• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 63 subscribers
  • Views 228 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS65218D0: DCDC4 output protection against short and current overload

Lenio Cacula
Genius 16730 points
Part Number: TPS65218D0

The DCDC4 is specified to have an average current limit of 3A @ 3.6V.

1. Can you please elaborate on the behavior of the device or the DCDC4 output in particular when the limit is reached?

2. Will it shutdown the device or simply droop the voltage to maintain the current within bounds?

3. What if the current has large ripple? Will the peaks be clamped, or will the device maintain operation while having spikes of 5 or 6A with an average below 3A?

4. What happens when the output is suddenly shorted to ground?

Thanks for the help!

  • 0
    TI__Mastermind 30310 points

    Lenio,

    I do not have a scope capture or simulation to share with you specifically for DCDC4, but my understanding is as follows:

    Lenio Cacula said:
    1. Can you please elaborate on the behavior of the device or the DCDC4 output in particular when the limit is reached?

    The current through the FETs (and the current in the inductor) is limited to 3A by entering a pulse-skipping mode.

    Lenio Cacula said:
    2. Will it shutdown the device or simply droop the voltage to maintain the current within bounds?

    The current is kept within the limit and the voltage droops as a result. Eventually, a VPG fault (under-voltage) will occur and the power-down sequence will start.

    Lenio Cacula said:
    3. What if the current has large ripple? Will the peaks be clamped, or will the device maintain operation while having spikes of 5 or 6A with an average below 3A?

    Any current exceeding 3A will be stopped by skipping a set number of switching cycles and then re-trying.

    Lenio Cacula said:
    4. What happens when the output is suddenly shorted to ground?

    The device will try to turn on, prevent currents that exceed 3A, and after 5ms the PG timeout will expire, so the entire PMIC will shut down due to a fault.