FS3871-DS-15 EN 55583

FS3871-DS-15 EN 55583
FS3871-DS-15_EN
May 2014
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REV. 1.5
Datasheet
FS3871
LINEAR CHARGE MANAGEMENT IC FOR LITHIUM-ION AND LITHIUM-POLYMER
Fortune Semiconductor Corporation
富晶電子股份有限公司
23F., No.29-5,Sec. 2, Zhongzheng E. Rd.,
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Danshui Town, Taipei County 251, Taiwan
Tel.:886-2-28094742
Fax:886-2-28094874
www.ic-fortune.com
This manual contains new product information. Fortune Semiconductor Corporation reserves the rights to modify the
product specification without further notice. No liability is assumed by Fortune Semiconductor Corporation as a result of the
use of this product. No rights under any patent accompany the sale of the product.
1.
General Description
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The FS3871 Lithium-Ion (Li-Ion) and Lithium-Polymer
(Li-Pol) linear charge-management ICs are designed for
cost sensitive and compact portable electronics. They
combine high-accuracy current and voltage regulation,
battery conditioning, temperature monitoring, charge
termination, charge-status indication, and Automatic
charge-rate compensation in a single 8-pin IC. TSSOP
package is offered to fit a wide range of end applications.
The FS3871 continuously measures battery temperature
using an external thermistor. For safety, the FS3871
inhibits charge until the battery temperature is within
user-defined thresholds. The FS3871 then charges the
battery in three phases: conditioning, constant current and
constant voltage. If the battery voltage is below the
low-voltage threshold, V(min), the FS3871 pre-charges
using a low current to condition the battery. The
conditioning charge rate is approximately 10% of the
regulation current. The conditioning current also minimizes
heat dissipation in the external pass element during the
initial stage of the charge. After conditioning, the FS3871
applies a constant current to the battery. An external
sense-resistor sets the current. The sense-resistor can be
on either the high or low side of the battery without
additional components. The constant-current phase
continues until the battery reaches the charge-regulation
voltage.
The available 8-pin TSSOP-8/MSOP-8 package is offered
for balanced area and cost effective requirements for
size-sensitive applications.
The FS3871 is suitable for the control of charge sequences
of a variety of portable battery-powered applications, such
as cellular phone’s travel and base charger devices, digital
camera, digital-video camcorder (DV), MP3 player ,etc.
processor interface.
Automatic battery-recharge feature.
Charge termination by minimum current.
Automatic low-power sleep mode when VCC is removed.
Low-cost peripheral components of capacitor and resistor
combinations for minimum BOM cost in manufacturing
considerations.
Evaluation (EV) board is available for quick evaluation.
TSSOP-8/MSOP-8 Green Package.
2.
Features
Ideal for Single (4.1 V or 4.2 V) and Dual-Cell (8.2 V or 8.4
V) Li-Ion or Li-Poly Packs. (Dual-Cell is not available now)
0.3 V dropout voltage for minimizing heat dissipation.
Better than 1% voltage regulation accuracy with preset
voltages.
Automatic Dynamic Compensation of battery pack’s
internal impedance to reduce charge time.
Optional cell-temperature monitoring before and during
charge.
Integrated voltage and current
regulation with
programmable charge-current and high or low-side current
sensing.
Integrated cell conditioning for reviving deeply discharged
cells and minimizing heat dissipation during initial stage of
charge.
Charge status output for single or dual LED or host
3.
Applications
Cellular phone external base or built-in charger
MP3/MP4 player
External charger through USB
Digital still camera (DSC)
Digital video camcorder (DV)
Portable electronic device charger, etc.
4.
Pin Configuration
(TSSOP-8 TOP VIEW)
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(MSOP-8 TOP VIEW)
5.
6.
Ordering Information
Product Number Description
Package Type
FS3871D-G
CHARGE REGULATION VOLTAGE : 4.2V
TSSOP-8
FS3871E-G
CHARGE REGULATION VOLTAGE : 4.2V
MSOP-8
Pin Description
I/O
Pin No. Of
TSSOP
Pin No. Of
MSOP
SNS
I
1
7
Current sense input
BAT
I
2
8
Voltage sense input
VCC
I
3
1
Supply voltage
TS
I
4
2
Temperature sense input
STAT
I/O
5
3
Charge status output
VSS
-
6
4
Ground
CC
O
7
5
Charge control output
CRC
I
8
6
Charge-rate compensation input
Name
7.
