TPS54531: Power Output Issue

TUSHAR GAUTAM

Part Number: TPS54531

Hello TI,

I used TPS54531 for 3.3V, 3.5A output for 5V input. When I plug in the power source I don't receive any output at once. I get output in few attempts and it remains stable further.

Below is the circuit I made. Please suggest,

over 4 years ago

0 Zhao Ma over 4 years ago

TI__Genius 15135 points

Hi, TUSHAR

Could you send use the waveforms?

Please probe the PH, VOUT, VIN voltage and zoom in.

0 TUSHAR GAUTAM over 4 years ago in reply to Zhao Ma

Prodigy 130 points

Hello Zhao,

Here are the images for both the cases

Not-Working

Non-Working.zip

Working

Working.zip

0 Zhao Ma over 4 years ago in reply to TUSHAR GAUTAM

TI__Genius 15135 points

Hi, TUSHAR

From the below waveform, VIN voltage is not stable, the valley voltage is about 2.5195V which will trigger UVLO(threshold is 3.5V), which will cause the device stop switching.

So please check why there is big ripple on input voltage, and are the input caps(C70 and C71) placed closely to VIN pin?

Besides, could you send me the layout for reviewing? layout screenshot is ok.

0 TUSHAR GAUTAM over 4 years ago in reply to Zhao Ma

Prodigy 130 points

Hello Zhao,

I have tried with mutiple input supply sources and it is coming like this only for few of the attempts.

Please see the layout below,

Thanks,

Tushar

0 Shawn Nie over 4 years ago in reply to TUSHAR GAUTAM

TI__Genius 10070 points

Hi,

I think the boot UVLO is triggered, please make sure there is no output voltage before powering on.

Or you can try to increase VIN to see whether still has this issue.

Shawn

0 TUSHAR GAUTAM over 4 years ago in reply to Shawn Nie

Prodigy 130 points

I tried increasing Vin and still it didn't work .

There is no UVLO trigger we see.

0 Shawn Nie over 4 years ago in reply to TUSHAR GAUTAM

TI__Genius 10070 points

Hi,

I mean " BOOT UVLO", not "VIN UVLO".

You can try to set VIN=12V, and check if there is this issue.

Also, you can discharge the output voltage to 0, then power on, and check this issue.

Shawn

0 TUSHAR GAUTAM over 4 years ago in reply to Shawn Nie

Prodigy 130 points

This is working fine for 12V input by my use-case is to get 3.3V 3A from 5V input. Please suggest.

0 Shawn Nie over 4 years ago in reply to TUSHAR GAUTAM

TI__Genius 10070 points

Hi,

Did you check "you can discharge the output voltage to 0, then power on, and check this issue."? How about it?

Shawn

Power management

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TPS54531: Power Output Issue