• State
  • Locked Locked
  • Replies 2 replies
  • Subscribers 62 subscribers
  • Views 985 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 - reference design not work?

zima
Prodigy 20 points
Other Parts Discussed in Thread: TPS40211, PMP

Hello.

I want to experiment with TPS40211, so i started with slightly modified reference design by TI (documents PMP4729, PMP2708).

I am little bit surprised, that this doesn't work. LEDs only flashing, driver is continuosly restarting.

I try change R9 for lowering current, R7+R10 for modifying Isns (over-current) or change D1 (Zener) for over-voltage. All without any result.

All components and values are used by this documents. Input voltage is 8V...12V and output is for 3...4 LEDs with 1.44A. I am using CREE XP-G LEDs with forward voltage 3V (3.56V @ 1.5A).

Please, can anyone help me?

Thanks.

Aleš

  • 0
    TI__Guru 56985 points

    Ales,

     

    What modifications did you make from the base PMP designs to the reference design?

    Did you make the modifications yourself, or are you working with a reference design from TI's design services?

     

    What input voltage are you running from?  Does you input have sufficient current capability to support 10-14V output?

    Are you using a TI provided PCB board?  A customer PCB that you designed?  A standard bread board?

    Have you tried driving a 10ohm resistive load?  1 LED in series with an 8-ohm resistor?

    Have you tried increasing the soft-start time by increasing C7 (220nF provides approximately 4ms ramp to LED current, you can try extending this by increasing C7 to 1uF and see if you have an inrush or overshoot issue.

  • 0 in reply to Peter James Miller
    Prodigy 20 points

    Hello Peter,

    Thank You for your reply.

    My modifications differs from PMP4729 design only by deleting reverse polarity protection circuit and dimming circuit, with PMP2708 is identical.

    Input voltage is 12V nominal with required range 8V-13V. Input voltage tested up to 16V without any positive result. With high current input capable ofcourse.

    PCB designed and created myself with Eagle CAD.

    Resistive load i have not try, only different LED configurations.

    I tried to change C7, it should only affect the frequency of the restarting (as expected).