Datasheet AIC1802CCS, AIC1802BCS, AIC1802 Datasheet (AIC)

AIC1802

µ

µ

*C

TC

*C

TD

1µF

M2

Q1

Two-Cell Lithium-Ion Battery Protection IC

n FEATURES

l Ultra-Low Quiescent Current at 10

VC=3.5V).

l Ultra-Low Power-Down Current at 0.2

=3.8V, VC=1.9V).

l Wide Supply Range: 2 to 18V.
l Precision Overcharge Protection Voltage

4.35V ± 30mV for the AIC1802A

4.30V ± 30mV for the AIC1802B

4.25V ± 30mV for the AIC1802C

l Built-in Delay Circuits for Overcharge, Over-

discharge and Overcurrent Protection.

l Overcharge and Overdischarge Delay Time

can be Extended by External Capacitors.

l Built-in Cell-balancing Bleeding Network under

Overcharge Condition.

n APPLICATIONS

l Protection IC for Two-Cell Lithium-Ion Battery

Pack.

A (VCC=7V,

A (V

CC

n DESCRIPTION

The AIC1802 battery protection IC is designed
to protect lithium-ion batteries from damage due
to overcharging, overdischarging, and
overcurrent for two series cells in portable
phones and laptop computers. It can be a part of
the low-cost charge control system within a two­cell lithium-ion battery pack.

Safe and full utilization charging is ensured by
the accurate ±30mV overcharge detection.
Three different specification values for
overcharge protection voltage are provided for
various protection requirements. The very low
standby current drains little current from the
cells while in storage.

n TYPICAL APPLICATION CIRCUIT

**R1

C1

C2

BATTERY 2

M1

CEM9926

1µF

**R2

*CTC & CTD are optional for delay time adjustment.
**R1 & R2: Refer application informations.

Protection Circuit for Two-Cell Lithium-Ion Battery Pack

DS-1802-03 July 13, 00 www.analog.com.tw

8

VCC TC

6

VC TD

4

GND OC

2

OD CS

AIC1802

5

3

1

7

R6
1K

R3
1M

CEM9926

C3

0.01µF

V

+

BAT

R4
1M

R5
1M

V

-

BAT

1

n ORDERING INFORMATION

AIC1

802ACS

VCVCODTD

GNDCSTC

OC13428657

+

+

V

V

432

1

I

V

CSCTC

V

COICC

AIC1802

AIC1802 XCX

PACKAGE TYPE
S: SOP-8

OVERCHARGE
PROTECTION VOLTAGE
A: 4.35V
B: 4.30V
C: 4.25V

ORDER NUMBER

AIC1802BCS
AIC1802CCS
(PLASTIC SO8)

PIN CONFIGURATION

TOP VIEW

n ABSOLUTE MAXIMUM RATINGS

Supply Voltage ....................................……………..................................................... 18V

DC Voltage Applied on VC, CS, OC, OD Pins ...............…………….............................. 18V

DC Voltage Applied on TC, TD Pins ...............…………………..…….............................. 5V

Operating Temperature Range .......................................….………….............. -40°C~85°C

Storage Temperature Range .........................…………………..................... - 65°C~150°C

n TEST CIRCUIT

I

OC VCC

OD CS

TD VC

GND TC

C

TD

AIC1802

8

7

6

5

CC

2

AIC1802

n ELECTRICAL CHARACTERISTICS (Ta=25 °C, unless otherwise specified.)

PARAMETER TEST CONDITIONS SYMBOL MIN. TYP. MAX. UNIT

Supply Current in Normal Mode VCC=7V, VC=3.5V I

Supply Current in Power-Down
Mode

VCC=4.8V, VC=2.4V I

VC Pin Input Current VCC=7V, VC=3.5V I

AIC1802A 4.32 4.35 4.38

AIC1802B 4.27 4.30 4.33 Overcharge Protection Voltage

V

AIC1802C

Overcharge Release Voltage V

Overdischarge Protection
Voltage

V

Overdischarge Release Voltage V

Overcurrent Protection Voltage VCC=7V V

Overcharge Delay Time (1)

VCC=8.6V, VC=4.3V,
CTC=0µF

T

CC

PD

C

OCP

OCR

ODP

ODR

OIP

OC1

10 15 µA

0.8 1.2 µA

400 600 nA

V

4.22 4.25 4.28

3.85 4.0 4.15 V

2.25 2.4 2.55 V

2.85 3.0 3.15 V

135 150 165 mV

12 25 38 mS

Overcharge Delay Time (2)

