• State
  • Locked Locked
  • Replies 5 replies
  • Subscribers 62 subscribers
  • Views 134 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

Original question:

TPS61220: Standby current is too high when enable pin is LOW (Vin=3V, EN=0, No load at Vout)

TPS61220: TPS61220

Yilmaz Kalafat
Prodigy 20 points
Part Number: TPS61220

Hello Wenhao,

I saw that my issue was closed due to inactivity from my side. I was not able to look into the problem because of other activities. A short update:

  • I checked the waveform at pin 5. It has always a high voltage, no drop or unwanted switching when enable pin connect to GND. I conclude that the TPS is really turned oFF and not switching
  • Separated the TPS circuit from the load and measured the current into pin5. I measure 8,5uA (EN=0, In=3V). This current should be much lower.

After checking so many TPS61220 parts and looking at the data sheet, I can say that this current is the leakage current of internal switching FET  (body diode). I will send the barcodes (on the tapes) to Ti customer service to check whether they are genuine or not.  

Thanks for the feedback regarding the layout. I will implement your suggestions in next revision.

Kind regards,

Yilmaz 

  • 0
    TI__Genius 16750 points

    Hi Yilmaz,

    Thanks for reaching out.

    Just confirm with you, D203 is not populated, right?

    What if you unpopulated the T202? Is the current still above 10uA? Since the leakage current flows into L is large, we can estimate if it flows to output side.

    Thanks,

    Regards,

    Bryce

  • 0 in reply to Bryce Xun
    Prodigy 20 points

    Hello Bryce,

    Correct, D203 is not populated. I tried the following steps (always kept EN=0V, Uin= 3V):

    - Remove T202 -> No change, Iin>= 10uA

    - Removed input/output cap's to eliminate leakage currents due to solder process ->  No change, Iin>= 10uA

    - Removed the voltage divider resistors at the output (R248, R249, R250) -> current dropped to 8,5uA

    With these steps , I eliminated the components around the IC. The current doesn't go immediately to 10uA. It start around 3,5uA and in a time span of 30 to 40 seconds it reaches 10uA. Our solution will be to add another FET switch between battery and the TPS61220 input.

    Kind regards,

    Yilmaz

  • 0 in reply to Yilmaz Kalafat
    TI__Genius 16750 points

    Hi Yilmaz,

    Thanks for your update.

    As you mentioned in the before thread, you observed that 'current fluctuates a lot and has some ripple'. 'It start around 3,5uA and in a time span of 30 to 40 seconds it reaches 10uA.' I guess the 10uA current is the quiescent current. Pls check the EN pin voltage at this time. 

    Pls try to connect a 100k ohm to replace R349 to ensure that EN pin is true 0V.

    Regards,

    Bryce

  • 0 in reply to Bryce Xun
    Prodigy 20 points

    Hi Bryce,

    I replaced R349 with 100k and removed R351, no change. I would expect a quiescent current around 3-3,5uA. The output divider resistors draw around 2,16uA. I would expect 10uA or higher when enable is active and there no load connected. At least this is my understanding if i read the data sheet correctly. I made a short video clip to show the behaviour (R349=100k, R351=removed, T202=removed, Uin=3V).

    Attached link gives you access to my Google drive.  

    https://drive.google.com/file/d/1xEsYo49TKWn5omrzw-TkvMdn7R-toXNG/view?usp=sharing

    Kind regards,

    Yilmaz

  • 0 in reply to Yilmaz Kalafat
    TI__Genius 16750 points

    Hi Yilmaz,

    Thanks for update.

    Sorry I can't log in the external website. Could you show the pictures here and including the EN pin waveforms?

    Regards,

    Bryce