Description
Pin Description Package Marking Information
Part Number
Package Type
Marking
FS3871D-G
TSSOP-8
FS3871D
*******
FS3871E-G
MSOP-8
3871E
*******
Top line: Part Number.
Bottom line : Lot No.
Functional Block Diagram
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8.
FS3871 Functional Block Diagram
Typical Application Circuit
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9.
Figure1. FS3871 Typical Application for one cell
10. Charge profile
Figure2.
11. Absolute Maximum Ratings
((unless otherwise noted))
Rating
-0.3 to 18
-0.3 to VCC+0.3
20
10
40
300
–10 to 70
-40~125
300
Unit
V
V
mA
mA
mA
mW
C
C
C
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Parameter
Supply voltage (Vcc with respect to GND)
Input voltage, SNS, BAT, TS, CRC (all with respect to GND)
Sink current (STAT pin) not to exceed PD
Source current (STAT pin) not to exceed PD
Output current (CC pin) not to exceed PD
Total power dissipation, PD (at 25℃)
Operating free-air temperature range, TA
Storage temperature range, Tstg
Lead temperature (soldering, 10 s)
12. Electrical Characteristics
13. DC Characteristics
(TA=25C, unless otherwise noted)
PARAMETER
VO(REG)
TEST CONDITIONS
V(BAT)+0.3 V ≤ VCC ≤ VCC(max)
TYP
MAX
UNIT
4.158
4.200
4.242
V
VO(REG)–98 VO(REG)–100 VO(REG)–102
mV
mV
mV
V(RCH)
V(min)
V(SNS)
MIN
V
3.04
3.10
3.16
V
High-side current sensing configuration
95.4
105
115.5
mV
Low-side current sensing configuration
90
110
130
mV
V(TS1)
TS pin voltage
29.1
30.0
30.9
%V
V(TS2)
TS pin voltage
58.3
60.0
61.8
%V
G(CRC)
V(BAT)+0.3 V ≤ VCC ≤ VCC(max)
1.87
2.2
2.53
V/V
0.70
V
VOL(STAT)
IOL = 10mA
VOH(STAT)
IOH = 3mA
VOL(CC)
I(VCC)
VCC-0.5
V
IO(CC) = 2 mA (sink)
VCC > VCC(min), Excluding external loads
0.1
1.5
V
0.2
mA
IIB(BAT)
V(BAT) = V(REG)
2
uA
IIB(SNS)
V(SNS)= 5 V
2
uA
IIB(TS)
V(TS) = 5 V
2
uA
IIB(CRC)
V(CRC) = 5 V
2
uA
I(VCCS)
V(BAT) ≥ V(min), V(BAT) – VCC ≥ 0.8 V
2
µA
IO(CC)
Not to exceed power rating specification (PD)
40
mA
I(TERM)
I(PRECHG)
Voltage at pin SNS, relative to VCC for
high-side sensing,0°C ≤ TA ≤ 50°C
Voltage at pin SNS, relative to VCC for
high-side sensing, 0°C ≤ TA ≤ 50°C, VCC = 5
V
0.5
5
–30
–14
–4
mV
3
13
22
mV
14. Typical Operating Characteristics
(Cin=0.1μF, Cout=4.7μF, TA=+25℃, unless otherwise noted.)
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VO(REG) VS Temperature
VRCH VS Temperature
Vmin VS Temperature
15. Detail Description
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Precharge mode
FS3871’s charge qualification is based on battery
temperature and voltage. The FS3871 suspends
charge if the battery temperature is outside the
V(TS1) to V(TS2) range and suspends charge until
the battery temperature is within the allowed range.
The FS3871 also checks the battery voltage. If the
battery voltage is below the precharge threshold
V(min), the FS3871 uses precharge to condition the
battery. The conditioning charge rate I(PRECHG) is
set at approximately 10% of the regulation current.
The conditioning current also minimizes heat
dissipation in the external pass-element during the
initial stage of charge. See Figure 2.
Sleep mode
The FS3871 enters the sleep mode if the VCC falls
below the voltage at the BAT input. This feature
prevents draining the battery pack during the
absence of VCC.
Constant current regulation charge mode
The FS3871 regulates current while the battery-pack
voltage is less than the regulation voltage, VO(REG).
