• State Resolved
  • Locked Locked
  • Replies 6 replies
  • Subscribers 63 subscribers
  • Views 614 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.

TPS63070EVM-693: LED driver application noise issue

Sam Shyu36
Intellectual 735 points
Part Number: TPS63070EVM-693

Dear Sir,

We use TPS63070EVM-693 and follow below Application report to modified for LED driver. But have noise can be heard from L1. Do you have any solution for fix this noise issue? Thanks!

Application report:  www.ti.com/.../slva419b.pdf

Best Regards,

Sam Shyu

  • 0
    TI__Guru 65340 points
    Hello Sam,

    Which setup of the app note did you use? How much current is going through the diode?
    Could you please measure the output voltage of the converter as well as the reference voltage?
    Are you using the part in PWM mode?

    Best regards,
    Brigitte
  • 0 in reply to Brigitte
    Intellectual 735 points
    Hello Brigitte,

    Which setup of the app note did you use?
    Sam:　Figure 3. Value as below.
    How much current is going through the diode?
    Sam: 134mA
    Could you please measure the output voltage of the converter as well as the reference voltage?
    Sam: Will measure and update to you soon.
    Are you using the part in PWM mode?
    Sam: No. VREF tie to 3.3V. EN pin pull high to Vin.

    ILED: 0.134 A
    R1: 4220 Ohms
    R2: 1100 Ohms
    R3: 1.1 Ohms
    VREF: 3.3 V
    VIN: 3.8 V

    Best regards,
    Sam Shyu
  • 0 in reply to Sam Shyu36
    TI__Mastermind 20900 points
    Hello Sam,

    with 134mA output current the part is running in PFM mode which might cause lower switching frequencies that could induce the acoustic noise.
    Try using forced PWM mode by pulling PS/SYNC pin to LOW.

    Other measures to try to lower acoustic noise from an inductor is to use smaller form factor or lowering the output voltage ripple by increasing the output capacitor.

    Please let us know whether the inductor and output caps are still original on the EVM. If not, please share the part numbers.

    regards,
    Julian
  • 0 in reply to Julian Hagedorn
    Intellectual 735 points

    Hi Julian,

    The inductor and output caps are still original on the EVM. I will try your suggestion. Very thanks!

    regards,
    Sam Shyu

  • 0 in reply to Sam Shyu36
    Intellectual 735 points

    Hi Brigitte,

    I pull low PS pin to GND for into PWM mode had fix this noise issue. Very thanks your help~

    Best regards,
    Sam Shyu

  • 0 in reply to Sam Shyu36
    Intellectual 735 points
    Hi Julian,

    Pull low PS pin to GND for into PWM mode had fix this noise issue. Very thanks your help~



    Best regards,
    Sam Shyu