The bq25890, bq25892 are highly-integrated5-A switch-mode battery charge management and system power path management device for single cellLi-Ion and Li-polymer battery. The devices support high input voltage fast charging. The lowimpedance power path optimizes switch-mode operation efficiency, reduces battery charging time andextends battery life during discharging phase.

The I2C Serial interface with charging and system settingsmakes the device a truly flexible solution.

The bq25890/2 is a highly-integrated 5-A switch-mode battery charge management and systempower path management device for single cell Li-Ion and Li-polymer battery. It features fastcharging with high input voltage support for a wide range of smartphone, tablet and portabledevices. Its low impedance power path optimizes switch-mode operation efficiency, reduces batterycharging time and extends battery life during discharging phase. It also integrates Input CurrentOptimizer (ICO) and Resistance Compensation (IRCOMP) to deliver maximum charging power to battery.The solution is highly integrated with input reverse-blocking FET (RBFET, Q1), high-side switchingFET (HSFET, Q2), low-side switching FET (LSFET, Q3), and battery FET (BATFET, Q4) between systemand battery. It also integrates the bootstrap diode for the high-side gate drive and batterymonitor for simplified system design. The I2C serial interface withcharging and system settings makes the device a truly flexible solution.

The device supports a wide range of input sources, including standard USB host port, USBcharging port, and USB compliant adjustable high voltage adapter. To support fast charging usingadjustable high voltage adapter, the bq25890 provides support forMaxChargeTM handshake using D+/D– pins and DSEL pin for USB switchcontrol. In addition, both bq25890 and bq25892 include interface to support adjustable high voltageadapter using input current pulse protocol. To set the default input current limit, device uses thebuilt-in USB interface (bq25890) or takes the result from detection circuit in the system(bq25892), such as USB PHY device. The device is compliant with USB 2.0 and USB 3.0 power spec withinput current and voltage regulation. In addition, the Input Current Optimizer (ICO) supports thedetection of maximum power point detection of the input source without overload. The device alsomeets USB On-the-Go (OTG) operation power rating specification by supplying 5 V (Adjustable 4.5 Vto 5.5 V) on VBUS with current limit up to 2.4 A.

The power path management regulates the system slightly above battery voltage but doesnot drop below 3.5-V 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 Supplement 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. The PG output (bq25892) indicates if a good powersource 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

(Picture: Diagram)