●The bq24745 is a high-efficiency, synchronous battery charger with an integrated input-current comparator, offering low component count for space-constrained, multi-chemistry battery-charging applications. The input-current, charge-current, and charge-voltage DACs allow very high regulation accuracies that can be easily programmed by the system power-management microcontroller using the SMBus interface. The bq24745 charges two, three, or four series Li+ cells, and is available in a 28-pin, 5-mm × 5 mm QFN package.
●The bq24745 features dynamic power management (DPM) and input power limiting. These features reduce battery-charge current when the input power limit is reached to avoid overloading the ac adaptor when supplying the load and the battery charger simultaneously. A highly accurate current-sense amplifier enables precise measurement of input current from the ac adapter, allowing monitoring the overall system power. If the adapter current is above the programmed low-power threshold, a signal is sent to host so that the system optimizes its performance to the power available from the adapter. An integrated comparator monitors the input current through the current-sense amplifier, and indicates when the input current exceeds a programmable threshold limit.
● NMOS-NMOS Synchronous Buck Converter with
●300-kHz Frequency and >95% Efficiency
● 30-ns Minimum Driver Dead-Time and
●99.5% Maximum Effective Duty Cycle
● High-Accuracy Voltage and Current Regulation
● ±0.5% Charge Voltage Accuracy
● ±3% Charge Current Accuracy
● ±3% Adapter Current Accuracy
● ±2% Input Current Sense Amp Accuracy
● Integration
● Input Current Comparator, With Adjustable
●Threshold and Hysteresis
● Internal Soft-Start
● Safety
● Dynamic Power Management (DPM)
● Up to 19.2-V Battery Voltage
● 7-V–24-V AC/DC-Adapter Operating Range
● Simplified SMBus Control Interface
● Charge Voltage DAC (1.024 V–19.2 V)
● Charge Current DAC (128 mA–8.064 A)
● Adapter Current Limit DPM DAC
●(256 mA–11.008 A)
● Status and Monitoring Outputs
● AC/DC Adapter Present With
●Adjustable Voltage Threshold
● Input Current Comparator With Adjustable
●Threshold and Hysteresis
● Current Sense Amplifier for Current Drawn
●From Input Source
● Charge Any Battery Chemistry: Li+, NiCd,
●NiMH, Lead Acid, Etc.
● Charge Enable Pin
● < 10-µA Battery Current With Adapter Removed
● < 1-mA Input DCIN Current With Adapter
●Present and Charge Disabled
● 28-Pin, 5-mm × 5-mm QFN Package
Part 3D Model