Overdischarge Delay Time (1)

Overdischarge Delay Time (2)

Overcurrent Delay Time (1)

Overcurrent Delay Time (2)

OC Pin Source Current

VCC=8.6V, VC=4.3V,
CTC=0.47µF

VCC=4.8V, VC=2.4V,
CTD=0µF

VCC=4.8V, VC=2.4V,
CTD=0.47µF

VCC=7V, VC=3.5V,
VCS=0.15V

VCC=7V, VC=3.5V,
VCS=0.36V

VCC=8.6V, VC=4.3V,
OC Pin Short to GND

T

T

T

OD Pin Output “H” Voltage V

T

T

I

OC2

OD1

OD2

OI1

OI2

CO

DL

0.7 1.1 1.5 S

12 25 38 mS

0.7 1.1 1.5 S

4 9 14 mS

1.0 2.0 3.0 mS

270 400 530 µA

VCC-0.1 VCC-0.02 V

3

n ELECTRICAL CHARACTERISTICS (Continued)

AIC1802

PARAMETER TEST CONDITIONS

SYMBOL

OD Pin Output “L” Voltage V

Charge Detection Threshold

VCC=4.8V V

Voltage

Unbalance Discharge Current VCC=8.3V, VC=4V I

TYPICAL PERFORMANCE CHARACTERISTICS

n

10.7

10.5

10.3

10.1

Supply Current vs. Supply Voltage

VC=1/2VCC
TA=25°C

0.8

0.65

0.5

MIN. TYP. MAX. UNIT

DH

CH

UD

Power-down Current vs. Supply Voltage

0.01 0.1 V

-0.55 -0.4 V

5.4 7.7 10 mA

VC=1/2VCC
TA=25°C

Supply Current (µA)

9.9

9.7

5.5 6.5 7.5 8.5

Supply Voltage (V)

Overcharge Protection Voltage vs. Temperature

4.32

4.315

AIC1802B

4.31

4.305

Overcharge Protection Voltage (V)

4.3
0 10 20 30 40 50 60 70-10-20

Temperature (°C)

0.35

Power-Down Current (µA)

0.2

3.8 4.3 4.8 5.3 5.8

Supply Voltage (V)

Overcurrent Protection Voltage vs. Temperature

150

VCC=7V

147.5

142.5

Overcurrent Protection Voltage (mV)

VC=3.5V

145

140

0 10 20 30 40 50 60 70-10-20

Temperature (°C)

4

TYPICAL PERFORMANCE CHARACTERISTICS (Continued)

µ

(V)

Overcharge Release Voltage vs. Temperature

Overdischarge Release Voltage (V)

n

AIC1802

Supply Current vs. Temperature

12.5

A)

11.5

10.5

Supply Current (

9.5

8.5
0 10 20 30 40 50 60 70-10-20

Temperature (°C)

Overdischarge Protection Voltage vs. Temperature

2.420

2.415

2.410

2.405

VCC=7V
VC=3.5V

1.1

0.9

0.7

Power-Down Current (µA)

0.5

4.025

4.020

4.015

Power-Down Current vs. Temperature

VCC=4.8V
VC=2.4V

0 10 20 30 40 50 60 70-10-20

Temperature (°C)

2.400

Overdischarge Protection Voltage

2.395

-20 -10 0 10 20 30 40 50 60 70

Temperature (°C)

Overdischarge Release Voltage vs. Temperature

3.025

3.020

3.015

3.010

3.005

-20 -10 0 10 20 30 40 50 60 70

Temperature (°C)

4.010

Overcharge Release Voltage (V)

4.005

-20 -10 0 10 20 30 40 50 60 70

Temperature (°C)

70

5

BLOCK DIAGRAM

VCC

VCC

DETECTOR

DETECTOR 2

DETECTOR 1

DETECTOR 1

DETECTOR 2

UP

DISCHARGE

n

AIC1802

8

6

VC

OD

4

2

GND

PIN DESCRIPTIONS

n

450

450

OVERCHARGE

OVERDISCHARGE

UNBALANCE

OVERCHARGE

OVERDISCHARGE

OVERCURRENT
DELAY CIRCUIT

OVERCURRENT

OVERCHARGE

DELAY CIRCUIT

OVERDISCHARGE

DELAY CIRCUIT

POWER-

LOGIC

CONTROL

TIMING

GENERATION

CHARGE

DETECTION

DOWN

WAKE-

5

TC

3

TD

1

OC

7

CS

PIN 1: OC - PMOS open drain output for

control of the charge control
MOSFET M2. When overcharge
occurs, this pin sources current to
switch the external NPN Q1 on,
and charging is inhibited by
turning off the charge control
MOSFET M2.

