AIC1804-BCSTB - Analog Integrations Corporation

AIC1804

Three- Cell Or Four-Cell Lithium-Ion Battery

Protection IC

Analog Integrations Corporation 4F, 9 Industry E. 9th Rd, Science-Based Industrial Park, Hsinchu, Taiwan DS-1652-03 012102

TEL: 886-3-5772500 FAX: 886-3-5772510 www.analog.com.tw 1

n FEATURES

l Cell Number Selection Function to Select 3 or 4

cells Protection.

l Ultra-Low Quiescent Current at 17

A (4-Cell,

VCELL=3.5V).

l Ultra-Low Power-Down Current at 2.2

A (4-Cell,

VCELL=2.3V)

l Wide Supply Voltage Range: 2V to 18V.

l Precision Overcharge Protection Voltage:

4.35V± 30mV for the AIC1804A

4.30V± 30mV for the AIC1804B

4.25V± 30mV for the AIC1804C

4.20V± 30mV for the AIC1804D

l Externally Set Overcharge, Overdischarge and

Overcurrent Delay Time.

l Built-in Cell-balancing Bleeding Network under

Overcharge Condition.

l Three Detection Levels for Overcurrent Protection.

n APPLICATIONS

l Protection IC for Three- or Four-Cell Lithium-Ion

Battery Packs.

n DESCRIPTION

The AIC1804 is designed to protect the lithium-

ion battery from damage or degrading the lifetime

due to overcharging, overdischarging and

overcurrent for three-cell or four-cell lithium-ion

battery powered systems such as notebook PCs .

It can also provide the cell-balancing “bleeding”

function to automatically discharge the

overcharged cell until the overcharge condition is

released.

Safe and full utilization charging is ensured by

the accurate ±30mV overcharge detection. Four

different specification values for overcharge

protection voltage are provided for various

protection requirements. The very low standby

current drains little current from the cell while in

storage.

n TYPICAL APPLICATION CIRCUIT

0.1

BATT-

AIC1804

GND

UD4

UD3

VC3

BAT4

200

UD2

VC2

BAT3

UD1

VCC

BAT1

VC1

BAT2

NSL

BATT+

FUSE

SI4435

2N3906

82nF

2.2nF

Protection Circuit for Four-Cell Lithium-Ion Battery Pack

AIC1804

n ORDERING INFORMATION

AIC1804-XCXXX PIN CONFIGURATION

TOP VIEW

NSL

VCC

UD1

VC2

VC1

UD2

UD3

VC3

UD4

GND

PACKING TYPE

TR: TAPE & REEL

TB: TUBE

PACKAGE TYPE

S: SMALL OUTLINE

OVERCHARGE

PROTECTION VOLTAGE

A: 4.35V

B: 4.30V

C: 4.25V

D: 4.20V

Example: AIC1804-ACSTR

à 4.35V version, in SO-16 Package &

Tape & Reel Packing Type

n ABSOLUTE MAXIMUM RATINGS

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

DC Voltage Applied on other Pins .........…………………..…....................................... 18V

Operating Temperature Range............................………………......................... -20°C~70°C

Storage Temperature Range .............................……..………..................... - 65°C ~125°C

