LED Short/Open Detection

[Mistico_Pereyra]

open circuit detection

Hello guys,

I can not find a circuit or methodology to detect an open circuit or short circuit of the LED of the circuit bellow. The restriction is that i musn't affect or disturb the LED current (I_LED) beacuse it modifies the LED light intensity.

Thanks for your help in advice

 

[Old Nick]

led short circuit

I'm not sure what you mean? Detect an open circuit where, the LED?

If you have an open circuit the diode will not have any current passing through, but I guess you're trying to do something different. Please explain clearly and I'll see if I can help you, I have a lot of experience designing circuits with LED's etc.

 

[Mistico_Pereyra]

short circuit detection

Hello Nick,

As you say i want to detect malfunctions in the LED (Open/short circuits). I have a set of LED's (with the same configuration than in the picture) and in case of failure of one of them the microcontroller (which drives the LED's) of the system must inform to other device the failure by serial comunication.

So, I want to detect a short/Open circuit in the LED but witout affecting the current through it while normal operation.
Thanks for your help in advice

 

[Old Nick]

led shorted

I still can't figure out what you're trying to do, shorts/opens don't just occur at random (unless you're going to be violent with these circuits), they are errors in construction which you should fix during the construction process . You'll be able to see this by the LED's not working.
The only way I can think of to do what I think you're trying to do is to monitor the voltage (and hence the current) across the resistor on every line. Or put a single resistor in series with the array of LED's and monitor the current that way.