I2C Controlled 3A Single-Cell Battery Charger with High Input Voltage
Capability and Narrow Voltage DC (NVDC) Power Path Management
The SGM41511 is a battery charger and system power path
management device with integrated converter and power
switches for use with single-cell Li-Ion or Li-polymer batteries.
This highly integrated 3A device is capable for fast charging
and supports a wide input voltage range suitable for smart
phones, tablets and portable systems. I2C programming
makes it a very flexible powering and charger design solution.
The device includes four main power switches: input reverse
blocking FET (RBFET, Q1), high-side switching FET for buck
or boost mode (HSFET, Q2), low-side switching FET for buck
or boost mode switching (LSFET, Q3) and battery FET that
controls the interconnection of the system and battery
(BATFET, Q4). The bootstrap diode for the high-side gate
driving is also integrated. The internal power path has a very
low impedance that reduces the charging time and maximizes
the battery discharge efficiency. Moreover the input voltage
and current regulations provide maximum charging power
delivery to the battery with various types of input sources.
A wide range of input sources are supported, including
standard USB host, charging ports and USB compliant high
voltage adapters. The default input current limit is
automatically selected based on the built-in USB interface.
This limit is determined by the detection circuit in the system
(e.g. USB PHY). SGM41511 is USB 2.0 and USB 3.0 power
specifications compliant with input current and voltage
regulation. It also meets USB On-The-Go (OTG) power rating
specification and is capable to boost the battery voltage to
supply 5.15V on VBUS with 1.2A (or 0.5A) current limit.
The system voltage is regulated slightly above the battery
voltage by the power path management circuit and is kept
above the programmable minimum system voltage (3.5V by
default). Therefore, system power is maintained even if the
battery is completely depleted or removed. Dynamic power
management (DPM) feature is also included that
automatically reduces the charge current if the input current
or voltage limit is reached. If the system load continues to
increase after reduction of charge current down to zero, the
power path management provides the deficit from battery by
discharging battery to the system until the system power
demand is fulfilled. This is called supplement mode and
prevents input source overloading.
Starting and termination of a charging cycle can be
accomplished without software control. The sensed battery
voltage is used to decide for starting phase of charge in one
of the three phases of charge cycle: pre-conditioning,
constant current or constant voltage. When the charge
current falls below a preset limit and the battery voltage is
above recharge threshold, the charger function will
automatically terminate and end the charging cycle. If the
voltage of a charged battery falls below the recharge
threshold, the charger starts another charging cycle.
Several safety features are provided in the SGM41511 such
as over-voltage and over-current protections, battery
temperature monitoring, charging safety timing, thermal
shutdown and input UVLO. TS pin is connected to an NTC
thermistor for battery temperature monitoring and protection
in both charge and boost modes according to JEITA profile.
This device also features thermal regulation in which the
charge current is reduced if the junction temperature exceeds
80°C or 120℃ (selectable).
Charging status is reported by the STAT output and
fault/status bits. A negative pulse is sent to the nINT output
pin as soon as a fault occurs to notify the host. BATFET reset
control is provided by nQON pin to exit ship mode or for a full
The device is available in a Green TQFN-4×4-24L package.
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SG Micro Corp