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LP8556: LP8556 - I2C and LED Channels

Thomas Pressentin
Prodigy 10 points
Part Number: LP8556

Hello,

we want to use an LP8556 in our design and have two questiosn about it, i hope i can get help here.

For the package type there are 3 different Devices given.  LED Channel Count 5,4, or 6.
Which channels are useable in which part? There is no description which of the 6 channels are lost in the 4 and 5 channel devices.

Under device option is written „PWM ONLY“ – Recommended for Systems without an I2C master. So I2C cannot be used for these devices?
Or is a communication between a master and the LP8556 via I2C always possible and i have to change a register, so i can use I2C instead of PWM to controll the backlight?

I really hoope there is an easy answer for these two questions.

Best regards,
Thomas

  • 0
    TI__Prodigy 600 points
    This item has been assigned; someone will reply shortly.
  • 0 in reply to Rodney Jones
    TI__Intellectual 1985 points

    Hi Thomas,

    For 4 LED configuration, LED1, 2, 3, 4 are used; for 5 LED configuration, LED 1, 2, 3, 4, 5 are used. The high number LEDs are the one to give up first. You can refer to Table 6 in the datasheet for more information.

    I2C communication is always possible for all options. For those options with "PWM Only", it is also possible to use I2C communication; these options are meant for system without I2C capability and wish to control the brightness with external PWM signal only. If you plan to use these options, take note that if you plan to use I2C to control the brightness or making changes to some of the setup, you have to make sure external PWM is not active when the device is enabled or else LEDs will turn on before you can make changes to the registers.

    Regards
    H L