BQ24745数据手册集成电路（IC）的电池充电器规格书PDF

描述 Description

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.

特性 Features

·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
·Present and Charge Disabled
· 28-Pin, 5-mm × 5-mm QFN Package