WEBENCH® Tools: Why Webench power tool suggested using this Hot-Swap Controller (TPS2420) for my design?

Ahmed Khalaf

Other Parts Discussed in Thread: TPS2420

Tool/software: WEBENCH® Design Tools

Hi,

I was trying to build dc to dc converter that has one input which is anywhere between 9V-20V and has 4 outputs: 5v @ 2.5A, 3.3V @ 2.5A, 3.3 @ 1.5A, and 1.5V @ 1.5A. So, I sequenced the outputs and checked the Hot-Swap box and clicked next, then I noticed that my generated circuit has the TPS2420 as a Hot-Swap Controller which can have 4A as a maximum output current while the total of needed currents through the 4 outputs should be around 8A !!!!

Kindly, what is the thing that I'm misunderstanding here?

over 7 years ago

0 Praveen Badiger over 7 years ago

TI__Expert 8365 points

Hi Ahmed,

The maximum input current requirement for all the Power supply is 1.53A. i.e Input current=(Output Voltage*Output current) /Input Voltage, detail calculation is shown below. Hence 4A Hotswap is sufficient to provide 1.53A supply current to all power supply.

Thanks & Regards,

Praveen B

0 Ahmed Khalaf over 7 years ago in reply to Praveen Badiger

Prodigy 230 points

Hi Praveen,
Thanks for the response. But as I stated in my question my design will have 4 outputs and the total required current by all these 4 outputs will be around 8A, so the 4A Hotswap won't be sufficient, right?

0 Gerold Dhanabalan - High Performance Radar over 7 years ago in reply to Ahmed Khalaf

TI__Genius 14455 points

Hi Ahmed

The peak current of 8A will be supplied by the input caps of the buck converters. The average current will be much lower - you can calculate it assuming Vinmin of 9V as Praveen mentioned. So the current supplied by the hotswap will be much lower and will replinish the charge on the input capacitor of each of the buck converters.

Please let us know if you have more questions.

Regards,

Gerold

0 Ahmed Khalaf over 7 years ago in reply to Gerold Dhanabalan - High Performance Radar

Prodigy 230 points

Cool, now I got it! Thanks a lot Gerold! Thanks to Praveen too!

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WEBENCH® Tools: Why Webench power tool suggested using this Hot-Swap Controller (TPS2420) for my design?