TPS2490: Short Circuit Current Limit

RAMAKRISHNA NAGARAJU GUDLA

Part Number: TPS2490

Tool/software:

Hello Team,

Greetings !!!

We are using "TPS2490DGSR" in our design for limiting the current for brakes. Attached the snap of the circuit for reference.

To address the EOL, the MOSFET Q13 is replaced in the latest revision from FDB024N06 (Fairchild) to STB100N6F7 (ST Microelectronics).

Now while testing , the short circuit behavior is drastically changed. The older revision is limiting the current to 5Amps where as the new design is showing as 60Amps and damaging the down side circuit components.

I wonder , by changing the MOSFET Q13 , to have same short circuit protection, what else to be done (modifications) in this host swap circuit that is based on "TPS2490DGSR".

I am giving the MOSFET Q13 part numbers since the experts can differentiate the parameters of interest rather I miss to provided the needed specifications.

Thanks in advance for all the support.

Thanks and Regards

G R K Nagaraju

1 month ago

0 RAMAKRISHNA NAGARAJU GUDLA 1 month ago

Prodigy 155 points

0 Avishek Pal 1 month ago in reply to RAMAKRISHNA NAGARAJU GUDLA

TI__Mastermind 39530 points

Thanks for reaching out. Could you please perform the following experiments with both the MOSFETs and share the waveform.

Start-Up into Short Circuit (Example: Figure 21 in the TPS2490 datasheet),
Load step (Example: Figure 24 in the TPS2490 datasheet),
Hot short on Output (Example: Figure 25 in the TPS2490 datasheet).

0 RAMAKRISHNA NAGARAJU GUDLA 1 month ago

Prodigy 155 points

Hi,

Thanks for the recommendations. I can do the measurements for the good board. But for the damaging the board , I am not sure if I can capture the snaps. Thank

0 RAMAKRISHNA NAGARAJU GUDLA 21 days ago

Prodigy 155 points

Hello Team,

I am able to take the captures as suggested with FDB024N06 (Fairchild) at Q13 and then with STB100N6F7 (ST Microelectronics) at Q13.

I am attaching here. When I switched the MOSFET to STB100N6F7 (ST Microelectronics) as I mentioned the components are getting damaging and the scope says over voltage on its probe since there seems huge current on the current probe.

Here my questions

1) It seems the current is not working properly. It supposed to limit the current by 16Amps. Does the Power Limit allowing the over current and damaging the parts?

2) Why is the Gate signal not turning OFF fully when there is a fault?

3) What makes the STB100N6F7 (ST Microelectronics) special that the host swap controller not limiting the current.?

4) What happens if I just remove the functionality of the power limit?

5) Do you see any changes needed in the circuit that to work with STB100N6F7 (ST Microelectronics) at Q13?

Please help me here.

Thanks for your support.

0 RAMAKRISHNA NAGARAJU GUDLA 21 days ago in reply to RAMAKRISHNA NAGARAJU GUDLA

Prodigy 155 points

TPS2490DGSR_Captures.zip

0 Avishek Pal 21 days ago in reply to RAMAKRISHNA NAGARAJU GUDLA

TI__Mastermind 39530 points

I will go through the waveforms and get back to you by Monday.

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TPS2490: Short Circuit Current Limit