n TEST CIRCUIT

AIC180

VCC

NSL

UD4

GND

ICC

UD1

200

0.1

VCC

IC1

UD2

0.1

VC1

IC2

UD3

0.1

VC2

IC3

UD4

0.1

VC3

CTD

1nF

CTC

1nF

CTI

2.2nF

AIC1804

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

PARAMETER TEST CONDITIONS SYMBOL MIN. TYP. MAX. UNIT

VCC Pin Input Current in Normal

Mode VCELL=3.5V ICC 17 26 µA

VC1 Pin Input Current in Normal

Mode VCELL=3.5V IC1 0.7 1.8 µA

VC2 Pin Input Current in Normal

Mode VCELL=3.5V IC2 0.4 1.0 µA

VC3 Pin Input Current in Normal

Mode VCELL=3.5V IC3 0.2 0.5 µA

Vcc Pin Input Current in Power-

Down Mode VCELL=2.3V ICC(PD) 2.2 4.0 µA

VC1,VC2,VC3 Input Current in

Power-Down Mode VCELL=2.3V IC(PD) 0.01 0.15 µA

AIC1804A 4.32 4.35 4.38

AIC1804B 4.27 4.30 4.33

AIC1804C 4.22 4.25 4.28

Overcharge Protection Voltage

AIC1804D

VOCP

4.17 4.20 4.23

Overcharge Hysteresis Voltage VHYS 150 200 250 mV

Overdischarge Protection Voltage VODP 2.27 2.40 2.53 V

Overdischarge Release Voltage VODR 2.85 3.00 3.15 V

Overcurrent Protection Voltage VCELL=3.5V VOIP 135 150 165 mV

Overcharge Delay Time

VCELL1=VOCP - 30mV

→VOCP+30mV

VCELL2= VCELL3= VCELL4=

3.5V, CTC=1nF

TOC 10 21 32 mS

Overdischarge Delay Time VCELL1= 2.5V→ 2.3V

VCELL2= VCELL3= VCELL4=

3.5V, CTD=1nF TOD 10 21 32 mS

Overcurrent Delay Time (1) VCELL= 3.5V,0.15V<VCC -

VCS <0.3V,CTI=2.2nF TOI1 7 15 23 mS

AIC1804

n ELECTRICAL CHARACTERISTICS (Continued)

PARAMETER TEST CONDITIONS SYMBOL MIN. TYP. MAX. UNIT

Overcurrent Delay Time (2) VCELL=3.5V,

0.3V<VCC-VCS<1.0V TOI2 2 4 6 mS

Overcurrent Delay Time (3) VCELL=3.5V, VCC– VCS>1.0V TOI3 150 300 450 µS

OC Pin Sink Current VCELL1=4.4V,

VCELL2= VCELL3= VCELL4=3.5V,

OC Pin Short to VCC

IOC 2.2 3.2 4.2 mA

OD Pin Output “H” Voltage VDH VCC-0.15V VCC-0.03V V

OD Pin Output “L” Voltage VDL 0.01 0.15 V

Charge Detection Threshold

Voltage VCELL=2.3V VCH VCC+0.4 VCC+0.55 V

UD1 Pin Cell-Balancing

Bleeding Current VCELL1=4.4V,

VCELL2= VCELL3= VCELL4=3.5V IUD1 6.5 9.3 12.1 mA

UD2 Pin Cell-Balancing

Bleeding Current VCELL2=4.4V,

VCELL1= VCELL3= VCELL4=3.5V IUD2 6.3 9.0 11.7 mA

UD3 Pin Cell-Balancing

Bleeding Current VCELL3=4.4V,

VCELL1= VCELL2= VCELL4=3.5V IUD3 6.2 8.8 11.4 mA

UD4 Pin Cell-Balancing

Bleeding Current VCELL4=4.4V,

VCELL1= VCELL2= VCELL3=3.5V IUD4 6.4 9.2 12.0 mA

Note: VCELL means the battery cell voltage. Therefore,

VCELL1 = VCC – VC1

VCELL2 = VC1 – VC2

VCELL3 = VC2 – VC3

VCELL4 = VC3

AIC1804

n TYPICAL PERFORMANCE CHARACTERISTICS

10.4 11.2 12.0 12.8 13.6 14.4 15.2 16.0

Fig. 1 Vcc Pin Input Current vs. Supply Voltage

Vcc Pin Input Current (

µA)

Supply Voltage (V)

TA=25°C

6.0 6.4 6.8 7.2 7.6 8.0 8.4 8.8 9.2

1.0

1.2

1.4

1.6

1.8

2.0

2.2

TA=25°C

Fig. 2 Vcc Pin Power-Down Current vs. Supply Voltage

Vcc Pin Power-Down Current (

Supply Voltage (V)

