EUP8202 [EUTECH]
Switch Mode Li-Ion/Polymer Battery Charger; 开关模式锂离子/聚合物电池充电器
| 型号： | EUP8202 |
| 厂家： | 
EUTECH MICROELECTRONICS INC |
| 描述： | Switch Mode Li-Ion/Polymer Battery Charger |
| 文件： | 总21页 (文件大小：553K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
EUP8202-4.2/8.4
Switch Mode Li-Ion/Polymer
Battery Charger
DESCRIPTION
FEATURES
z
Wide Input Supply Voltage Range:
4.7V to 20V – 4.2 Version
8.9V to 20V – 8.4 Version
500kHz Switching Frequency
End-of-Charge Current Detection Output
3 Hour Charge Termination Timer
The EUP8202 is a constant current, constant voltage
Li-Ion battery charger controller that uses a current mode
PWM step-down (buck) switching architecture. With a
500kHz switching frequency, the EUP8202 provides a
small, simple and efficient solution to fast charge one
(4.2V) or two (8.4V) cell lithium-ion batteries.
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The EUP8202 charges the battery in three phases:
conditioning, constant current, and constant voltage. An
external sense resistor sets the charge current with ±10%
accuracy. An internal resistor divider and precision
reference set the final float voltage to 4.2V per cell with ±
1% accuracy. An internal comparator detects the near
end-of-charge condition while an internal timer sets the
total charge time and terminates the charge cycle. The
EUP8202 automatically re-starts the charge if the battery
voltage falls below an internal threshold, 4.05V per cell.
The EUP8202 also automatically enters sleep mode when
DC supplies are removed.
z ±1% Charge Voltage Accuracy
z ±10% Charge Current Accuracy
z
z
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Low 10µA Reverse Battery Drain Current
Automatic Battery Recharge
Automatic Trickle Charging of Low Voltage
Batteries
z
Automatic Sleep Mode for Low Power
Consumption
Battery Temperature Sensing
Stable with Ceramic Output Capacitor
8-Lead SOP and 10-Lead TDFN Packages
RoHS Compliant and 100% Lead (Pb)-Free
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The EUP8202 is available in the 8-lead SOP and 10-lead
TDFN packages.
APPLICATIONS
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Small Notebook Computer
Portable DVD
Handheld Instruments
Typical Operating Performance
Efficiency vs Input voltage
Efficiency vs Input voltage
100
100
95
90
85
80
75
70
65
60
(Curves include input diode)
(Curves include input diode)
95
90
85
80
75
70
EUP8202-8.4
EUP8202-4.2
VBAT=3.8V
VBAT=4.0V
VBAT=7.0V
VBAT=8.0V
65
60
8
10
12
14
16
18
20
5
10
15
20
Input Voltage (V)
Input Voltage (V)
DS8202 Ver 1.1 Nov.2007
1
EUP8202-4.2/8.4
Typical Application Circuit
Figure 1. 2A Single/Dual Cells Li-Ion Battery Charger
Figure 2. 1.5A Single/Dual Cells Li-Ion Battery Charger
DS8202 Ver 1.1 Nov.2007
2
EUP8202-4.2/8.4
Block Diagram
Figure 3.
DS8202 Ver 1.1 Nov.2007
3
EUP8202-4.2/8.4
Pin Configurations
Package Type
Pin Configurations
Package Type
Pin Configurations
TDFN-10
SOP-8
Pin Description
PIN
TDFN-10 SOP-8
DESCRIPTION
Compensation, Soft-Start and Shutdown Control Pin. Charging begins when the
COMP pin reaches 850mV. The recommended compensation components are a
2.2µF (or larger) capacitor and a 0.5k series resistor. A 100µA current into the
compensation capacitor also sets the soft-start slew rate. Pulling the COMP pin
below 280mV will shut down the charger.
COMP
1
1
VCC
2
3
2
Positive Supply Voltage Input.
Gate Drive Output. Driver Output for the external P-Channel MOSFET. The
voltage at this pin is internally clamped to 8V below VCC, allowing a low
voltage MOSFET with gate-to-source breakdown voltage of 8V or less to be
used.
3
GATE
PGND
SGND
GND
4
5
-
-
-
4
5
IC Ground.
6
Charge Status Output.
CHRG
Battery Sense Input. A bypass capacitor of 22µF is required to minimize ripple
voltage. When VBAT is within 250mV of VCC, the EUP8202 is forced into sleep
mode, dropping ICC to 10µA.
