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TPS2394: TPS2394

Michael Chang
Prodigy 150 points
Part Number: TPS2394
Other Parts Discussed in Thread: TPS2350, TPS23521, LM5067

I have a few questions on TPS2394. 

For the design tool which is titled by "slvc064a. TPS2350_DesignCalculator_RevA", 

Q1. there is a note - that is "TPS2350/TPS2394 is intended for low power (<250W)". 

This power limit comes from where? - FET driving (sink/source current capability) or other viewpoint?

Q2. During the test, I inceased Cramp (controlling the inrush current's slew rate) to 10nF in order to meet to our customer's spec. 

Now, the inrush current met to the spec. but I'm afraid that there are some maximum limit to Cramp value. 

Are there any side effects if Cramp is increased? 

Q3. If TPS2394 is not proper for the application (>250W), pls recommend the other Hot swap controller. 

Our spec are Po 1300W, Vin -48Vdc

Thanks

Michael

  • 0
    TI__Expert 5940 points

    Michael,

    Sorry for the delay,

    The TPS2394 has an older di/dt based current regulation mode for inrush control. When Cramp reaches 0.25v (2.5mv across Rsns) the gate charge current in to Cramp changes from .5uA to 10uA with a sharp rising rate on the regulation current into Cout.  If Cout is large (like what would be on a high power output, its rate of change of Vout vs the increasing charge current would not be sufficient to keep the FET within it's SOA range.  The device also has no power limit for the FET (SOA protection) so a power into short would likely be destructive for the FET.  It is recommended you look at the new TPS23521 instead.  It has a much more advanced inrush control (and a very advanced SOA control) that can handle higher power and higher Cout conditions.  It is the highest performance device of its type on the market today. See attached as a relative comparison.

    BrianTPS2394 vs TPS23521.pdf

  • 0 in reply to Brian Daugherty
    Prodigy 150 points
    Dear

    Thanks for the reply. We'd already changed TPS2394 to LM5067. According to your data, LM5067 is also not suitable to our power range (1,300W). After the additional test, I'll let you know the test results.