TPS2595: Using it for currents <0.5A

HI KR,

Daniel Schmitz said:

I noticed was the trigger level was not within tolerance of the TPS259533.

Do you mean ILIM accuracy is not within the limits when you are keeping the limit less than 0.5A? 

Daniel Schmitz said:

So technically, I should be fine using it below the recommended 0.5A? Or is there another reason for the lower current limit? If so, what can be the issue with using it below 0.5A?

Yes, this won't damage the device but will cause very very high inaccuracy for current limit.

If you need lower current eFuse, please consider using TPS2596 or TPS25961 device. 

Best Regards,
Arush

Hi Arush

Thanks for the quick answer! I've now created my own account, this was actually my question.

Arush Gupta said:

Do you mean ILIM accuracy is not within the limits when you are keeping the limit less than 0.5A? 

Yes, i was talking about the ILM accuracy.

Arush Gupta said:

Yes, this won't damage the device but will cause very very high inaccuracy for current limit.

What do you mean with the very very high inaccuracy?
Is the calculation formula just way off and fine tuning the value until it suits my needs is still reliable?
Or is it highly unlikely that two different TPS with the same ILM-resistor, which triggers at a current lower than 0.5A, trigger at somewhat the same current? But I guess you cannot really answer that, since you only test the tolerance within the proposed current range.

Best Regards

Domink

Hi Dominik,

The part is designed such that it gives good accuracy and is reliable for the ILIM range of 0.5A to 4A.

Dominik Brändle said:

Is the calculation formula just way off and fine tuning the value until it suits my needs is still reliable?

The calculation formula is based on curve fitting over mean current limit data of n devices and is only valid within the designed ILIM range of device. It can be a good start point if you wish to use it and then you can fine tune the value.    

Dominik Brändle said:

is it highly unlikely that two different TPS with the same ILM-resistor, which triggers at a current lower than 0.5A, trigger at somewhat the same current? But I guess you cannot really answer that, since you only test the tolerance within the proposed current range.

When I mentioned very bad accuracy if you keep the ILIM below 0.5A, you will have high variation due to process variation. Yes, we are not testing the device's current limit below 0.5A ILIM so I cannot share any numbers but because by design we did not optimize the device for this range, process variations increase.

At what scale are you using this device. Also is TPS2596 not a good match for your application? Any specific reason for not changing? 

Best Regards,
Arush

Hi Arush

Thanks for the extensive reply!

Arush Gupta said:

At what scale are you using this device.

We are using it for currents as low as 100mA (R_ILM = 33k), where they generally trigger at around 74mA. This would actually be fine for our application, as long as the trigger stays around 74mA with all of them. But since this is not the case, we'll likely have to switch.

Arush Gupta said:

Also is TPS2596 not a good match for your application? Any specific reason for not changing?

The main problem is, I only noticed the lower current limit of the TPS2595 after our first prototype was already made and therefore I wanted to check first, before changing the eFuse.
The footprint of the TPS2596 is way too big and the lower current limit does not solve our issue either.
The TPS25961 is then the only option, so I have to change.

Thanks a lot for your help, it was a pleasure!

Best regards,
Dominik