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TPS92511: Behavior when ILED<40mA

Shinichi Inoue
Guru 21841 points
Part Number: TPS92511


Dear Specialists,

My customer'd like to know when ILED is 40mA.

I would be grateful if you could advise.

---

Since it is necessary to set the LED current consumption to about 40mA due to the system current consumption, I would like to use it with a resistor of 30kΩ or more.

What will happen at this time?

We are thinking that the accuracy of the LED current will deteriorate and that it will operate intermittently.

what else will happen?

---

I appreciate your great help in advance.

Best regards,

Shinichi

  • 0
    Guru 21841 points

    Dear TI'er

    I'm still looking forward to waiting your advice.

    I appreciate your great help.

    Best regards,

    Shinichi

  • 0 in reply to Shinichi Inoue
    TI__Genius 13001 points

    Hi Shinichi,

    I think the loop performance will be worse and loop may be unstable. So why not set higher IADJ and get smaller current with PWM dimming?

    BR,

    Robin

  • 0 in reply to Yuting Shao
    Guru 21841 points

    Hi Robin,

    Thank you for your reply.

    I obtained the customer's comment.

    Could you please see below and advise.

    ---

    Since it was necessary to set the LED current consumption to about 40mA due to the system current consumption, this model was evaluated with a resistor of 30kΩ or more.

    When I reviewed the data sheet again, I found a note and asked a question.

    Currently using it with 38kΩ, but there is no problem.

    Since the evaluation is progressing, if the current accuracy only deteriorates, I would like to use it as it is.

    Is there a risk of abnormal operation or damage to the circuit?

    ---

    I appreciate your great help and cooperation.

    Best regards,

    Shinichi

  • +1 in reply to Shinichi Inoue
    TI__Genius 13001 points

    Hi Shinichi,

    If worse output current accuracy is acceptable by customer, I think you can use it.

    BR,

    Robin

  • 0 in reply to Yuting Shao
    Guru 21841 points

    Hi Robin,

    Thank you for your reply.

    I understand the output current accuracy is worse when Ilim resistor value is >30kohm.

    I'll share this information with the customer.

    I appreciate your great help and cooperation.

    Best regards,

    Shinichi