Current Amplifier Sense Input. A sense resistor, RSENSE, must be connected
between the SENSE and BAT pins. The maximum charge current is equal to
100mV/RSENSE.
BAT
7
8
6
7
SENSE
NTC (Negative Temperature Coefficient) Thermistor Input. With an external
10kΩ NTC thermistor to ground, this pin senses the temperature of the battery
pack and stops the charger when the temperature is out of range. To disable the
temperature qualification function, ground the NTC pin.
NTC
NC
9
8
-
10
No Connect.
DS8202 Ver 1.1 Nov.2007
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EUP8202-4.2/8.4
Ordering Information
Order Number
Package Type
Marking
Operating Temperature range
xxxxx
P8202
1N
EUP8202-42JIR1
EUP8202-84JIR1
EUP8202-42DIR1
EUP8202-84DIR1
TDFN-10
-40 °C to 85°C
xxxxx
P8202
1P
TDFN-10
SOP-8
-40 °C to 85°C
-40 °C to 85°C
-40 °C to 85°C
xxxxx
P8202
1N
xxxxx
P8202
1P
SOP-8
EUP8202- □□ □ □ □ □
Lead Free Code
1: Lead Free 0: Lead
Packing
R: Tape & Reel
Operating temperature range
I: Industry Standard
Package Type
J: TDFN
D:SOP
Output Voltage Option
DS8202 Ver 1.1 Nov.2007
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EUP8202-4.2/8.4
Absolute Maximum Ratings
Supply Voltage (Vcc) -----------------------------------------------------------------------------------
22V
GATE ----------------------------------------------------------------------------------------- (Vcc-8V) to Vcc
BAT, SENSE ------------------------------------------------------------------------------------- -0.3V to 14V
CHRG ,NTC ----------------------------------------------------------------------------------------- -0.3V to 8V
Operating Temperature Range ---------------------------------------------------------------- -40℃ to 85℃
Storage Temperature Range ------------------------------------------------------------------ -65℃ to 125℃
Lead Temperature (Soldering, 10sec) -------------------------------------------------------------------- 260℃
Electrical Characteristics (TA = 25℃, VCC = 10V, unless otherwise noted.)
EUP8202-4.2
Min. Typ. Max.
Symbol
Parameter
Conditions
Unit
DC Characteristics
VCC
VCC Supply Voltage
4.7
20
5
V
Current Mode
1.5
1.5
10
mA
mA
µA
V
ICC
VCC Supply Current
Shutdown Mode
5
Sleep Mode
20
5V≦VCC ≦20V 0℃≦TA ≦85℃
3V≦VBAT ≦4V 0℃≦TA ≦85℃
VBAT = 1V
VBAT(FLT) Battery Regulated Float Voltage
VSNS(CHG) Constant Current Sense Voltage
VSNS(TRKL) Trickle Current Sense Voltage
4.158
90
4.2
100
15
4.242
110
22
mV
mV
8
Trickle Charge Threshold
VTRKL
VBAT = Rising
2.75
3.9
2.9
4.2
3.05
4.5
V
V
Voltage
VCC Undervoltage Lockout
VUV
VCC = Rising
Threshold Voltage
VCC Undervoltage Lockout
∆VUV
200
280
mV
mV
Hysteresis Voltage
Manual shutdown Threshold
VMSD
COMP Pin Falling
150
450
Voltage
Automatic shutdown Threshold
VASD
VCC - VBAT
250
100
mV
µA
Voltage
ICOMP
ICHRG
COMP Pin Output Current
VCOMP = 1.2V
CHRG Pin Weak Pull-Down
Current
VCHRG = 1V
15
10
25
35
50
µA
CHRG Pin Output Low
VCHRG
ICHRG = 1mA
20
25
mV
Voltage
REOC
End-of-Charge Ratio
Charge time Accuracy
VSNS(EOC) /VSNS(CHG)
32
10
%
%
tTIMER
0℃≦TA ≦50℃
75
70
85
85
95
µA
µA
mV
mV
V
INTC
NTC Pin Output Current
VNTC = 0.85V
-40℃≦TA ≦85℃
100
380
VNTC = Falling
Hysteresis
340
360
5
NTC Pin Thershold Voltage
(Hot)
VNTC-HOT
VNTC = Rising
Hysteresis
2.35
2.4
100
2.45
NTC Pin Thershold Voltage
(Cold)
VNTC-COLD
mV
DS8202 Ver 1.1 Nov.2007
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EUP8202-4.2/8.4
Electrical Characteristics (TA = 25℃, VCC = 10V, unless otherwise noted.)
