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

2.7 AAM Mode

At AAM mode Figure 2-8, PWML and PWMH alternate turn on in a complementary fashion with dead-time in between, as load current increases Figure 2-9, peak current increases while the switching frequency decreases.

GUID-20210804-CA0I-RLRG-KBKL-PL92PV4PTBM2-low.png Figure 2-8 AAM Mode Medium Load
GUID-20210804-CA0I-XSJJ-7QPQ-5KN3V3RDGKJF-low.png Figure 2-9 AAM Mode Heavy Load