SLVAEE9A October   2019  – July 2021 TPS2065C , TPS2065D , TPS2069C , TPS2069D , TPS25221

 

  1.   Trademarks
  2. 1Introduction
  3. 2Root cause of False Fault Glitch
  4. 3Solution for the Fault Glitch
    1. 3.1 With RC Filter to Eliminate Fault Glitch as Start-Up
    2. 3.2 Validate the Influence of RC Filter to Normal Operation
  5. 4Summary
  6. 5Revision History

2 Root cause of False Fault Glitch

The following process occurs as VIN ramps fast from 0 V to the recommended operation range:

  • Before VIN reach to UVLO threshold to start reset, the internal circuit status is unknown.
  • If VIN ramps pretty fast, the voltage on point B maybe coupled through C1.
  • If the voltage on point B is larger than the threshold voltage Vth, T3 may pull down the FAULT pin.
  • The whole circuit resumes to normal after the internal reset.
GUID-BA44CAED-0A35-4DAA-BD26-A11BB04EDA2B-low.pngFigure 2-1 Simplified Internal Circuit Between IN Pin and Fault Pin

Due to the unknown status of the gate of T3, the Fault pin has the chance to be pulled down to 0 V.