EUP8202-4.2
Unit
Symbol
Parameter
Conditions
Min. Typ. Max.
Recharge Battery Voltage Offset
V
BAT(FULLCHARGD) –VRECHRG, VBAT
∆VRECHRG from Full Charged Battery
100
150
200
1
mV
µA
Falling
Voltage
CHRG Pin Leakage Current
ILEAK
V
CHRG= 8V, Charging Stops
Oscillator
fOSC
Switching Frequency
Maximum Duty Cycle
450
500
550
100
kHz
%
DC
Gate Drive
tr
tf
Rise Time
Fall Time
CGATE =2000pF, 10% to 90%
20
50
ns
ns
CGATE =2000pF, 10% to 90%
VCC -VGATE ,
-40℃≦TA ≦85℃
∆VGATE Output Clamp Voltage
8
V
VCC≧9V
∆VGATEHI Output High Voltage
∆VGATELO Output Low Voltage
∆VGATEHI= VCC -VGATE , VCC≧7V
0.3
V
V
∆VGATELO= VCC -VGATE , VCC≧7V
4.5
Electrical Characteristics (TA =25℃,VCC =12V,unlessotherwisenoted.)
EUP8202-8.4
Min. Typ. Max.
Symbol
Parameter
Conditions
Unit
DC Characteristics
VCC
VCC Supply Voltage
8.9
20
5
V
Current Mode
1.5
1.5
10
mA
mA
µA
V
ICC
VCC Supply Current
Shutdown Mode
5
Sleep Mode
20
9V≦VCC ≦20V 0℃≦TA ≦85℃
6V≦VBAT ≦8V 0℃≦TA ≦85℃
VBAT = 1V
VBAT(FLT) Battery Regulated Float Voltage
VSNS(CHG) Constant Current Sense Voltage
VSNS(TRKL) Trickle Current Sense Voltage
8.316
90
8.4
100
15
8.484
110
22
mV
mV
8
Trickle Charge Threshold
VTRKL
VBAT = Rising
4.7
5
5.3
8.5
V
V
Voltage
VCC Undervoltage Lockout
VUV
V
CC = Rising
7.5
500
280
Threshold Voltage
VCC Undervoltage Lockout
∆VUV
mV
mV
Hysteresis Voltage
Manual shutdown Threshold
VMSD
COMP Pin Falling
150
15
450
35
Voltage
Automatic shutdown Threshold
VASD
VCC - VBAT
250
100
mV
µA
Voltage
ICOMP
ICHRG
COMP Pin Output Current
VCOMP = 1.2V
CHRG Pin Weak Pull-Down
Current
VCHRG = 1V
25
µA
DS8202 Ver 1.1 Nov.2007
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EUP8202-4.2/8.4
Electrical Characteristics (TA = 25℃, VCC = 12V, unless otherwise noted.)
EUP8202-8.4
Unit
Symbol
Parameter
Conditions
Min. Typ. Max.
