TPS54202: Output voltage overshoot

Fabio Gou

Expert 3965 points

Part Number: TPS54202

Tool/software:

The customer feedback that there is output voltage overshoot. Could you help to analysis it?

Yellow: Output voltage

Green: EN

Blue: Input voltage

1 month ago

0 Gui He 1 month ago

TI__Mastermind 26296 points

Hi Fabio

Can you please add SW waveform in the page and see is the switching stable during the start up ? And the soft start time should be 5ms.

Can you please also share the layout image?

Thanks and best regards.

0 Fabio Gou 1 month ago in reply to Gui He

TI__Expert 3965 points

The layout is as below

0 Gui He 1 month ago in reply to Fabio Gou

TI__Mastermind 26296 points

Hi fabio

Comments on the layout:

The feedback resistors(R403,R404) should be placed close FB pin, R404 should be placed close to FB pin and GND pin.

The Cin (C404) should be placed close to Vin and GND pins.

Thanks and best regards.

0 Fabio Gou 1 month ago in reply to Gui He

TI__Expert 3965 points

The green is the SW.

The yellow is the output voltage.

Why there is overshoot?

0 Gui He 1 month ago in reply to Fabio Gou

TI__Mastermind 26296 points

Hi Fabio

Seem from below image: EN seems is not the voltage divider from Vin, is it connected to other circuits?

0 Fabio Gou 1 month ago in reply to Gui He

TI__Expert 3965 points

The EN pin is connected to Vin.

0 Gui He 1 month ago in reply to Fabio Gou

TI__Mastermind 26296 points

Hi Fabio

EN is connected to Vin through a resistor divider seen from the schematic, but in the waveform, the EN slew rate changes t=t1, can customer check what happens after t1?

Thanks and best regards.

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TPS54202: Output voltage overshoot