Hi, my name is Brad Jolly, and I'm an Applications Engineer at Keysight Technologies.
In this video, I will discuss flexible IoT device battery life analysis with the Keysight
X8712.
So here's some data that's been acquired from our IoT device.
And what we really want to know is, first of all, how long is my battery life?
And secondly, what do I do about it?
In other words, where is my current being consumed?
And where is my device spending its time?
So what I'm going to do here is I'm going to drag these markers over here so that I
go from, say, the end of this cycle here to the end of this cycle here.
Okay, so I've got three full cycles, an integer number of cycles here, which is a good thing
to analyze.
And what I can then do is go to my analysis table and click "Analyze."
And I'll get all these various statistics.
And then I can enter my battery capacity in terms of amp hours.
So this is 240 milliamp hours, typical lithium ion coin cell.
Click "Analyze."
And then down here I've got all my statistics.
So this tells me that I can expect about 1,260 hours of battery life there.
But what it doesn't tell me is, so where is my battery being consumed?
And how much is it spending in each of these different modes?
And that's what these zones are for.
So I'm going to click on "Zones."
And you'll see that my current waveform is split up into ten zones.
If I want more resolution, I can go all the way up to 20.
If I want less, I can go all the way down to one.
Let's go down to, say, eight zones.
Okay, it's kind of arbitrary to a certain extent.
But let's look at it as a matter of eight zones.
And then what I'm going to do is look at the three prominent features of my waveform.
So I've got these RF spikes.
So I'm gonna call this RF spikes.
And if I look at it, I see they go up above negative ten.
So let's say from zero to negative 30 is an RF spike.
So anything that goes from here up to here we're going to call an RF spike.
I don't need to worry about this because anything from zero to negative 30 will automatically
include zero to negative ten.
So I don't need to worry about that.
I don't have volt meters involved in this particular system, although if I did I could
specify voltages that I want to look at.
Now, the other thing I notice is that most of the time I'm in a sleep mode, which is
zone one.
But sometimes I peak up to anywhere between zones two through eight.
So what I'm going to do is I'm going to say, okay, my current is active betweens zones
two and eight.
I'll call that active current.
And I'm in a sleep mode when I'm in zone one.
So I'm gonna call that sleep.
Gotta do it in the right order.
There we go.
So from zone one to zone one.
All right.
Now I click "Analyze" here.
And let's look at the results.
So you can see about 900 millipercent of the time, in other words, nine tenths of one percent
of the time, I'm in this green RF spike mode.
But notice that's 31 percent of the current is consumed in that mode.
Then I've, in these active current modes, just three and a half percent of the time.
But that's roughly two-thirds of my current consumption.
And about 96 percent of the time I'm in this sleep mode, but that's only 3.15 percent of
the current.
And what it's doing is it's going in here, and it's doing time slicing.
Okay.
So it's first looking for RF spikes.
Then it's looking for active current.
Then it's looking for sleep.
And if there's anything left over, that goes into this other category.
Now, where I can see exactly how this time slicing is working is if I go into view, and
I look at my chart.
Okay.
Then I can turn on the zoom chart only.
So let me turn off everything but the zoom chart.
And you can see that it's using these same colors.
So the tan is the sleep.
The pink and green are the active current and the RF spikes respectively.
And let me go ahead and zoom in a little bit so you can get a better sense of it.
So let me zoom in and zoom in again.
And you can see that I've got the green for the RF spikes, the pink for the active current,
and then the rest of it is sleep.
I can double-click here.
And if I zoom in over here, you'll notice that it's all sleep mode.
There are no RF spikes.
There is no active current.
It's all in zone one.
So it's really all in what you're looking at.
Again, I can double-click here.
And if I zoom in some more and zoom in some more and zoom in even further, in this case
it'll be pretty much all green RF spikes 'cause that's what I've got specified in terms of
my zoom levels.
Now you've got a couple other charts that let you see what's happening here.
So I can look at my current consumption chart.
And again, that uses the same colors.
My RF spikes are 30 percent of the current.
Two-thirds of the current is in this pink active current.
And 3.15 percent is consumed in sleep modes.
On the other hand, I've also – can look at the time.
And you'll notice that the tan, 96 percent of the time, is the sleep.
The active current is about, what?
Three percent of the time.
And less than one percent of the time is these RF spikes.
So you can get insight into it in terms of either the time or in terms of the current
consumed in that time.
Thank you for watching.