CHRG Pin Output Low
Voltage
End-of-Charge Ratio
VCHRG
ICHRG = 1mA
VSNS(EOC) /VSNS(CHG)
20
15
50
mV
REOC
5
25
10
%
%
tTIMER
Charge time Accuracy
0℃≦TA ≦50℃
75
70
85
85
95
µA
µA
mV
mV
V
INTC
NTC Pin Output Current
VNTC = 0.85V
-40℃≦TA ≦85℃
100
380
VNTC = Falling
Hysteresis
340
360
5
NTC Pin Thershold Voltage
(Hot)
VNTC-HOT
VNTC = Rising
Hysteresis
2.35
200
2.4
100
2.45
NTC Pin Thershold Voltage
(Cold)
VNTC-COLD
mV
Recharge Battery Voltage Offset
V
BAT(FULLCHARGD) –VRECHRG, VBAT
∆VRECHRG from Full Charged Battery
300
500
400
1
mV
µA
Falling
Voltage
CHRG Pin Leakage Current
ILEAK
VCHRG= 8V, Charging Stops
Oscillator
fOSC
Switching Frequency
Maximum Duty Cycle
450
550
100
kHz
%
DC
Gate Drive
tr
tf
Rise Time
Fall Time
CGATE =2000pF, 10% to 90%
20
50
ns
ns
CGATE =2000pF, 10% to 90%
VCC-VGATE ,
40℃≦TA ≦85℃
∆VGATE Output Clamp Voltage
8
V
VCC≧9V
∆VGATEHI Output High Voltage
∆VGATELO Output Low Voltage
∆VGATEHI= VCC -VGATE , VCC≧7V
0.3
V
V
∆VGATELO= VCC -VGATE , VCC≧7V
4.5
DS8202 Ver 1.1 Nov.2007
8
EUP8202-4.2/8.4
Typical Operating Characteristics
Oscillator Frequency vs Temperature
Supply Current vs Vcc
2.0
(Current mode)
540
520
500
480
460
1.8
1.6
1.4
1.2
1.0
-40
-20
0
20
40
60
80
100
120
5
10
15
20
TEMPERATURE(°C)
Vcc (V)
Undervoltage Lockout Threshold vs Temperature
Supply Current vs Temperature
9
8
7
6
5
4
3
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
EUP8202-4.2
EUP8202-8.4
-40
-20
0
20
40
60
80
100
120
-40
-20
0
20
40
60
80
100
120
TEMPERATURE(°C)
TEMPERATURE(°C)
Oscillator Frequency vs Vcc
540
520
500
480
460
5
10
15
20
Vcc (V)
DS8202 Ver 1.1 Nov.2007
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EUP8202-4.2/8.4
Typical Operating Characteristics (continued)
CHRG Pin Weak Pull-Down Current vs Vcc
CHRG Pin Output Low Voltage vs Vcc
28
26
24
22
30
VCHRG=8V
Iload=1mA
25
20
15
10
5
10
15
20
5
10
15
20
Vcc (V)
Vcc (V)
Recharge Voltage Offset from Full Charged
Voltage vs Vcc
CHRG Pin Output Low Voltage vs Temperature
25
20
15
10
5
160
155
150
145
140
Iload=1mA
EUP8202-4.2
-40
-20
0
20
40
60
80
100
120
5
10
15
20
Vcc (V)
TEMPERATURE(°C)
Recharge Voltage Offset from Full Charged
Voltage vs Vcc
CHRG Pin Weak Pull-Down Current vs Temperature
32
30
28
26
24
22
320
VCHRG=8V
EUP8202-8.4
315
310
305
300
295
290
285
280
-40
-20
0
20
40
60
80
100
120
5
10
15
20
Vcc (V)
TEMPERATURE(°C)
DS8202 Ver 1.1 Nov.2007
10
EUP8202-4.2/8.4
Typical Operating Characteristics (continued)
COMP Pin Output Current vs Vcc
Current Mode Sense Voltage vs Vcc
104
102
100
98
102
VCOMP=1.2V
VBAT=4.0V
EUP8202-4.2
100
98
96
96
94
94
5
10
15
20
5
10
15
20
Vcc (V)
Vcc (V)
COMP Pin Output Current vs Temperature
Current Mode Sense Voltage vs Vcc
120
106
104
102
100
98
VCOMP=1.2V
VBAT=8V
EUP8202-8.4
118
116
114
112
110
108
106
104
102
-40
-20
0
20
40
60
80
100
120
5
10
15
20
TEMPERATURE(°C)
Vcc (V)
Current Mode Sense Voltage vs Temperature
104
103
102
101
100
99
98
97
96
-40
-20
0
20
40
60
80
100
120
TEMPERATURE(°C)
DS8202 Ver 1.1 Nov.2007
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EUP8202-4.2/8.4
Typical Operating Characteristics (continued)
Trickle Charge Voltage vs Vcc
Trickle Charge Voltage vs Temperature
5.2
5.1
5.0
4.9
4.8
3.00
EUP8202-8.4
EUP8202-4.2
2.95
2.90
2.85
2.80
5
10
15
20
-40
-20
0
20
40
60
80
100
120
Vcc (V)
TEMPERATURE(°C)
Trickle Charge Sense Voltage vs Temperature
Trickle Charge Voltage vs Vcc
20
3.0
2.9
2.8
VBAT=2.5V
EUP8202-4.2
EUP8202-4.2
18
16
14
12
10
8
-40
-20
0
20
40
60
80
100
120
5
10
15
20
TEMPERATURE(°C)
Vcc (V)
Trickle Charge Sense Voltage vs Vcc
Trickle Charge Voltage vs Temperature
25
5.2
VBAT=2.5V
EUP8202-4.2V
EUP8202-8.4
20
15
10
5
5.1
5.0
4.9
4.8
5
10
15
20
-40
-20
0
20
