DS9455 00

®
RT9455
Switch-Mode Single Cell Li-Ion Battery Charger
with USB-OTG
General Description
Features
The RT9455 is a switch-mode single cell Li-Ion/Li-Polymer
battery charger for portable applications. It integrates a
synchronous PWM controller, power MOSFETs, input
current sensing, high accuracy voltage regulation and
charge termination circuits. The RT9455 also features USB
On-The-Go (OTG).
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The RT9455 optimizes the charging task by using a control
algorithm to vary the charge rate via different modes,
including pre-charge mode, fast charge mode, and constant
voltage mode. The key charge parameters can be
programmed via the I2C interface. The RT9455 resumes
the charge cycle whenever the battery voltage falls below
an internal threshold and automatically enters sleep mode
when the input power supply is removed.
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Other features include under-voltage protection, overvoltage protection, thermal regulation and reverse leakage
protection.
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The RT9455 is available in the small WL-CSP-16B
1.7x1.77 (BSC) package.
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Marking Information


1A : Product Code
1AW
W : Date Code
Support Quick Start for Charger
High Accuracy Voltage/Current Regulation
Input Current Regulation : 100mA/500mA/700mA/
1A
Minimum Input Voltage Regulation : 4V/4.25V/4.5V
Charge Voltage Regulation Accuracy : ±1% (0 to
85°°C)
Charge Current Regulation Accuracy : ±5%
Built-In Input Current Sensing and Limiting
Integrated Power MOSFETS for up to 1.55A Charge
Rate
Integrated Sensing Resistors for Charging Current
Sensing
Synchronous 1.5MHz Fixed Frequency PWM
Controller with up to 95% Duty Cycle
Reverse Leakage Protection to Prevent Battery
Drainage
Thermal Regulation and Protection
Over-Temperature Protection
Input Over-Voltage Protection
IRQ Output for Communication with I2C
Automatic Charging
RoHS Compliant and Halogen Free
Applications
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Cellular Telephones
Personal Information Appliances
MP3 Players
Portable Instruments
Simplified Application Circuit
To Adaptor/USB
VIN
OTG
SCL
SDA
IRQ
VMID
RT9455
LX
ISNSIN
BATS
GND
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DS9455-00 April 2014
+
Battery
is a registered trademark of Richtek Technology Corporation.
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1
RT9455
Ordering Information
Pin Configurations
RT9455
(TOP VIEW)
Package Type
WSC : WL-CSP-16B 1.7x1.77 (BSC)
Note :
Richtek products are :

RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020.

Suitable for use in SnPb or Pb-free soldering processes.
A1
A2
A3
A4
VIN
VIN
IRQ
BATS
B1
B2
B3
B4
VMID
VMID
OTG
ISNSIN
C1
C2
C3
C4
LX
LX
AGND
SCL
D1
D2
PGND PGND
D3
D4
BOOT
SDA
WL-CSP-16B 1.7x1.77 (BSC)
Functional Pin Description
Pin No.
Pin Name
Pin Function
A1, A2
VIN
Power Input.
A3
IRQ
IRQ Output Node.
A4
BATS
Feedback Voltage Input for Battery.
B1, B2
VMID
Connection Point Between Reverse Blocking MOSFET and High-Side
MOSFET.
B3
OTG
Boost Mode Control Input or Current Regulation Setting for Average Input
Current.
B4
ISNSIN
Charge Current Sense Input.
LX
Switch Node.
C3
AGND
Analog Ground.
C4
SCL
Clock Input for I C. Open-drain output, connect a 10k pull-up resistor.
D1, D2
PGND
Power Ground for Switching Charger.
D3
BOOT
Bootstrap Supply for High-Side MOSFET. Connect a capacitor between BOOT
and LX.
D4
SDA
Data Input for I C. Open-drain output, connect a 10k pull-up resistor.
C1, C2
2
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2
2
is a registered trademark of Richtek Technology Corporation.
DS9455-00 April 2014
RT9455
Function Block Diagram
VIN
Protection
OVP, UVLO,
OTP, Timer
Gate
Driver 1
VMID
BOOT
Loop
Control
Base
VDD, Ibias,
VREF, OSC
Gate
Driver 2
LX
PGND
SCL
SDA
2
I C
State
Machine
Current
Sense
ISNSIN
BATS
AGND
OTG
IRQ
Operation
The RT9455 is a switch mode charger with USB-OTG
support for single cell Li-Ion battery in portable applications.
Loop Controller and PWM and Driver
Base circuits provide the internal power, VDD and reference
voltage and bias current.
The multi-loop controller controls the PWM signal during
the charging process. The PWM circuit controls the power
stage through the driver. It makes sure that the battery is
well-charged with suitable current, voltage and dietemperature.
Current Sense
I2C Interface
Current sense circuit regulates the output current up to
1.5A to battery
The I 2C interface is used to program the charging
parameters, ex : output current and output voltage.
Protection Circuits
State Machine
The protection block includes the OVP, UVLO, OTP, Timer
and other circuits. It turns off the charging when the charger
IC or input power is in abnormal level.
The State Machine controls the operation of the switching
charger and outputs the interrupt via the IRQ pin if there is
any fault be triggered.
Base Circuits
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3
RT9455
Flow Charts
Yes
2
Any I C?
Yes
No
Charge Start
TMR_EN = 1?
Reset Timer
--------------------T32min mode
Yes
No
2
Any I C?
Yes
Any state
No
32 min?
Yes
Timer Fault
----------------------Disable Charging
No
VIN ,VBATS < 2.4V
No
POR Reset
No
VIN > 2.4V and
Yes
Yes
VIN > 3.3V ?
VBATS > 2.4V ?
Charge Configure
2
(I C is Programmable)
No
2
Clean I C
Any State If VIN < 2.4V and
VBATS < 2.4V
Power On
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DS9455-00 April 2014
RT9455
Charger Flow
Power on
disable charge
----------------Charge Configure Mode
Yes
32 min timer fault?
2
No
Load I C with default
settings
VBATS > VPREC?
Any state
No
PreCharge Mode
Yes
Fast-Charge to CV mode
No
TE is enabled?
Yes
No
ICHRG < IEOC?
No
Yes
Yes
BATD_EN is enabled?
Yes
Sink 0.5mA from battery
---------------------------------Start 262ms timer
Yes
No
Charge done
262ms timer expired?
No
VBATS < VREC?
Yes
No
VBATS < VREC ?
Copyright © 2014 Richtek Technology Corporation. All rights reserved.
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Battery Detection Mode
(Detect every 2s)
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5
RT9455
OTG Flow
Battery power on
No
OPA_MODE = 1 and
HZ = 0?
OTG_EN = 1?
Yes
Yes
No
OTG_PL = 1?
OTG Configure Mode
Yes
Yes
No
No
OTG pin from low to high?
Any fault except Over
Load ?
