LM5160-Q1: LM5160-Q1: Power ON issue

Namdev Patil

Part Number: LM5160-Q1

Tool/software:

Dear TI Support Team,

We are using LM5160QPWPRQ1 part. Refer SCH here:

https://community.nxp.com/t5/S32K-Knowledge-Base/Automotive-Electrical-E-compressor-Aircon-RDB-based-on-S32K142/ta-p/1414316

But turn-on behaviour is very erratic. Divider on EN/UNLO is 51k & 10k.

Sometimes it turns on at 8V, sometimes to 9V..14V.....and so on. We are not able to conclude. We need min turn ON voltage 8V.

We think it has some relation with rise time (slew rate) of Enable signal.

Pls support.

Thanks.

BR,

Namdev Patil

Tata Autocomp-Air International

over 1 year ago

0 David Baba over 1 year ago

TI__Mastermind 40040 points

Hello Namdev,

Looking at the schematic, is R98 installed? did you confirm the voltage at the Enable pin, is it turning on at 1.24V? Please can you measure.

Thanks.

David.

0 Namdev Patil over 1 year ago in reply to David Baba

Prodigy 30 points

we tried with voltage divider 51k (top)and 10k(bottom) below.

0 Namdev Patil over 1 year ago in reply to David Baba

Prodigy 30 points

0 Timothy Hegarty over 1 year ago in reply to Namdev Patil

TI__Guru 74052 points

Hi Namdev,

Send on the waveform of VIN and EN/UVLO voltages at startup. I assume this is a Fly-Buck topology, not flyback as indicated.

Regards,

Tim

0 Namdev Patil over 1 year ago in reply to Timothy Hegarty

Prodigy 30 points

pls find attached waveform. Voltage divider on EN 51k (top) and R26 11k (bottom).

we checked with 8V, 9V......14V....sometimes turns on, sometime not....no repeatable

result. Not sure, what issue with Enable pin.

0 David Baba over 1 year ago in reply to Namdev Patil

TI__Mastermind 40040 points

Hello Namdev,

I believe it could be a partially damaged device. Have you tried changing the device, when you do, are you observing the same issue?

Thanks.

David.

0 Namdev Patil over 1 year ago in reply to David Baba

Prodigy 30 points

Device not damaged. this is same issue with all PCBs. Enable has severe issue with power ON. This is really surprising. TI should know the issue.

0 David Baba over 1 year ago in reply to Namdev Patil

TI__Mastermind 40040 points

Hello Namdev,

can you show another waveform with the discrepancy at voltage turn on. thanks.

David.

0 David Baba over 1 year ago in reply to David Baba

TI__Mastermind 40040 points

Hello Namdev,

Also can you measure the Switch node voltage for me as well as provide me with the full schematic and BOM. I am particularly interested in the Switch node at the turn on point.

Thanks.

David.

0 David Baba over 1 year ago in reply to David Baba

TI__Mastermind 40040 points

Hello Namdev,

Will close these threads due to inactivity, feel free to re-open thread if needed.

Thanks.

David.

Power management

Power management forum

LM5160-Q1: LM5160-Q1: Power ON issue