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BQ24725A ACTIVE SMBus 1-4 cell Buck battery charge controller with N-Channel power MOSFET selector This is a lower quiescent current and higher charge current alternative.

Product details

Number of series cells 2, 3, 4 Charge current (max) (A) 2 Vin (max) (V) 28 Cell chemistry Li-Ion/Li-Polymer Battery charge voltage (min) (V) 8.4 Battery charge voltage (max) (V) 16.8 Absolute max Vin (max) (V) 30 Control topology Switch-Mode Buck Control interface Standalone (RC-Settable) Features Power Path Vin (min) (V) 7 Rating Catalog Operating temperature range (°C) -40 to 125
Number of series cells 2, 3, 4 Charge current (max) (A) 2 Vin (max) (V) 28 Cell chemistry Li-Ion/Li-Polymer Battery charge voltage (min) (V) 8.4 Battery charge voltage (max) (V) 16.8 Absolute max Vin (max) (V) 30 Control topology Switch-Mode Buck Control interface Standalone (RC-Settable) Features Power Path Vin (min) (V) 7 Rating Catalog Operating temperature range (°C) -40 to 125
TSSOP (PW) 24 49.92 mm² 7.8 x 6.4
  • Dynamic Power Management, DPM Minimizes Battery Charge Time
  • Integrated Selector Supports Battery Conditioning and Smart Battery Learn Cycle
  • Zero Volt Operation
  • Selector Feedback Circuit Ensures Break-Before-Make Transition
  • ±0.4% Charge Voltage Accuracy, Suitable for Charging Li-Ion Cells
  • ±4% Charge Current Accuracy
  • 300-kHz Integrated PWM Controller for High-Efficiency Buck Regulation
  • Depleted Battery Detection and Indication to Protect Battery From Over Discharge
  • 20-µA Sleep Mode Current for Low Battery Drain
  • 24-Pin TSSOP Package and 5 mm × 5 mm QFN package (bq24703 only)

  • Dynamic Power Management, DPM Minimizes Battery Charge Time
  • Integrated Selector Supports Battery Conditioning and Smart Battery Learn Cycle
  • Zero Volt Operation
  • Selector Feedback Circuit Ensures Break-Before-Make Transition
  • ±0.4% Charge Voltage Accuracy, Suitable for Charging Li-Ion Cells
  • ±4% Charge Current Accuracy
  • 300-kHz Integrated PWM Controller for High-Efficiency Buck Regulation
  • Depleted Battery Detection and Indication to Protect Battery From Over Discharge
  • 20-µA Sleep Mode Current for Low Battery Drain
  • 24-Pin TSSOP Package and 5 mm × 5 mm QFN package (bq24703 only)

The bq24702/bq24703 is a highly integrated battery charge controller and selector tailored for notebook and sub-notebook PC applications.

The bq24702/bq24703 uses dynamic power management (DPM) to minimize battery charge time by maximizing use of available wall-adapter power. This is achieved by dynamically adjusting the battery charge current based on the total system (adapter) current.

The bq24702/bq24703 uses a fixed frequency, pulse width modulator (PWM) to accurately control battery charge current and voltage. Charge current limits can be programmed from a keyboard controller DAC or by external resistor dividers from the precision 5-V, ±0.6%, externally bypassed voltage reference (VREF), supplied by the bq24702/bq24703.

The battery voltage limit can be programmed by using the internal 1.196-V, ±0.5% precision reference, making it suitable for the critical charging demands of lithium-ion cells. Also, the bq24702/bq24703 provides an option to override the precision reference and drive the error amplifier either directly from an external reference or from a resistor divider off the 5 V supplied by the integrated circuit.

The selector function allows the manual selection of the system power source, battery or wall-adapter power. The bq24702/bq24703 supports battery-conditioning and battery-learn cycles through the ACSEL function. The ACSEL function allows manual selection of the battery or wall power as the main system power. It also provides autonomous switching to the remaining source (battery or ac power) should the selected system power source terminate (refer to Available Options table for the differences between the bq24702 and the bq24703). The bq24702/bq24703 also provides an alarm function to indicate a depleted battery condition.

The bq24702/bq24703 PWM controller is ideally suited for operation in a buck converter for applications when the wall-adapter voltage is greater than the battery voltage.

The bq24702/bq24703 is a highly integrated battery charge controller and selector tailored for notebook and sub-notebook PC applications.

The bq24702/bq24703 uses dynamic power management (DPM) to minimize battery charge time by maximizing use of available wall-adapter power. This is achieved by dynamically adjusting the battery charge current based on the total system (adapter) current.

The bq24702/bq24703 uses a fixed frequency, pulse width modulator (PWM) to accurately control battery charge current and voltage. Charge current limits can be programmed from a keyboard controller DAC or by external resistor dividers from the precision 5-V, ±0.6%, externally bypassed voltage reference (VREF), supplied by the bq24702/bq24703.

The battery voltage limit can be programmed by using the internal 1.196-V, ±0.5% precision reference, making it suitable for the critical charging demands of lithium-ion cells. Also, the bq24702/bq24703 provides an option to override the precision reference and drive the error amplifier either directly from an external reference or from a resistor divider off the 5 V supplied by the integrated circuit.

The selector function allows the manual selection of the system power source, battery or wall-adapter power. The bq24702/bq24703 supports battery-conditioning and battery-learn cycles through the ACSEL function. The ACSEL function allows manual selection of the battery or wall power as the main system power. It also provides autonomous switching to the remaining source (battery or ac power) should the selected system power source terminate (refer to Available Options table for the differences between the bq24702 and the bq24703). The bq24702/bq24703 also provides an alarm function to indicate a depleted battery condition.

The bq24702/bq24703 PWM controller is ideally suited for operation in a buck converter for applications when the wall-adapter voltage is greater than the battery voltage.

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Type Title Date
* Data sheet Multichemistry Battery Charger Controller & System Power Selector datasheet (Rev. E) 18 Oct 2007
Application note Dynamic Power-Path Mgmt & Dynamic Power Mgmt (Rev. A) 01 May 2018
Application note How to Review a Multicell Switching Charger Schematic 21 Sep 2011
EVM User's guide BQ24702/03 EVM for Multi-Chemistry Battery Charge Controller (Rev. A) 14 Feb 2005

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TSSOP (PW) 24 Ultra Librarian

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