TPS43060 - BOOT pin shorted to ground

John Chen65

Other Parts Discussed in Thread: TPS43060

Hello

We are facing a problem that boot pin of TPS43060 shorted to ground when plugged in DC voltage (35V) into system directly without any soft-start and enable pin was low level (Vout = 0V). In this design we set the output voltage is 51V, but even it wasn't work to continues output voltage, it will be damaged by input voltage pluuged.

Did you ever seen the problem before? Do you have any idea about that?

Thanks,

John

over 9 years ago

0 JohnTucker over 9 years ago

TI__Guru**** 191445 points

Hot plugging the input supply can cause transients that may exceed the abs max (40 V) of the VIN pin. Can you check to see if this is happening?

0 John Chen65 over 9 years ago in reply to JohnTucker

Prodigy 250 points

Thanks for your response.
The Vin pin was connected to a 12v of buck converter, it was difference with phase pin. The timing will be the 35v first plugged into system then buck converter works to output 12v, BUT in this testing, we didn't enable the buck converter. The problem only happened on 35v applying into phase pin, and cause BOOT pin damaged.
May I know how many amps can be sinking for the phase and BOOT pin?

Thanks,
John

0 John Chen65 over 9 years ago in reply to John Chen65

Prodigy 250 points

I'm sorry, in the previously post has some typo, the controller is TPS43060, and the problem is BOOT pin damaged not Vin.

0 JohnTucker over 9 years ago in reply to John Chen65

TI__Guru**** 191445 points

35 V should not damage SW or BOOT, but hot plugging can cause transients up to 2 x 35, which will exceed the abs max voltage.

0 John Chen65 over 9 years ago in reply to JohnTucker

Prodigy 250 points

we can't observed this transient on the SW or BOOT pin, but we found That SW pin has a current sinking, the setup was used 6.8ohm on SW pin to inductor, measured a voltage on the resistor. We guess the pin damaged by current sinking over itself withstand. Also using 6.8 ohm will not damaged SW or BOOT pins during hot plugged into 35V. We would like to know how many amps this pin can be accepted.
Thanks,
John

0 John Chen65 over 9 years ago in reply to John Chen65

Prodigy 250 points

Hi all,

do you have any update?

thanks,

John

0 JohnTucker over 9 years ago in reply to John Chen65

TI__Guru**** 191445 points

Let me see if I can find someone who supports that controller.

0 Qian Chen over 9 years ago in reply to John Chen65

TI__Mastermind 24075 points

Hi John,

How much is the sinking current into SW pin when the boot pin is damaged, do you have a waveform?

Also, you said by adding a 6.8ohm resistor between SW pin and swich node, no damage happens, is this true?

For quick response, can we discuss by email?

My email: Q-CHEN AT TI.COM

Thanks

Qian

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TPS43060 - BOOT pin shorted to ground