OTG pin from high to low?
No
No
Yes
No
Yes
OTG pin keeps high?
OTG pin keeps low?
OTG Mode
Yes
Yes
No
OTG Configure Mode
OTG Configure Mode
Yes
Over Load ?
Yes
Any fault except Over
Load ?
Any fault except Over
Load ?
No
Yes
OTG Mode
OTG Mode
Yes
No
No
Over Load ?
Over Load ?
Yes
Yes
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Set to HZ mode
is a registered trademark of Richtek Technology Corporation.
DS9455-00 April 2014
RT9455
Absolute Maximum Ratings
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(Note 1)
Supply Input Voltage, VIN -----------------------------------------------------------------------------------------------MID, BOOT -----------------------------------------------------------------------------------------------------------------LX -----------------------------------------------------------------------------------------------------------------------------MID − VIN, BOOT − LX ---------------------------------------------------------------------------------------------------Other Pins -------------------------------------------------------------------------------------------------------------------Power Dissipation, PD @ TA = 25°C
WL-CSP-16B 1.7x1.77 (BSC) ------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2)
WL-CSP-16B 1.7x1.77 (BSC), θJA ------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) -------------------------------------------------------------------------------Junction Temperature -----------------------------------------------------------------------------------------------------Storage Temperature Range --------------------------------------------------------------------------------------------ESD Susceptibility (Note 3)
HBM (Human Body Model) ----------------------------------------------------------------------------------------------MM (Machine Model) ------------------------------------------------------------------------------------------------------
Recommended Operating Conditions
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−0.3V to 20V
−0.3V to 20V
−0.3V to 10V
−0.3V to 6V
−0.3V to 6V
2.09W
47.8°C/W
260°C
150°C
−65°C to 150°C
2kV
200V
(Note 4)
Supply Input Voltage, VIN ------------------------------------------------------------------------------------------------ 4.3V to 6V
Junction Temperature Range --------------------------------------------------------------------------------------------- −40°C to 125°C
Ambient Temperature Range --------------------------------------------------------------------------------------------- −40°C to 85°C
Electrical Characteristics
(VIN = 5V, VBAT = 4.2V, L = 1μH, CIN = 2.2μF, CBATS = 10μF, TA = 25°C, unless otherwise specified)
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
6.4
6.7
7
V
--
150
--
mV
110
117
124
%
--
10
--
%
--
165
--
°C
--
10
--
°C
Charge Current Begins to Reduce
--
120
--
°C
Protection
VIN OVP Threshold Voltage
VIN OVP Hysteresis
(Battery OVP  VOREG) / VOREG
Battery OVP
Battery OVP Hysteresis
Over-Temperature Protection
OTP
OTP Hysteresis
Thermal Regulation Threshold
Sleep Mode Comparator
Sleep-Mode Entry Threshold
VIN  VBATS
VSLP
2.5V < VBATS < VBATREG, VIN Falling
0
0.04
0.1
V
Sleep-Mode Exit Hysteresis
VIN  VBATS
VSLPEXIT
2.5V < VBATS < VBATREG
40
100
200
mV
Sleep-Mode Deglitch Time
TSLP
VIN Rising Above VSLP + VSLPEXIT
--
128
--
ms
3.05
3.3
3.55
V
--
150
--
mV
Under-Voltage Lockout Threshold
IC Active Threshold Voltage
VUVLO
VIN Rising
IC Active Hysteresis
VUVLO
VIN Falling from UVLO
Copyright © 2014 Richtek Technology Corporation. All rights reserved.
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RT9455
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
PWM switching, ICHRG = IBAT = 0mA
--
10
--
mA
PWM Is Not Switching.
ICHRG = IBAT = 0mA
--
--
5
mA
High Impendence Mode
--
--
150
A
IBAT
VBATS = 4.2V, VIN = 0V, Charger Off.
--
--
15
A
VMIVR
I C Programmable Per 0.25V
4
--
4.5
V
5
--
5
%
USB Charge Mode, IAICR = 100mA
80
90
100
USB Charge Mode, IAICR = 500mA
400
450
500
I C Programmable Per 20mV
3.5
--
4.44
V
0 to 85°C
1
--
1
%
VBATS Falling, Below VBATREG
50
125
200
mV
--
128
--
ms
I C Programmable Per 0.15A
0.5
--
1.55
A
500mA to 1.55A
5
--
5
%
2
--
3
V
5
--
5
%
20
--
60
mA
50
--
50
%
I C Programmable Per 10%
10
--
30
%
As IAICR = 100mA
--
50
--
mA
IEOC[1:0] = 00
5
10
15
IEOC[1:0] = 10
14
20
26
IEOC[1:0] = 01 or 11
24
30
36
ICHRG < IEOC, VBATS > VREC
--
32
--
s
Internal MOSFET
On-Resistance
From VIN to LX, as IAICR[1:0] = 11
--
300
450
m
Internal MOSFET
On-Resistance
From LX to PGND
--
120
200
m
Charging Efficiency
VIN = 5V, VBATS = 4V, and ICHRG = 1A
--
85
--
%
--
1.5
--
MHz
Input Currents
VIN Supply Current
Leakage Current from Battery
IQ
Input Power Regulation
Minimum Input Voltage
Regulation
2
VMIVR Accuracy
Average Input Current
Regulation Accuracy
IAICR
mA
Battery Voltage Regulation
Battery Voltage Regulation
VBATREG
VBATREG Accuracy
Re-Charge Threshold
VREC
Re-Charge Deglitch
TREC
2
Charging Current Regulation
Output Charging Current
ICHRG
ICHRG Accuracy
Pre-Charge Threshold
VPREC
2
2
I C Programmable Per 0.2V
VPREC Accuracy
Pre-Charge Current
IPREC
2
I C Programmable Per 20mA
IPREC Accuracy
Charge Termination Detection
End of Charge Current
IEOC
Fixed IEOC
IEOC Accuracy
Deglitch Time for EOC
TEOC
2
%
PWM
Oscillator Frequency
OSC
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DS9455-00 April 2014
RT9455
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
10
--
10
%
--
95
--
%
0
--
--
%
2
2.75
3.5
A
4.425
--
5.6
V
3
--
3
%
--
85
--
%
0.5
--
--
A
2.5
3.25
4
A
--
6
--
V
--
200
--
mV
As Boost Start-Up
2.75
2.9
3.05
During Boost Mode
2.35
2.5
2.65
--
200
--
mV
--
--
0.4
V
Frequency Accuracy
Maximum Duty Cycle
At Minimum Voltage Input
Minimum Duty Cycle
Peak OCP as Charger Mode
ICHRGOCP
Boost Mode Operation
2
Output Voltage Level
VOTG
To VMID, I C Programmable Per
25mV
Output Voltage Accuracy
VIN = 5V, VBATS = 4V,
and IIN = 0.4A
Efficiency
MAX Output Current
Peak Over Current
Protection
VIN OVP as OTG Boost
VBATS = 3.7V
VIN OVP Hysteresis
Minimum Battery Voltage for
Boost
VBATMIN
Minimum Battery Voltage
Hysteresis
V
2
I C Characteristics
Output Low Voltage
VOL
IDS = 10mA
SCL, SDA Input Threshold
Voltage
VIH
Logic High Threshold
1.3
--
--
VIL
Logic Low Threshold
--
--
0.4
--
--
400
SCL Clock
V
kHz
Note 1. Stresses beyond those listed “Absolute Maximum Ratings” may cause permanent damage to the device. These are
stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in
the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may
affect device reliability.
