Battery Charger. RT9451 Datasheet

RT9451 Charger. Datasheet pdf. Equivalent

RT9451 Datasheet
Recommendation RT9451 Datasheet
Part RT9451
Description Switch-Mode Single Cell Li-ion Battery Charger
Feature RT9451; ® RT9451 Switch-Mode Single Cell Li-ion Battery Charger with USB OTG General Description The RT945.
Manufacture Richtek Technology
Datasheet
Download RT9451 Datasheet




Richtek Technology RT9451
®
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+Ddetection, 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+Ddetection 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
Mobile Phones and Smart Phones
MP3 Players
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
VIN VIN MID
CIN
Control
Inputs
USB Charger
Detection
SCL
SDA
LX
VIO
DP
DM BATS
GND
CMID
L
CSYSS + Battery
Copyright ©2017 Richtek Technology Corporation. All rights reserved.
DS9451-01 March 2017
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
1



Richtek Technology RT9451
RT9451
Features
Integrated Switching Charger and 50mA LDO in a
Single Package
Charges Faster Than Linear Chargers
High Accuracy Voltage and Current Regulation
Charge Voltage Regulation Accuracy : ±1%
Charge Current Regulation Accuracy : ±5%
Minimum Input Voltage Regulation : 4.2V to 4.76V
with Step of 80mV
Bad Adaptor Detection and Rejection
Safety Limit Register for Maximum Charge Voltage
and Current Limiting
High Efficiency Mini-USB/AC Battery Charger for
Single Cell Li-Ion and Li-Polymer Battery Packs
28V Absolute Maximum Input Voltage Rating
12V Maximum Operating Input Voltage
Built-In Input Current Sensing and Limiting
Integrated Power FETs for Up to 4A Charge Rate
Programmable Charge Parameters through I2C
Interface (up to 400 Kbps) :
Input Current
Fast Charge/Termination Current
Charge Voltage (3.5V to 4.44V)
Safety Timer
Termination Enable
Synchronous Fixed Frequency PWM Controller
Operating at 375kHz With 0% to 99% Duty Cycle
Automatic High Impedance Mode for Low Power
Consumption
Safety Timer with Reset Control
Thermal Regulation and Protection
Input/Output Over-Voltage Protections
Status Output for Charging and Faults
USB Friendly Boot-Up Sequence
Automatic Charging
Boost Mode Operation for USB OTG
Input Voltage Range (BATS) : 2.5V to 4.5V
Output Voltage for VIN : 4.425V to 5.506V
RoHS Compliant and Halogen Free
Marking Information
0Q= : Product Code
0Q=YM
DNN
YMDNN : Date Code
Pin Configuration
(TOP VIEW)
VIN
VIN
VIN
VIN
INT
VIO
DP
DM
32 31 30 29 28 27 26 25
1 24
2 23
3 22
4
GND
21
5 20
6 33 19
7 18
8 17
9 10 11 12 13 14 15 16
PGND
PGND
PGND
PGND
GND
VDDP
BOOT
MID_LDO
WQFN-32L 4x4
Copyright ©2017 Richtek Technology Corporation. All rights reserved.
www.richtek.com
2
is a registered trademark of Richtek Technology Corporation.
DS9451-01 March 2017



Richtek Technology RT9451
RT9451
Functional Pin Description
Pin No.
Pin Name
Pin Function
1 to 4
VIN
Power input. Bypass to PGND with a 10F ceramic capacitor. It also provides
power to the load in boost mode.
5 INT
Interrupt pin (open-drain). This pin is pulled low when a fault occurs.
6 VIO
I/O reference voltage. A VIO level above 0.6V disables automatic D+/D
detection.
7 DP
USB port D+ input connection.
8 DM
USB port Dinput connection.
9 SCL
10 SDA
I2C interface clock input. Open-drain output, connect a 10kpull-up resistor.
I2C interface data input. Open-drain output, connect a 10kpull-up resistor.
Charge status indicator. Pull low when charge is in progress. Open-drain for
11 STAT other conditions. This pin can also be controlled through I2C register. The STAT
can be used to drive a LED or communicate with a host processor.
12 OTG
Boost mode enable control. Boost mode is turned on whenever this pin is active.
Polarity is user defined through I2C register. The pin is disabled by default and
can be enabled through I2C register bit.
13
BATS
Auxiliary power supply. Connect to the battery pack to provide power in high
impedance mode. Bypass to GND with a 1F ceramic capacitor.
Charge current sense input. Battery current is sensed via the voltage drop
14
ISENL
across an external sense resistor. A 0.1F ceramic capacitor to PGND is
required.
15
ISENR
Battery voltage and current sense input. Bypass to PGND with a ceramic
capacitor (minimum 0.1F) if there are long inductive leads to battery.
16 LDO
LDO output. LDO is regulated to 4.9V and drives 60mA of current. Bypass LDO
to GND with a minimum 1F ceramic capacitor. LDO is enabled when VIN is
above the VIN UVLO threshold.
17 MID_LDO LDO input voltage. Please connect to MID.
18
BOOT
Bootstrap supply for high-side gate driver. Connect a 100nF ceramic capacitor
(voltage rating above 10V) from BOOT pin to LX pin.
19
VDDP
Internal bias regulator voltage for driver. Connect a 1F ceramic capacitor from
this output to PGND. External loads on VDDP is not allowed.
20, 33
(Exposed Pad)
GND
Pure ground. The exposed pad must be soldered to a large PCB and connected
to GND for maximum thermal dissipation.
21 to 25
PGND
Power ground.
26 to 30
LX
Switch node.
31, 32
MID
Connection point between reverse blocking MOSFET and high-side MOSFET.
Bypass to PGND with a minimum of 10F capacitor. No other circuits are
recommended to connect at MID pin.
Copyright ©2017 Richtek Technology Corporation. All rights reserved.
DS9451-01 March 2017
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
3





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