SLUAAF9 September   2021 UCC28782

 

  1.   Trademarks
  2. 1 Initial Board Visual Inspection and Start-up Check
  3. 2 Typical System Operating Waveforms
    1. 2.1 SBP2 Mode
    2. 2.2 SBP1 Mode
    3. 2.3 LPM mode
    4. 2.4 LPM to ABM Mode Transition
    5. 2.5 ABM Mode
    6. 2.6 ABM to AAM Mode Transition
    7. 2.7 AAM Mode
  4. 3Typical System Protection Waveforms
    1. 3.1 Over-Power Protection (OPP)
    2. 3.2 Output Overvoltage Protection (OVP)
    3. 3.3 Output Short-Circuit Protection (SCP)
  5. 4Common Issues and Solutions
    1. 4.1 VDD Boost Converter Survival Mode
      1. 4.1.1 Survival Mode Due To Boost Inductor DCR Too High.
      2. 4.1.2 System Stays In Survival Mode When the Output Voltage is Low Such as 3.3V/5V/9V
    2. 4.2 10% Load Efficiency Might not Meet spec. in USB-PD Application, Especially at 5 V/9 V Output Condition
    3. 4.3 Transient
      1. 4.3.1 BIN/BSW Pin Damage During LPM to ABM Mode Transition
      2. 4.3.2 SR MOSFET VDS Overstress at Survival Mode
      3. 4.3.3 SR MOSFET Vds Voltage Overstress Due to PWMH Partial Turn On At Load Transition
  6. 5References

2.4 LPM to ABM Mode Transition

As load increases, VCST reaches VCST(BUR), LPM mode transient to ABM, PWMH is enabled at ABM. A large negative current for example, balancing current can be observed when the first PWMH is enabled as shown in Figure 2-4.

GUID-20210804-CA0I-K9GN-QRG1-X7CJDW9PDCSF-low.png Figure 2-4 LPM to ABM Mode Transition