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SMBus-Controlled Level 2 Multi-Chemistry Battery Charger With Input Current Detect Comparator


Package | PIN: RHD | 28
Temp: S (0 to 0)
Carrier: Cut Tape
Qty Price
1-9 $7.27
10-24 $6.54
25-99 $6.11
100-249 $5.48
250-499 $5.11
500-749 $4.45
750-999 $3.85
1000+ $3.77


  • 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

Texas Instruments  BQ24745RHDT

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.