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TPS54202: TPS54202DDCR Quiscent current

user5225594
Prodigy 30 points
Part Number: TPS54202

Hi,

The quiescent current given for TPS54202 is 45 uA. When in no load condition we see on some of our boards the quiescent current varies a lot up to 150uA. Although the functionality is OK.

but on verification we found that by probing the FB line (contact with hand)  is making the currents come down.

Is there something that is happening with board and IC together, as when i replace the IC the boards currents are normal.  Please let me know if anything can cause this issue.

Thanks

Sumanth

  • 0
    TI__Genius 9280 points

    Hi ,

    The quiescent current given for TPS54202 is 45 uA, which is tested at EN and FB high (SW no switching). It means that devices is not switching .

    The 150 uA current is the current devices working in no loading condition and sw is still switching . 

    may i ask how do you probe the FB line ? 

    BRs,

    Young

  • 0 in reply to Young Zhao
    Prodigy 30 points

    Hi Young,

    Our circuit has regulator , Current of 50uA due to FB resistor divider circuit to regulator , and a small Device current of controller.

    Most of our boards show ~140uA in sleep, while some devices about 15% of them show more than around 200 + in sleep current at 12V input to regulator

    During analysis we found the regulator circuit is the cause of higher current.  if we touch the FB pin of regulator with metal pin , the device power input reduces, and when removed it again goes back to higher current..

    thanks

    sumanth

  • 0 in reply to user5225594
    TI__Genius 9280 points

    Hi sumanth,

    Could you help share your SCH ?

    BRs,

    Young

  • 0 in reply to user5225594
    TI__Genius 9280 points

    Hi,

    For the SCH , the Cout seems a little small for me, suggest to add one more 22uF .

    And need to confirm your concern is that the ~140uA VIN current was observed for normal , while sometimes this current value may vary to 200+ and when touch FB pin this 200+ VIN current may go to lower value ? 

    And could you help send some waveforms to young-zhao@ti.com for us to review ? VIN / SW/ Vout

    We can discuss this topic offline .

    BRs,

    Young