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TPS2482: TPS2482

Alek Yum
Prodigy 125 points
Part Number: TPS2482
Other Parts Discussed in Thread: CSD19536KTT

Hello. I have some troubles with TPS2482, i am using FET IRFS3607 and resistor with value 0.001 Om.  I have calculated PROG resistors to be 49 KOm and 4 KOm (for limitation on 200 W on 16V), but nothing happens there is no shut down while power overlimiting or short-circuit. But with another PROG resistors 100 KOm and 500 Om, at this case we there is shut down,but sometimes TPS shut-downs while powering-on. Maybe i am using equations from datasheet not correctly? P.S Also i checked values of resistors in excel calculator for TPS2482.

Thanks!

  • 0
    TI__Expert 5940 points
    Alek,

    Make sure you don't have anything 'red' in the calculator tool. Also make sure you have all of your inputs correct, including the total system load capacitance, including all downstream in any DC_DC converter's front end. Your Plimit looks a little low at 150W. You didn't state the timer cap. The FET selection isn't good for SOA so it risks damage, not sure if you see that or not. It is being operated in its thermal instability region. In general, stay away from Infineon and many IR FETs for hotswap applications - as they have lower SOA capability compared to other suppliers. Look at the CSD19536KTT, which is a much better SOA device - though this is mainly a fault protection item (probably not your issue at the moment), but possible a start up item if you have a lot of Cout. You should see an issue on the calculator tool's SOA plot. 100k and 500ohm is way off for Plim requirements. Look at Vin, Vout, timer, gate, I-in on your scope shots and you should be able to piece together what is going on.

    Brian
  • 0 in reply to Brian Daugherty
    Prodigy 125 points
    Thanks for answering, now i checked scheme with FET IRFS7530 with very simillar characteristics which have CSD19536KTT. It works good with shunt resistor 0.01 Om but i need to measure currrent more than 5 A, so i am using shunt 0.001 and it doesnt works with PROG resistors 100k and 10k, there is no over_current and short circuit proterction. What i need to do else while changing shunt resistor from 0.01 Om to 0.001 Om? Thanks!
  • 0 in reply to Alek Yum
    Prodigy 125 points
    So, i suppose i have solved my problem, the source of problem was DC-DC before TPS schematic, this DC-DC sometimes
    accidentally was in "safety shutdown" during my tests of TPS2482. So the result of my "headaches" are: IRFS3607 is not so good with TPS2482, maybe because of Rds (rather big) or something else and one of alternative FET is IRFS7530 (CSD19536KTT and others TI FETs are very rare in our region). So thanks for solving my problem!!