you do that
to supply kind of pulls down and sags
and anyways so the point is is there's
uh even though we're talking about DC is
that there is you know high frequency
effects here and so that's why it's
impedance not resistance to those planes
and so when you look at boards a lot of
the times you'll see like how there's
always like yeah capacitors all over the
place right yeah and the child of the
capacitor you know remember back again
that same circuits classic capacitor is
a short at high frequency well kind of
pitch it in your head as you start going
from like you know DC on out the
impedance of that inductor start going
to creep up well that's bad we wanted to
go back down what do we do hey let's
slap a capacitor on it because that's a
short that'll start pulling that
impedance back down but then at some
point there's some inductance associated
with that capacitance and it's gonna
start to go back up again and so you
look at these in these power plane
impedances they just look like kind of
like a waves on an ocean it's just kind
of these you know troughs and and peaks
and everything that are the impedance
and so that's what guys are like trying
to design towards whether they know it
or not yeah so basically like to Sun
that up when a system requires current
it's basically gonna be a load pulling
current and the supply is gonna dip a
little bit mm-hmm and if it's for
example writing one zero one zero it's
gonna pull and release yeah your current
power supply is going to ripple
yep set that's it exactly and and so
with with a lot of products like maybe
the ones that we designed here and
everything you know
we've got fairly good sized circuit
boards inside our scopes you know many
many layers you know robust power planes
robust ground planes things like that
but if you think about somebody that's
doing them some small form-factor
product like that maybe some IOT thing
or consumer electronics or even
smartphone kind of thing they probably
have room for dedicated power planes and
ground planes heck a lot of stuff I take
apart to fix at home only has like it's
only a two sided boards they have like a
power trace and a ground trace yeah well
that means that they're gonna be
fighting that impedance battle pretty
quick and so but where most people come
into this is they at least from the what
I've observed is the majority of people
try to use some intuition and based on
past experience to go through and make
the planes kind of as big as possible
and and keep distances as short as
possible and that's why you see the
trend of more and more like localized
power regulation you know maybe in the
past it used to be you just have one fat
hose that goes to your circuit board
supplying the power you just distributed
everywhere well now there's more
or localized regulation so you can keep
those distances shorter the other thing
that it does to is it was mind boggling
when I first got into this was for
example like a typical solid-state drive
has about twelve supplies in it
something like a tablet could have 50
some of our oscilloscopes have a hundred
and eighty supplies in it and some
next-generation mobile electronics a
hundred to two hundred now it's not like
there's a hundred different voltages 1.1
1.1 11.1 - no no there is there's
redundant voltages in there because what
happens is as one if they're all
connected the same spot as I turn on the
display it's going to yank a bunch of
power out of there there are a bunch of
current the supply is going to sag and
it's gonna sit in fact everything yeah
yeah and it's kind of like when I was in
college we rented a really old house and
if I was in the shower and somebody
flush the toilet all the cold water goes
down the toilet and I get scorched it's
like ah right see they put in some flow
regulators and all that what these are
doing the same thing so that when
somebody turns on the display it doesn't
like disrupt the you know the mp3 codec
or the the memory or something else so
that's why there is this these multiple
copies and then they also try to have
multiple phases so that they're again
even more robust for when they are
interesting when there's these these
demands on these on these voltage
regulators oh it's so they're gonna like
run three-phase power across the board
and rectify it out at different voltages
oh yeah no no I didn't I didn't mean it
that way what I meant is like there may
be like let's say there's a 1.5 volt
supply to something that actually maybe
like multiple 1.5 volt DC to DC
converters there and everything there
that are sharing the loads so these
regulators attached to the same rail if
one gets hit the other one is able to
stabilize it yeah okay yeah make sense
and you know so sort of like a you know
two or three of us carrying the load
instead of one of us care in the load I
was like that's gonna be brand new to me
as we're gonna have to pause for a
moment there
Wow - those connectors how did I miss
those connectors, the phone now phones
converting DC to AC and then rectifier
somewhere else yeah so let's see where
was I going anyway so okay so you've got
like all these supplies got a look at it
so most people they're just using kind
of an intuitive approach to this and
it's it's because a lot of folks don't
