for 1-Cell Li-ion or 1-Cell to 3-Cell NiCd/NiMH Batteries
DESCRIPTION
Si9731 is a chemistry independent battery charger designed
to pulse charge 1-cell to 3-cell NiCd/NiMH or 1-cell Li-ion
batteries. Battery charging is accomplished under direct
control from the system processor. An internal low R
DS(on)
MOSFET can be pulsed on and off at varying duty cycle by
the system processor to pulse charge the battery at high
charge current while minimizing heat dissipation. Provision is
also made to trickle charge a discharged battery until the
battery is charged to a high enough voltage to wake up the
processor so that the processor can take control of the
charging process. For charging Li-ion batteries, Si9731
includes a precision voltage reference and an error amplifier
for constant voltage (CV) charge mode. The Si9731 is
available in lead (Pb)-free TSSOP-16 package and is
classified over the industrial temperature range (- 40 °C to
+ 85 °C).
FEATURES
• Pulse charges 1-cell Li-ion or 1-cell to 3-cell
NiCd/NiMH batteries
• Integrated MOSFETs with bi-directional
reverse current blocking in "OFF" mode
• PWM controlled fast charging mode
• Low current trickle charge mode
• Pin selectable 4.1 V or 4.2 V charge termination for Li-ion
• Constant voltage (CV) termination for Li-ion
• Input over-voltage detector with automatic shutdown
• External shutdown
• Under 1 µA reverse battery leakage current in shutdown
• Complete isolation from battery to external power supply
in shutdown
• Thermal shutdown
• Minimum number of external components
• ESD protection to 4 kV on charger input and battery
output
• TSSOP-16 package (1.2 mm maximum height)
• Halogen-free according to IEC 61249-2-21 definition
•
Compliant to RoHS directive 2002/95/EC
APPLICATIONS
• Cellular phone battery charger
• Personal digital assistants
FUNCTIONAL BLOCK DIAGRAM
V
BAT
V
CHARGER
Fast
Charge
B
a
t
t
e
r
y
ON/OFF
Trickle
Charge
TRICKLECHARGEENABLE
CV
MODE
FAST CHARGE
GND
Charge Control
4.1/4.2 V_TAP
Document Number: 71321
S09-2249Rev. C, 26-Oct-09
www.vishay.com
1
Si9731
Vishay Siliconix
ABSOLUTE MAXIMUM RATINGS
Parameter
Voltages Referenced to GND = 0 V
V
CHARGER,
V
(CVMODE)
, V
(TRICKLECHARGEEN)
, V
(MAINCHARGEREN)
, V
(ON/OFF)
,
V
(4.1 V_TAP)
, V
(VBAT+)
, V
(CHARGERPOWER_ON)
, V
(CHARGERPRESENT)
,
V
(TRICKLE_VBAT)
V
(CHARGERPRESENTIN)
, V
(CHARGERPOWER_ONIN)
Maximum Input Current (I
CHARGER(max)
)
Maximum Sink Current
CHARGERPOWER_ON and CHARGERPRESENT Pins
Storage Temperature
Operating Junction Temperature
Power Dissipation (Package)
a
Thermal Impedance (Θ
JA
)
16-Pin TSSOP (Q Suffix)
b
16-Pin TSSOP
- 0.3 to 13.5
1.2
5
- 65 to 150
150
1.06
135
V
A
mA
°C
W
°C/W
Symbol
Limit
Unit
Notes:
a. Device Mounted with all leads soldered or welded to PC board.
b. Derate 10 mW/°C above 25 °C.
Stresses beyond those listed under “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 for extended periods may affect device reliability.
RECOMMENDED OPERATING RANGE
Parameter
Voltages Referenced to GND = 0 V
V
CHARGER
Ambient Temperature
V
REF
Bypass Capacitor
C
OUT
C
IN
See application drawing Figure 1.
