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TPS65217: Some issues regarding TPS65217 chip locking

Shawn Gu
Prodigy 10 points
Part Number: TPS65217

Hello, can you explain why using RLL (10k Ω) instead of BAT pin capacitors can prevent the chip from entering a locked state? I want to know the specific reason why this action is effective?

In fact, I conducted validation in the laboratory. I found that if AC repeatedly loses power in a short period of time, even if the capacitor on the BAT pin is replaced with RLL, the chip will still enter a locked state.

I really want to know the specific working principle. Looking forward to your reply!

  • 0
    TI__Mastermind 19310 points

    Hi Shawn,

    The goal of the RLL 10k is to drain any voltage on the BAT pins that may be keeping the VSYS voltage above the threshold for an internal digital reset to occur. There are other ways VSYS could be in UVLO but not low enough to reset the digital core of the PMIC but the RLL resistor should help if residual voltage on the BAT pins is the cause. This issue arises because the PMIC can get stuck in an unknown state when all voltages are in UVLO but the digital core has not reset.

    Avoiding the VIN brownout altogether is the best course of action but if you can fully reset the digital core by pulling VSYS to a low voltage (POR to cause a reload of the EEPROM registers) you should be able to return to an operational state.

    Regards,

    James