have access to maybe modeling and
simulation tools and I know like around
here you know we've got some modeling
and simulation tools but we're a large
enough corporation that we've got people
that are dedicated to support those
tools and be experts on them but you
know a lot of people aren't that
fortunate so they just kind of have to
take some rules of thumb and just say
well I'm just gonna make this you know
throw down a lot of copper and start
sprinkling a lot over engineering yeah
yeah exactly exactly that's cost and so
that so how do they know if they did a
good job or not well you go look at like
the datasheet for the FPGA or the little
microcontroller and it'll tell you on
these critical supplies you know that
maximum you know ripple and noise and
fuzz on the power supply is you know
plus minus 2% or 5% or whatever it is
and so they want to go measure that to
see if they've done their job or not and
so that's where most people jump in and
then excuse me after they've gone
through that a bit then they start to
kind of maybe think a little bit more
about next time when they lay it out
maybe they'll go take a class or maybe
read some of these books but in general
it seems like that's where most people
hang out is they sit there in that in
that world kind of measuring it after
the fact I'm not necessarily looking at
it and the impedance still made but more
than that in the time domain that stuff
it's interesting no I do have to ask you
brought some show until items for those
of us who are listening and not watching
you have a couple it looks like for
textbooks and some some printouts here
that you brought in was there just in
case we tried to stump you or something
like that
well this this is this is so that I can
try to pretend I you know I'm cleverly
disguised as a power expert and so this
this is part of the disguise is having a
stack of textbooks that's about eight
inches tall before you start believing
Kenny's claims I think I've come to a
conclusion is one that experts are
always learning so if you want to be an
expert
you have to keep learning but I think
you also might hold the record for most
patents in the company is that I don't
know if that's an official record do you
know how many patents you have so yeah a
lot yeah yeah quick acute story on that
so I'm our chief technology officer used
to have the most patents for this
particular division this location Jay
Alexander yeah he watches our channels
and now he has to watch so Jake
congratulated me a while back I think as
my boss had sent an email to some folks
saying you know hey you know Kenny got a
patent and so Jay had asked me how many
and I said you know I've I I tried I
don't I I try to remain humble on that
I'm not naturally I don't brag right
that's why I had to bring it up but yeah
and so uh I think the current count is
almost 30 and yeah when Jay and I were
having the conversation I think his
number was about 25 and I just got
number 26 or 27 and but hey you know
I've been having turning the crank for a
long time so that's but there's guys out
there I think at that company like
within keysight that have you know over
a hundred TLO guys I'd have to assume oh
yeah technology leadership you know ASIC
guys like Mike Byers and some of the
other guests we've had yeah so yeah so
there's there's definitely some some
intellectual giants out there but
anyways with the books the reason I
brought the books was because they
actually helped me out a lot like I said
when I first got into this I was a probe
designer not some kind of like power
engineer and everything so how am I
gonna help these guys I had to come up
to speed fast and so I Amazon hit Amazon
and was checking out power integrity and
start funding like one book was
published then two then three and so I
order them and just kind of read through
them and everything and for those that
are listening there's no point in me
kind of holding them all up and
everything but there's uh there's at
least three or four great resources out
there if you just go hit Amazon and type
in power integrity is there is there one
in particular that you choose like you
guys recommend
it's not an official endorsement yeah
yeah yeah you know a female if you don't
have much time to read at all there's a
book by dr. Eric Bogatin and his
original book called a signal long-lost
cousin yeah he originally wrote a book
called signal integrity and it then he
did an update to it that was called
signal integrity and power integrity
simplified okay and so it's the second
edition of his book and so there's about
two or three chapters in there and it's
a pretty good overview I think he's got
another edition out now that's got even
more content but if you just want to
start there it gives you some great
ideas about like why should I even care
you know what happens I mean as long as
it's there we're good and so he tells
you why you should care some steps to
take some measurements to make and it's
that's a good basic one to start with
and you know something that I wanted to
share just this this quick experience
was you know as we were going around and
starting to talk to people about some of
that techniques and things that we had
for for measuring the ripple of noise on
the supplies I remember talking to some
