UCC28782 integrates a boost converter to supply VDD in a wide output voltage range application, such as USB PD charger. The typical UVLO threshold of boost converter is 1.23 V, If BIN capacitors are occasionally completely discharged, shown in Figure 4-1, resulting in additional power losses, irregular operation and higher output ripple, this could be caused by boost inductor DCR too high which results in V_BIN UVLO not proper been detected (UVLO off threshold of V_BIN is around 1.23V, large DCR of boost inductor will lead to V_BIN always higher than 1.23 V during boost Mosfet turn on time.). The boost converter always turns on until the energy on BIN capacitors be consumed up.

Figure 4-1 Boost Inductor DCR > 1 ohm

Figure 4-2 Boost Inductor DCR = 0.56 ohm

Solution: Choose the boost inductor with DCR less than 1 ohm. 0.5 ohm ~0.7 ohm is preferred.