PIN 2: OD - Output pin for control of the

discharge control MOSFET M1.
When overdischarge occurs, this
pin goes low to turn off the
discharge control MOSFET M1
and discharging is inhibited.

PIN 3: TD - Overdischarge delay time setting

pin.

PIN 4: GND - Ground pin. This pin is to be

connected to the negative terminal
of the lower battery cell.

PIN 5: TC - Overcharge delay time setting

pin.

PIN 6: VC - To be connected to the positive

terminal of the lower cell and
the negative terminal of the
upper cell.

PIN 7: CS - Input pin for current sensing.

Using the drain-source voltage
of the discharge control
MOSFET M1 (voltage between
CS and GND), it senses
discharge current during normal
mode and detects whether
charging current is present
during power down mode.

PIN 8: VCC - Power supply pin. It is to be

connected to the positive
terminal of the upper cell.

6

APPLICATION INFORMATIONS

n

AIC1802

THE OPERATION

Overcharge Protection
When the voltage of either of the battery cells
exceeds V
beyond the overcharge delay time period,
charging is inhibited by the turning-off of the
charge control MOSFET M2. The overcharge
delay time (TOC) defaults to 25mS and can be
extended by adding a capacitor CTC. Inhibition of
charging is immediately released when the
voltage of the overcharged cell becomes lower
than V

OCR

discharge.

Overdischarge Protection
When the voltage of either of the battery cells
goes below V
voltage) beyond the overdischarge delay time
period, discharging is inhibited by the turning-off
of the discharge control MOSFET M1. The
overdischarge delay time (TOD) defaults to 25mS
and can be extended by adding a capacitor CTD.
Inhibition of discharging is immediately released
when the voltage of the overdischarged cell
becomes higher than V
release voltage) through charging.

Power-Down after Overdischarge
When overdischarge occurs, the AIC1802 will go
into power-down mode, turning off all the timing
generation and detection circuitry to reduce the
quiescent current to 0.8µA (VCC=4.8V). In the
unusual case where one battery cell is
overdischarged while the other under overcharge
condition, the AIC1802 will turn off all the

(overcharge protection voltage)

OCP

(overcharge release voltage) through

(overdischarge protection

ODP

(overdischarge

ODR

detection circuits except the overcharge detection
circuit for the cell under overcharge condition.

Charge Detection after Overdischarge
When overcharge occurs, the discharge control
MOSFET M1 turns off and discharging is inhibited.
However, charging is still permitted through the
parasitic diode of M1. Once the charger is
connected to the battery pack, the AIC1802
immediately turns on all the timing generation and
detection circuitry and goes into normal mode.
Charging is determined to be in progress if the
voltage between CS and GND is below –0.4V
(charge detection threshold voltage VCH)

Overcurrent Protection
In normal mode, the AIC1802 continuously

monitors the discharge current by sensing the
voltage of CS pin. If the voltage of CS pin
exceeds V
beyond overcurrent delay time TOI period, the
overcurrent protection circuit operates and
discharging is inhibited by turning-off of the
discharge control MOSFET M1. Discharging must
be inhibited for at least 256mS after overcurrent
takes place to avoid damage to external control
MOSFETs due to rapidly switching transient
between V
overcurrent condition returns to the normal mode
when the load is released and the impedance
between the V
higher. For the sake of protection of the external
MOSFETs, the larger the CS pin voltage (which
means the larger discharge current) the shorter
the overcurrent delay time. The relationship
between voltage of CS pin and overcurrent delay

(overcurrent protection voltage)

OIP

and V

BAT+

and V

BAT+

BAT-

terminals. The

BAT-

terminals is 10MΩ or

7

time TOI is tabulated as below.

