• State Resolved
  • Locked Locked
  • Replies 8 replies
  • Subscribers 63 subscribers
  • Views 610 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.

TPS63031: Audible noise with power save-enabled

Asael7
Intellectual 270 points
Part Number: TPS63031

I have designed a board where I use the TPS63031. The input voltage is from a Li-ion battery (3.3 V to 4.2 V), nominal current is less than 5 mA and max current is 500 mA.

I use an inductor with a Isat = 1.29 A.

There is an audible noise, the noise is higher when maximum current is present.

I attached the schematic of the DC-DC converter.

In the board, I don't have the choice to change to power-save disabled, so, I don't know if it's something exclusive of power save-enabled or  it would have the same problem with power-save disabled.

Could you help me to understand the possible causes of the problem.

  • 0
    TI__Mastermind 21565 points

    Hi Asael:

    Sorry, there may something wrong about the Website. I couldn't see your schematic. Do you mind to upload it again and check if you could see it. If the issue is still exist, I will check if there is another way to upload.

    For your question, may I know the condition when there is noise? Is it happened for whole Vin range? It's appreciate if you could catch the waveform about Vin, L1 ,L2 , Vout. Better with Icoil. Thank you.

  • 0 in reply to Minqiu Xie
    Intellectual 270 points

    Noise I think is because with power-save enabled, with the typical current less than 5 mA, the frequency is in the audible range, like 6 Hz, 660 Hz and about 10 kHz. But, The loudest sound is identifiable when there are changes between typical current and maximum current.

    But I would like to know if that is the cause or is there any other cause.

    Give some hours and I'll upload the waveforms.

    This is the schematic.

  • 0 in reply to Asael7
    Intellectual 270 points

    I attached the waveforms of VIN and VOUT, L1 and L2, I can't measure it.

    The bottom signal in the images is VOUT and the other is VIN.

    In first image the frequency is 625 Hz. This is when typical current is consume, less or equal to 5 mA.

    Second image is before maximum current is consume and the frequency is 5 kHz.

    Same thing is when voltage goes from maximum current to typical current. In transition about 5 kHz and then with typical current is about 600 Hz.

  • 0 in reply to Asael7
    TI__Mastermind 21565 points

    Hi Asael:

    The TPS63031 has higher than 2MHz switch frequency. So the frequency you see in the waveform about full load is not exactly switch frequency. 

    May I recommend you to debug the system step by step? It will be easier to locate the issue.

    1. Replace the battery with a stable power supply. Make sure the Vin is stable during the whole test.

    2. Replace the load with Resistance. And varied resistance to get 5mA, 200mA, 500mA.

    3. Test again to see if there is any audible noise. If exist, catch the waveform, better with Icoil. If not exist, it's reasonable to assume it caused by the battery or load condition.

    We could do deeper analysis after that.

     

  • 0 in reply to Minqiu Xie
    Intellectual 270 points

    Frequency in the waveform indicated with the cursors are in Hz or kHz. When the cursors indicate about 600 Hz the load is a light load and when the cursors indicate 5 kHz is before the full load. With full load I have a greater frequency. 

    1. I replaced the battery with a stable power supply and I listened an audible noise.

    As soon as posible I will do step 2 and 3.

  • 0 in reply to Asael7
    TI__Mastermind 21565 points

    Hi Asael:

    The frequency you mentioned is caused by unstable probably. And we should locate which factor is unstable, the Vin, or Load, or Converter.

    Did you test the Vin when using power supply?  As I want's to check if the Vin pin is stable.

     

    Waiting for your updating~

  • 0 in reply to Minqiu Xie
    Intellectual 270 points

    I have replaced the load. With 5 mA there's an audible noise. With 200 mA and 500 mA there isn't an audible noise.

  • 0 in reply to Asael7
    TI__Mastermind 21565 points

    Hi Asael:

    It maybe caused by the power save mode from your test. If power-save mode is enabled, the converter stops operating if the average inductor current gets lower than about 100 mA and the output voltage is at or above its nominal value. If the output voltage decreases below its nominal value, the device ramps up the output voltage again by starting operation using a programmed average inductor current higher than required by the current load condition.

    You could try to disable the power save mode. Besides, it may do some help if you choose integrated inductance.