Wearable Device current characterization with a DMM

Wearable Device current characterization with a DMM
10 Aug

Hello, my name is See Kai I'm Application Engineer with Keysight Technologies

In this video, I'm going to show you how to characterize the current consumption of a wearable devices such as the fitband that I have over here Wearable devices typically draw very low current in the stand by mode and higher current in the operating mode To characterize the current consumption, I'm going to use the Keysight Truevolt Digital Multimeter 34470A Before I get started, let me go a head and dissemble this fitband and connect it to the digital multimeter So now we have the fitband dissembles and I'm connecting the digital multimeter in series with the battery and the PC board

So now I have the device in the stand by mode and the multimeter is actually reading in the micro-amp range Over here is the nano-amp and pico-amp range over here And the device now is actually drawing about 22 nano-amps current in the stand by mode So now the fitband is in the normal operating mode

As you can see the number is actually changing quite a bit I'm going to turn the display mode to trend chart As you can see the current is actually jumping up and down For more details on the reading, I'm going to turn on the statistic Over here you can see the minimum current draw from the battery is about 4 micro-amps and the maximum current is about 2

3 milli-amps I'm going to turn on the blue light on the fitband and see how much current it draws And this will be the blue light It is about 14 milli-amps And green light

All right, it's slightly lower than the blue light here Maybe vibration mode it's will draw more current So you can see the trend chart actually give us a very clear reading The maximum ready now draw from the battery is 40 milli-amps Let's say if you are interested in seeing the final details on how much current is drawn by this fitband, you can actually do this by using the digitizing mode

So in the case, I'm setting the sampling rate to 10 thousand readings per second and for a duration of 5 seconds Once this is done, I will hit the start button And the digitising completed To view the data, I'm going to switch the trend chart and zoom in to see final details and also pan around to the data point that I'm interested in I can also turn on the cursor

Track the cursor and move the cursor to the peaks to get the current value on the chart Further to this, I can also save the digitized reading into the pendrive or by connecting to the computer As you can see, the digital multimeter has some great features for characterising low current consumption devices If you like to learn more, please visit our website or subscribe to our youtube channel for more interesting videos Thank you for watching

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