The FS3871 monitors charge current at the SNS
input by the voltage drop across a sense-resistor,
RSNS, in series with the battery pack. In high-side
current sensing configuration (Figure 1), RSNS is
between the VCC and SNS
The following formula calculates the value of the
sense resistor:
R SNS 
Figure3 TS Input Thresholds
The temperature sensing circuit is immune to any
fluctuation in VCC, since both the external voltage
divider and the internal thresholds (V(TS1) and
V(TS2)) are referenced to VCC.The resistor values
of R(T1) and R(T2) are calculated by the following
equations:
For NTC Thermistors:
V(sns)
Io (REG)
For PTC Thermistors
Where IO(REG) is the desired charging current.
Charge termination and recharge
The FS3871 monitors the charging current during
the voltage-regulation phase. The FS3871 declares
a done condition and terminates charge when the
current tapers off to the charge termination threshold,
I(TERM). A new charge cycle begins when the
battery
voltage
falls
below
the
V(RCH)
threshold.(See figure 2)
Battery temperature monitoring
The FS3871 continuously monitors temperature by
measuring the voltage between the TS and VSS
pins. A negative- or a positive-temperature
coefficient thermistor (NTC, PTC) and an external
voltage divider typically develop this voltage. (See
Figure 1.) The FS3871 compares this voltage
against its internal V(TS1) and V(TS2) thresholds to
determine if charging is allowed. (See Figure 3.)
Where R(TC) is the cold temperature resistance and
R(TH) is the hot temperature resistance of thermistor,
as specified by the thermistor manufacturer.RT1 or
RT2 can be omitted If only one temperature (hot or
cold) setting is required. Applying a voltage between
the V(TS1) and V(TS2) thresholds to pin TS disables
the temperature-sensing feature.
Charge status indication
The FS3871 indicates the status of the charger on
the 3-state STAT pin. The following table shows the
statuses of this pin .
Condition
STAT pin
Battery conditioning and charging
High
Charge complete(done)
Low
Temperature fault or sleep mode
Hi-Z
through this pin, is scaled by a factor of G(CRC) and
summed
with
the
regulation
threshold,
VO(REG).This process increases the output voltage
to compensate for the battery pack’s internal
impedance and for undesired voltage drops in the
circuit.
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Voltage regulation phase
The voltage regulation feedback is through the BAT
pin. This input is tied directly to the positive side of
the battery pack. The FS3871 monitors the
battery-pack voltage between the BAT and VSS
pins.
The FS3871 is offered in two fixed-voltage versions:
4.2V and 8.4 V.
Other regulation voltages can be achieved by adding
a voltage divider between the positive and negative
terminals of the battery pack .The voltage divider
presents scaled battery-pack voltage to BAT input.
The CRC setup requires the following information:
1.Total impedance of battery pack (Z(PACK))
2. Maximum charging current (I(REG))
The voltage drop across the internal impedance of
battery pack, V(Z), can then be calculated using the
following equation:
V(CRC) 
V(Z)
G (CRC)
V(PACK)  VO(REG)  [G (CRC) * V(CRC) ]
The resistor values RB1 and RB2 for the voltage
divider are calculated by the following equation:
V(CELL)
RB1
 [N *
] 1
RB2
VO(REG)
Where:
N = Number of cells in series
V(CELL) = Desired regulation voltage per cell
Automatic charge-rate compensation
For internal impedance of the battery pack, the
FS3871 uses the proprietary automatic charge-rate
compensation technique (CRC).
The CRC pin must not be left floating. The feature is
disabled by connecting the CRC pin to VCC in
high-side current-sensing configuration, and to VSS
in low-side current-sensing configuration.
Compensation is achieved through input pin CRC. A
portion of the current-sense voltage, presented
Where V(CRC) is the voltage on CRC pin. This
voltage is referenced to VCC in high-side current
sensing configuration and to VSS for low-side
sensing. V(PACK) is the voltage across the battery
pack.The values of R(CRC1) and R(CRC2) can be
calculated using the following equation:
V(CRC)
V(SNS)

R (CRC2)
R (CRC1)  R (CRC2)
16. Application Information
Selecting an external pass-transistor
The FS3871 drives an external PNP transistor or
P-channel MOSFET to control the charging current.
The specifications must be concerned are the
voltage and current rating and package power
dissipation. The following examples illustrate the
design process for either device:
PNP transistor:
Selection steps for a P-channel MOSFET: We will
use the following conditions: VI=5V; I(REG)=1A,
4.2-V single-cell Li-Ion. VI is the input voltage to the
charger and I(REG) is the desired charge current.
