Description
The BQ24725A is a high-efficiency, synchronous battery charger, offering low component count for space-constraint, multi-chemistry battery charging applications.The BQ24725A 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 BQ24725A uses an internal input current register or external ILIM pin to throttle down PWM modulation to reduce the charge current.
Features
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 batter 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 up to 19.2V ±3% Charge current accuracy up to 8.128A ±3% Input current accuracy up to 8.064A ±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 20-pin 3.5 x 3.5 mm2 VQFN Package
