Choosing the Right Instrument for Measuring and Characterizing Battery Drain of Wearable IoT Devices

Choosing the Right Instrument for Measuring and Characterizing Battery Drain of Wearable IoT Devices
11 Aug

Hello I'm Chris Kelly, Applications Engineer with Keysight Technologies

My 33 years in the instrument development lab for Hewlett Packard, Agilent, and Keysight have given me experience that will help you make your decisions on how to measure this difficult problem of battery drain, current analysis in wireless IoT devices We know that these currents vary widely On the CX3300 we can see a waveform that shows a 200:1 ratio between high and low states On the oscilloscope with scope probes we can see this is a very infrequent event It may only happen at a 1000:1 duty cycle

And how do I pick which of these things will solve my problem? Well, I'll pose to you three questions that you can use to do that First of all, what are the high and low currents? These devices span a very wide range from femtoamps to amps If you choose a device that is at the low end, that's probably the right end for an IoT device Very low battery consumption Secondly, the question you should ask yourself is: How fast does my signal change? How much bandwidth do I need? As I look across these instruments, my DMM in digitizing can handle a 10 kHz signal without much problem at all

200 kHz in my power analyzer is a reasonable range Around 3 MHz with an oscilloscope The current probe is Probing is a difficult problem, and the current probe can take you up to 3 MHz with good resolution Finally, if I need instant answers quickly, the CX3300 can take me there with powerful analysis capability The last question that you want to ask maybe is: Is this for an R&D application or is this for manufacturing? If it's in R&D, clearly some of the higher capability instruments will help your engineers get to an answer quickly On the other hand, in manufacturing I might be able to slow my device down or make simpler measurements where a DMM is a much more appropriate tool for that purpose In this series of videos we've been overviewing the wide range of Keysight solutions that can be used to meet your measurement needs with these low power IoT devices

I hope you found this series useful Thank you

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