®
RT9527
Single Cell Li-Ion Battery Charger with Adjustable Charging
Current for Portable Applications
General Description
The RT9527 is a low cost single-cell Li-ion charger for low
current charge applications.
The RT9527 can be powered up from an AC adapter or
USB (Universal Serial Bus) port inputs. The RT9527 enters
sleep mode when VIN power is removed. The RT9527
optimizes the charging task by using a control algorithm,
which includes pre-charge mode, fast-charge mode and
constant voltage mode. The charging task is kept in
constant voltage mode to hold the battery in a full charge
condition. The charge current is adjustable via an external
resistor. The internal thermal feedback circuitry regulates
the die temperature to optimize the charge rate for all
ambient temperatures. The RT9527 features 28V
maximum rating voltages for VIN. Other features include
under voltage protection and over voltage protection for
the AC adapter supply.
The RT9527 is available in a WDFN-8L 2x2 package.
Features
28V Maximum Rating for AC Adapter
Internal Integrated Power FETs
Adjustable Charging Current
Programmable Safe Charge Timer
NTC Thermistor Input
Battery Reverse Protection
ISET Pin Short Protection
Charge Status Indicator
AC Adapter Power Good Status Indicator
End of Charge Current is 10% of Fast-Charge Current
Under Voltage Protection
Over Voltage Protection
Thermal Feedback Optimized Charge Rate
Small Thermally Enhanced 8-Lead WDFN Package
RoHS Compliant and Halogen Free
Applications
Ordering Information
RT9527
Package Type
QW : WDFN-8L 2x2 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
Note :
Richtek products are :
½
Cellular Phones
Digital Cameras
PDAs and Smart Phone
Portable Instruments
Marking Information
0S : Product Code
0SW
W : Date Code
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.
½
Simplified Application Circuit
Input Power
VIN
RT9527
BAT
Battery
TIMER
ISET
PGOOD
CHG
GND
Indicator
Copyright
©
2017 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9527-03 January 2017
www.richtek.com
1
RT9527
Pin Configuration
(TOP VIEW)
VIN
PGOOD
CHG
GND
GND
1
2
3
4
8
7
6
5
9
BAT
TS
TIMER
ISET
WDFN-8L 2x2
Functional Pin Description
Pin No.
1
2
3
Pin Name
VIN
PGOOD
CHG
Pin Function
Supply voltage input. VIN can withstand up to 28V input.
Power good status output. Active-low, open-drain output.
Charger status output. Active-low, open-drain output.
Ground. The exposed pad must be soldered to a large PCB and connected to
GND for maximum power dissipation.
Charge current setting.
Safe-charge timer setting.
Temperature sense input. The TS pin connects to a battery’s thermistor to
determine whether the battery is too hot or too cold for charging operation. If the
battery’s temperature is out of range, charging is paused until it re-enters the
valid range.
Charge current output for battery.
4,
GND
9 (Exposed Pad)
5
6
7
8
ISET
TIMER
TS
BAT
Functional Block Diagram
BAT
Switch
Well
VIN
BASE
V
REF
I
BIAS
Thermal
Circuit
Too Cold
+
-
+
VIN
TS
Sleep
Mode
ISET
Current
Set Block
OVP
Logic
UVLO
CC/CV/TR
Multi Loop
Controller
Too Hot
-
TIMER
TMIER
CHG
PGOOD
GND
Copyright
©
2017 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
2
DS9527-03 January 2017
RT9527
Operation
The RT9527 is a Li-ion charger that can support the input
voltage range from 4.4V to 6V. It provides a wide fast-
charge current setting ranging from 10mA up to 600mA.
Change Current Setting
The charging current is adjustable via an external resistor
between the ISET and GND pin.
UVLO
If the input voltage (VIN ) is lower than the threshold voltage
V
UVLO
− ΔV
UVLO
, the charger will stop charging until VIN
is larger than V
UVLO
.
OVP
If the input voltage (VIN) is higher than the threshold voltage
V
OVP
, the internal OVP signal will go high and the charger
will stop charging until VIN is below V
OVP
− ΔV
OVP
.
Switch Well
The switch well will choose the highest voltage between
VIN and BAT to prevent the power switch from damage.
Sleep Mode
When the voltage difference between VIN and BAT is under
V
OS_L
, the charger will enter sleep mode to save the system
power consumption.
CC/CV/TR Multi Loop Controller
There are constant current loop, constant voltage loop and
thermal regulation loop to control the charging current.
Too Hot or Too Cold
The temperature sense input TS pin can be connected a
thermistor to determine whether the battery is too hot or
too cold for charging operation. If the battery's temperature
is out of range, charging is paused until it re-enters the
valid range.
PGOOD
The PGOOD is an open-drain output used to indicate the
input voltage status. PGOOD will assert low when VIN is
in the proper working range.
CHG
The CHG pin is an open-drain output. CHG will assert low
when the charger starts to charge the battery and become
high impedance when the termination current is reached.
TIMER
The charger contains the safety timer. When the charging
time is longer than t
PCHG
in the pre-charge mode or t
FCHG
in the fast-charge mode, time fault happens. Then, the
charger will be turned off and the CHG pin will become
high impedance.