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

Fig. 3 Vcc Pin Input Current vs. Temperature

CELL

=3.5V

Vcc Pin Input Current (

Temperature (

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

1.6

1.8

2.0

2.2

2.4

2.6

2.8

3.0

VCELL=2.3V

Fig. 4 Vcc Pin Power-Down Current vs. Temperature

Vcc Pin Power-Down Current (uA)

Temperature (°C)

4.20

4.22

4.24

4.26

4.28

4.30

Fig. 5 Overcharge Protection Voltage vs. Temperature

Overcharge Protection Voltage (V)

-20 0 20 40 60 70

AIC1804C

Temperature (

2.36

2.37

2.38

2.39

2.40

2.41

2.42

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

Fig. 6 Overdischarge Protection Voltage vs. Temperature

Overdischarge Protection Voltage (V)

Temperature (

)

AIC1804

n TYPICAL PERFORMANCE CHARACTERISTICS (Continued)

148.0

148.5

149.0

149.5

150.0

150.5

151.0

151.5

152.0

Fig. 7 Overcurrent Protection Voltage vs. Temperature

Overcurrent Protection Voltage (V)

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

Temperature(

VCELL=3.5V

Fig. 8 Overcharge/Overdischarge Delay Time vs.

Temperature

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

CTC /CTD=1nF

Overcharge/Overdischarge Delay Time (mS)

Temperature(°C)

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

VCELL =3.5V

Fig. 9 Overcurrent Delay Time 1 vs. Temperature

Overcurrent Delay Time 1 (mS)

Temperature (

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

4.02

4.03

4.04

4.05

4.06

4.07

4.08

Fig. 10 Overcharge Release Voltage vs. Temperature

Overcharge Release Voltage (V)

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

2.97

2.98

2.99

3.00

3.01

Fig.

Overdischarge Release Voltage vs. Temperature

Overdischarge Release Voltage (V)

Temperature (

AIC1804

n BLOCK DIAGRAM

Battery

Voltage

Sense

Circuit

450

400

350

300

VC2

VC1

VCC

UD4

UD3

UD2

VC3

UD1

GND

Wake-Up Control

VCC-1V

VCC-0.3V

VCC-0.15V

VCC+0.4V

Power-Down

Control

1.2V

Overcharge Delay

Circuit

Overcurrent Delay

Circuit

TITD

Overdischarge Delay

Circuit

n PIN DESCRIPTIONS

PIN 1: NSL- Input pin for cell number

selection. Connect this pin to

VCC for three-cell application

and to GND for four-cell

application.

PIN 2: OC- NMOS open drain output for

control of the charge control

MOSFET M2. When overcharge

occurs, this pin sinks current to

switch the external PNP Q1 on,

and charging is inhibited by

turning off the charge control

MOSFET M2.

PIN 3: CS- Input pin for current sensing.

Using the drain-source voltage of

the discharge control MOSFET

M1 (voltage between VCC and

CS), it senses discharge

current during normal mode

and detects whether charging

current is present during

power-down mode.

PIN 4: OD - Output pin for control

of discharge control MOSFET M1. When overdischarge occurs, this

PIN 5: TD -Overdischarge delay time setting

pin.

PIN 6: TI - Overcurrent delay time setting

pin.

PIN 7: TC - Overcharge delay time setting

pin.

PIN 8: GND - Ground pin. This pin is to be

connected to the negative

terminal of the battery cell BAT4.

PIN 9: UD4- This pin is to be connected to the

positive terminal of the battery

cell BAT4 for cell-balancing

bleeding function under

overcharge condition.

PIN10: VC3- Input pin for battery BAT4

voltage sensing. This pin is to be

connected to the positive

terminal of the battery cell BAT4.

AIC1804

PIN11: UD3 - This pin is to be connected to

the positive terminal of the

battery cell BAT3 for cell-

balancing bleeding function

under overcharge condition.