1. Determine the maximum power dissipation, PD ,
in the transistor.The worst case power dissipation
happens when the cell voltage, V(constant), is at its
lowest (typically 3.1V at the beginning of current
regulation phase) and VI is at its maximum. Where
VD is the forward voltage drop across the
reverse-blocking diode (if one is used), and VCS is
the voltage drop across the current sense resistor.
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Selection steps for a PNP bipolar transistor:
Example: VI = 4.5 V, I(REG) = 1 A, 4.2-V single-cell
Li-Ion .VI is the input voltage to the charger and
I(REG) is the desired charge current (see Figure 1).
1. Determine the maximum power dissipation, PD, in
the transistor.
The worst case power dissipation happens when the
cell voltage, V(BAT), is at its lowest (typically 3 V at
the beginning of current regulation phase) and VI is
at its maximum. Where VCS is the voltage drop
across the current sense resistor.
PD=(VI-VCS-VBAT)×IREG
PD=(4.5-0.1-3.)×1A
PD=1.4W
2. Determine the package size needed in order
to keep the junction temperature below the
manufacturer’s recommended value, T(J)max.
θ JA 
θ JA
θ JA
TJ(MAX)  TA(MAX)
PD
(150  40)

1.4
 78C/W
Now choose a device package with a theta at least
10% below this value to account for additional thetas
other than the device. A SOT223 package, for
3. Select a collector-emitter voltage, V(CE), rating
greater than the maximum input voltage. A 15-V
device will be adequate in this example. Select a
device that has at least 50% higher drain current IC
rating than the desired charge current I(REG).
4. Using the following equation, calculate the
minimum beta (β
βmin 
Ic(max)
IB
PD=(VI(MAX)-VD-VCS-VBAT)×IREG
PD=(5.5-0.4-0.2-3.1)×1A
PD=1.8W
2. Determine the package size needed in order to
keep the junction temperature below the
manufacturer’s recommended value, TJMAX.
Calculate the total theta,θ(°C/W), needed. It is
recommended to choose a package with a lower
θ JA
than the number calculated above.
θ JA 
TJ(MAX)  TA(MAX)
PD
(150  40)
θ JA 
1.8
θ JA  61C/W
3. Select a drain-source voltage, V(DS), rating
greater than the maximum input voltage. A 12V
device will be adequate in this example.
4. Select a device that has at least 50% higher drain
current (ID) rating than the desired charge current
I(REG).
5. Verify that the available drive is large enough to
supply the desired charge current.
where Ic(max) is the maximum collector current (in
this case same as I(REG)), and IB is the base
current.
V(GS)=(VD+V(CS)+VOL(CC))-VI(min)
V(GS)=(0.4+0.2+1)
V(GS)=-2.9
Selecting input/output capacitor
In analog circuit applications, all that is needed is a
high-frequency decoupling capacitor. A 0.1 uF
ceramic, placed in proximity to VCC and VSS pins,
works well. If a high ripple and noise input power is
chosen, it should have enough capacitance to
reduce the disturbance. A 0.1uF to 10uF output
capacitor is recommended to control the output
voltage and keep the output voltage ripple small
when the battery is disconnected.
P-Channel MOSFET
Where V(GS) is the gate-to-source voltage, VD is
the forward voltage drop across the reverse-blocking
diode.(if one is used), and VCS is the voltage drop
across the current sense resistor, and VOL(CC) is
the CC pin output low voltage specification for the
FS3871.
Select a MOSFET with gate threshold voltage,
V(GSth),rating less than the calculated V(GS).
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17. Package Outline
18. Revise History
Version
Date
Page
2006/07/01
2006/11/09
2007/03/21
All
4
5
7
14
1.3
1.4
2010/02/10
2011/12/26
1.5
2014/05/22
4
3
7
12
2
Description
New release
Revise datasheet format
Revise Ordering Information to FS3871D/FS3871E
Revise Operating free-air temperature range from -20~70C to
-10~70C
Revise IIB max current to 2uA
Add Revise History
Revise Ordering Information to FS3871D/FS3871E-G
Revise TSSOP-8/MSOP-8 Green Package
Revise MAX_V(SNS)L 130mV
Revise Package Outline
Revise company address
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1.0
1.1
1.2
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