DESCRIPTION
The is a high-efficiency, synchronous battery charger, offering low component count for space-constraint, multi-chemistry battery charging applications. The bq24735 supports Turbo Boost by allowing battery discharge energy to the system when system power demand is temporarily higher than the adapter maximum power level so that adapter will not crash. The bq24735 utilizes two charge pumps to separately drive n-channel MOSFETs (ACFET, RBFET, and BATFET) for automatic system power source selection. SMBus controlled input current, charge current, and charge voltage DACs allow for very high regulation accuracies that can be easily programmed by the system power management micro-controller. The bq24735 uses an internal input current register or external ILIM pin to throttle down PWM modulation to reduce the charge current. The bq24735 charges one, two, three, or four series Li+ cells, and is available 3.5×3.5 mm2 QFN package.
FEATURES
Adapter and Battery Provides Power to System Together to Support Intel® CPU Turbo Boost Mode SMBus Host-Controlled NMOS-NMOS Synchronous Buck Converter with Programmable 615kHz, 750kHz, and 885kHz Switching Frequencies Automatic N-channel MOSFET Selection of System Power Source from Adapter or Battery Driven by Internal Charge Pumps Enhanced Safety Features for Over Voltage Protection, Over Current Protection, Battery, Inductor and MOSFET Short Circuit Protection Programmable Input Current, Charge Voltage, Charge Current Limits  ±0.5% Charge Voltage Accuracy  ±3% Charge Current Accuracy  ±3% Input Current Accuracy ±2% 20x Adapter Current or Charge Current Amplifier Output Accuracy Programmable Battery Depletion Threshold, and Battery LEARN Function Programmable Adapter Detection and Indicator Integrated Soft Start Integrated Loop Compensation Real Time System Control on ILIM pin to Limit Charge Current AC Adapter Operating Range 4.5V-24V 5µA Off-State Battery Discharge Current 0.65mA (0.8mA max) Adapter Standby Quiescent Current 3.5 mm2 QFN Package
