TPS62361B / Unexpected high output voltage at turning VIN on and off

S.Satoshi

Hi All,

I have a question for TPS62361B.

I tested to turn on and off VIN continuously, then the short duration high voltage are happened on Vout. Do you have any idea to prevent this unexpected behavior? Please see attached pdf for high resolution image.

TPS62361BEVM-655_Unexpected high output voltage at turning VIN on and off.pdf

Your quick response will be appreciated.

Best Regards,

Sonoki / Japan Disty

over 9 years ago

0 Chris Glaser over 9 years ago

TI__Guru*** 142730 points

Is this situation possible in the final system? Usually, the host would disable all rails through the EN pin. currently, you violate the abs max rating for the EN pin which cannot go above Vin plus a diode drop.

You might try PFM/PWM operation to see if this fixes the issue. But the best way is to pull EN low while Vin is still present.

0 S.Satoshi over 9 years ago in reply to Chris Glaser

Guru 21675 points

Hi Chris-san,

Sorry for delayed response. Our customer changed the setting to PFM/PWM and VIN=EN and tried to turn on and off VIN, then they still confirmed overshoot at power-up as attached. Is this expected operation? And can we reduce this overshoot?

TPS62361BEVM-655_Unexpected high output voltage at turning VIN on and off_2.pdf

Best Regards,

Sonoki

0 Chris Glaser over 9 years ago in reply to S.Satoshi

TI__Guru*** 142730 points

Do you need to tie EN to Vin or can this be controlled by a host? I recommend pulling EN low when you want to turn off the device.

I also recommend PFM/PWM mode. Have you tried this?

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TPS62361B / Unexpected high output voltage at turning VIN on and off