Evaluating IV LED characteristics using a source / measure unit
Evaluating the current-voltage (IV) characteristics of light-emitting diodes (LEDs) requires the ability to output and measure both voltage and current. You can perform these measurements using a source / measure unit (SMU). A single-channel SMU is sufficient to test the basic IV parameters of an LED. Use two channels for optical tests, with one channel measuring photo diode current and the other driving the LED.
Protect your device by setting a limit on the voltage or current output and use pulsed measurements to prevent device self-heating from distorting measurement results. Also, consider implementing a 4-wire measurement scheme to overcome the voltage error caused by test lead residual resistance. Have one pair of leads forcing current and the other monitoring voltage to eliminate cable resistance effects by only measuring the voltage drop across the device-under-test. Four-wire measurements keep the voltage between sense points at the specified voltage, characterizing the device under specified measurement conditions.
LED IV characterization solution
Characterizing the IV properties of high energy-efficient LEDs requires extensive current and voltage measurement capabilities. The Keysight LED IV characterization solution includes the PZ2100 series SMU, offering 20 SMU channels in a 1U rack space with integrated pulser / digitizer, and the PW9251A PathWave IV Curve Measurement software. This solution enables you to perform LED IV characterizations under various operating conditions at extremely low current and voltage levels to validate your LED's design, identify any faults or issues, and optimize its performance.