TPS54540: When Vin =8V, output is abnormal

Amelie Zheng

Part Number: TPS54540

Hi Team,

My customer use TPS54540 as the first power stage in automotive. change 12V to 5V.

However, met the following problem: ACC ignition power does not start. It means it can't work in STAR-STOP when Vin drop to 8V.

When the Vin is 8V, output is sawtooth wave..when Vin is lower than 8V, the output goes down..

As my understand, if Vout =5V, the minimum Vin is 5.7V. 8V is much higher than 5.7V. Why it doesn't work?

Any advice?

Thanks!

0 Iven Su over 5 years ago

Hi,

If there is no load, TPS54540 might have a saw-tooth output voltage. Do you have the schematic? That would be helpful.

0 Amelie Zheng over 5 years ago in reply to Iven Su

Hi Iven,

Thanks for your reply.

Customer use for changing 12V to 5V. The output current is about 1.2A.

I think this IC is broken and now ask customer to prepare CQE material.

0 Iven Su over 5 years ago in reply to Amelie Zheng

OK, thanks, I will close the thread. If you have any updates need further help, you can send an email to me (iven-su@ti.com).

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