LM25069: Hot-swap design - help needed

Ponnusamy M

Prodigy 80 points

Part Number: LM25069

Hi,

Our design uses LM25069 hot-swap controller.

Following are the design inputs for which the hot-swap controller to be designed:

Vin (min/typ/max): 11.5V/12.1V/12.5V
I(max): 44A
Rsense: 0.75mOhms (two 1.5mOhms in parallel)
CLoad: 810uF
MOSFET PN: SiRA20BDP (SiRA20BDP N-Channel 25 V (D-S) MOSFET | Vishay)
MOSFET Qty: 1 [Note: if required, two MOSFETs can be used in parallel]
Use of dv/dt control: Can be used, if needed
Maximum ambient Temperature: 70C
Pass "Hot-Short" on Output? : Yes
Pass "Start into short"? : Yes
Is the Load Off Until PG Asserted? Yes (Load can be made controllable)
Can a hot board be plugged back in? Yes

We tried using the LM25609 QuickCalculator (https://www.ti.com/lit/zip/snvu085) but unable to pick the "Desired Maximum FET Power Limit" from the MOSFET datasheet. Pl let us know what is the value to be chosen for the above application.

It would be great if you could help in designing the hot-swap circuit using the LM25069 for the above design parameters.

Best Regards,

Pons

over 3 years ago

0 Avishek Pal over 3 years ago

TI__Mastermind 41050 points

Hi Ponnusamy,

Thanks for your interest on Texas Instruments Hot Swap controllers. I will get back to you tomorrow.

0 Ponnusamy M over 3 years ago in reply to Avishek Pal

Prodigy 80 points

Hi Avishek,

Thanks for the ack. We will wait for further details from you.

Pl let us know if any further data needed.

- Pons

0 Avishek Pal over 3 years ago in reply to Ponnusamy M

TI__Mastermind 41050 points

Hi Ponnusamy,

I am not able to understand the SOA curve of this SiRA20BDP MOSFET. I am not sure which line corresponds to which time duration.

Please confirm with Vishay and let me know. This is an important information without which we will not be able to design.

0 Ponnusamy M over 3 years ago in reply to Avishek Pal

Prodigy 80 points

Hi Avishek,

We have checked in a similar Device from Vishay.

Looks like the 100uSec curve is not shown (which appears at the top right corner of the SOA graph).

We have marked the lines against the time duration in the below image. Pl refer the same.

Best Regards,

Pons

0 Ponnusamy M over 3 years ago in reply to Ponnusamy M

Prodigy 80 points

Hi Avishek,

PFB the updated SOA graph received from Vishay, FYR.

Best Regards,

Pons

0 Avishek Pal over 3 years ago in reply to Ponnusamy M

TI__Mastermind 41050 points

Hi Pons,

I am wondering how 10 sec curve can come above the 1 sec curve.

0 Ponnusamy M over 3 years ago in reply to Avishek Pal

Prodigy 80 points

Hi Avishek,

We will check with Vishay on this. Thanks for pointing this out.

Pl use the manually edited graph shared Y'day for the analysis till we get a response from Vishay.

Best Regards,

Pons

0 Ponnusamy M over 3 years ago in reply to Ponnusamy M

Prodigy 80 points

Hi Avishek,

Pl use the the below graph as the edited graph shared Y'day also having the 10sec/1sec text issue. We are checking with Vishay for the same.

Best Regards,

Pons

0 Avishek Pal over 3 years ago in reply to Ponnusamy M

TI__Mastermind 41050 points

Hi Pons,

Please see the attached design calculator and let me know if there is any query.

LM25069_Design_Calculator.xlsx

0 Ponnusamy M over 3 years ago in reply to Avishek Pal

Prodigy 80 points

Hi Avishek,

Thanks for the filled-in design calculator. We will get back in case of queries.

Best Regards,

Pons

Power management

Power management forum

LM25069: Hot-swap design - help needed