of the first users they were in the lab
that they called their Sippy lab so this
is a very large you know like fortune no
integrity integrity exactly and like
sippy cups the anyways and so that's the
thing is they're they're so tightly
related is that power integrity will
affect your signal integrity fire
integrity also affects your EMI and your
EMC but it was so these guys and a lot
of the more of up like progressive or in
the forefront companies everything have
these SIPI labs or things so when in
there and I was talking to the manager of the
power integrity part and you know were
showing him how to make some
measurements and he's like wow that's
great results that's better than I could
get before and everything and he says
you know what I wish there was a button
I could push that would tell me is it
worth improving the design anymore
because he says you know like his
engineers we can always like
tweak it and try to improve
is it worth it you know what am I going to
get from this and everything and so I
think there's without getting into
endorsing particular products there are
some more tools out there now be
analysis applications or even some of
these textbooks that can kind of help
you understand then what you can get
because get this there's multiple papers
that say power supply induced jitter is
the single biggest source of data jitter
in a digital system interesting and I've
got that color yeah I've got a couple of
cool little IOT development kits you
know so if I was like I want to make my
little fishtank monitor for at home or
whatever was I I take these and I can
without even trying they start stumbling
and dropping bits which would be
basically okay that's either gonna
affect my battery life because you know
I didn't I didn't you know my error
checking says okay some of the data
again send me the data again send me the
data again or maybe it's actually things
freeze up and so that power supply
adduced jitter is really kind of the
thing that people are looking at and so
there's some some papers out okay we've
got some but basically if you go check
that out if you clean up your supplies
you're gonna get a lot more a lot more
margin in that domain so to clean up a
supply is it like a bypass capacitor
thing you have to go through or what's
what does that look like wire brush soft
bristled toothbrush yeah the majority of
time that's really what it is is it like
when remember when I was talking about
that that flat and Peeta's profile well
let's say you've got some some noise
that's showing up in your system that's
we instruct people like after you've
looked at the power supply in the time
domain good thing to do is go look at it
in the frequency domain throw up an FFT
and then you'll start seeing some spikes
in there at the various frequencies and
that's usually a good way to kind of get
a fingerprint or you know tell some DNA
for like who's committing the crime you
like okay I see a 100 MHz megahertz spike
or whatever and so they sudden you know
okay so that's starting to bleed through
now I need to do something to try to
suppress that hundred megahertz noise
for my supply and if you know the
frequency you can work backwards into
the impedance that you need to hell
exactly exactly so if you were to go
look at that impedance profile you're
probably see that your impedance is
starting to pick up around that 100
megahertz it's like okay let's go pick a
cap that's gonna knock that down about
there and go plop that down and
everything and that's that's kind of at
the easiest that's what most people do
okay and and you want to put that if I
remember right I was just reading about
learning more about this you want to put
it like right by your load yeah you
don't want to put it out by your power
like that's a source of your power rail
you want to put it right where the chip
is going to need it or whatever your load
is yeah you know it seems like there's
some general rules in the universe that
apply to just about everything and like
closer to closer to the device is always
better whether you're like putting down
the bypass caps or like we're always
telling people like if you're making a
measurement or you're gonna go measure
the signal well you want to measure it
at the receiver right see what the
receivers in and because that's going to
tell you a lot more so those general
ideas of like closer to the the device
that's being powered or closer took the
device that you're concerned about and
so yeah you go through those they're you
know there's one thing that so I think
before you get in the white band gap
yeah it's been like 24 minutes no sorry
I told you it goes quick so we might
have a whole nother podcast on wide
bandgap semiconductors that's cool power I think that'd
be pretty cool too you know there's like
going to tease it like gallium arsenide
universe witching I just throw this out
real quick this is from the US
Department of Energy hands looking at
this just a little while ago and they'll
actually pay for guys like you and me to
go back and get a degree in Power
Engineering and the reason is is because
these wide bandgap semiconductors
gallium nitride silicon carbide if for
example we were to just go through and
change the existing motor controllers
