The bq25896 is a highly-integrated 3-A switch-mode battery chargemanagement and system power path management device for single cell Li-Ion and Li-polymer battery.The devices support high input voltage fast charging. The low impedance power path optimizesswitch-mode operation efficiency, reduces battery charging time and extends battery life duringdischarging phase. The I2C Serial interface with charging and systemsettings makes the device a truly flexible solution.
The bq25896 is a highly-integrated 3-A switch-mode battery chargemanagement and system power path management device for single cell Li-Ion and Li-polymer battery.It features fast charging with high input voltage support for a wide range of smartphone, tabletand portable devices. Its low impedance power path optimizes switch-mode operation efficiency,reduces battery charging time and extends battery life during discharging phase. It also integratesInput Current Optimizer (ICO) and Resistance Compensation (IRCOMP) to deliver maximum chargingpower to battery. The solution is highly integrated with input reverse-blocking FET (RBFET, Q1),high-side switching FET (HSFET, Q2), low-side switching FET (LSFET, Q3), and battery FET (BATFET,Q4) between system and battery. It also integrates the bootstrap diode for the high-side gate driveand battery monitor for simplified system design. The I2C serialinterface with charging and system settings makes the device a truly flexible solution.
The device supports a wide range of input sources and takes the resultfrom detection circuit in the system, such as USB PHY device. The input current and voltageregulation selection is compactible with USB 2.0 and USB 3.0 power spec. In addition, the InputCurrent Optimizer (ICO) supports the detection of maximum power point detection of the input sourcewithout overload. The device also meets USB On-the-Go (OTG) operation power rating specification bysupplying 5 V (Adjustable 4.5V-5.5V) on VBUS with current limit up to 2 A.
The power path management regulates the system slightly above battery voltage but doesnot drop below 3.5V minimum system voltage (programmable). With this feature, the system maintainsoperation even when the battery is completely depleted or removed. When the input current limit orvoltage limit is reached, the power path management automatically reduces the charge current tozero. As the system load continues to increase, the power path discharges the battery until thesystem power requirement is met. This Supplemental Mode operation preventsoverloading the input source.
The device initiates and completes a charging cycle without software control. Itautomatically detects the battery voltage and charges the battery in three phases:pre-conditioning, constant current and constant voltage. At the end of the charging cycle, thecharger automatically terminates when the charge current is below a preset limit in the constantvoltage phase. When the full battery falls below the recharge threshold, the charger willautomatically start another charging cycle.
The charger provides various safety features for battery charging and system operations,including battery temperature negative thermistor monitoring, charging safety timer andovervoltage/overcurrent protections. The thermal regulation reduces charge current when thejunction temperature exceeds 120°C (programmable). The STAT output reports the charging status andany fault conditions. ThePG output indicates if a good power source is present. The INT immediately notifies host when fault occurs.
The device also provides a 7-bit analog-to-digital converter (ADC) for monitoring chargecurrent and input/battery/system (VBUS, BAT, SYS, TS) voltages. The QON pin provides BATFETenable/reset control to exit low power ship mode or full system reset function.
The device family is available in 24-pin, 4 x 4 mm2 x 0.75 mmthin WQFN package.
Feature
- High Efficiency 3-A, 1.5-MHz Switch Mode Buck Charge
- 92.5% Charge Efficiency at 2 A and 90.5% Charge Efficiency at 3 A Charge Current
- Optimize for High Voltage Input (9 V / 12 V)
- Low Power PFM mode for Light Load Operations
- USB On-the-Go (OTG) with Adjustable Output from 4.5 V to 5.5 V
- Selectable 500-KHz / 1.5-MHz Boost Converter with up-to 2 A Output
- 93% Boost Efficiency at 5 V at 1 A Output
- Accurate Hiccup Mode Overcurent Protection
- Support down-to 2.5V Battery
- Support PWM only or PFM/PWM control for Light Load Efficiency
- Single Input to Support USB Input and Adjustable High Voltage Adapters
- Support 3.9-V to 14-V Input Voltage Range
- Input Current Limit (100 mA to 3.25 A with 50-mA resolution) to Support USB2.0, USB3.0 standard and High Voltage Adapters
- Maximum Power Tracking by Input Voltage Limit up-to 14V for Wide Range of Adapters
- Input Current Optimizer (ICO) to Maximize Input Power without Overloading Adapters
- Resistance Compensation (IRCOMP) from Charger Output to Cell Terminal
- Highest Battery Discharge Efficiency with 11-mΩ Battery Discharge MOSFET up to 9 A
- Integrated ADC for System Monitor
(Voltage, Temperature, Charge Current) - Narrow VDC (NVDC) Power Path Management
- Instant-on Works with No Battery or Deeply Discharged Battery
- Ideal Diode Operation in Battery Supplement Mode
- BATFET Control to Support Ship Mode, Wake Up, and Full System Reset
- Flexible Autonomous and I2C Mode for Optimal System Performance
- High Integration includes all MOSFETs, Current Sensing and Loop Compensation
- 12-μA Low Battery Leakage Current to Support Ship Mode
- High Accuracy
- ±0.5% Charge Voltage Regulation
- ±5% Charge Current Regulation
- ±7.5% Input Current Regulation
- Safety
- Battery Temperature Sensing for Charge and Boost Mode
- Thermal Regulation and Thermal Shutdown
