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TPS720xx sequencing combinations

Aaron Paxton
Expert 5565 points

There are many power rails in my systems that all must sequence up very specifically. I want to understand all ways I can and cannot use this part regarding potential "sneak paths" where output voltage might show up when I don't want it.

Can we guarantee no output voltage from the TPS72010 under the following scenarios:

  • Vin = 0V, Vbias = 3.3, Ven = 0V?
  • Vin = 0V, Vbias = 0V, Ven = 3.3V?
  • Vin= 0V, Vbias =3.3V, Ven=3.3V?

The light load regulation with Vin floating feature description in the TPS72010 datasheet implies a sneak path from Vbias to Vin. How much load needs to be applied to Vin to guarantee the output does not come up when Vbias and Ven are at 3.3V?

Could a more detailed device block diagram of the TPS72010 (that shows internal protections diodes and other current paths between pin) be provided?

  • 0
    TI__Guru 55940 points

    Hi Aaron,

    • Vin = 0V, Vbias = 3.3V, Ven = 0V
      • A logic low on EN will turn off the device.  Therefore, no output voltage.
    • Vin = 0V, Vbias = 0V, Ven = 3.3V
      • The output of the device will follow the bias or input voltage at start up; therefore, with no bias or input, the device will have no output.
    • Vin = 0V, Vbias = 3.3V, Ven = 3.3V
      • Regardless of load, with TPS72010, the bias pin will be able to drive a small current through the load.  Therefore, this condition will have an output voltage.  With a larger load, this output may be a lower voltage than the nominal output of the device (ie dropout), but there will be an output.
    Please let me know if you have any further questions.
    Very Respectfully,
    Ryan