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DLP4710EVM-LC: Replacing LEDs for more light output

Thomas Kurmann
Prodigy 10 points
Part Number: DLP4710EVM-LC
Other Parts Discussed in Thread: DLPA3005

For our structured light application we require a higher light output from the DLP4710EVM-LC module. From my understanding currently the blue LED is a Osram LE CG P1A 3.35V 16A module. We are planning on replacing this module with the more powerful LE B P2MQ 14V 12A. Looking at the schematics and datasheet, it seems that the dlpa3005 and power FETs would support this voltage / current range.

I would have two questions regarding feasibility of this modification:

- In the datasheet of the dlpa3005 it is written that V_LED_ANODE can be up to 6.2V, yet in some threads in this forum it was mentioned that V_LED_ANODE can be up to 0.85*V_IN (in this case 16.15V). Can you confirm that this is the case?

- The startup current seems to be fixed at 10A, is there a way to modify this value (make it lower) and make it persistent?

Thank you very much for your support!

  • 0
    TI__Genius 16870 points

    Hi,

    The highest validated VLED is 6.3 V - this value was chosen because of the LEDs available years ago when this was validated. however in theory the highest VLED that could be driven is 0.85x VIN. its just that in our EVMs we limit the current going through the LEDs in such a way that VLED does not exceed 6.3V

    To date the highest VLED voltage that has been validated is 15.5V for DLPA3005. the datasheet has a backlog of updates that include this. for legal reasons exceeding 6.3V VLED is to be done at your own risk. It will take testing on your device to ensure that you are not exceeding the VLED limit with the LEDs you are using.

    You can change the startup currents using the Display and Light Control EVM GUI. in the firmware tab you can select "update flash image" and there will be fields where you can change the startup currents persistently.

    Regards,
    Arthur

  • 0 in reply to Arthur Brown
    Prodigy 10 points

    Hi Arthur,

    Thank you for answering the questions. We will make sure to not surpass the VLED limits by limiting the current to a safe level. We could change the startup currents as you described.

    Another question popped up regarding thermal limits. From the datasheet (section 7.6) I assume the calculations of dmd temperatures are based on constant illumination. For our application we are planning on illuminating for 1-2s (60-120x patterns with 15ms duration), then having at least a 30s pause. Would a LED with 3x the light power output significantly reduce the life-span of the dmd?

    Thank you!

  • +1 in reply to Thomas Kurmann
    TI__Genius 16870 points

    Hi,

    You are correct, the power limits for the DMD assumes constant illumination. And you can get away with higher power for shorter durations of time.

    Here is a TI white paper over the topic. This is from our cinema group, but the materials and process for Pico and cinema DMDs are similar, so I assume the information applies https://www.ti.com/lit/wp/dlpa027/dlpa027.pdf?ts=1629823476101&ref_url=https%253A%252F%252Fwww.google.com%252F

    The general rule from this paper appears to be that if you obey the average power/time limits given in the data sheet, and if the instantaneous temperature of the DMD doesn't exceed 150 C you should be fine.

    Regards,

    Arthur