TPS55165-Q1: I have a PCB with the following circuit:

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Part Number: TPS55165-Q1

I have a PCB with the following circuit:

If you connect a 24V lead-acid battery, the housing of the TPS55165 gets a crack at pins 4-6. After that, the chip no longer works.

The problem can be reproduced with 30V on a laboratory power supply. The problem does not occur with a 12V lead-acid battery.

Warum wird der Chip zerstört, obwohl er bis zu 40V funktionieren sollte laut Datenblatt? Wie kann das Problem behoben werden?

over 3 years ago

0 Jan-Gerd Meinen over 3 years ago

Prodigy 30 points

This is the schematic to the Porblem above

0 Jasper Li over 3 years ago in reply to Jan-Gerd Meinen

TI__Mastermind 46905 points

Hi,

did you measure the input voltage waveform when the power supply is firstly connected? maybe the overshoot in the input voltage damage the IC.

0 Jan-Gerd Meinen over 3 years ago in reply to Jan-Gerd Meinen

Prodigy 30 points

Hi,

i didn't measure the input waveform.

Where should the overshoot in the input voltage come from? No overshoot is to be expected from a lead-acid battery.

If the IC was destroyed by an overshoot of the input voltage, how can this be prevented?

0 Jasper Li over 3 years ago in reply to Jan-Gerd Meinen

TI__Mastermind 46905 points

Hi,

The voltage of the battery may be not equal to the voltage at the converter's input pin, because of the parasitic inductor. please check there could be voltage spike in the input of the device.

a TVS closed to the DC/DC converter may help to clamp the voltage.

0 Jan-Gerd Meinen over 3 years ago

Prodigy 30 points

Hi,

I was able to measure the overshoot at the input voltage. A TVS diode fixed the problem. It would have been helpful if the TVS diode had been mentioned in the data sheet.

0 Jasper Li over 3 years ago in reply to Jan-Gerd Meinen

TI__Mastermind 46905 points

thanks for the update and suggestion. we will consider if similar application note can be added.

I closed the post, but you can still reply it if there is further question.

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TPS55165-Q1: I have a PCB with the following circuit: