• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 2 answers
  • Subscribers 28 subscribers
  • Views 394 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DLP3030Q1EVM: DLP3030Q1EVM

Weite Chi
Prodigy 90 points
Part Number: DLP3030Q1EVM
Other Parts Discussed in Thread: DLP3030PGUQ1EVM

Dears,

This is Taiwan OFILM Hardware engineer Weite.

We had buy one DLP3030Q1EVM(develop PGU optical engine)

In the DLPC120ACP, the R/G/B current Duty (LDC Index) settings are fixed(only different LDCs can be selected, and the Duty cannot be adjusted by yourself).

I want to ask:

1. How to modify the R/G/B LED current Duty setting(Not choosing a different INDEX),

2. Why the R/G/B current Duty is not the same in one cycle

3. Why the R/G/B current Duty sum (high level) is less than one cycle


Many thanks & Best Wishes

Weite

T：＋886 35601326#16
P：+886-930795792
E：weite.chi@ofilm.com

  • 0
    TI__Expert 3015 points

    Hi Weite - 

    Thanks for your question.

    1) The RGB Duty Cycle is fixed by the creation of the DLPC120 flash firmware. This firmware is generated by the TI Applications Engineer team (myself included). Can you please let me know which RGB Duty Cycle(s) you are interested in, and I can provide a new flash build. 

    Note that when you change the duty cycle, you will impact the color point, and the RGB white point calibration data that is loaded onto the system will no longer guarantee robust color performance.

    2) The RGB Duty Cycle of the DLP3030PGUQ1EVM is selected to try to optimize the brightness at the target 6500K color point. Traditionally this means that green time > red time > blue time.

    3) The total RGB LED on-time does not sum up to 100% of the total frame time. There are a few factors:

    • DMD Duty Cycle
      • The DMD duty cycle can be throttled or reduced down to something like 90/10 or 70/30. This value is chosen to set the brightness needed by the application. Generally, this DMD can support the brightness requirements without the need for 100/0 DMD duty cycle.
    • DMD miromirror transition time
      • When the DMD micromirrors reset (i.e. transition from -12 degrees to +12 degrees, or vice versa), the LEDs are turned off during this transition. This results in some dark time.

    Hopefully this answered your questions. But please let me know if you have additional questions. And I look forward to your RGB duty cycle request from Question 1, so that I can provide new firmware.

    Regards,

    Ross

  • 0 in reply to Ross Schneider
    Prodigy 90 points

    Dear Ross,

    Thanks for your immediate reply..

    From question 1: RGB duty cycle will be requested later.

    Then I had other question:

    Why the Duty is not a continuous (high level) but changes high and low in a cycle.

    Like below(G LED LDC Index0)

    Many thanks & Best Wishes.

    Weite

  • 0 in reply to Weite Chi
    TI__Expert 7070 points

    Hi Weite,

    Because we have three LEDs, they are not turning on all at the same time there is a sequence. So if you were to probe the Red, Green, and Blue individually onto an oscilloscope you will see that they form a more continuous signal when combined.

    For example you can see below image where the red, green, and blue pulses are spliced and split up. So if you are looking just at green for example you will see some pulses when the Green LED is on but then gaps where the Red LED is on or the Blue LED is on. 

    Thanks,

    Alex Chan

  • 0 in reply to Alexander Chan
    Prodigy 90 points

    Hi Alex, Ross,

    Thanks for your replies...

    I will click "This resolved my issue" to closed this issue.

    The RGB duty cycle request will be confirmation then opening another issue.

    Many thanks & Best Wishes,

    Weite