measure diode max current

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siongboon

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Hi Friends,

Is there a theory or method to measure the maximum current that a diode can handle, without access to a datasheet?
I can't think of a solution without damaging the diode.
There are instrument that can do diode measurement, so there must be a way.

Thank you for your pointers.
Siong Boon
 


A maximum forward current in a P/N junction diode is usually determined by junction maximum temperature. It depends on material and diode design, also reliability is important.

If you can, measure diode temperature. To be on a safe side , when the temperature SLOWLY approaches 100 deg.C, I would stop and say this can be the limit. Remember, P/N junction current is an exponential function of temperature, so it can grow quite fast as you push the current.

If you need to know the PULSE maximum current, generally it depends on duty cycle.
 

You first must define your use condition and what
constitutes "maximum". Continuous, pulsed repetitive,
pulsed once? What degradation is to be accepted or
rejected?

Then it becomes a matter of testing. You do not know
a priori what the diode's temperature limit is, before
some bad thing happens. So calculating temperature
rise won't be especially useful until.

Even packaging has an effect, and possibly more from
cycling than temperature itself.
 

The application is a instrument to measure the max forward current of the diode.

I heard from a friend that he is using LED controller which can automatic adjust the max current limit for an unknown LED light panel.
Some instrument can measure the parameter of transistor and diode through their leads.
But in theory I am not able to figure it out.

Using temperature method seems to be difficult and troublesome,
because the component package various.

After searching the web, I think it may not be possible to auto detect the max current of a diode can handle,
without damaging it. Temperature detection may be the best way perhaps.
 

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