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Dimming DLPC6401 over I2C

Joachim Bargsten
Prodigy 40 points
Other Parts Discussed in Thread: DLPC6401

Hello


I am programming at the moment an interface for the DLPC6401 using the I2C.

I want to reduce the LED current to reduce the brightness. But at the moment I can change the values, but there is no influence on the LED current.

May be someone has experience with this and can send me more information which addresses I have to change to have influence to the current.

My aim is to reduce the brightness of the image, is there a different way to do this?


Kind regards


J.Bargsten

  • 0
    TI__Prodigy 750 points
    Hello Joachim, What address values were you trying to change?
    There are several different setting related to LED current.
    1) LED Max Current Duty Cycle2) LED Current PWM3) LED Max Current
    You will want to change the LED Current PWM setting to directly change the LED current.
    Regards,RP
  • 0 in reply to Roger Perry
    Prodigy 40 points

    Hello Roger

    I have tried different values, here are the actually values.
    Maybe you can give me an information which values I should change to see a result.

    LED Current address 4Bh:
    Byte 0 = 0   Byte 1 = 6C   Byte 2 = 0   Byte 3 = 81   Byte 4 = 0   Byte 5 = 9B


    LED MAX Current 58h:
    Byte 0 = 0   Byte 1 = FF   Byte 2 = 0   Byte 3 = FF   Byte 4 = 0   Byte 5 = FF


    Brightness Controll 23h:
    Byte 0 = 0   Byte 1 = 0   Byte 2 = 0   Byte 3 = 0   Byte 4 = 0   Byte 5 = 0


    Get LED Sensor Value 4Ch:
    Byte 0 = 0   Byte 1 = 0   Byte 2 = 0   Byte 3 = 0   Byte 4 = 0   Byte 5 = 0


    Internal Sensor Word 5Ah:
    Byte 0 = 8   Byte 1 = 47   Byte 2 = 4   Byte 3 = 79   Byte 4 = 5   Byte 5 = E


    CCI Control 57h:
    Byte 0 = 8

    Regards, Joachim

  • 0 in reply to Joachim Bargsten
    TI__Intellectual 2200 points

    Hi Joachim

    Your current command sent correctly, but since DPP6401F automatically adjusts the currents for maintaining the White Point, this command is primarily intended to be read only. However, if you want to explicitly control the LED PWMs, then you can do so by disabling the White Point Correction algorithm.

    CCI Control 57h:
    Byte 0 = 0  // Write 0 will disable the CCI (WPC).

     

    Regards,

     

    Frank Xu