out there for like pumps and things like
that we could save enough electricity
for a million homes it's because there's
so much more efficient if we change how
many homes are in the u.s. home sizes
like do two ish cup could be a couple
hundred million populations what all the
homes if we went through and changed
just like
existing like
you know that your wall warts and the
motor controllers and stuff like that
it's it it's about maybe five six
percent of the homes in the u.s. right
just just from changing those out
anyways it's it's the wave of the future
for power power electric perfect so
we're gonna talk about that next episode
real quick on the census data there was
just really interesting research study
out this is totally unrelated but I have
to share because it's so cool um so you
know like Facebook advertising says oh I
can reach this many people in this age
gap if you look at what the social media
sites say they can reach from
advertising standpoint and what the US
Census the data says Facebook is
claiming and these other you know
advertising tech companies are claiming
to reach like forty percent more people
than the US says actually exists in the
country I believe that this well I don't
want to draw okay I probably believe
Facebook over it's gotta be somewhere in
the middle because I'm not gonna go
there anyway yeah so at the end of every
podcast episode we like to ask our
guests a stupid question
so I think I know what your question is
but go for it no okay well I can ask it
for you because this is what you'd come
up with okay what is your favorite power
real voltage and why I didn't think of
that
Wow I'd have to say three point three
okay I love the symmetry of that number
number but I remember with three point
three was the small stuff you know
everything was five volts when I first
started working and as like oh you're
working with the small stuff three point
three but it's just the symmetry of that
three point three yeah that's that's the
favorite it's nice
did you have a question too I do okay so
I like five volts because a USB good so
we've been talking a lot about power
integrity and so it sounds like that's
getting a lot of attention
what other part of electronics designs
do you feel like deserves more integrity
doesn't have enough integrity yeah who
doesn't have enough in
no I yeah Tony who's Native security
what do you think lots of competing guys
yeah you know unfortunately I uh
my wife's car got broken into yesterday
and her purse got stolen we had to
freeze all the credit cards and so that
brings a certain it's probably good to
do anyway after what happened a few
weeks ago well that's that's what I'm
saying so actually the blessing in
disguise errs were getting new credit
cards issued across the board and I
thought about that last night trying to
make a lemonade out of lemons is going
wall Hey okay so somebody hijacked all
my stuff from that one credit bureau
some that information is bogus now you
know where where people are starting
right now that the other thing with
integrity is just counting the milliamps
that go everywhere you know that people
are trying to save power whether it's to
be green 2 save the planet or be green 2
save some green and so that's the other
phase of this that where I think we're
starting to see a take off is just how
many coulombs and I scooping up and
throw it away and everything how much
how much current am I using it's being
distributed cleanly but is it being used
effectively yeah yeah yeah yeah exactly
so you know whether we're whether we're
trying to save the planet or you know I
did a thing like about 10 years ago got
an infrared camera and for work well
what's the first thing you do well he'll
you take that take a selfie yeah gotta
go check stuff out right it's like no
the kids and and you know so checking
out the dog and it's like whoa he's well
insulated only his nose glows in his
ears or something like that then we're
like doing handprints on the wall as I
moved around the house the number of
things that were glowing that I thought
were off you know go down to the
basement wow look at the treadmill oh
look at the you know the the the the the
furnace you know the thermostat and just
how much of that is wasted and so
whether that's whether you're green for
that or just being green 2 save the
utility bill is that I think that's the
that's the other Porsche is just using
it more efficiently soft power switches
are cheaper I think that's what it comes
down to yeah yeah we all of our favorite
youtubers very very very very fond of
actual physical power switches yes yes
we do yeah
they shout out Dave dance yeah an
electric boom actually did a great video
with the thermal camera he ran around it
pretty nice so you can go check that out
all right so we are officially out of
time so thanks for tuning in make sure
you subscribe to the podcast give us a
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feeds on EES talk tech comm EE stack
tech comm i'm daniel bogdanoff mike
coffman and patent heavy Kenny Johnson
is with us and we'll have him back next
time to talk about wide wide bandgap
semiconductor powers power or something
I don't know we'll figure it out next
episode thanks for watching see you next
time Cheers adios guys
you
you
