Current shunt selection and clamping diode selection with AD8208

Hello Glane,

In order to determine the right shunt resistor, we need to take note of the maximum power dissipation and minimum current accuracy first. The 12-volt, 5-ohm solenoid will be drawing 2.4A, and thus, a power dissipation of 28.8W; Am I correct to assume that this will be our maximum load to consider? Can you share with us your full circuit for this application, the specific solenoid used, as well as your target accuracy at minimum load current?

Can you also share why you preferred to configure your system as low-side sensed? High-side sensed has a lot of advantage over low-side sensed such as fault detection, simplified wiring, and absence of grounding issues. Its only general disadvantage against low-side sensed is that you’ll need to use amplifier that has a larger common mode voltage range, and these are generally more expensive, but since you’re already using AD8208, which already has a high common-mode voltage range (-2V to +45V) to begin with, it may be good to consider the high-side sensed configuration.

Here’s an article from Analog Dialogue if you want to look more into this setup: https://www.analog.com/en/analog-dialogue/articles/current-measurement-in-solenoids.html

-jean