I have a customer that wants to measure the health of some LED's (several watts) by monitoring the voltage/current of each when they are turned on. They have 8 LEDs and board space is a premium, so we are looking at using 3 of the INA3221's.
They want to receive a flag when the avg current is too low. I have come up with two ways of doing this using the INA3221:
Option 1: Set the current warning thresholds at the undercurrent threshold and have their system consider the alerts/flags as Pass/LED Health=GOOD alerts. If their system doesn't receive an alert, then there is an issue with the health of that particular LED.
Option 2: Reverse the polarity of the shunt measurements and then the lower threshold would become the larger threshold. This will only work is the alerts from the INA3221 are not absolute value maximum thresholds. Is this the case? I saw on page 27 of the datasheet that negative measurements can be made, but I need to know if the alerts will be tripped when the threshold is exceeded in the positive direction (thres=-30 and it is tripped for any value >-30mV; i.e. -29mV, -10mV, etc... ). Or are the thresholds only set for the absolute values of the measurements (thres=-30mV and is tripped for any value <30mV; i.e. -31mV, -40mV, etc...).
Thanks for your support!
Cheers,
Joe Howard
Bay Area AFA
