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TPS63070: TPS63070

Slava Gotlib
Prodigy 10 points
Part Number: TPS63070

Tool/software:

Hello,

In my design i am using TPS63070 power supply. 

The input voltage is from 4.3V to 6V (four 1.5V batteries).

The current consumption is about 10mA (light load).

The output voltage configured to 5.2V 

Please find attached picture of my design.

When I measure the input current, I see on scope current pulses every 200usec. and 100-140mA amplitude (please see attached scope picture).

So, my question is why I have these current pulses and how i can remove them.

Thank you and regards.

Slava Gotlib

 

My design

  • 0
    TI__Mastermind 32350 points

    Hi  Slava Gotlib,

    It is because device working with PFM mode to save power. if you do not care about the efficiency, you can just connect PS_SYNC pin to GND to set FPWM mode for device.

    Regards

    Tao

  • +1 in reply to Tao Zhang
    Prodigy 10 points

    Hi Tao,

    You are right, it is cause because PFM mode. But if I do care about the efficiency, how can I remove or reduce this effect?

    And another question please, during the development stage how I can expect this effect? Because in datasheet I didn't find any graph or information about this.

    Also, when I simulate this component with "webench power designer" i didn't saw any current spiks (Maybe you can advise me where I can see this).

    Thank you and regards

    Slava

  • 0 in reply to Slava Gotlib
    TI__Mastermind 32350 points

    Hi  Slava,

    As you seen, frequancy of  these spikes are realy low,  which makes them hard to handle with. Ideally, you can place a double pole at low frequency(may be one tenth  the frequency of your spikes). Another thing to remind is that actual frequency of spikes change with load.

    Slava Gotlib said:
    And another question please, during the development stage how I can expect this effect?

    They are nromal behavior for a device working in PFM mode, i think just make sure the peak current will not out of capability of your battery is good.

    For Webench design, you can see the current spikes by adding Iin waveforms.

     

    Regards

    Tao

  • 0 in reply to Tao Zhang
    Prodigy 10 points

    Thank you Tao!

  • +1 in reply to Slava Gotlib
    TI__Mastermind 32350 points

    Hi  Slava,

    Can you help to close this thread without new reply if no further questions?

    Regards

    Tao