The BQ25606 device is a highly-integrated standalone
battery charge management and system power path management device for single cell Li-Ion and
Li-polymer battery. The low impedance power path optimizes switch-mode operation efficiency,
reduces battery charging time and extends battery life during discharging phase.
The BQ25606 is
a highly-integrated standalone 3.0-A
switch-mode battery charge management 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
standalone chargers and portable devices. Its low impedance power
path optimizes switch-mode operation efficiency, reduces battery charging time and extends battery
life during discharging phase. Its input voltage and current regulation deliver maximum charging power 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 drive for
simplified system design.
The device supports a wide range of input sources, including standard USB host port, USB
charging port, and USB compliant high voltage adapter. The device sets default input current
limit based on the built-in USB interface. The device is compliant with USB
2.0 and USB 3.0 power spec with input current and voltage regulation. When
the device built-in USB interface identifies the input adaptor is unknown, the devices input
current limit is determined by the ILIM pin setting resistor value. The device also meets
USB On-the-Go (OTG) operation power rating specification by supplying 5.15 V on VBUS with constant
current limit up to 1.2A.
The power path management regulates the system slightly above battery voltage but does
not drop below 3.5 V minimum system voltage. 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 to zero. As the system load continues to
increase, the power path discharges 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 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 overcurrent protections. The thermal regulation reduces charge current when the
junction temperature exceeds 110°C. The STAT output reports the charging status and any fault conditions. Other
safety features include battery temperature sensing for charge and boost mode, thermal regulation
and thermal shutdown and input UVLO and overvoltage protection.
The device family is available in 24-pin, 4 mm x
4 mm QFN package.