Consumption profile equipment

Question

Hi all,

I've been searching for tools to measure ( profile) the dynamic consumption of devices in normal operation and then give a report.

features desirable:

measure Max current, Average current
Max Voltage, Average current
Configurable voltage supply ( 0 ~ 12V )
can afford at least 1A
Good Software for reporting
Possibility to connect a battery and log the voltage and current

For instance, I've found was this one, but it is limited to 5V output max which is too low for my case (12v would be better ) :

https://www.qoitech.com/

If you people had a pleasant experience with any tool and can share, I'd appreciate it!

thanks,

hlipka · Answer

The JouleScope should tick all boxes - 15V, 3A, 250kHz bandwidth. Its not exactly cheap, but for what it does its also not too expensive. Look for more current reviews - from what I remember the software had some quirks initially, but they might be resolved now.

michaelkellett · Answer

It depends a lot on exactly what you want to measure, most power supplies and even data loggers struggle with the dynamic range of the current drawn by IOT like devices,

1A maximum is not uncommon but the sleep current might be down in the uA or less region.

Very few systems can measure and log this if you want to catch fast spikes of high current - the Keysight boxes can but you are looking at £5k+.

As Shabaz points out, if you want to simulate a battery then that's a whole extra can of worms.

I looked at the Qoitech and I did not like what I saw, the claimed operating temperature range is 15C - 25C - this looks like a company that doesn't know what it's doing.

The detail in their specs is just a joke comapred with that from Keysight, R & S, Keithley etc. And they seem to want loads of extra money for software licenses.

Like Shabaz, I've always ended up using multiple instruments, bench psu with computer control, Keithley DMM6500 (nice programmable DMM with fast logging if needed), or maybe use Kesysight DAQ.

Can you tell us a bit more about the typical current profiles of things you want to measure ?

MK

shabaz · Answer

Hi Joao, I think today if I had the choice, I'd go for a bench supply and a datalogger (see BK Precision or Hioki for instance), or a nice multimeter like DMM6500, and log to it or disk. Some of the all-in-one units intended for IoT use suggest they simulate a battery, but the only decent simulation of a LiPo is in Fortran, and so unless they are running that, I don't know how much value that is. The instruments above would be more versatile (albeit more costly). For low cost, a microcontroller and an ADC board could be used (could be an off-the-shelf ADC eval board).

shabaz · Answer

Hi Joao, Your comments make sense. Also, incidentally, if there's a difference from (say) a few hundred nA between the lowest current sleep mode and the next level of current draw (say 1mA), then it can be possible to can spot that, at a useful bandwidth, and still be able to handle the highest expected current, with a single sense resistor (i.e. no switching) and a very low-cost INAxxx board (from TI), if the sense resistor is sized well per device-under-test, because a lot of IoT DUTs won't consume more than a few hundred milliamps of current (and your mentioned values also support this), and some will be just in tens of milliamps if they use low power radios. However if there are several sleep ranges close to each other then that's harder. Anyway, that could be part of an ultra-cheap option, sometimes needed perhaps. There's a short discussion here: Using the INA210-214 for Current Measurement for IoT Devices where it also mentions the possibility of moving the sizing problem to plugging in/out different gain INAxxx chips, instead of swapping out sense resistors, for different desired ranges.

Consumption profile equipment

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