• State
  • Locked Locked
  • Replies 4 replies
  • Subscribers 63 subscribers
  • Views 496 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

TPS40211 datasheet, error in equation 59?

FordFairlane
Expert 1505 points
Other Parts Discussed in Thread: TPS40211, TPS40211EVM-352

Hello

In TPS40211 datasheet (SLUS772C), in desing example 1, I think the result in Zout equation 59 on page 30 is wrong. Could anybody check this?

Where could I get more information about desing example 2?

I'm using TPS40211 to drive LEDs in continuous current mode.

Thank you in advance

  • 0
    TI__Guru 56825 points

    Ford,

    Regarding the issue with Equation 59:

    1) Do you believe the symbolic equation (equation 59) is incorrect or do you believe there is an error in the numeric solution (Equation 60)?

     

    Regarding Example 2 for TPS40211 LED drive:

    This example is detailed in the TPS40211EVM-352  - http://focus.ti.com/docs/toolsw/folders/print/tps40211evm-352.html 

  • 0 in reply to Peter James Miller
    Expert 1505 points

    My numeric result is different from the datasheet, but I don't know where is the error, maybe it's my mistake, or the symbolic equation or the numeric solution. Maybe the symbolic equation is incorrect because the numeric solution is a reasonable result.

    Actually, I prefer the transfer function to draw the Bode Plot to design the compensation net with my components and my crossover frequency. I need the transfer function using the TPS40211 in constant current mode, like SLUU351 to drive LEDS up to 24V, but usually works at 20V. The input is from 11V to 15V. I'm using a Type 2 compensation.

    Thank you

  • 0 in reply to FordFairlane
    TI__Guru 56825 points

    Ford,

    I will check the numeric solution in Equation 60 to see if there is an error there, thank you for the assistance with that portion of the solution.

  • 0 in reply to Peter James Miller
    Expert 1505 points

    Hello!

    In TPS40211 datasheet (SLUS772C), in desing example 1, I think the result in Zout equation 59 on page 30 is wrong. Could anybody check this?

    My numeric result is different from the datasheet, but I don't know where is the error, maybe it's my mistake, or the symbolic equation or the numeric solution. Maybe the symbolic equation is incorrect because the numeric solution is a reasonable result.

    Actually, I prefer the transfer function to draw the Bode Plot to design the compensation net with my components and my crossover frequency. I need the transfer function using the TPS40211 in constant current mode, like SLUU351 to drive LEDS up to 24V, but usually works at 20V. The input is from 11V to 15V. I'm using a Type 2 compensation.

    Thank you