LM5143-Q1: Output Rising Waveform

Xiaowei Zhang

Part Number: LM5143-Q1
Other Parts Discussed in Thread: LM5143, LM5143A-Q1, LM5137-Q1

Tool/software:

Hi team,

My customer Valeo are using LM5143 for their project, 3.3V output. Can you please help check if the output waveform at power up meet IC spec? Thank you

SCH: 0876.LM5143_SCH.pdf

Output:

Best Regards,

Xiaowei Zhang

2 months ago

0 Onkar Bhakare 2 months ago

TI__Genius 11076 points

Hi Xiaowei

To better analyze the issue, could you please ask them to probe following node

SS
COMP

Additionally, share QuickStart if available

Thank you

Regards

Onkar Bhakare

0 Timothy Hegarty 2 months ago in reply to Onkar Bhakare

TI__Guru 68767 points

Unfortunately, this becomes evident with 2-phases designs. One option is to use the LM5137-Q1 controller, the next gen of the LM5143A-Q1.

Regards,

Tim

0 Xiaowei Zhang 2 months ago in reply to Timothy Hegarty

TI__Intellectual 2860 points

Hi Tim,

Valeo asked the cause of this?

Timothy Hegarty said:
this becomes evident with 2-phases designs. One option is to use the LM5137-Q1 controller, the next gen of the LM5143A-Q1.

Best Regards,

Xiaowei Zhang

0 Timothy Hegarty 2 months ago in reply to Xiaowei Zhang

TI__Guru 68767 points

Xiaowei,

SS has a built-in offset where it needs to rise to ~60mV to allow switching and for the gate drivers to come out of standby. This effect has more impact in multiphase setups, as the COMP to CS gain is higher.

Regards,

Tim

0 Xiaowei Zhang 2 months ago in reply to Timothy Hegarty

TI__Intellectual 2860 points

Hi Tim,

Valeo asked if there any risk of this?

Best Regards,

Xiaowei Zhang

0 Timothy Hegarty 2 months ago in reply to Xiaowei Zhang

TI__Guru 68767 points

No risk to the circuit, as long as the startup behavior is acceptable for the customer and the application.

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LM5143-Q1: Output Rising Waveform