Note 2. θJA is measured at TA = 25°C on a high effective thermal conductivity four-layer test board per JEDEC 51-7.
Note 3. Devices are ESD sensitive. Handling precaution is recommended.
Note 4. The device is not guaranteed to function outside its operating conditions.
Copyright © 2014 Richtek Technology Corporation. All rights reserved.
DS9455-00 April 2014
is a registered trademark of Richtek Technology Corporation.
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9
RT9455
Typical Application Circuit
RT9455
To Adaptor/USB
A1, A2
VIN
0.47µF
VMID
BOOT
A4 OTG
C4 SCL
D4 SDA
A3 IRQ
LX
ISNSIN
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10
0.47µF
D3
100nF
C1, C2
1µH
B4
68m
BATS
AGND
PGND
D1, D2 C3
Copyright © 2014 Richtek Technology Corporation. All rights reserved.
B1, B2
0.1µF
A4
+
Battery
10µF
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DS9455-00 April 2014
RT9455
Typical Operating Characteristics
Charge Mode
Efficiency vs. VBAT
Efficiency vs. VBAT
94
94
92
92
90
88
86
VIN
VIN
VIN
VIN
84
82
=
=
=
=
4.5V
5V
5.5V
6V
80
Efficiency (%)
Efficiency (%)
90
88
86
84
VIN
VIN
VIN
VIN
82
80
78
=
=
=
=
4.5V
5V
5.5V
6V
ICHRG = 950mA, no input current limit
ICHRG = 500mA, no input current limit
76
78
2.2 2.4 2.6 2.8
3
3.2 3.4 3.6 3.8
4
2.2 2.4 2.6 2.8
4.2 4.4
3
3.2 3.4 3.6 3.8
4
VBAT (V)
VBAT (V)
Adapter Insertion
Battery Insertion/Removal
VIN
(5V/Div)
VBAT
(2V/Div)
VLX
(5V/Div)
VLX
(5V/Div)
I IN
(500mA/Div)
IBAT
(500mA/Div)
VIN = 0V to 5V, VBAT = 3.5V
Time (50ms/Div)
4.2 4.4
VIN = 5V, AICR = 500mA, VOREG = 4.44V
Time (1s/Div)
PWM Charging
VLX
(5V/Div)
ILX
(500mA/Div)
VIN = 5V, VBAT = 2.6V, ICHRG = 1.25A
Time (250ns/Div)
Copyright © 2014 Richtek Technology Corporation. All rights reserved.
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11
RT9455
Boost Mode
Efficiency vs. Load Current
PWM Boost
100
90
Efficiency (%)
80
VBAT
VBAT
VBAT
VBAT
70
60
=
=
=
=
4.2V
3.9V
3.6V
3.3V
VLX
(5V/Div)
50
40
30
20
10
VIN = 5V
I LOAD
(500mA/Div)
VBAT = 3.5V, ILOAD = 200mA
0
0
50
100 150 200 250 300 350 400 450 500
Time (250ns/Div)
Load Current (mA)
Time Constant for 32s Timer
VIN Overload
VIN
(5V/Div)
VIN
(5V/Div)
IRQ
(2V/Div)
IRQ
(1V/Div)
ILX
(500mA/Div)
I LOAD
(500mA/Div)
VBAT = 3.7V, ILOAD = 100mA
VBAT = 3.7V, RL = 2Ω
Time (5s/Div)
Time (5ms/Div)
Load Step Up Response
Load Step Down Response
V IN_ac
(500mV/Div)
V IN_ac
(500mV/Div)
VBAT_ac
(200mV/Div)
VBAT_ac
(200mV/Div)
VLX
(5V/Div)
VLX
(5V/Div)
I LOAD
(200mA/Div)
I LOAD
(200mA/Div)
VBAT = 3.8V, ILOAD = 0A to 200mA
Time (100μs/Div)
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VBAT = 3.8V, ILOAD = 0A to 200mA
Time (100μs/Div)
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DS9455-00 April 2014
RT9455
Input Voltage vs. Load Current
Input Voltage vs. VBAT
5.16
5.20
5.14
Input voltage (V)
Input Voltage (V)
5.15
5.10
5.05
ILOAD = 50mA
ILOAD = 100mA
ILOAD = 200mA
5.00
5.12
5.10
5.08
VIN
VIN
VIN
VIN
5.06
5.04
4.95
=
=
=
=
3.3V
3.7V
4.1V
4.3V
5.02
VIN = 5V
VIN = 5V
5.00
4.90
2.5
2.7
2.9
3.1
3.3
3.5
3.7
3.9
4.1
VBAT (V)
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4.3
0
25
50
75
100
125
150
175
200
Load Current (mA)
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RT9455
Applications Information
The RT9455 is an integrated solution of single-cell Li-ion
and Li-polymer battery charger for portable applications.
The part integrates a synchronous PWM controller with
power MOSFETs to provide input voltage MIVR (Minimum
Input Voltage Regulation), input current sensing, high
accuracy current and voltage regulation, and charge
termination in a small package for space limited devices.
The part also features USB OTG (On-The-Go).
The RT9455 has three operation modes : charge mode,
boost mode (USB OTG), and high impedance mode. In
charge mode, the RT9455 supports a precision charging
system for single cell. In boost mode, the RT9455 works
as the Boost converter and boosts the voltage from battery
to VIN pin for sourcing the OTG devices. In high impedance
mode, the RT9455 stops charging or boosting and
operates in a mode with low current from VIN or battery to
reduce the power consumption when the portable device
is in standby mode.
Start
Notice that the RT9455 does not integrate input power
source (AC adapter or USB input) detection. Thus, the
RT9455 does not set the charge current automatically.
The charge current needs to be set via I2C interface by
the host. The RT9455 application mechanism and I2C
compatible interface are introduced in later sections. The
slave address for this device is “0100010”.
I2C Interface Timing Diagram
The RT9455 acts as an I2C -bus slave. The I2C -bus master
configures the settings for charge mode and boost mode
by sending command bytes to the RT9455 via the 2-wire
I2C -bus. After the START condition, the I2C master sends
a chip address. This address is seven bits long followed
by an eighth bit which is a data direction bit (R/W). The
second byte selects the register to which the data will be
written. The third byte contains data to the selected
register.