PIN12: VC2 - Input pin for battery BAT3

voltage sensing. This pin is to be

connected to the positive

terminal of the battery cell BAT3.

PIN13: UD2 - This pin is to be connected to the

positive terminal of the battery

cell BAT2 for cell-balancing

bleeding function under

overcharge condition.

PIN14: VC1 - Input pin for battery BAT2

voltage sensing. This pin is to be

connected to the positive

terminal of the battery cell BAT2.

PIN15: UD1 -

This pin is to be connected to the positive terminal of the battery BAT1 for cell-balancin

PIN16: VCC - Power supply pin and input for

battery BAT1 voltage sensing.

This pin is to be connected to the

positive terminal of the battery

cell BAT1.

n APPLICATION INFORMATIONS

THE OPERATION

Initialization

On initial power-up, such as connecting the

battery pack for the first time to the AIC1804, the

AIC1804 enters the power-down mode. A

charger must be applied to the AIC1804 circuit

to enable the pack.

Overcharge Protection

When the voltage of either of the battery cells

exceeds the overcharge protection voltage

(VOCP) beyond the overcharge delay time (TOC)

period, charging is inhibited by the turning-off of

the charge control MOSFET M2. The

overcharge delay time is set by the external

capacitor C

TC. Inhibition of charging is

immediately released when the voltage of the

overcharged cell becomes lower than

overcharge release voltage (VOCR or VOCP-VHYS)

through discharging.

Overdischarge Protection

When the voltage of either of the battery cells

falls below the overdischarge protection voltage

(VODP) beyond the overdischarge delay time

(TOD) period, discharging is inhibited by the

turning-off of the discharge control MOSFET M1.

The overdischarge delay time is set by the

external capacitor C

TD. Inhibition of discharging

is immediately released when the voltage of the

overdischarge cell becomes higher than the

overdischarge release voltage (VODR) through

charging.

Overcurrent Protection

In normal mode, the AIC1804 continuously

monitors the discharge current by sensing the

voltage of CS pin. If the voltage V

CC-VCS

exceeds the overcurrent protection voltage (VOIP)

beyond the overcurrent delay time (TOI) period,

the overcurrent protection circuit operates and

discharging is inhibited by the 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 BATT+ and BATT-

terminals. The overcurrent condition returns to

normal mode when the load is released and the

impedance between the BATT+ and BATT-

terminals is 20MΩ or higher.

The AIC1804 is provided with the three

overcurrent detection levels (0.15V, 0.3V and

1.0V) and the three overcurrent delay time (TOI1,

TOI2 and TOI3) corresponding to each overcurrent

detection level. T

OI1 is set by the external

capacitor CTI. TOI2 and T

OI3 default to 4mS and

AIC1804

300µs respectively, and can not be adjusted due

to protection of external MOSFETs

Cell-Balancing Bleeding after

Overcharge

When either of the battery cells is overcharged,

the AIC1804 provides the cell-balancing

bleeding function to discharge the overcharged

cell at about 9mA until the voltage of the

overcharged cell decreases to overcharge

release voltage (VOCR or V

OCP-VHYS).

Connecting UD1, UD2, UD3 and UD4 pins to the

positive terminals of battery cells BAT1, BAT2,

BAT3 and BAT4 accomplish this function,

respectively. Inserting resistors along UD 2 pin to

BAT2 positive terminal path and UD4 pin to

BAT4 positive terminal path can decrease the

bleeding current.

Power-Down after Overdischarge

When overdischarge occurs, the AIC1804 will go

into power-down mode, turning off all the timing

generation and detection circuitry to reduce the

quiescent current to about 2.2µA (VCC=9.2V). In

the unusual case where one battery cell is

overdischarged while another one under

overcharge condition, the AIC1804 will turn off

all the detection circuitry except the overcharge

detection circuit for the cell under overcharge

condition.

