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TPS40170 for 60V supply voltage

Lucifer
Expert 2600 points
Other Parts Discussed in Thread: TPS40170

Dear Sir,

I am going to use TPS40170 for our power chain for 48~56V vin , 12v/20A vout. So far I am studying PMP6680 EVM  which vin is 43V~53V.

I check TPS40170 specification VIN MAX is 60V. Can PMP6680 EVM can work up to 60vin? if not which component should I change? Thanks.

  • 0
    TI__Mastermind 41310 points

    passerby,

    I am moving your post to the product group forum. They should be able to answer your question about the PMP6680.

  • 0 in reply to Britt Brooks - Online Design Tools
    TI__Expert 3085 points

    I have forwarded your question to the experts in TI. They will be getting back to you on this.

  • 0 in reply to Surinder Singh
    TI__Expert 3085 points

    Here is the recommendations:

    The PMP6680 design will work at 60V Vin. However, this is getting close to the 62V abs max on the TPS40170 VIN and the SW (Phase) pins. We suggest make the following changes to make it work:

    • Increase C1 voltage rating to 80V min.
    • Add a snubber between the SW pin and Gnd (across bottom FETs). Ringing from stray parasitics and/or a poor layout can cause the voltage at the SW pin to easily exceed Vin, so care must be taken to damp it. A high BW oscilloscope and very short probe tips should be used when viewing this point. A suggested a starting R-C snubber value is 1000pF and 10 ohms (0.5W – 1W package). See attached snubber calculation article.
    • Consider slowing the switch node down slightly by increasing the four gate resistors from 0 ohms to a small value, such as 3.3 ohms. This can reduce potential SW node ringing, but will likely increase FET losses.
    • Keep R5 at 0 ohms, otherwise the OC trip point may be reduced (by using a non-zero filter resistor). 
    • Please see the attached PDF document on Snubber design.

    Thanks,

    Surinder

    Power Tips - Calculating an R-C snubber.pdf