The 1st Byte
(Slave Address, R/W)
The 2nd Byte
(Data Address, Data)
The 3rd Byte (Data)
0 1 0 0 0 1 0 R/W
B7B6B5B4B3B2B1B0
C7C6C5C4C3C2C1C0
Stop
S
P
SCL
SDA
1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9
0 A6 A5 A4 A3 A2 A1 A0 W ACK B7 B6 B5 B4 B3 B2 B1 B0 ACK C7 C6 C5 C4 C3 C2 C1 C0 ACK
S = Start Condition
ACK = Acknowledge
W = Write (SDA = “0”)
P = Stop Condition
R = Read (SDA = “1”)
Charge Mode Operation
Support Quick Start Feature of Charger
When the battery voltage is lower than 2.4V by overdischarge condition, RT9455 charges the battery with
60mA to wake up the battery. Once the voltage level is
higher than 2.4V, RT9455 charges the battery to higher
level with large current and makes sure that the system
could work normally in short period with OTG pin pulled
high.
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14
Minimum Input Voltage Regulation (MIVR)
The RT9455 features input voltage MIVR function to prevent
input voltage drop due to insufficient current provided by
the adaptor or USB input. If MIVR function is enabled, the
input voltage decreases when the over current of the input
power source occurs and is regulated at a predetermined
voltage level which can be set as 4V, 4.25V or 4.5V by I2C
interface to MIVR[1:0] in the register of address 0x05 the
CHMIVRI bit is set to high. At this time, the current drawn
by the RT9455 equals to the maximum current value that
the input power can provide at the predetermined voltage
level, instead of the set value. The MIVR function is initially
disabled.
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RT9455
Fast-Charge Mode and Settings
VIN
VIN MIVR
Expected IIN
Final IIN
IIN
As the BATS pin rises above VPREC, the charger enters
fast-charge mode and starts switching. Notice that the
RT9455 does not integrate input power source (AC adapter
or USB input) detection. Thus, the RT9455 does not set
the charge current automatically. Unlike the linear charger
(LDO), the switching charger (Buck converter) is a current
amplifier. The current drawn by the RT9455 is different
from the current into the battery. The user can set the
Average Input Current Regulation (AICR) and output charge
current (ICHRG) respectively.
set charge current
Figure 1. Minimum Input Voltage Regulation (MIVR)
Charge Profile
The RT9455 provides a precision Li-ion or Li-polymer
charging solution for single-cell applications. Input current
limit, charge current, termination current, charge voltage
and input voltage MIVR are all programmable via the I2C
interface. In charge mode, the RT9455 has five control
loops to regulate input current, charge current, charge
voltage, input voltage MIVR and device junction
temperature. During the charging process, all five loops
(if MIVR is enabled) are enabled and the dominant one
will take over the control.
For normal charging process, the Li-ion or Li-polymer
battery is charged in three charging modes depending on
the battery voltage. At the beginning of the charging
process, the RT9455 is in pre-charge mode. When the
battery voltage rises above pre-charge threshold voltage
(VPREC), the RT9455 enters fast-charge mode. Once the
battery voltage is close to the regulation voltage (VOREG),
the RT9455 enters constant voltage mode.
Pre-Charge Mode
For life-cycle consideration, the battery can not be charged
with large current under low battery condition. When the
BATS pin voltage is below pre-charge threshold voltage
(VPREC), the charger is in pre-charge mode with a weak
charge current which equals to the pre-charge current
(IPREC). In pre-charge mode, the charger basically works
as an LDO. The pre-charge current also acts as the current
limit when the BATS pin is shorted.
Copyright © 2014 Richtek Technology Corporation. All rights reserved.
DS9455-00 April 2014
Cycle-by-Cycle Current Limit
The charger of the RT9455 has an embedded cycle-bycycle current limit for inductor. Once the inductor current
touches the threshold (2.5A typ.), the charger stops
charging immediately to prevent over current from damaging
the device. Notice that, the mechanism can not be disabled
by any way.
Average Input Current Regulation (AICR)
The AICR setting is controlled by the AICR section (bit 7
and 6) in the register of address 0x01. The written value of
“00” is for USB100 mode with the maximum current limit
of 100mA, “01” is for USB 500 mode with the maximum
current limit of 400mA and “10” is for the maximum
current limit of 1000mA. If the application does not need
input current limit, write “11” into the IINLIMIT section.
Charge Current (ICHRG)
The charge current into the battery is determined by the
sense resistor (RSENSE) and ICHRG section (bit4, bit5, and
bit6) in the register of address 0x06. The voltage between
the ISENL and ISENR pins is regulated to the voltage
control by ICHRG section. The charge current equals to
the voltage between the ISENL and ISENR pins (VICHRG)
divided by RSENSE :
ICHRG =
VICHRG
RSENSE
For example, for a 68mΩ sense resistor, the charge current
can be set from 500mA (ICHRG [2:0] = 000) to 1550mA
(ICHRG [2:0] = 111).
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RT9455
When input current limit and charge current are both set,
the charge current in fast charge phase is calculated as
below :
V
 IIN_LIMIT

  
ICHRG = MIN  ICHRG , 
D

 RSENSE 
where D is the duty cycle and η is the efficiency.
which can be selected in Sel_SWFreg section in the
register of address 0x01.
Frequency Reduction for Efficiency Improvement
The switching frequency of the RT9455 is normally
1.5MHz. However, for improving efficiency, the RT9455
can also operate at 0.75MHz and 0.5MHz, which frequency
are changed automatically depending on the energy
demand. During the CC phase, the power flowing into the
battery raises with the increased battery voltage. Hence,
when battery voltage reaches the level, the switching
frequency steps down to 0.75MHz/0.5MHz. Then, if the
battery voltage keeps rising, the switching frequency will
be decreased please make sure the inductor will not be
saturated with a lager ripple current.
Constant Voltage Mode and Settings
The RT9455 enters constant voltage mode when the BATS
voltage is close to the output-charge voltage (VOREG). Once
in this mode, the charge current begins to decrease. For
default settings (charge current termination is disabled),
the RT9455 does not turn off and always regulates the
battery voltage at VOREG. However, once the charge current
termination is enabled, the charger terminates if the charge
current is below termination current (IEOC) in constant
voltage mode. The charge current termination function is
controlled by the I2C interface in the “TE” bit via the
register of address 0x01.
After termination, a new charge cycle restarts when one
of the following conditions is detected :
Output Charge Voltage (VOREG)
The output-charge voltage is set by the I2C interface in
the CV section (Bit2 to Bit7 bits) via the register of address
0x02. Its range is from 3.5V to 4.45V. The default is 4V
(011001).
