TPS22811: is the Active Current Limiting feature only enabled during the startup?

Hi Aki,

Thanks for reaching out. Current limit is only during startup. This is a load switch device so it does not have current limit during steady state. Please look at eFuse TPS25981 that has current limit .

Regards

Kunal Goel

Hi Kunal,

Thank you. Customer was evaluating TPS25981 for 12V output now. They would like to understand whether TPS25981 can support the below 2 conditions:

1) The cap load is 3300uF, startup current is 3A, startup time requirement is 25ms;

2) If setting the ILIM=5A for TPS25981, when the load current is 9A, which is still below the short-circuit threshold 10A, can it continue to operate before customer disables it using the the load current monitor signal?

Hi Aki,

I will get back by friday EOD India time on this.

Regards

Kunal Goel

Hi Aki,

1.We cannot fix both startup current and startup time. For eg: We can choose startup time as 25ms. For 25ms, dvdt cap should be around 7.5nF . Now charge current will be around 1.4A. As per design calculator device can support this.

Customer can use design calculator available on product page . They can input requirements and calculator will tell whether startup will be successful or not. 

2. Device will allow up to 2 times current limit until timer duration. Please have a look at 8.3.3.2 Circuit-Breaker During Steady-State in datasheet. 9A should be fine. How will customer disable? If they are using some external logic then they have to make sure that TIMER is not over before they try to disable.

Regards

Kunal Goel

Hi Kunal,

Can TPS25981 support CC mode test? I remembered the previous efuse was not suggested to test using CC mode. 

Hi Aki,

For checking OCP response during steady state I think it should be fine to use CC mode as device is circuit breaking and not limiting current. 

Regards

Kunal Goel

Kunal,

Normally customers will use CC mode for all the test conditions, including start up. 

Hi Aki,

During startup also CC load can be issue as it is not a practical load. A practical load will slowly increase current draw as VOUT increases. I will recommend keeping CC load turn on voltage above 3V. 

If customer has CR mode available then I would recommend that.

Regards

Kunal Goel