3 ms·
Looks like it switches different ranges. ST makes something similar that has similar dynamic range without switching. They use analog circuitry (op amps and jun
by Neywiny 1y ago
Looks like it switches different ranges. ST makes something similar that has similar dynamic range without switching. They use analog circuitry (op amps and junk) to compensate for the resistor drop, so the path is uninterrupted. I've had systems where the auto-ranging on a bench meter is enough to cause it to reset. I can't find a schematic for the PPKII (haven't looked too hard though) but if it's actually switching the supply, that can cause issues to devices downstream. Especially if that switching causes a voltage drop change.
- readmodifywrite 1y agoIt switches the detection range, but not the actual power supply. You can ramp from <5 uA up to 500 mA and back all you want. I haven't noticed any glitching on the actual supply. Schematics: https://www.nordicsemi.com/Products/Development-hardware/Power-Profiler-Kit-2/Download https://www.nordicsemi.com/Products/Development-hardware/Pow...
- dragontamer 1y agoWith the onset of cheap 16-bit, 18-bit or even 24-bit sigma delta ADCs, it isn't a very hard circuit to shove a 1 Ohm sense resistor, 2.048V reference and have sensing down to 31uA (16-bit), 8uA (18-bit) or less for 24-bit ADC. SigmaDelta gets pricy if you want higher speeds though. But it's possible.
- ranma42 1y agoI have the ST one (X-NUCLEO-LPM01A), but its range is actually not enough for something like an ESP32, it goes into "overload" as the max current is 50mA for dynamic (100kHz bandwith) and 200mA for "static" measurements. Looks like the PPKII can do up to 1A.