TPS25985: Design Calculation of Resistor and Capacitor for Imon, Ilimit, and Iref(1.2V)

Hi Kapil,

Thanks for your interest on TPS25985.

Please use the design calculator, available at  TPS25985 Design Calculator. If you still have any more query, kindly let us know.

Hello Avishek,

Thanks for sharing the input. I have designed the schematic by considering below points.

1. 12Vin , 5% tolerance

2. Iout- 34A

3. Ilimit/ Iocp- 37.4

4. Ver- 1V

5. Gimon (uA/A)- 18.8

Can you review it and share your comment?

Hi Kapil,

Schematic looks fine.

Please make sure that TFPGA_VCC_3V3 is generated from the input to the TPS25985.

Hello Avishek,

This voltage TFPGA_VCC_3V3 is generating from another source (5V) which is coming before 12V. Means as per the power sequencing, 3.3V generating first and then the 12V input is coming in the TPS25985 (Coming from another source). I think this will not be an issue right, what do you say?

Yeah... No issues... 

Thank you !!

Done Avishek.

Thanks... Please reach out to me if you need any help on this device in near future. 

Hello Avishek,

One query related Auto-Retry and Latch-off feature.

Can you tell how both the features are working? Is there any change in design point of view? 

I have done the design with TPS259850RQPR (Latch-off), do I need to care in terms of Hardware/ Software implementation?

Please clarify?

Hello Avishek,

I had done some research on theory point of view, but would you please elaborate what is this difference in terms of working point of view? 

Hi Kapil, 

After the device shuts down due to a fault which is internally latched, it stays latched off till the device is power cycled or re-enabled in case of TPS259850 variant or restarts automatically after a fixed delay of 100 ms in TPS259851 variant.  

Hello Avishek,

As you can see the design, The En pin has controlling through Voltage divider, so it will always enabled as soon as the 12V is coming in Hot-swap controller. 

So Can you suggest what can we do in this case?

Hi Kapil,

Which behavior are you expecting in your design, auto-retry or latch off? I am not clear about your concern here. Please could you explain in detail. 

Hello Avishek,

As I mentioned earlier, I have done the design with this partTPS259850RQPR (Latch-off), the function is latch-off. 

Now if the fault condition will come then to re-enable the IC how can I control?

do I need to care in terms of Hardware/ Software implementation?