| Electronics > Projects, Designs, and Technical Stuff |
| Measuring wide range current draw of micropower applications |
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| ogden:
--- Quote from: Amper on October 30, 2019, 10:05:05 pm ---Sadly no, the pulses are the variable. They depend on all sorts of factors like humidity, temperature, supply voltage, discharge rate of the geiger and so on. --- End quote --- I see. Then perhaps 10$ solution is to buy MSP‑EXP430FR2433 which is cheapest ready to use wide dynamic range MCU power measurement tool one can buy known to me. Those who will jump-in with "but msp430 is not Tiny13" can cool down because standalone tool work w/o connection to msp430 as well. |
| OM222O:
--- Quote from: Amper on October 30, 2019, 10:17:57 pm ---Yes, the sensing and logic is pretty straight forward. I just never realized that i could drive the fets this way just having the source vary by shunt voltage. I guess thats because i always use them in power electronics where i want the best ground path i can get... --- End quote --- Those specific fets are logic level fets. if you drive them with 5V, the source can be as high as 2V and the fets are still fully on! However I would worry about more important things if you have 2V across your shunt :-DD |
| Amper:
The ti board looks really nice, if it can do this it will be worth it just for this meter function on its own... |
| jbb:
Yes, wide dynamic range measurements are a problem. I’m grappling with it at work... I see three options: * Spend lots of money on really expensive kit. Keysight would be very happy to help you spend some tens of thousands. Joulescope might be workable. * Arrange your measurement to work on the ‘active’ current only, and just assume the ‘low’ current is 6uA. You could also calculate an expected ‘sleep’ current using data sheet values. * Split the current into 2 channels: one for the boost converter input and the other for everything else. This would divide up the big dynamic range problem into two easier problems.[\li] |
| SiliconWizard:
This has been discussed in several threads before. You'll probably find most practical solutions in them. Eg: https://www.eevblog.com/forum/projects/measuring-small-current-complicated/ https://www.eevblog.com/forum/testgear/battery-energy-consumption-how-to-measure-it/ https://www.eevblog.com/forum/testgear/high-dynamic-range-current-vs-time-measurement-at-low-cost/ https://www.eevblog.com/forum/oshw/metering-both-sleep-and-active-current/ |
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