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Original question:

LP8556: Could it lighten 72 LEDs at the same time?

LP8556: Register setting

Cindy Chang
Intellectual 2475 points
Part Number: LP8556

Hi team,

Due to customer hopes LED to change the brightness smoothly, the set BTR_MODE=01  to achieve the highest current through I2C, and then use PWM to cut out 4096 levels.

Register value 00=67, 01=87,16=3f, 9e=28, A0=F0, A1=78, A2=00, A3=5e, A4=72, A5=04, A6=80, A9=A0

The above is the setting of their current register. First define the maximum current through 00, and then use A0 and A1 to define the 4096 steps.

May I have have your help to check if their setting is correct?

Thank you.

Best Regards,

Cindy

  • 0
    TI__Genius 13001 points

    Hi Cindy,

    Please refer the Figure 7 in the datasheet. The maximum current is set by current_max(A1[6:4]) rather than brightness(00[7:0]). And you can configure current with A0[7:0] and A1[3:0] to achieve 12-bit dimming through I2C.

    Since the brightness(00[7:0]) only has 8 bits, "use PWM to cut out 4096 levels" is impossible.

    BR,

    Robin