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TPD4S014 soft start, slew rate

Charles H
Intellectual 895 points
Other Parts Discussed in Thread: TPD4S214, TPD4S014

I have a requirement for a USB protected switch.

My application is for a USB powered device where I must protect the device from faults occurring on USB VBUS.

I really like the TPD4S214 part because it provides reverse voltage protection. 

I have a question though about the TPD4S014 part.

Does this part support soft-start? If so, what is the slew rate?

The TPD4S014 part has a delayed turn-on at 16ms. However, I’m interested in soft-start which would slowly turn on the integral FET and limit the input in-rush current.

The TPD4S214 part has both delayed turn-on and soft-start.

Can you please let me know about the slew rate and soft start on the TPD4S014?

  • 0
    TI__Guru 71526 points

    Hi Charles,

      Thanks for the inquiry, nice to hear from you.

    The TPD4Sx14 are similar devices, but have some basic differences.  The soft-start feature is included only in the TPD4S214.  The 16ms delay of the '014 allows the VBUS to stabilize before closing the switch, and acts as a de-glitch to prevent unnecessary switching. Note that a big difference is that the '014 does not have current-sensing, no OCP and requires an external device for this purpose, if so needed.  The '214 on the other hand, has OCP and current sensing built-in, so your requirement for In-rush current protection is available only in the '214.

    Note also the '214 is USB3.0 and USB2.0 compatible, the '014 only USB2.0. 

    What is the type of product this is being proposed for?   We can certainly assist with other portions of the design. 

    Let me know if you need an additional information. 

    -Leonard

    ACAT Dallas   

       

  • 0
    TI__Guru 71526 points

    some additional information on on-rush of the TPD4S014, insight by Ed Walker:

    You can get a good idea of the slew rates and inrush by looking at Figure 10 page 8 in the datasheet.  USB allows a 10uF cap on Vbus as shown in Fig 1 of the datasheet, and the Inrush as shown in this graph (Fig 10): 

      

      

      -Leonard (thanks Ed!)