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LP5569: LP5569 No Illumination

LWeth
Prodigy 30 points
Part Number: LP5569

I have an issue with a TI LP5569 LED driver part that I’m wondering if you could help with?

Just trying to get one LED to illuminate:

I set the Enable bit and see input current rise to what I would expect (170uA from datasheet), I set LED0 current to default, LED0 PWM to 100% and Control Reg to 0xA4 (disabling charge pump as we have external VCC and turning on PWM master override), these commands are received by the LP5569, the acknowledge bits of the data transmission are low (measured on picoscope). There is however no current flow through the LED.

Additionally, If I try write any command to the 2 x "LED CONTROL ENGINE" registers the current goes to double the maximum specified on the datasheet. I am wondering if this is a clue?

Attached is the schematic of the setup I am currently using.

I am thinking of getting the development board in to see whether it is a setup error or not. Do you think this would be good avenue to explore?

Any help would be appreciated, thank you in advance.

  • 0
    TI__Genius 9255 points

    Hi LWeth,

    Please have the following try first:

    -power up

    -write FFh to address 42h

    -write 0100 0000 to address 00h

    -write 0000 1100 to address 07h(don't choose PWM input master fading)

    -write FFh to address 16h

    -write AFh to address 22h

    if there is any questions, keep contacting me. 

    Best Regard 

    Monet Xu

  • 0 in reply to Monet Xu
    Prodigy 30 points

    Hi there,

    What does writing FF to address 0x42H achieve, is this not just engine variable A?

    I have resorted to purchasing the EVM board and using the EVM software to ensure my I2C commands are correct.

    Will update with findings.

    Kind regards.

  • 0 in reply to LWeth
    TI__Genius 9255 points

    Hi LWeth,

    sorry for my mistake.

    Writing FF to address 0x3Fh for software reset.

    Keep connecting and if here is any updating, reopen these question is OK~

    Best Regard

    Monet Xu