40
60
80
100
120
Vcc (V)
TEMPERATURE(°C)
DS8202 Ver 1.1 Nov.2007
12
EUP8202-4.2/8.4
Typical Operating Characteristics (continued)
End-of-Charge Ratio vs Temperature
Trickle Charge Sense Voltage vs Temperature
22
20
18
16
14
12
20
EUP8202-8.4
VBAT=4V
EUP8202-8.4
18
16
14
12
10
8
-40
-20
0
20
40
60
80
100
120
-40
-20
0
20
40
60
80
100
120
TEMPERATURE(°C)
TEMPERATURE(°C)
End-of-Charge Ratio vs Vcc
Trickle Charge Sense Voltage vs Vcc
25
EUP8202-4.2
VBAT=4V
EUP8202-8.4V
28
20
15
10
5
26
24
22
5
10
15
20
5
10
15
20
Vcc (V)
Vcc (V)
End-of-Charge Ratio vs Vcc
End-of-Charge Ratio vs Temperature
22
20
18
16
14
30
28
26
24
22
20
EUP8202-8.4
EUP8202-4.2
5
10
15
20
-40
-20
0
20
40
60
80
100
120
Vcc (V)
TEMPERATURE(°C)
DS8202 Ver 1.1 Nov.2007
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EUP8202-4.2/8.4
Typical Operating Characteristics (continued)
NTC Pin Output Current vs Temperature
NTC Pin Output Current vs Vcc
94
88
86
84
VNTC=0V
92
VNTC=0V
90
88
86
84
82
80
-40
-20
0
20
40
60
80
100
120
5
10
15
20
Vcc (V)
TEMPERATURE(°C)
DS8202 Ver 1.1 Nov.2007
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EUP8202-4.2/8.4
Application Information
Figure 4. Operational Flow Chart
DS8202 Ver 1.1 Nov.2007
15
EUP8202-4.2/8.4
OPERATION
and the CHRG pin is forced high impedance. To restart
the charge cycle, remove and reapply the input voltage or
momentarily shut the charger down. Also, a new charge
cycle will begin if the battery voltage drops below the
recharge threshold voltage of 4.05V per cell.
The EUP8202 is a constant current, constant voltage
Li-Ion battery charger controller that uses a current mode
PWM step-down (buck) switching architecture. The
charge current is set by an external sense resistor (RSENSE
across the SENSE and BAT pins. The final battery float
voltage is internally set to 4.2V per cell. For batteries like
lithium-ion that require accurate final float voltage, the
internal 2.4V reference, voltage amplifier and the resistor
divider provide regulation with ±1% accuracy.
)
When the input voltage is present, the charger can be shut
down (ICC =1.5mA) by pulling the COMP pin low. When
the input voltage is not present, the charger goes into
sleep mode, dropping ICC to 10µA. This will greatly
reduce the current drain on the battery and increase the
standby time.
A
10kΩ NTC (negative temperature coefficient)
thermistor can be connected from the NTC pin to ground
for battery temperature qualification. The charge cycle is
suspended when the temperature is outside of the 0°C to
50°C window.
APPLICATIONS INFORMATION
Undervoltage Lockout (UVLO)
An undervoltage lockout circuit monitors the input
voltage and keeps the charger off until VCC rises above
the UVLO threshold (4.2V for the 4.2 version, 7.5V for
the 8.4 version) and at least 250mV above the battery
voltage. To prevent oscillation around the threshold
voltage, the UVLO circuit has 200mV per cell of built-in
hysteresis. When specifying minimum input voltage
requirements, the voltage drop across the input blocking
diode must be added to the minimum VCC supply voltage
specification.
Figure 5.Typical Charge Profile
A charge cycle begins when the voltage at the VCC pin
rises above the UVLO level and is 250mV or more
greater than the battery voltage. At the beginning of the
charge cycle, if the battery voltage is less than the trickle
charge threshold, 2.9V for the 4.2 version and 5V for the
8.4 version, the charger goes into trickle charge mode.
The trickle charge current is internally set to 15% of the
full-scale current. If the battery voltage stays low for 30
minutes, the battery is considered faulty and the charge
cycle is terminated.