Termination Current (IEOC)
If the end of charge detection and shutdown control for
EOC are both enable (TE bit = “1”, TE_SHDN_EN bit =
“1”), the end-of-charge current is determined by both the
change current (I CHRG) and I EOC percentage. I EOC
percentage is set by the I2C interface in the IEOC section
via the register of address 0x05. Its range is from 10% to
30% with an step of 10%. The end-of-charge current is
calculated as below :
IEOC = ICHRG  IEOC_percentage
Safety Timer in Charge Mode and in OTG Mode
To implement safety mechanism, the RT9455 has two
timer modes : T32min mode with a 32-minute timer for
charger mode and T32sec mode with a 32-second timer
for OTG mode.
In the charger mode, a the beginning of a charging
operation, the RT9455 enters T32min mode and starts a
32-minute timer that can be reset by any read or write
action performed by the host through the I2C interface. If
the 32-minute timer expires, the charging operation is
terminated and shows the fault bit CH32MI.
In the OTG mode, at the beginning of a OTG operation,
the RT9455 enters T32sec mode and starts a 32-second
timer that can be reset by any read or write action
performed by the host through the I2C interface. If the 32second timer expires, the OTG operation will keep going
but shows the fault bit BST32SI.
Input Voltage Protection in Charge Mode

The BATS pin voltage falls below the VOREG − VRECH
threshold.
During charge mode, there are two protection mechanisms
against poor input power source.

VIN Power On Reset (POR).
Sleep Mode (VIN − VBATS < VSLP)

CEB bit toggle or RST bit is set (via I2C interface).
The RT9455 enters sleep mode if the voltage drop between
the VIN and BATS pins falls below VSLP. In sleep mode,
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RT9455
the reverse blocking switch and PWM are all turned off.
This function prevents battery drain during poor or no input
power source.
Input Over-Voltage Protection
When VIN voltage rises above the input over-voltage
threshold (VOVP_IN), the RT9455 stops charging and then
sets fault status bits and sends out fault pulse via the
STAT pin. The condition is released when VIN falls below
VOVP_IN − ΔVOVP_IN. The RT9455 then resumes charging
operation.
Control Bits
CHG_EN Bit (Charge Mode)
The CHG_EN bit in control register of address 0x07 is
used to disable or enable the charge process. A value of
“0” disable the charge, while a value of “1” enable the
charge.
RST Bit
The RST bit in control register of address 0x04 is used to
reset the RT9455 back to its default value at power-up,
regardless of its charging or boosting process.
Boost Mode Operation (OTG)
HZ (High Impedance Mode) Bit
Trigger and Operation
The RT9455 features USB OTG. When OTG function is
enabled, the synchronous boost control loop takes over
the power MOSFETs and reverses the power flow from
the battery to the VIN pin. In normal boost mode, the MID
pin is regulated to 5V (typ.) and provides up to 500mA
current to support other USB OTG devices connected to
the USB connector.
Output Over-Voltage Protection
In boost mode, the output over-voltage protection is
triggered when the VIN voltage is above the output OVP
threshold (6V typ.). When OVP occurs and the boost mode
is triggered by the OTG pin, the RT9455 goes back to
Boost Configure 1 state. When VIN returns to normal
operating range, the condition is released and the boost
resumes switching. However, if the boost mode is triggered
by OPA bit, the RT9455 resets the OPA bit and goes back
to Charge Configure state with default charge parameters.
Output Overload Protection
The RT9455 provides an overload protection to prevent
the device and battery from damage when VIN is overload.
Once overload condition is detected, the reverse blocking
switch operates in linear region to limit the output current
while the MID voltage remains in voltage regulation. If the
overload condition lasts for more than 32ms, the RT9455
will recognise the overload fault condition and resets
registers to the default settings.
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When the HZ bit is set to “1” and the OTG pin is not in
active status, the RT9455 operates in high impedance
mode. The condition is released by POR or setting the
HZ bit to “0”.
OPA Bit
The OPA bit is the operation mode control bit, which is
dependent on the status of HZ.
OPA
bit
HZ
bit
0
0
1
0
X
1
Operation
Charge mode (no fault)
Charge configure (fault, VIN > V UVLO)
High impedance mode (VIN < VUVLO )
Boost mode (no fault)
Go to charge configure when any fault
High impedance mode
Battery Protection
Battery Over-Voltage Protection in Charge Mode
The RT9455 monitors the BATS voltage for output overvoltage protection. In charge mode, if the BATS voltage
rises above VOVP_BAT x VOREG, such as when the battery
is suddenly removed, the RT9455 stops charging and then
sets fault status bits and sends out fault pulse at the
STAT pin. The condition is released when the BATS voltage
falls below (VOVP_BAT − ΔVOVP_BAT) x VOVP_BAT. The RT9455
then resumes charging process with default settings and
the fault is cleared.
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RT9455
Battery Detection During Normal Charging
Thermal Considerations
The RT9455 provides a battery absent detection scheme
to detect insertion or removal of the battery pack. The
battery detection scheme is valid only when the charge
current termination is enabled (TE bit = “1”).
For continuous operation, do not exceed absolute
maximum junction temperature. The maximum power
dissipation depends on the thermal resistance of the IC
package, PCB layout, rate of surrounding airflow, and
difference between junction and ambient temperature. The
maximum power dissipation can be calculated by the
following formula :
I2C Setting Example
The example below demonstrates the charge parameter
setting of the RT9455 through the I2C interface. The
component values follow that shown in typical application
circuit.
Charge Mode
RSENSE = 68mΩ
VIN MIVR = 4.25V
Average Input Current Regulation, AICR = 1A
Battery regulation voltage, VOREG = 4.2V
Output Charge Current, ICHRG = 1.55A
Termination Charge Current, IEOC = 10%
PD(MAX) = (TJ(MAX) − TA) / θJA
where TJ(MAX) is the maximum junction temperature, TA is
the ambient temperature, and θJA is the junction to ambient
thermal resistance.
For recommended operating condition specifications, the
maximum junction temperature is 125°C. The junction to
ambient thermal resistance, θJA, is layout dependent. For
WL-CSP-16B 1.7x1.77 (BSC) package, the thermal
resistance, θJA, is 47.8°C/W on a standard JEDEC 51-7
four-layer thermal test board. The maximum power
dissipation at TA = 25°C can be calculated by the following
formula :
PD(MAX) = (125°C − 25°C) / (47.8°C/W) = 2.09W for
WL-CSP-16B 1.7x1.77 (BSC) package
The maximum power dissipation depends on the operating
ambient temperature for fixed T J(MAX) and thermal
resistance, θJA. The derating curve in Figure 2 allows the
designer to see the effect of rising ambient temperature
on the maximum power dissipation.
