• State TI Thinks Resolved
  • Locked Locked
  • Replies 5 replies
  • Answers 2 answers
  • Subscribers 62 subscribers
  • Views 94 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS92520-Q1: Can the device respect fliker relating requirement?

zhiyuan zhang
Intellectual 620 points
Part Number: TPS92520-Q1

Hello expert,

    Below is the customer requirement. How to understand this? Does it mean we should set the PWM dimming frequency no less than 1000Hz?

  • 0
    Intellectual 620 points

        Addition requirement as below: to keep the off time less than 0.00025s, for dimming frequency 1k we should limit the duty less than 75%. Am I right?

  • 0
    TI__Mastermind 18955 points

    Hello Zhiyuan,

    I would talk to the customer about clarification, but from the graph it seems in order to support the entire duty cycle range the PWM frequency needs to be a min of 1000 Hz.  That is how I am interpreting it.  It looks like it allows you to do variations in pwm duty cycle (%) depending on PWM frequency.  That allows them to do dynamic adjustments.  You really need to talk to the customer about getting clarification.  I have never seen this type of plot.

    -fhoude

  • 0 in reply to zhiyuan zhang
    TI__Mastermind 18955 points

    The image is cut off on the bottom and the resolution isn't great.  Can you give me a better image.  I think you are probably write, but I can't confirm without the better image.  Again, this is a customer requirement and I think you should get clarification from them.  I haven't seen this plot before.

    -fhoude

  • 0 in reply to fhoude
    Intellectual 620 points

     Hello fhoude,

       ASSIST, CFD, IEEE1789 seems to be the flicker standard, customer just ask us to respect it.

      Below is the picture with higher resolution

  • 0 in reply to zhiyuan zhang
    TI__Mastermind 18955 points

    I am looking at this standard and this isn't an automotive standard.  I have a copy of the IEEE 1789 standard and I am not seeing any of these plots.  We regularly operate in some of the "forbidden areas" and I am not sure how our application pertains to this standard.  I couldn't find anything in the standard that talks about drop amplitude or duration.  Please go back to your customer and get clarification from them.  I don't know how to help you.  

    -fhoude