8.3.11 Cycle-by-Cycle Charge Undercurrent

In the BQ24650, if the SRP-SRN voltage decreases below 5 mV, the low-side FET is turned off for the remainder of the switching cycle to prevent negative inductor current. During DCM, the low-side FET only turns on when the bootstrap capacitor voltage drops below 4.2 V to provide refresh charge for the bootstrap capacitor. This is important to prevent negative inductor current from causing a boost effect in which the input voltage increases as power is transferred from the battery to the input capacitors and lead to an overvoltage stress on the VCC node and potentially cause damage to the system.