Maximum Power Dissipation (W)1
During normal charging process, once the charge done
condition is satisfied (V BATS > V OREG − V RECH and
termination current is detected), the RT9455 turns off the
PWM converter and initiates a discharge current (detection
current) for a detection time period. After that, the RT9455
checks the BATS voltage. If it is still above the recharge
threshold, the battery is present and charge done is
detected. If the BATS voltage is below the recharge
threshold, the battery is absent. Thus, the RT9455 stops
charging and the charge parameters are reset to the default
values. The charge resumes after a period of tDET (2sec.
typ.).
3.0
Four-Layer PCB
2.5
2.0
1.5
1.0
0.5
0.0
0
25
50
75
100
125
Ambient Temperature (°C)
Figure 2. Derating Curve of Maximum Power Dissipation
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RT9455
VIN MIVR and AICR
Slave address
Start
0 1 0 0 0 1 0 0
AICR
1A
Data address 0x01
W
0 0 0 0 0 0 0 1
1 0 0 0 1 0 0 0
Stop
Enable Termination
Current
VOREG
Slave address
Start
0 1 0 0 0 1 0 0
VOREG
4.2V
Data address 0x02
W
0 0 0 0 0 0 1 0
1 0 0 0 1 1 1 0
Stop
VIN MIVR, IEOC
Slave address
Start
Start
W
Data address 0x05
0 1 0 0 0 1 0 0
0 0 0 0 0 1 0 1
Slave address
Data address 0x06
W
0 1 0 0 0 1 0 0
IEOC
20%
VIN MIVR
1 0 0 1 1 0 1 0
Stop
ICHRG
0 0 0 0 0 1 1 0
0 1 1 1 0 0 1 0
Stop
High Impedance Mode
Slave address
Start
Data address 0x01
W
0 1 0 0 0 1 0 0
HZ
0 0 0 0 0 0 0 1
X X X X X X 1 X
Stop
Boost Mode
There are two methods to trigger boost mode.
I2C - Triggered Boost Mode
Slave address
Start
0
1
0
0
0
1
Data address 0x01
W
0
0
0
0
0
0
0
0
0
HZ OPA
1
X X X X X X 0
1
Stop
OTG Pin - Triggered Boost Mode (Pull High or Pull Low)
Pull Low
Slave address
Start
W
0 1 0 0 0 1 0 0
OTG_EN
Data address 0x02
0 0 0 0 0 0 1 0
X X X X X X 1 1
Stop
OTG_PL
Pull High
Slave address
Start
W
0 1 0 0 0 1 0 0
OTG_EN
Data address 0x02
0 0 0 0 0 0 1 0
X X X X X X 0 1
Stop
OTG_PL
Keep Monitoring RT9455
Slave address
Start
W
0 1 0 0 0 1 0 0
Data address 0x00
Charger Status
0 0 0 0 0 0 0 0
0 1 0 0 0 1 0 1
X X X X X X X X
Stop
< 32 min
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RT9455
Layout Considerations

Place the input and output capacitors as close to the
input and output pins as possible.

The battery voltage sensing point should be placed after
the output capacitor.

Keep the main power traces as wide and short as
possible.

To optimize current sense accuracy, connect the traces
to RSENSE with Kelvin sense connection.

The output inductor and bootstrap capacitor should be
placed close to the chip and LX pins.
Place the input and output
capacitors to the input and
output pins as close as possible.
To optimize current sense accuracy,
Connect the traces to RSENSE with
Kelvin sense connection.
A1
A2
A3
A4
VIN
VIN
IRQ
BATS
B1
B2
B3
B4
VMID
VMID
OTG
ISNSIN
C1
C2
C3
C4
LX
LX
AGND
SCL
D1
D2
PGND PGND
The output inductor and bootstrap
capacitor should be placed close to
the chip and the LX pins.
D3
D4
BOOT
SDA
Keep the main power traces as
wide and short as possible.
Figure 3. PCB Layout Guide
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RT9455
Device Address : 0100010
Address
Name
Bit7
Device ID
0x03
0x00
0x02
0x04
0x05
0x06
0x07
0x08
Bit5
Bit4
Bit3
VENDOR_ID
Bit2
Bit1
Bit0
CHIP_REV
Reset Value
0
0
0
0
1
0
0
1
Read/Write
R
R
R
R
R
R
R
R
Control1
Reserved
Reserved
OTG_
PinP
Reserved
0
1
0
0
0
0
0
0
R/W
R/W
R
R
R
R
R
R
TE_SHDN
_EN
Higher_
OCP
TE
IAICR_
INT
HZ
OPA_
MODE
Reset
Value
Read/Write
Control2
0x01
Bit6
Reset
Value
Read/Write
Control3
Reset
Value
Read/Write
IAICR[1:0]
0
0
0
0
0
0
0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
VOREG[5:0]
1
1
0
0
1
1
0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Control5
Reset
Value
Read/Write
Reserved Reserved Reserved Reserved Reserved Reserved Reserved
1
0
0
0
0
0
0
0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
TMR_EN
Reserved
1
0
1
1
1
0
1
0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Control6 IAICR_SEL
Reset
0
Value
Read/Write
R/W
MIVR[1:0]
IPREC[1:0]
ICHRG[2:0]
Reserved
IEOC[1:0]
VPREC[2:0]
0
0
0
0
0
1
0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reserved BATD_EN Reserved CHG_EN
VMREG[3:0]
0
0
0
1
0
0
0
0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
TSDI
VINOVPI
0
0
0
0
0
0
0
0
R
R
R
R
R
R
R
R
Reserved Reserved Reserved Reserved Reserved
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DS9455-00 April 2014
OTG_PL OTG_EN
0
RST
IRQ1
Reset
Value
Read/Write
BOOST PWR_Rdy
0
Control4
Reset
Value
Read/Write
Control7
Reset
Value
Read/Write
STAT
BATAB
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RT9455
Address
Name
Bit7
CHRVPI
0x09
IRQ2
Reset
Value
Read/Write
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Reserved CHBATOVI CHTERMI CHRCHGI CH32MI CHTREGI CHMIVRI
0
0
0
0
0
0
0
0
R
R
R
R
R
R
R
R
0x0A
IRQ3
BSTVINOVI BSTOLI BSTLOWVI Reserved BST32SI Reserved Reserved Reserved
Reset
0
0
0
0
0
0
0
0
Value
Read/Write
R
R
R
R
R
R
R
R
0x0B
Mask 1
Reset
Value
Read/Write
Mask 2
0x0C
Reset
Value
Read/Write
Mask 3
0x0D
Reset
Value
Read/Write
TSDM
VINOVPIM Reserved Reserved Reserved Reserved Reserved BATABM
0
0
R/W
R/W
0
0
0
0
0
0
0
R/W
R/W
R/W
R/W
R/W
R/W
CHBATOVI CHTERMI CHRCHGI
CHTREGI CHMIVRI
CHRVPIM Reserved
CH32MIM
M
M
M
M
M
0
0
0
0
0
