TPS22810: Voltage drops

DVI17

Part Number: TPS22810

Hi,

We use power switch TPS22810DRV on our PCB. We leave both QOD and CT floating, use one GPIO of MCU to control EN/UVLO pin. Vin=4.2V, no load on the Vout.

Now all of our boards have the same problem. When powered up, the board input voltage drops, the current goes up, it looks like somewhere short on the board. However, we haven't found any short pins on the chip. If we take off TPS22810 from the board, the input voltage is back to normal, other parts on the board works fine. Does anybody know what this problem could be?

over 7 years ago

0 Aleksandras_Kaknevicius over 7 years ago

TI__Genius 15740 points

Hi DVI17,

Leaving both QOD and CT floating should not cause any issues, and the VIN voltage is well within range. What is the thermal pad connected to? It should be connected to GND. If VIN is connected instead, then this could create a connection between power and ground.

Thanks,

Alek Kaknevicius

0 DVI17 over 7 years ago in reply to Aleksandras_Kaknevicius

Prodigy 100 points

Hi Alek,
The thermal pad is connected to GND. Thanks.

DVI17

0 Aleksandras_Kaknevicius over 7 years ago in reply to DVI17

TI__Genius 15740 points

Hi DVI17,

Do you have any layout or schematic snippets you can share here?

Thanks,

Alek Kaknevicius

0 DVI17 over 7 years ago in reply to Aleksandras_Kaknevicius

Prodigy 100 points

Here is the schematic. Wen I tested the board, I took off the resistor R11, which means all ICs supplied by Vcc were not powered up, only U7 and and two TVI diode(D1, D2) were powered. Thanks.

Schematic1.docx

0 Aleksandras_Kaknevicius over 7 years ago in reply to DVI17

TI__Genius 15740 points

Hi DVI17,

According to your schematic, the pinout for the TPS22810 is incorrect. You have VIN and GND swapped since VIN should be pin 6 and GND should be pin 4. This reverse polarity can be the cause for the short on your board.

Thanks,

Alek Kaknevicius

0 DVI17 over 7 years ago in reply to Aleksandras_Kaknevicius

Prodigy 100 points

Sorry, it's our mistake. Thank you so much.

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TPS22810: Voltage drops