When the battery voltage exceeds the trickle charge
threshold, the charger goes into the full-scale constant
current charge mode. In constant current mode, the
charge current is set by the external sense resistor RSENSE
and an internal 100mV reference;
Trickle Charge and Defective Battery Detection
At the beginning of a charge cycle, if the battery voltage
is below the trickle charge threshold, the charger goes
into trickle charge mode with the charge current reduced
to 15% of the full-scale current. If the low-battery
voltage persists for 30 minutes, the battery is considered
defective, the charge cycle is terminated and the
pin is forced high impedance.
CHRG
V
15mV
SNS(TRKL)
I
=
=
TRKL
R
R
V
100mV
SNS(CHG)
I
=
=
Shutdown
CHG
R
R
SENSE
SENSE
The EUP8202 can be shut down by pulling the COMP
pin to ground which pulls the GATE pin high turning off
the external P-channel MOSFET. When the COMP pin is
released, the internal timer is reset and a new charge
When the battery voltage approaches the programmed
float voltage, the charge current will start to decrease.
When the current drops to 25% (4.2 version) or 15% (8.4
version) of the full-scale charge current, an internal
comparator turns off the internal pull-down N-channel
cycle starts. In shutdown, the output of the
pin
CHRG
is high impedance and the quiescent current remains at
1.5mA. Removing the input power supply will put the
charger into sleep mode. If the voltage at the VCC pin
drops below (VBAT + 250mV) or below the UVLO level,
the EUP8202 goes into a low current (ICC = 10µA) sleep
mode, reducing the battery drain current.
MOSFET at the
pin, and connects a weak
CHRG
current source to ground to indicate a near end-of-charge
condition.
An internal 3 hour timer determines the total charge time.
After a time out occurs, the charge cycle is terminated
DS8202 Ver 1.1 Nov.2007
16
EUP8202-4.2/8.4
pin changes to a high impedance state and the 390k
resistor will then pull the pin high to indicate charging
has stopped.
CHRG Status Output Pin
When a charge cycle starts, the
pin is pulled to
CHRG
ground by an internal N-channel MOSFET which is
capable of driving an LED. When the charge current
drops below the End-of-Charge threshold for more than
120µs, the N-channel MOSFET turns off and a weak
25µA current source to ground is connected to the
Gate Drive
The EUP8202gate driver can provide high transient
currents to drive the external pass transistor. The rise and
fall times are typically 20ns and 50ns respectively when
driving a 2000pF load, which is typical for a P-channel
MOSFET with RDS(ON) in the range of 50mΩ.
A voltage clamp is added to limit the gate drive to 8V
below VCC. For example, if VCC is 10V then the GATE
output will pull down to 2V max. This allows low
voltage P-channel MOSFETs with superior RDS(ON) to be
used as the pass transistor thus increasing efficiency.
pin. This weak 25µA pull-down remains until
CHRG
the timer ends the charge cycle, or the charger is in
manual shutdown or sleep mode.
Table1:
Status Pin Summary
CHRG
CHARGE STATE
Pin
CHRG
Trickle Charge in Process
Constant Current Charge in Process
Constant Voltage Charge in Process
Strong On
Strong On
Strong On
Strong On
(remains the
same)
Hi-Z
Hi-Z
Weak On
Weak On
Stability
Both the current loop and the voltage loop share a
common, high impedance, compensation node (COMP
pin). A series capacitor and resistor on this pin
compensates both loops. The resistor is included to
provide a zero in the loop response and boost the phase
margin. The compensation capacitor also provides a
soft-start function for the charger. Upon start-up, then
ramp at a rate set by the internal 100µA pullup current
source and the external capacitor. Battery charge current
starts ramping up when the COMP pin voltage reaches
0.85V and full current is achieved with the COMP pin at
1.3V. With a 2.2µF capacitor, time to reach full charge
current is about 10ms. Capacitance can be increased if a
longer start-up time is needed.
Charge Suspend (Temperature)
Timer Fault
Sleep / Shutdown
End of Charge
Battery Disconnected
After a time out occurs (charge cycle ends), the pin will
become high impedance. By using two different value
resistors, a microprocessor can detect three states from
this pin (charging, end-of-charge and charging stopped)
see Figure 6.