0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
BSTVINOVI
BSTLOWVI
BST32SI
BSTOLIM
Reserved
Reserved Reserved Reserved
M
M
M
0
0
0
0
0
0
0
0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
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0
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RT9455
Detail Table Descriptions
Address
Name
Bit7
Device ID
0x03
Bit4
Bit3
VENDOR_ID
Bit2
Bit1
Bit0
CHIP_REV
0
0
0
0
1
0
0
1
Read/Write
R
R
R
R
R
R
R
R
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
CHIP_REV
Name
Control1
0x00
Bit5
Reset Value
VENDOR_ID
Address
Bit6
Vendor Identification
Chip Revision
Bit7
Bit6
Reserved Reserved
STAT
BOOST
PWR_Rdy OTG_PinP Reserved
Reset Value
0
1
0
0
0
0
0
0
Read/Write
R/W
R/W
R
R
R
R
R
R
STAT
BOOST
Charger status bit
00 : Ready
01 : Charge in progress
10 : Charge done
11 : Fault
1 : Boost mode, 0 : Not in Boost mode
PWR_Rdy
Power status bit
0 : VIN > VOVP or VIN < VUVLO or VIN < BATS + VSLP (Power Fault)
1 : UVLO < VIN < VOVP & VIN > BATS + VSLP (Power Ready)
OTG_PinP
OTG pin polarity
0 : OTG input pin is low
1 : OTG input pin is high
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RT9455
Address
Name
Control2
0x01
Bit6
IAICR[1:0]
Reset Value
0
1
Read/Write
R/W
R/W
IAICR[1:0]
TE_SHDN_EN
Higher_OCP
TE
IAICR_INT
HZ
R/W
R/W
Bit3
Bit2
Bit1
Bit0
TE
IAICR_INT
HZ
OPA_MODE
0
0
0
0
R/W
R/W
R/W
R/W
When IAICR_SEL = 0
00 : VIN 100mA current limit, 01 : VIN 500mA current limit,
10 : VIN 1A current limit, 11 : no input current limit (default 01)
When IAICR_SEL = 1
00 : VIN 100mA current limit, 01 : VIN 700mA current limit,
10 : VIN 700mA current limit, 11 : no input current limit (default 01)
0 : When EOC is triggered, charge is not shutdown
1 : When EOC is triggered, charge is shutdown
The OCP level selection bit
0 : Buck OCP = 2.75A, OTG OCP = 3.25A
1 : Buck OCP = 3.75A, OTG OCP = 4.25A
1 : Enable end of charge detection, 0 : Disable end of charge detection (default 0)
IAICR setting bit
0 : decided by external OTG pin, 100mA current limit when OTG pin is low and 500mA
current limit when OTG pin is high
2
1 : decided by internal I C IAICR[1:0] code
Name
1 : Boost mode, 0 : Charger mode (default 0)
Bit7
Bit6
Control3
0x02
Bit5
Bit4
TE_SHDN_
Higher_OCP
EN
0
0
1 : High impedance mode, 0 : Not high impedance mode (default 0)
OPA_MODE
Address
Bit7
Reset Value
Read/Write
Bit5
Bit4
Bit3
Bit2
VOREG[5:0]
0
1
1
0
0
1
Bit1
Bit0
OTG_PL
OTG_EN
1
0
OTG_PL
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Battery regulation voltage / Boost output voltage. The delta-V of the Battery regulation
voltage is 20mV. The delta-V of the Boost output voltage is 25mV. Only from 101000 to
101001, the delta-V is 30mV for battery regulation voltage.
00 0000 : 3.5V / 4.425V
00 0001 : 3.52V / 4.45V
00 0010 : 3.54V / 4.475V
...
01 1000 : 3.98V / 5.025V
01 1001 : 4V / 5.05V (default 011001)
01 1010 : 4.02V / 5.075V
...
10 1000 : 4.3V / 5.425V
10 1001 : 4.33V / 5.45V
10 1010 : 4.35V / 5.475V
10 1011 : 4.37V / 5.5V
...
10 1111 : 4.45V / 5.6V
...
11 1111 : 4.45V / 5.6V
1 : Active at High level, 0 : Active at low level (default 1)
OTG_EN
1 : Enable OTG Pin, 0 : Disable OTG Pin (default 0)
VOREG[5:0]
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is a registered trademark of Richtek Technology Corporation.
DS9455-00 April 2014
RT9455
Address
0x04
Name
Bit7
Control4
RST
Reset Value
0
0
0
0
0
0
0
0
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit1
Bit0
RST
Address
Name
Control5
0x05
Bit6
Bit5
Bit2
Bit1
Bit0
Reserved Reserved Reserved Reserved Reserved Reserved Reserved
Write
1 : Charger in reset mode, 0 : No effect, Read : always get "0"
Bit7
Bit6
Bit5
TMR_EN Reserved
Bit4
VMIVR[1:0]
Bit3
Bit2
IPREC[1:0]
IEOC[1:0]
1
0
1
1
1
0
1
0
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
0 : Disable internal timer function, 1 : Enable internal timer function (default 1)
VMIVR[1:0]
00 : 4V
01 : 4.25V
10 : 4.5V
11 : disable (default 11)
IPREC[1:0]
00 : 20mA
01 : 40mA
1X : 60mA (default 10)
IEOC[1:0]
00 : 10%
01 : 30%
10 : 20% (default 10)
11 : 30%
0x06
Bit3
Reset Value
TMR_EN
Address
Bit4
Name
Bit7
IAICR_
Control6
SEL
Reset Value
0
Bit6
0
0
0
0
0
1
0
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit5
Bit4
ICHRG[2:0]
Bit3
Bit2
Reserved
Bit1
Bit0
VPREC[2:0]
IAICR_SEL
0 : AICR is defined by IAICR [1:0]
1: AICR 500mA and 1A becomes 700mA
ICHRG[2:0]
External Sensing R : Charge current sense voltage (current equivalent for 68m sense
resistor)
000 : 34mV (500mA) (default 000)
001 : 44.2mV (650mA)
010 : 54.4mV (800mA)
--110 : 95.2mV (1400mA)
111 : 105.4mV (1550mA)
VPREC[2:0]
000 : 2V
001 : 2.2V
010 : 2.4V (default 010)
011 : 2.6V
100 : 2.8V
101 : 3V
…
111 : 3V
Copyright © 2014 Richtek Technology Corporation. All rights reserved.
DS9455-00 April 2014
is a registered trademark of Richtek Technology Corporation.
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25
RT9455
Address
Name
Control 7
0x07
Bit7
Bit6
Bit5
Bit4
Bit3
Reserved BATD_EN Reserved CHG_EN
0
0
0
1
0
0
0
0
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
CHG_EN
Charger enable
0 : charger is disabled, 1 : charger is enabled
VMREG[3:0]
Bit7
IRQ 1
TSDI
Reset Value
0
0
0
0
0
0
0
0
Read/Write
R
R
R
R
R
R
R
R
VINOVPI
BATAB
Name
IRQ 2
0x09
Maximum battery regulation voltage/Maximum Boost output voltage.
