WEBENCH® Tools/TPS40304: Why I calculate Rs resister is different webench simulation?

Chen Bogey8

Part Number: TPS40304

Tool/software: WEBENCH® Design Tools

Hi Sir

Why I calculate Rs resister is different webench simulation? My cal is Rs is 1.74K, webench is 3.4K. and by the way, may we know what's different between TPS40304 and TPS40304A?

My condition Vin 12V Vout 1.2V Iout 25A expect Iocp 32A. TPS40304OCP.xlsx

over 7 years ago

0 Alan Martin over 7 years ago

TI__Expert 4365 points

Hello,

It looks like the RDSon value you are using is 0.84 milliohm which is a room temperature value with 10V Vgs. The actual gate drive voltage from the IC is around 6.5V. Webench is using a more conservative RDSon value of 1.4 milliohms in its calculation.

0 Chen Bogey8 over 7 years ago in reply to Alan Martin

Mastermind 9990 points

Hi Sir

But Even i use Rdson change to 1.4mohm, i figure out Rs around 2.6K. Is something parameter i miss?

Bogey

Power management

Power management forum

WEBENCH® Tools/TPS40304: Why I calculate Rs resister is different webench simulation?