Automatic Battery Recharge
After the 3 hour charge cycle is completed and both the
battery and the input power supply (wall adapter) are still
connected, a new charge cycle will begin if the battery
voltage drops below 4.05V per cell due to self-discharge
or external loading. This will keep the battery capacity at
more than 80% at all times without manually restarting
the charge cycle.
Battery Temperature Detection
A negative temperature coefficient (NTC) thermistor
located close to the battery pack can be used to monitor
battery temperature and will not allow charging unless
the battery temperature is within an acceptable range.
Connect a 10kΩ thermistor from the NTC pin to ground.
If the temperature rises to 50°C, the resistance of the
NTC will be approximately 4.2kΩ. With the 85µA
pull-up current source, the Hot temperature voltage
threshold is 360mV. For Cold temperature, the voltage
threshold is set at 2.4V which is equal to 0°C (RNTC ≅
28kΩ) with 85µA of pull-up current. If the temperature is
outside the window, the GATE pin will be pulled up to
VCC and the timer frozen while the output status at the
Figure 6. Microprocessor Interface
To detect the charge mode, force the digital output pin,
OUT, high and measure the voltage at the
pin.
CHRG
The N-channel MOSFET will pull the pin low even with
a 2k pull-up resistor. Once the charge current drops
below the End-of-Charge threshold, the N-channel
MOSFET is turned off and a 25µA current source is
connected to the
pin. The IN pin will then be
CHRG
pulled high by the 2k resistor connected to OUT. Now
force the OUT pin into a high impedance state, the
current source will pull the pin low through the 390k
pin remains the same. The charge cycle begins
CHRG
resistor. When the internal timer has expired, the
CHRG
or resumes once the temperature is within the acceptable
DS8202 Ver 1.1 Nov.2007
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EUP8202-4.2/8.4
range. Short the NTC pin to ground to disable the
temperature qualification feature. However the user may
modify these thresholds by adding two external resistor.
See figure 8.
for filtering and has the necessary RMS current rating.
Switching ripple current splits between the battery and
the output capacitor depending on the ESR of the output
capacitor and the battery impedance. EMI considerations
usually make it desirable to minimize ripple current in
the battery leads. Ferrite beads or an inductor may be
added to increase battery impedance at the 500kHz
switching frequency. If the ESR of the output capacitor is
0.2Ω and the battery impedance is raised to 4Ω with a
bead or inductor, only 5% of the current ripple will flow
in the battery.
Design Example
As a design example, take a charger with the following
specifications:
Figure 7. Temperature Sensing Configuration
For single cell charge, VIN = 5V to 20V, VBAT = 4V
nominal, IBAT =1.5A, fOSC = 500kHz, IEOC=0.375A, see
Figure 2.
First, calculate the SENSE resistor :
100mV
R
=
= 68mꢀ
SENSE
1.5A
Choose the inductor for about 65% ripple current at the
maximum VIN:
4V
500kHz)(0.65)(1.5A
4V
20V
L =
1 −
= 6.56µH
Figure 8. Temperature Sensing Thresholds
Input and Output Capacitors
(
)
Selecting a standard value of 6.8µH results in a
maximum ripple current of :
Since the input capacitor is assumed to absorb all input
switching ripple current in the converter, it must have an
adequate ripple current rating. Worst-case RMS ripple
current is approximately one-half of output charge
current. Actual capacitance value is not critical. Solid
tantalum capacitors have a high ripple current rating in a
relatively small surface mount package, but caution must
be used when tantalum capacitors are used for input
bypass. High input surge currents can be created when
the adapter is hot-plugged to the charger and solid
tantalum capacitors have a known failure mechanism
when subjected to very high turn-on surge currents.
Selecting the highest possible voltage rating on the
capacitor will minimize problems. Consult with the
manufacturer before use.