The delta-V of Maximum battery regulation voltage is 20mV. The delta-V of Maximum Boost
output voltage is 25mV.
0000 : 4.2V / 5.3V (Default 0000)
0001 : 4.22V / 5.325V
0010 : 4.24V / 5.35V
...
1011 : 4.43V / 5.575V
1100 : 4.45V / 5.6V
…
1111 : 4.45V / 5.6V
Name
TSDI
Address
Bit0
Reset Value
Battery detection when charge done
0 : disable battery detection, 1 : enable battery detection
0x08
Bit1
VMREG[3:0]
BATD_EN
Address
Bit2
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
VINOVPI Reserved Reserved Reserved Reserved Reserved
Bit0
BATAB
Thermal shutdown fault. Set if the die temperature exceeds the thermal shutdown threshold.
When TSDI occurs, REG0 x 01[7:6]-AICR is reset to 01.
VIN over voltage protection. Set when VIN > VIN_OVP is detected
Battery absence
Bit7
Bit6
Bit5
Bit4
Bit3
CHRVPI Reserved CHBATOVI CHTERMI CHRCHGI
Bit2
CH32MI
Bit1
Bit0
CHTREGI CHMIVRI
Reset Value
0
0
0
0
0
0
0
0
Read/Write
R
R
R
R
R
R
R
R
CHRVPI
Charger fault. Reverse protection (VIN < BATS + VSLP)
CHBATOVI
Charger fault. Battery OVP
CHTERMI
Charge terminated
CHRCHGI
Recharge request (VBATS < VOREG  VRECH)
CH32MI
Charger fault. 32m time-out (fault)
CHTREGI
Charger warning. Thermal regulation loop active.
CHMIVRI
Charger warning. Input voltage MIVR loop active.
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is a registered trademark of Richtek Technology Corporation.
DS9455-00 April 2014
RT9455
Address
Name
IRQ 3
0x0A
Bit7
Bit6
Bit5
Bit0
BSTVINOVI BSTOLI BSTLOWVI Reserved BST32SI Reserved Reserved Reserved
0
0
0
0
0
0
Read/Write
R
R
R
R
R
R
R
R
Bit3
Bit2
Bit1
Bit0
Boost fault. VIN OVP (VIN > VIN_BOVP)
Boost fault. Over load.
Boost fault. Battery voltage is too low.
BST32SI
Boost fault. 32s time-out fault.
Reserved
N/A
Reserved
N/A
Reserved
N/A
Name
Bit7
Bit6
Bit5
Bit4
MASK1
TSDM
Reset Value
0
0
0
0
0
0
0
0
Read/Write
R/W
R/W
R
R
R
R
R/W
R/W
VINOVPIM Reserved Reserved Reserved Reserved Reserved
TSDM
TSDI fault interrupt mask
0 : interrupt is not masked, 1 : interrupt is masked
VINOVPIM
VIN OVP fault interrupt mask
0 : interrupt is not masked, 1 : interrupt is masked
BATABM
Battery absence fault interrupt mask
0 : interrupt is not masked, 1 : interrupt is masked
0x0C
Bit1
0
BSTLOWVI
Address
Bit2
0
BSTOLI
0x0B
Bit3
Reset Value
BSTBUSOVI
Address
Bit4
Name
Bit7
Bit6
Read/Write
R/W
R/W
BATABM
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
CHBATO
MASK2 CHRVPIM Reserved
CHTERMIM CHRCHGIM CH32MIM CHTREGIM CHMIVRM
VIM
Reset Value
0
0
0
0
0
0
0
0
R/W
R/W
R/W
CHRVPIM
Charger reverse protection interrupt mask
0 : interrupt is not masked, 1 : interrupt is masked
CHBATOVIM
Charger battery over voltage interrupt mask
0 : interrupt is not masked, 1 : interrupt is masked
CHTERMIM
Charge terminated interrupt mask
0 : interrupt is not masked, 1 : interrupt is masked
CHRCHGIM
Charger recharge request interrupt mask
0 : interrupt is not masked, 1 : interrupt is masked
CH32MIM
Charger 32m timeout interrupt mask
0 : interrupt is not masked, 1 : interrupt is masked
CHTREGIM
Charger thermal regulation loop active interrupt mask
0 : interrupt is not masked, 1 : interrupt is masked
CHMIVRM
Charger input current voltage MIVR active interrupt mask
0 : interrupt is not masked, 1 : interrupt is masked
Copyright © 2014 Richtek Technology Corporation. All rights reserved.
DS9455-00 April 2014
R/W
R/W
R/W
is a registered trademark of Richtek Technology Corporation.
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27
RT9455
Address
0x0D
Name
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
BSTLOW
BSTVINO
Reserved BST32SIM Reserved Reserved Reserved
BSTOLIM
MASK3
VIM
VIM
Reset Value
0
0
0
0
0
0
0
0
Read/Write
R/W
R/W
R/W
R/W
BSTVINOVIM
Boost VIN over voltage interrupt mask
0 : interrupt is not masked, 1 : interrupt is masked
BSTOLIM
Boost over load interrupt mask
0 : interrupt is not masked, 1 : interrupt is masked
BSTLOWVIM
Boost low battery voltage interrupt mask
0 : interrupt is not masked, 1 : interrupt is masked
BST32SIM
Boost 32s time out interrupt mask
0 : interrupt is not masked, 1 : interrupt is masked
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R/W
R/W
R/W
R/W
is a registered trademark of Richtek Technology Corporation.
DS9455-00 April 2014
RT9455
Outline Dimension
Symbol
Dimensions In Millimeters
Dimensions In Inches
Min.
Max.
Min.
Max.
A
0.500
0.600
0.020
0.024
A1
0.170
0.230
0.007
0.009
b
0.240
0.300
0.009
0.012
D
1.720
1.820
0.068
0.072
D1
E
1.200
1.650
0.047
1.750
0.065
0.069
E1
1.200
0.047
e
0.400
0.016
16B WL-CSP 1.7x1.77 Package (BSC)
Richtek Technology Corporation
14F, No. 8, Tai Yuen 1st Street, Chupei City
Hsinchu, Taiwan, R.O.C.
Tel: (8863)5526789
Richtek products are sold by description only. Richtek reserves the right to change the circuitry and/or specifications without notice at any time. Customers should
obtain the latest relevant information and data sheets before placing orders and should verify that such information is current and complete. Richtek cannot
assume responsibility for use of any circuitry other than circuitry entirely embodied in a Richtek product. Information furnished by Richtek is believed to be
accurate and reliable. However, no responsibility is assumed by Richtek or its subsidiaries for its use; nor for any infringements of patents or other rights of third
parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Richtek or its subsidiaries.
DS9455-00 April 2014
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29