Product Number:

Die size:
1.884 x 1.814mm
Est. process technology:
Est. number of metal and poly layer:

For more information, please contact us


1-4 Cell Li+ Battery SMBus Charge Controller for Supporting Turbo Boost Mode with N-Channel Power MOSFET Selector


The bq24735 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 system when system power demand is temporarily higher than 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 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 in a 20-pin, 3.5×3.5 mm2 QFN package



2• 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 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 QFN Package APPLICATIONS
    • Portable Notebook Computers, UMPC, Ultra-Thin Notebook, and Netbook
    • Handheld Terminal
    • Industrial and Medical Equipment
    • Portable Equipment