V

(V) T

CS

OI

(S)
150m 9.0m
200m 5.6m
300m 2.8m
360m 2.0m

1V

3V

540µ

290µ

C

(F) T

TC

0µ

0.1µ

0.3µ

0.47µ

0.57µ

C

(F) T

TD

(S)

OC

25m

320m

890m

1.12

1.43

(S)

OD

AIC1802

5V

270µ

Unbalanced Discharge after Overcharge
When either of the battery cells is overcharged,
the AIC1802 will automatically discharge the
overcharged cell at about 7.7mA until the voltage
of the overcharged cell is equal to the voltage of
the other cell. If the voltage of the other cell is
below V

, the internal cell-balance “bleeding”

OCR

will proceed until the voltage of the overcharged
cell decreases to V

OCR

.

DESIGN GUIDE

Adjustment of Overcharge and

Overdischarge Delay Time

Both the overcharge and overdischarge delay
times default to 25mS and can be extended by
adding the external capacitors CTC and CTD,
respectively. Increasing the capacitance value will
increase the delay time. The relationship between
capacitance of the external capacitors and delay
time is tabulated as below:

0µ

0.1µ

0.3µ

0.47µ

0.57µ

25m

320m

820m

1.08

1.39

Selection of External Control MOSFETs
Because the overcurrent protection voltage is

preset, the threshold current for overcurrent
detection is determined by the turn-on resistance
of the discharge control MOSFET M1. The turn­on resistance of the external control MOSFETs
can be determined by the equation: RON=V

OIP/IT

(IT is the overcurrent threshold current). For
example, if the overcurrent threshold current IT is
designed to be 5A, the turn-on resistance of the
external control MOSFETs must be 30mΩ. Users
should be aware that turn-on resistance of the
MOSFET changes with temperature variation due
to heat dissipation. It changes with the voltage
between gate and source as well. (Turn-on
resistance of a MOSFET increases as the voltage
between gate and source decreases). Once the
turn-on resistance of the external MOSFET

8

AIC1802

changes, the overcurrent threshold current will
change accordingly.

Suppressing the Ripple and Disturbance

from Charger

To suppress the ripple and disturbance from
charger, connecting C1 to cell 1 and C2 to cell 2 is
necessary.

Controlling the Charge Control MOSFET
R3, R4, R5 and NPN transistor Q1 are used to
switch the charge control MOSFET M2. If
overcharge does not occur, no current flows out
from OC pin and Q1 are turned off, then M2 is
turned on. When overcharge occurs, current flows
out from OC pin and Q1 is turned on, which turns
off M2 in turn. High resistance for R3, R4, and R5
is recommended for reducing loading of the
batteries.

release voltage and bleeding function. The
relationship among Vrelease1,Vrelease2, R1, and
R2 is shown as following equations:
Vrelease1=V
Vrelease2=V
where

Vrelease1 is Battery 1, real overcharge release
voltage
Vrelease2 is Battery 2, real overcharge release
voltage

Therefore, resistance of R1 and R2 should not
higher than 30Ω. Otherwise, overcharge release
voltage would be higher than overcharge
protection voltage and the charging current may
oscillate. In addition, if overcharge protection
function occurs, AIC1802 will discharge the
overcharged cell and will stop bleeding function
even if the voltage is not equal to the other. The
recommended resistance of R1 and R2 is from 20
to 30Ω.

OCR+IUD

OCR+IUD

*R1
*R2

Latch-Up Protraction at CS Pin
R6 is used for latch-up protection when charger is
connected under overdischarge condition, and
also for overstress protection when charger is
connected in reverse. The charge detection
function after overdischarge is possibly disabled
by larger value of R6. Resistance of 1KΩ is
recommended.

Selection of R1 and R 2

R1 and R2 are used to avoid large current flow
through the battery pack under the situation of IC
damage or pin short. On the other hand,
resistance of R1 and R2 will affect overcharge

Effect of C3

C3 has to be applied to the circuit. Because C3
will keep AIC1802 to be charged after
overdischarge occurred. In addition, when the
differential voltage between charger and battery
pack is higher than 2.1V and overcharge
protection function work, C3 will avoid battery
pack from being charged even if the battery
voltage lower than 4V (To avoid battery pack from
being charged under charger malfunction
situation). The battery pack can be charged again
till remove it from charger.

9

n PHYSICAL DIMENSIONS

e

A

E

L

l 8 LEAD PLASTIC SO (unit: mm)

AIC1802

D

SYMBOL MIN MAX

A 1.35 1.75

A1 0.10 0.25

H

B 0.33 0.51
C 0.19 0.25
D 4.80 5.00
E 3.80 4.00

e 1.27(TYP)

C

A1

B

H 5.80 6.20

L 0.40 1.27

10