DLP4500: LED current setting

Hello Raymond,

   1. On page 25 in the user manual of DLP4500, it says "The DLP LightCrafter 4500 is an actively cooled system that has a thermal limit resulting in total simultaneous red, green, and blue LED currents less than 4.3 A for continuous LED operation.". Does that mean my current of R, G, and B should not add up to more 4.3A for a long time? If so, the default setting (R104, G135, B130) will exceed 4.3A, is that normal?

Vivek> It 4.3 A for each LED. Please refer to "1.2.1.1 Light Engine Thermal Limits" section on page 11.

          2. I would like to request for a complete data sheet for the RGB performance graph on page 25. As I would like to determine the white balanced point at different current combinations. Thank you!

Vivek> Actual light out for each color will vary from unit to unit due to variation  in LED performance from batch to batch. In addition, mechanical alignment and placement variation with in optical engine will also impact actual light output from the projector.

Typically, our customer do a baseline white point balance for a representation unit. They could take one of the following options:

 1. Dynamic white point balance - add a sensor to optical engine and dynamically balance white point based on the current light out from LED.  This is the best option because it not only takes care unit of  unit to unit variation but also address color-point shift due to aging. It does add cost and makes system complex.

2. Factory calibration - Calibrate each unit and make minor adjustment from baseline to adapt for unit variation. It is often implemented as LUT update in factory.

Hope this answers your question.

regards,

Vivek