This question already has an answer here:
- Measuring uA current with DMM? 1 answer
For a battery powered sensor node, I need to be able to measure current levels that have a dynamic range from 0.1uA [standby current] to 100mA [peak current].
For this, I am thinking of a high-side current shunt resistor and amplifier feeding an ADC. For the shunt, I could go with a 0.1ohm resistor to minimize the voltage drop in the peak current case [but lose capability to measure standby current], or go with a 10ohm resistor to have some shot at being able to measure the standby current of 0.1uA [but risk too high a voltage drop in the peak current case].
This must be a pretty standard problem for people measuring currents at sensor nodes.
For someone who might have resolved a similar issue in the past,
What circuit did you design for measuring currents ranging from 0.1uA to 100mA [being able to measure standby currents of the order of 0.1uA is critical for me]
What type of shunt resistor and amplifier did you select?
[Edit: This question is different from the one here as I am trying to design a single circuit that would measure across 0.1uA to 100mA - without having to manually switch resistors. The main solution in the answer to the other question requires one to set beforehand the current range to be measured. My question addresses a different problem.]