Chroma DC Load Simulates LED for Driver Testing

PR Log (Press Release) – Sep 02, 2009 – Chroma Systems Solutions Inc., a leader in power test instruments and systems, announced the release of the industry's first LED simulator for driver testing. The 63110A electronic load allows the forward voltage (Vf) and operating resistance (Rd) to be adjusted to the LED’s V-I curve and simulates ripple current characteristics of typical LED’s. The 63110A load also has increased bandwidth to allow for PWM dimming testing. Until now, LED drivers have been typically tested with actual LED’s or resistive elements. Chroma’s new electronic load is of particular interest to engineers who strive for faster test methods, automation and repeatable load characteristics which modern electronic loads provide.

When using a resistor as a load, the V-I curve of the resistor is not able to simulate the V-I curve of the LED. This can cause the LED driver to not start up due to the difference in V-I characteristic between the resistors and LED’s. When using conventional e-loads, the CR and CV mode settings characterize the LED under stable operation and therefore, are unable to simulate turn on or PWM brightness control characteristics. This may cause the LED driver to function improperly or trigger protection circuits. Using LED’s as the load creates issues regarding LED aging and driver requirements may require use of different LED types or number of LED’s making production testing or change-over inconvenient. The 63110A was specifically designed to simulate LED I-V curve and characteristics to eliminate conventional load disadvantages. Not only can it test in stable conditions but it can also test turn on and PWM dimming characteristics of the LED driver and the Rd value can be adjusted according to the LED V-I curve.

Waveforms are available to view on Chroma’s website -http://www.chromausa.com/dcloads/63110a.html - showing comparisons of Chroma’s 63110A LED simulation functions including start up voltage and current, dimming current and ripple current against conventional methods.  The 63110A modular DC electronic load - 2A/300V/100Wx2 channels - is used with Chroma's 2 or 4 channel mainframes and includes the same key features found in our 6310A series of modular loads.