The bq2004 Fast Charge IC pro-vides comprehensive fast charge control functions together with high-speed switching power control circuitry on a monolithic CMOS device. Integration of closed-loop current control circuitry allows the bq2004 to be the basis of a cost-effective so-lution for stand-alone and system integrated chargers for batteries ofone or more cells. Switch-activated discharge-before-charge allows bq2004-based chargers to support battery conditioning and capacity determination. High-efficiency power conversion is accomplished using the bq2004 as a hysteretic PWM controller for switch-mode regulation of the charging current. The bq2004 may alterna-tively be used to gate an externally regulated charging current. Fast charge may begin on applica-tion of the charging supply, replacement of the battery, or switch de-pression. For safety, fast charge is inhibited unless/until the battery temperature and voltage are within configured limits. Temperature, voltage, and time are monitored throughout fast charge. Fast charge is terminated by any of the following: \Delta Rate of temperature time(\Delta T/\Delta t) \Delta Peak voltage detection (PVD) \Delta Negative delta voltage (-\Delta V) \Delta Maximum voltage \Delta Maximum temperature \Delta Maximum time After fast charge, optional top-offand pulsed current maintenance phases are available.