Copyright
©
2017 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9527-03 January 2017
www.richtek.com
3
RT9527
Absolute Maximum Ratings
(Note 1)
−0.3V
to 28V
−0.3V
to 28V
−0.3V
to 6V
2.19W
45.5°C/W
Supply Input Voltage, VIN ----------------------------------------------------------------------------------------------
CHG, PGOOD, TS ------------------------------------------------------------------------------------------------------
Other Pins -----------------------------------------------------------------------------------------------------------------
Power Dissipation, P
D
@ T
A
= 25°C
WDFN-8L 2x2 -------------------------------------------------------------------------------------------------------------
Package Thermal Resistance (Note 2)
WDFN-8L 2x2,
θ
JA
-------------------------------------------------------------------------------------------------------
WDFN-8L 2x2,
θ
JC
------------------------------------------------------------------------------------------------------- 11.5°C/W
Lead Temperature (Soldering, 10 sec.) ----------------------------------------------------------------------------- 260°C
Junction Temperature --------------------------------------------------------------------------------------------------- 150°C
Storage Temperature Range -------------------------------------------------------------------------------------------
−65°C
to 150°C
ESD Susceptibility (Note 3)
HBM (Human Body Model) -------------------------------------------------------------------------------------------- 2kV
(Note 4)
Recommended Operating Conditions
Supply Input Voltage, VIN
---------------------------------------------------------------------------------------------- 4.4V to 6V
Junction Temperature Range ------------------------------------------------------------------------------------------
−40°C
to 125°C
Ambient Temperature Range ------------------------------------------------------------------------------------------
−40°C
to 85°C
Electrical Characteristics
(V
IN
= 5V, V
BAT
= 4V, T
A
= 25°C, unless otherwise specified)
Parameter
Supply Input
VIN Under Voltage Lockout
Threshold
VIN Under Voltage Lockout
Hysteresis
VIN
BAT VOS Rising
VIN
BAT VOS Falling
VIN Standby Current
BAT Sleep Leakage Current
Voltage Regulation
Battery Voltage Regulation
Re-Charge Threshold
Current Regulation
VIN Charge Setting Range
Symbol
Test Conditions
Min
Typ
Max
Unit
V
UVLO
V
UVLO
V
OS_H
V
OS_L
I
STANDBY
I
SLEEP
V
REG
V
IN
= 0V to 5V
V
IN
= 5V to 0V
3.1
--
--
10
3.3
240
100
50
1
--
4.2
100
0.8
--
600
600
3.5
--
200
--
2
1
4.242
140
--
600
690
V
mV
mV
mV
mA
A
V
mV
mA
V
BAT
= 4.5V
V
IN
= 0V
0C to 85C
I
BAT
= 450mA
--
--
4.158
60
--
10
V
REGCHG
Battery Regulation
Recharge Level
VIN Power FET On-Resistance R
DS(ON)
I
CHG
K
CHG_F1
Fast-Charge Current Factor
K
CHG_F2
I
CHG_F1
= K
CHG_F1
/ R
ISET
,
I
CHG_F1
= 10mA to 50mA
I
CHG_F2
= K
CHG_F2
/ R
ISET
,
I
CHG_F2
= 50mA to 600mA
510
570
A
630
Copyright
©
2017 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
4
DS9527-03 January 2017
RT9527
Parameter
Pre-Charge Current Factor
Pre-Charge
BAT Pre-Charge Threshold
BAT Pre-Charge Threshold
Hysteresis
Charge Termination
Termination Current Ratio
Protection
Thermal Regulation
Over Voltage Protection
Over Voltage Protect Hysteresis
ISET Pin Short Protection
NTC
Cold Temperature Fault
Threshold Voltage
V
COLD
Rising Threshold
60
--
Falling Threshold
29
--
61
2
30
2
62
--
31
--
%V
IN
%V
IN
%V
IN
%V
IN
T
REG
V
OVP
V
OVP
R
SHORT
--
6.2
--
375
125
6.5
0.2
500
--
6.8
--
625
C
V
V
I
TERMI
V
BAT
> V
PREC
, I
CHG
< I
TERMI
,
CHG = L to H
5
10
15
%
V
PRECH
V
PRECH
V
BAT
Falling
2.7
--
2.8
200
2.9
--
V
mV
Symbol
K
CHG_P
Test Conditions
I
CHG_P
= K
CHG_P
/ R
ISET
Min
30
Typ
60
Max
90
Unit
A
Cold Temperature Fault
V
COLD
Threshold Hysteresis
Hot Temperature Fault Threshold
V
HOT
Voltage
Hot Temperature Fault Threshold
V
HOT
Hysteresis
Timer
Pre-Charge Fault Time
Fast-Charge Fault Time
Other
PGOOD Pull Down Voltage
CHG Pull Down Voltage
PGOOD Deglitch Time
V
PGOOD
V
CHG
t
PGOOD
t
PCHG
t
FCHG
C
TIMER
= 1F (1 / 8 x t
FCH G
)
C
TIMER
= 1F
I
PGOOD
= 5mA
I
CHG
= 5mA
Time measured from the edge
V
IN
= 0V to 5V in 1s to PGOOD = L
1440
1800
2160
s
s
11520 14400 17280
--
--
--
--
--
--
--
--
--
--
--
200
200
2
50
2
25
25
25
100
25
25
--
--
--
--
--
--
--
--
--
--
--
mV
mV
ms
s
ms
ms
ms
ms
ms
ms
ms
Input Over Voltage Blanking Time t
OVP
Input Over Voltage Recovery
Time
Pre-Charge to Fast-Charge
Deglitch Time
Fast-charge to Pre-Charge
Deglitch Time
Termination Deglitch Time
Recharge Deglitch Time
Sleep Deglitch Time
Pack Temperature Fault
Detection Deglitch Time
t
OVP_R
t
PF
t
FP
t
TERMI
t
RECHG
t
NO-IN
t
TS
Copyright
©
2017 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9527-03 January 2017
www.richtek.com
5
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