TPS61022: Output problem

Jay Guo

Prodigy 40 points

Part Number: TPS61022

Hello,

I am using TPS61022RWUT to get a 5.1V output from 3,3V input. here is the schematic:

with 3.3V input, the output is 3.3V too. I measured voltage at FB, it is 0.39V only. Can you advice?

Thank you.

Jay

over 4 years ago

0 Zack Liu over 4 years ago

TI__Mastermind 34231 points

Hi Jay,

I can't see your schematic. Can you share the schematic and layout?

0 Jay Guo over 4 years ago in reply to Zack Liu

Prodigy 40 points

Please see schematic and Layout.

Thank you.

Jay

0 Zack Liu over 4 years ago in reply to Jay Guo

TI__Mastermind 34231 points

Hi Jay,

1. Can you share the chosen inductor L1 part number or datasheet? It looks like this inductor package is really small, which saturation current is very high enouhg.

2. The issue is related to layout. For boost converter, it's essential to place the output capacitors C3, C4, C5 close to Vout pin and GND pin. Normally the PCB second layer is a whole GND plane and IC GND pin, feedback lower resistor is connected through GND vias. I didn't see there is GND vias so the feedback has problem. Please follow the layout guideline: https://www.ti.com/lit/an/slvaes4/slvaes4.pdf?ts=1602553079116&ref_url=https%253A%252F%252Fwww.ti.com%252Fsitesearch%252Fdocs%252Funiversalsearch.tsp%253FsearchTerm%253DTPS61022%2Blayout%2Bguideline

0 Jay Guo over 4 years ago in reply to Zack Liu

Prodigy 40 points

Hi Zack,

Thanks for your help. Here is the inductor: ASPI-0530HI-1R0M-T2, FIXED IND 1UH 7A 14 MOHM SMD.

Jay

0 Zack Liu over 4 years ago in reply to Jay Guo

TI__Mastermind 34231 points

Hi Jay,

Thanks. This inductor should be OK for this design. Please go ahead to optimize the layout.

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TPS61022: Output problem