3.0 to 12
- 40 to + 85
0.1
2.2
2.2
µF
V
°C
Symbol
Limit
Unit
SPECIFICATIONS
Test Conditions Unless Specified
- 40 °C < T
A
< + 85 °C
3.0 V
≤
V
CHARGER
≤
6.5 V, V
ON/OFF
= 1.5 V
Min.
a
3.0
Rising Edge of Battery Charger
- 10 °C < T
A
< + 40 °C
- 40 °C < T
A
< + 85 °C
- 10 °C < T
A
< + 40 °C
- 40 °C < T
A
< + 85 °C
2.45
70
V
CHARGER
= 5.0 V
I
BAT+
= 1 mA
MAINCHARGEREN
= 5.0 V
CVMODE = 5.0 V
4.050
4.025
4.150
4.125
4.70
3.12
2.6
90
4.1
4.1
4.2
4.2
4.95
0.11
Rising Edge, V
BAT+
Latch
Comparator
Offset Voltage,
V
CHARGER
- V
BAT+
MAINCHARGEEN-High
MAINCHARGEEN-Low
3.24
3.33
- 0.08 - 0.04 - 0.01
0.01
0.04
0.07
0.08
Typ.
b
Max.
a
12
2.75
110
4.150
4.150
4.250
4.250
5.15
V
Parameter
External Charger Voltage
Under Voltage Lockout on Charger
UVLO Hysteresis
Regulated Output Voltage 4.1 V_TAP to V
BAT
Symbol
V
CHARGER
V
UVLO
UVLO
HYST
Unit
V
mV
V
TERM+
Regulated Output Voltage 4.1 V_TAP Open
Battery Over Voltage Protection
Battery Over Voltage Hysteresis
Battery Minimum Operating Voltage
Charger Voltage to Battery Voltage
Comparator Offset
Charger Voltage to Battery Voltage
Comparator Hysteresis
V
OVP
V
OVP_HYS
V
BAT(min)
V
OS_CB
Rising Edge of V
BAT+
www.vishay.com
2
Document Number: 71321
S09-2249Rev. C, 26-Oct-09
Si9731
Vishay Siliconix
SPECIFICATIONS
Test Conditions Unless Specified
- 40 °C < T
A
< + 85 °C
3.0 V
≤
V
CHARGER
≤
6.5 V, V
ON/OFF
= 1.5 V
1 mA
≤
I
BAT+
≤
600 mA
V
ON/OFF
= 0 V, V
CHARGER
= 4.5 V
Pin 12 to Pin 14
Pin 12 to GND
V
BAT+
= 4.2 V
V
ON/OFF
= 0 V
V
CHARGER
= 0 V
MAINCHARGEREN
≥
1.5 V
V
CHARGER
= 4.5 V
TRICKLECHARGEEN
≤
0.4 V
CVMODE
≥
1.5 V
Rising Edge of Battery Charger
12.0
6
6
12.8
0.4
V
OH
= 6.5 V
I
OL
= 1 mA
0.1
2
0.4
0.4
1.5
0.7
130
10
1.5
0.3
100
10
µA
°C
V
13.4
V
-1
-1
Min.
a
Typ.
b
Max.
a
Parameter
Symbol
I
IN(VCHARGER Pin)
ON-Mode
I
IN(VCHARGER Pin)
OFF-Mode
R
FB1
R
FB2
+ R
FB3
I
PIN13
+ I
PIN14
Q1 R
DS(on)
Q2 R
DS(on)
c
Unit
Quiescent Current (Normal Mode)
Quiescent Current (Shutdown Mode)
Feedback Resistor
Battery Leakage Current
Q1 ON Resistance
Q2 ON Resistance
Q5 ON Resistance
1
0.1
1
41
0.1
0.1
3
1
mA
µA
kΩ
1
2
400
10
µA
mΩ
Ω
Q5 R
DS(on)
V
CHARGER(OVD)
V
CHARGER(OVD)
_HYS
Over Voltage Detect Threshold
Over Voltage Detect Threshold Hysteresis
Output High
Leakage
Current
Output Low
Voltage
Logic Low
Voltage
Logic High
Voltage
Pull Down
Current
CHARGERPRESENT and
CHARGERPOWER_ON
I
OH
V
OL
V
IL
V
IH
I
P/D
T
S/D
T
HYST
V
ON/OFF(high)
V
ON/OFF(low)
V
ON/OFF(hyst)
µA
CHARGERPRESENTIN,
CHARGERPOWER_ONIN,
TRICKLECHARGEEN,
MAINCHARGEEN or
CVMODE
Thermal Shutdown Temperature
c
Thermal Shutdown Hysteresis
c
Shutdown High Voltage Logic Level
Shutdown Low Voltage Logic Level
Shutdown Hysteresis
V
mV
Notes:
a. The algebraic convention whereby the most negative value is a minimum and the most positive a maximum, is used in this data sheet.
b. Typical values are for DESIGN AID ONLY, not guaranteed or subject to production testing.
c. Guaranteed by design and characterization, not subject to production testing.
