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LP5018: LED output state when the LED output is stopped

Part Number: LP5018
Other Parts Discussed in Thread: TEST

I would like to ask about the LED output state when the LED output is stopped.

①Set LED output duty to 0% when EN = Hi
② LED output is forcibly stopped when EN = Low

Is there any difference in the LED output status between these two methods?
(For example, is the phenomenon that the LED output does not turn off and lights up for a moment using the method of ①?)

Best Regards,

Y.Ottey

  • Hi Ottey,

    Ultralow Quiescent Current:

    Shutdown Mode: 1 μA (Maximum) With EN Low.

    Power Saving Mode: 10 μA (Typical) With EN High and All LEDs Off for > 30 ms.

  • Dear Charles,

    Thank you for your reply.

    I would like to ask additional questions.

    1. As a meaning of your answer, is it okay to recognize that there is a difference in Quiescent Current between methods ① and ②?

    2. In the case of Method ①, we think that there will be a delay time from when Duty is set to 0% in the resist until Duty changes to 0%.

    At that time, does the phenomenon that the connected LED lights up before Duty changes to 0%?

    Regards,

    Y.Ottey

  • Hi Ottey,

         1. Yes.

         2. You have to send the command to turn off LED and it takes some time. Before the end of your turn off command, the state of LED will not change.

  • Dear Charles,

    Thank you for your reply.

    I would like to ask more questions.

    Isn't the operating state of the drive circuit inside this device different between the methods ① and ② in my post?
    This device is operated with a constant current circuit, and in the case of methods (1) and (2), the constant current source is considered to be OFF.

    Further, regarding the leakage current, when the duty was 0%, the data sheet had the following description.

    Is the leakage current in the case of EN = Low the same as the value range described above as in method ②?

    Regards,

    Y.Ottey

  • Dear Charles,

    Thank you for your reply.

    I would like to ask more questions.

    Isn't the operating state of the drive circuit inside this device different between the methods ① and ② in my post?
    This device is operated with a constant current circuit, and in the case of methods (1) and (2), the constant current source is considered to be OFF.

    Further, regarding the leakage current, when the duty was 0%, the data sheet had the following description.

    Is the leakage current in the case of EN = Low the same as the value range described above as in method ②?

    Regards,

    Y.Ottey

  • Hi Ottey,

         What's the accuracy requirement in your application? Please clarify your target more clearly.

         The LED will not go on if chip is shut down. The Ilkg of LED and corresponding channel not only depends on the chip, but also depends on the characteristic of LED.

          We don't have the Ilkg data under EN=L. If you are interested in it, you can test it by yourself. But the channel is supposed to be high resistivity state and the leakage current is very low.

  • Dear Charles,

    Thank you for your reply.

    We are checking the accuracy requirement.

    We have received additional questions from our customers.

    Is there data on the delay time from when Duty is set to 0% until the output actually reaches 0%?

    If you know, please let me know the delay time from setting Duty to 0% until the actual output is actually 0%.

    Best Regards,

    Y.Ottey

  • Hi Ottey,

        You can test it on your board.