I2C controlled 1-cell, 1.5-A, battery charger with 20-mA termination | RTW | 24 | -40 to 85

The BQ25618E/619E integrates charge

and voltage protection in a single device. It offers low termination current for switching

chargers to charge wearable devices to full battery capacity. The BQ25618E/BQ25619E low

quiescent current reduces battery leakage down to 7µA in Ship Mode, which conserves

battery energy to extend the shelf life for the device. The BQ25619E is in a 4mm x 4mm QFN

package for easy layout. The BQ25618E is in a 2.0mm x 2.4mm WCSP package for space-limited

designs.

The BQ25618E/619E is a highly integrated 1.5A switch-mode battery charge

management and system power path management device for Li-ion and Li-polymer

battery. It features fast charging with high input voltage support for a wide range

of applications including earbuds (True Wireless or TWS), earphone charging case,

and wearables. Its low impedance power path optimizes switch-mode operation

efficiency, reduces battery charging time, and extends battery run time during

discharging phase. Its input voltage and current regulation, low termination

current,and battery

remote sensing deliver maximum charging power to the 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 drive for simplified system design. The I2C serial

interface with charging and system settings makes the device a truly flexible solution.

The device supports a wide range of

input sources, including standard USB host port, USB charging port, USB compliant

high voltage adapter and wireless power. It is compliant with USB 2.0 and USB 3.0

power spec with input current and voltage regulation. The device takes the result from the detection circuit in the system, such as

USB PHY device.

The power path management regulates the system

slightly above battery voltage but does not drop below 3.5V minimum system voltage

(programmable) with adapter

applied. With this feature, the system maintains operation even when the battery is

completely depleted or removed. When the input current limit or voltage limit is

reached, the power path management automatically reduces the charge current. As the

system load continues to increase, the battery starts to discharge the battery until

the system power requirement is met. This supplement mode prevents overloading the

input source.

The device initiates and completes a

charging cycle without software control. It senses the battery voltage and charges

the battery in three phases: pre-conditioning, constant current and constant

voltage. At the end of the charging cycle, the charger automatically terminates when

the charge current is below a preset limit and the battery voltage is higher than

the recharge threshold. If the fully charged battery falls below the recharge

threshold, the charger automatically starts another charging cycle.

The charger provides various safety

features for battery charging and system operations, including battery negative

temperature coefficient thermistor monitoring, charging safety timer and overvoltage

and over-current protections. Thermal regulation reduces charge current when the

junction temperature exceeds 110°C. The status register reports the charging status and any fault conditions. With I2C, the VBUSGD bit indicates if a good power source is

present, and the INT output immediately notifies host when

a fault occurs.

The device also provides the

QON pin for BATFET enable and reset control to exit low

power ship mode or full system reset function.

The BQ25619E device is available in a

24-pin, 4mm × 4mm x 0.75mm thin WQFN package.

The BQ25618E is available in a 30-ball, 2.0mm x 2.4mm WCSP package.