ZVCHG (0-V charging) is a special function that allows charging a severely depleted battery that is below the FET driver charge pump shutdown voltage (V_{DRIVER_SHUT}). The BQ2980 has ZVCHG enabled, while the BQ2982 device has it disabled.

In BQ2980, if V_BAT > V_0INH and VDD < V_{DRIVER_SHUT}-V_{DRIVER_SHUT_HYS} and the charger voltage at PACK+ is > V_0CHGR, then the CHG output will be driven to the voltage of the PACK pin, allowing charging. ZVCHG mode in the BQ2980 is exited when V_BAT > V_{DRIVER_SHUT}, at which point the charge pump is enabled, and CHG transitions to being driven by the charge pump. In the BQ2982, ZVCHG is entirely disabled, so charging is disabled whenever VDD < V_{DRIVER_SHUT}–V_{DRIVER_SHUT_HYS}.

For BQ2980 and BQ2982, when the voltage on VDD is below V_0INH, the CHG output becomes high impedance, and any leakage current flowing through the CHG FET may cause this voltage to rise and reenable charging. If this is undesired, a high impedance resistor can be included between the CHG FET gate and source to overcome any leakage and ensure the FET remains disabled in this case. This resistance should be as high as possible while still ensuring the FET is disabled, since it will increase the device operating current when the CHG driver is enabled. Because gate leakage is typically extremely low, a gate-source resistance of 50 MΩ to 100 MΩ may be sufficient to overcome the leakage.