RT9451 Datasheet, PDF (1/37 Pages) Richtek Technology Corporation – Switch-Mode Single Cell Li-ion Battery Charger with USB OTG

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RT9451
Switch-Mode Single Cell Li-ion Battery Charger with USB OTG
General Description
The RT9451 integrates a high efficiency USB friendly switch
mode charger with On-The-Go (OTG) support for single
cell Li-ion and Li-polymer batteries, D+D− detection, and
a 50mA LDO regulator into a single chip.
The charger features a synchronous 375kHz PWM
controller with integrated power MOSFETs, input current
sensing and regulation, Minimum Input Voltage Regulation
(MIVR), high accuracy charge current and voltage
regulation, and charge termination. It charges the battery
in three phases : low current pre-charge, constant current
fast charge, and constant voltage trickle charge. The input
current is automatically limited to the value set by the
host. The charger can be configured to terminate charge
based on user-selectable minimum current level and
automatically restart the charge cycle if the battery voltage
falls below the recharge threshold. A safety timer with
reset control provides a safety backup for I²C interface.
The charger automatically enters sleep mode or high
impedance mode when the input supply is removed. The
charge status is reported to the host using the I²C interface
and the STAT pin. The D+D− detection circuit allows
automatic detection of a USB wall charger. If a wall charger
is detected, the input current limit will automatically
increase from 500mA to 975mA.
In OTG mode, the PWM controller boosts the battery
voltage to 5V and provides up to 1.6A of current to the
USB output. At very light load, the Boost operates in burst
mode to optimize efficiency. OTG mode can be enabled
either through I²C interface or GPIO control.
Applications
z Mobile Phones and Smart Phones
z MP3 Players
z Handheld Devices
Ordering Information
RT9451
Package Type
QW : WQFN-32L 4x4 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
Note :
Richtek products are :
` RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
` Suitable for use in SnPb or Pb-free soldering processes.
Simplified Application Circuit
RT9451
V_IN
VIN
MID
C_IN
Control
Inputs
USB Charger
Detection
SCL
SDA
LX
VIO
DP
DM
BATS
GND
C_MID
L
C_{SYSS + Battery}
Copyright ©2013 Richtek Technology Corporation. All rights reserved.
DS9451-00 September 2013
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
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