Document Number: 71321
S09-2249Rev. C, 26-Oct-09
www.vishay.com
3
Si9731
Vishay Siliconix
PIN CONFIGURATION
TSSOP-16
CHARGERPRESENTIN
CHARGERPOWER_ONIN
V
CHARGER
ON/OFF
TRICKLECHARGEEN
CVMODE
MAINCHARGEEN
(N/C)
1
2
3
4
5
6
7
8
Top View
16
15
14
CHARGERPRESENT = (XCHARGERPRESENT)
CHARGERPOWER_ON = (XCHARGERPOWER_ON)
V
BAT+
TRICKLE_V
BAT
4.1 V_TAP
GND
(N/C)
V
REF
Si9731DQ
13
12
11
10
9
ORDERING INFORMATION
Part Number
Si9731DQ-T1-E3
Temperature Range
- 40 to 85 °C
Package
Tape and Reel
PIN DESCRIPTION
Pin Number
1
2
3
4
5
6
7
8, 10
9
11
12
13
14
15
16
Name
CHARGERPRESENTIN
V
CHARGER
ON/OFF
TRICKLECHARGEEN
CVMODE
MAINCHARGEEN
N/C
V
REF
GND
4.1 V_TAP
TRICKLE_V
BAT
V
BAT+
CHARGERPOWER_ON
CHARGERPRESENT
Function
Logic input for CHARGERPRESENT output
External charger
Master shutdown pin. Taking ON/OFF low shuts down the charger and quiescent current drops
to under 1 µA
Taking this pin high disables trickle (slow) charging
A logic high enables the error amplifier to linearly drive the gate of MOSFET Q1 when
MAINCHARGEREN is high.
An external PWM signal at MAINCHARGEREN pin controls the ON/OFF duty cycle of the Fast
Charge MOSFET, Q1.
Do not connect external circuitry to this pin. Circuitry internal to the IC is connected to this pin.
Internal 1.30 V precision bandgap reference voltage. Do not apply loads to this pin.
Low impedance system ground
Connect this pin to V
BAT+
for 4.1 V charge termination in constant voltage mode
Resistor connected between this pin and V
BAT
to limit the trickle charge current.
Charger output connected to battery’s positive terminal
Open drain logic output
Open drain logic output
CHARGERPOWER_ONIN Logic input for CHARGERPOWER_ON output
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4
Document Number: 71321
S09-2249Rev. C, 26-Oct-09
Si9731
Vishay Siliconix
TABLE 1: BATTERY CHARGING CONTROL LOGIC
Nominal Voltage Values
V
CHARGER
Not Present
Not Present
OK to Charge
a
Over Voltage
V
CHARGER
> 12.8 V
TRICKLE
CHARGEEN
X
X
X
X
LOW
HIGH
LOW
Present
OK to Charge
a
HIGH
LOW
CVMODE
X
X
X
X
LOW
LOW
LOW
LOW
HIGH
MAIN
CHARGEEN
X
X
X
X
LOW
LOW
HIGH
HIGH
LOW
ON/OFF
X
X
X
LOW
HIGH
HIGH
HIGH
HIGH
HIGH
Q1
b
OFF
OFF
OFF
OFF
OFF
OFF
ON
ON
OFF
Q2
OFF
OFF
OFF
OFF
ON
OFF
OFF
OFF
OFF
Not Charging
Not Charging
Not Charging
Not Charging (Shutdown)
Trickle Charge
Not Charging
(Current pulse off during Constant
Current Charge)
Constant Current Charge
(current pulse on)
Not Charging
(Current pulse off during Constant
Current Charge with output limited
to 4.1 V/4.2 V or end of charge in Li-Ion
charging)
Constant Current Charge
(Output Limited to 4.1 V/4.2 V or
Constant Voltage Charge)
Mode
HIGH
LOW
HIGH
HIGH
HIGH
HIGH
LOW
HIGH
HIGH
HIGH
HIGH
HIGH
OFF
ON
ON
OFF
OFF
OFF
Notes:
a. "OK to Charge" is a flag signal that is enabled by satisfying all the following conditions:
1. Battery voltage is below 5 V
2. Charger voltage is greater than 3 V but below 12.8 V
3. If MAINCHARGEEN = Logic Low, V
CHARGER
> V
BAT
+ 40 mV,
If MAINCHARGEEN = Logic High, V
CHARGER
> V
BAT
- 40 mV
4. ON/OFF pin is at logic high.
b. Q1 drive is determined by the error amplifier during constant voltage mode.
Q1 drive is a combination of Q1 drive (digital) and the output of the error amplifier using the analog adder. The combinations are:
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