TPS2491: TPS2491

Alex Volkov49

Part Number: TPS2491
Other Parts Discussed in Thread: CSD19536KTT, CSD19532Q5B, TPS2490

Good day!
I have a problem. I use the TPS2491 chip to protect the output from a short circuit.
When used from a battery, the micro-laugh does not turn off the output and the following happens (shown in the diagram). What are we doing wrong and how to make it work as a short circuit protection.
Calculations were carried out in your program. The file shows the calculations.

TPS249x_8x_Design_Calculator_REV_B.xlsx

over 6 years ago

0 Rakesh over 6 years ago

TI__Guru** 105361 points

Hi Alex,

Welcome to E2E!
Let me review the files and get back to you.

Best Regards,
Rakesh

0 Rakesh over 6 years ago in reply to Rakesh

TI__Guru** 105361 points

Hi Alex,

The design does not have SOA margin.
The current limit is set at 50A and single (high Ron ) FET would not able to support. Adjust the current limit to just above the max load current IOUT(MAX) 25A by increasing Rs.
If you want to continue with CSD19532Q5B, you may need two FETs in parallel. The other option is low Ron CSD19536KTT FET.

Best Regards,
Rakesh

0 Alex Volkov49 over 6 years ago in reply to Rakesh

Prodigy 20 points

Thanks, but changing to a transistor with less resistance didn't help. NTMFS5H409N transistors were used. It did not help. Upon further study of the circuit, we came to the conclusion that when the microcircuit is connected to the battery, the transistors die during the operation in the linear mode, due to the non-instantaneous opening of the transistor. The problem was solved by changing the micro-laugh from TPS2491 to TPS2490.

0 Rakesh over 6 years ago in reply to Alex Volkov49

TI__Guru** 105361 points

Hi Alex,

Unfortunately, I did not found datasheet of NTMFS5H409N on web.
Please let me know if you have any follow up questions else Please to close this thread.

Best Regards,
Rakesh

0 Rakesh over 6 years ago in reply to Rakesh

TI__Guru** 105361 points

Hi Alex,

You mentioned that "The problem was solved by changing the micro-laugh from TPS2491 to TPS2490." Can you please detail us on this.

1m Ohm sets current limit at 50A which does not give us a feasible design. Please refer attached calculator

5672.TPS249x_8x_Design_Calculator_REV_B.xlsx

Best Regards,

Rakesh

0 Rakesh over 6 years ago in reply to Rakesh

TI__Guru** 105361 points

Hi Alex,

Can you please update ?

Best Regards,
Rakesh

0 Rakesh over 6 years ago in reply to Rakesh

TI__Guru** 105361 points

Hi Alex,

Please reopen the thread as soon as you get details.

Best Regards,
Rakesh

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TPS2491: TPS2491