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LP5891-Q1: Questions about LP5891-Q1

Chase Jeong
Mastermind 7505 points
Part Number: LP5891-Q1

Tool/software:

Dear TI experts,

My customer checks the specification of LP5891-Q1. Could you check the questions from my customer?

1. If I use red LED only, Can I apply 3.3V to VCC,VLEDR,VLEDGB power rails?

2. Is there any worse point if I use only 5V power supply to LP5891-Q1 copared to apply 3.3V? (for example, worse efficiency, worse thermal characteristics ans so on)

3. Datasheet says that LP5891-Q1 has 48 current source channels from 0.2 mA to 20 mA.

Then If my customer use all channels which have 20mA current consumption, and if my customer connect 16 LEDs per 1 channel,

48 lines * 16 LEDs * 20mA = 15.36A <- Is my calculation right?

Please check these issues. Thanks.

Best regards,

Chase

  • 0
    TI__Genius 9255 points

    Hi Chase,

    Chase Jeong said:
    1. If I use red LED only, Can I apply 3.3V to VCC,VLEDR,VLEDGB power rails?

    Yes. but I suggest selecting the suitable VLED based on the LED spec. if you choose higher VLED, the IC will suffer higher dissipation. if you select lower VLED, the headroom is not enough to output target current.

    Chase Jeong said:
    2. Is there any worse point if I use only 5V power supply to LP5891-Q1 copared to apply 3.3V? (for example, worse efficiency, worse thermal characteristics ans so on)

    if using 5V for VLED, the EMI will worse, if using 5V for VLED, same concern in the above

    Chase Jeong said:
    48 lines * 16 LEDs * 20mA = 15.36A <- Is my calculation right?

    No, the 20mA is peak current. if using 16 lines, the average current is 20mA / 16 lines = 1.25mA, so total current is 20mA * 48 = 0.96A.

    by the way, could I know who is end customer? does this for real project or platform?

    BR

    Monet Xu