TPS40057: TPS40057 quiescent current issues

Hello,

I want to understand what the sources for this current draw are. Can you please share your schematic?

Thank you,
Katelyn

Dear Mam

Thanks for your reply.

pls find the attached schematic and MOSFET datasheet.

Awaiting for your quick reply.

24V_12V.pdfKIA-Semicon-Tech-KNB3306B_C176838.pdf

Hello,

Thank you for sharing the schematic. I do not anything that I would expect to draw 10's mAs. Can you confirm that this test is done with no load on the output, and not with a light load?

Thank you,
Katelyn

HI

Yes. The test is done only at no load condition ( I have removed the LED's resistor R4 ).

Even in this state Current consumption of the converter is 27mA.

Pls find the below test case and share your comments:

I have removed the HDRV & LDRV resistors ( 0 Ohms ) - Now I am purposely breaking the switching pules from the controller to TOP & Bottom MOSFET's . Because of this case the product is not producing the desired output of 13.5V.

Now the controller IC consuming 3 mA.

If I am soldering R7 & R8 - Now the TOP & Bottom mosfets are start switching & producing the output of required 13.5V -
Again the converter start consuming 27mA of current.

I have also tried the below methods:

1) Changed the switching frequency

2) Changed the compensation network

3) Changed the both TOP & BOTTOM MOSFET with very low RDs ON - Low gate charge & Gate TH

4) Changes the inductance too

These all are not given as expected result.

so pls share your comments.

Hi Katelyn

Any update on this reg...?

Awaiting for your fb

Hello,

Thank you for taking these measurements. When you remove the FETs, you do measure 3mA. This matches the Electrical Characteristics table in the datasheet.  You can see that the test condition specifies: "Output drivers not switching, VFB ≥ 0.75 V".  This means that the switching quiescent current will be higher. I would recommend that you use a device that has light load operation.  One option would be the LM25141. http://www.ti.com/lit/ds/symlink/lm25141.pdf

Best Regards,

Katelyn

Hi katelyn

Greetings for the day,

Yes, Without FETS the controller consumes ~3mA only.

Because of the absent of light load operation, The part TPS40057 consuming high Quiescent current...? May I conclude like this....?

Since I have chosen the below listed parts for low quiescent current (less than 10mA)

1)         LM25117PMHE/NOPB        

2)         LM3150MH/NOPB
 
3)         LM5117PMHE/NOPB

Kindly review and provide your feedback / comments on the same.