4V
4V
20V
∆I
=
1 −
= 941.2mA
L
(
500kHz)(6.8µH
)
∆I
941.2mA
2
L
ILPK = I
+
= 1.5A +
≈1.975A
CHG
2
Next, choose the P-channel MOSFET. For example, a
TSSOP-8 package with RDS(ON) = 42mΩ (nom), 55mΩ
(max) offers a small solution. The maximum power
dissipation with VIN = 5V and VBAT = 4V at 50℃
ambient temperature is:
2
(
1.5A) (55mΩ)(4V
)
The selection of output capacitor COUT is primarily
determined by the ESR required to minimize ripple
voltage and load step transients. The output ripple ∆VOUT
is approximately bounded by:
P
=
= 0.099W
D
5V
TJ = 50℃ + (0.099W)(65℃/W) = 56.5℃
C
IN is chosen for an RMS current rating of about 0.8A at
85℃. The output capacitor is chosen for an ESR similar
to the battery impedance of about 100mΩ The ripple
voltage on the BAT pin is:
1
ꢁV ≤ ꢁI ESR +
OUT
L
8f
C
OSC
OUT
Since ∆IL increases with input voltage, the output ripple
is highest at maximum input voltage. Typically, once the
ESR requirement is satisfied, the capacitance is adequate
DS8202 Ver 1.1 Nov.2007
18
EUP8202-4.2/8.4
Board Layout Suggestions
∆I
ESR
)
)
When laying out the printed circuit board, the following
considerations should be taken to ensure proper operation
of the EUP8202.
L
(
max
2
V
=
=
OUT(RIPPLE)
GATE pin rise and fall times are 20ns and 50ns
respectively (with CGATE = 2000pF). To minimize
radiation, the catch diode, pass transistor and the input
bypass capacitor traces should be kept as short as
possible. The positive side of the input capacitor should
be close to the source of the P-channel MOSFET; it
provides the AC current to the pass transistor. The
connection between the catch diode and the pass
transistor should also be kept as short as possible. The
SENSE and BAT pins should be connected directly to the
sense resistor (Kelvin sensing) for best charge current
accuracy. Avoid routing the NTC PC board trace near the
MOSFET switch to minimize coupling switching noise
into the NTC pin.
(0.94A)(0.1Ω)
= 47mV
2
For dual cells charge,
VIN = 5V to 20V, VBAT = 8V nominal, IBAT =3A,
fOSC = 500kHz, IEOC=0.45A,
100mV
R
=
= 33mꢀ
SENSE
3A
Choose the inductor for about 50% ripple current at the
maximum VIN:
8V
500kHz)(0.5)(3A
8V
20V
L =
1 −
= 6.4µH
(
)
The compensation capacitor connected at the COMP pin
should return to the ground pin of the IC or as close to it
as possible. This will prevent ground noise from
disrupting the loop stability. The ground pin also works
as a heat sink, therefore use a generous amount of copper
around the ground pin. This is especially important for
high VCC and/or high gate capacitance applications.
Selecting a standard value of 6.8µH results in a
maximum ripple current of :
8V
8V
20V
∆I
=
1 −
= 1.441A
L
(
500kHz)(6.8µH
)
∆I
1.441A
2
L
ILPK = I
+
= 3A +
≈ 3.720A
CHG
2
The maximum power dissipation with VIN = 9V and VBAT
= 8V at 50℃ ambient temperature is:
2
(
3A) (55mΩ)(8V
)
P
=
= 0.44W
D
9V
TJ = 50℃ + (0.44W)(65℃/W) = 78.6℃
∆I
ESR)
)
L
(
max
2
V
=
=
OUT(RIPPLE)
1.441A0.1Ω
( )
= 72mV
2
The Schottky diode D2 shown in Figure 2 conducts
current when the pass transistor is off. In a low duty
cycle case, the current rating should be the same or
higher than the charge current. Also it should withstand
reverse voltage as high as VIN.
DS8202 Ver 1.1 Nov.2007
19
EUP8202-4.2/8.4
Packaging Information
TDFN-10
MILLIMETERS
INCHES
SYMBOLS
MIN.
0.70
0.00
2.90
MAX.
0.80
0.05
3.10
MIN.
MAX.
0.031
0.002
0.122
A
A1
D
0.028
0.000
0.114
E1
1.70
0.067
E
L
b
2.90
0.30
0.18
3.10
0.50
0.30
0.114
0.012
0.007
0.122
0.020
0.012
e
D1
0.50
2.40
0.020
0.094
DS8202 Ver 1.1 Nov.2007
20
EUP8202-4.2/8.4
SOP-8
MILLIMETERS
INCHES
MIN.
0.053
0.004
SYMBOLS
MIN.
1.35
0.10
MAX.
1.75
0.25
MAX.
0.069
0.010
A
A1
D
E
E1
L
4.90
3.90
0.193
0.153
5.80
6.20
0.228
0.244
0.40
0.31
1.27
0.51
0.016
0.012
0.050
0.020
b
e
1.27
0.050
DS8202 Ver 1.1 Nov.2007
21
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