Charge Detection after

Overdischarge

When overdischarge 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

AIC1804 immediately turns on all the timing

generation and detection circuitry and goes into

normal mode. Charging is determined to be in

progress if the CS pin voltage is higher than

VCC + 0.4V (charge detection threshold voltage

VCH).

DESIGN GUIDE

Cell Number Selection

The user must configure the AIC1804 for three

or four series cells application. For three-cell

application, NSL pin should be connected

directly to VCC pin. For four-cell application,

NSL pin should be connected directly to GND

pin.

No. of Series Cells NSL Pin

3-cell Connected to VCC

4-cell Connected to GND

The protection circuit for three-cell lithium-ion

battery pack is shown in application examples

Fig. 1.

Setting the Overcharge and

Overdischarge Delay Time

The overcharge delay time is set by the external

capacitor CTC and the overdischarge delay time

is set by the external capacitor C

TD. The

relationship between capacitance of the external

capacitors and delay time is tabulated as below.

CTC ‚C TD(nF) TOC ‚T OD(mS)

1 21

5 52

10 132

22 253

33 347

47 617

68 748

82 1004

100 1630

The delay time can also be approximately

calculated by the following equations (if CTC, CTD

≤ 82nF) :

TOC (mS) = 11.8 x CTC(nF)

TOD (mS) = 11.8 x CTD(nF)

AIC1804

Setting the Overcurrent Delay Time 1

The overcurrent delay time 1 (TOI1) at 0.15V <

VCC-VCS < 0.3V is set by the external capacitor

CTI, while the overcurrent delay time 2 and 3

(TOI2 and T

OI3) is fixed by IC internal circuit.The

relationship between capacitance of the external

capacitor and delay time is tabulated as below.

CTI (nF) TOI (mS)

1 4.8

2.2 15.0

3.3 18.8

5 23.6

6.8 31.0

10 61.8

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 turn-on resistance of the external control

MOSFETs can be determined by the equation:

RON=VOIP/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 changes,

the overcurrent threshold current will change

accordingly.

Suppressing the Ripple and

Disturbance from Charger

To suppress the ripple and disturbance from

charger, connecting R1 to R4 and C1 to C4 is

recommended. Larger R1 will cause larger error

of battery sense voltage.

Controlling the Charge Control

MOSFET

R5, R6, R7 and NPN transistor Q1 are used to

switch the charge control MOSFET M2. If

overcharge does not occur, no current flows into

OC pin and Q1 is turned off, then M2 is turned

on. When overcharge occurs, current flows into

OC pin and Q1 is turned on, which turns off M2

in turn.

Protection at CS Pin

R8 is used for protection of IC when charger is

connected in reverse. The charge detection

function after overdischarge is possibly disabled

by larger value of R8. Resistance of 1KΩ is

recommended.

AIC1804

n APPLICATION EXAMPLES

0.1

BAT1

BAT2

BAT3

0.1µ

0.1µF

0.1

BATT-

82nF

CTI

2.2nF

82nF

AIC1804

GND

UD4

UD3

VC3

UD2

VC2

UD1

VCC

VC1

NSL

BATT+

FUSE

SI4435

2N3906

Fig. 12 Protection Circuit for Three-Cell Lithium-Ion Battery Pack

n TIMING DIAGRAM

l Overcharge and Overdischarge Protection (V CS=VCC)

BAT4

BAT1

BAT2

BAT3

CELL

TOC

Hi-ZHi-Z

VOC

VOD CC

OCP

ODP

VODR

HYS

OCP

V-

AIC1804

l Overcurrent Protection (VCELL=3.5V)

VCC

- 1V

- 0.3V

- 0.15V

OI1

VCC

<256ms

256ms

Hi-Z

<TOI1OI3

<TOI2

>256ms

n PHYSICAL DIMENSIONS

l 16 LEAD PLASTIC SO (150 mil) (unit: mm)

SYMBOL MIN MAX

A1.35 1.75

A1 0.10 0.25

B0.33 0.51

C0.19 0.25

D9.80 10.00

E3.80 4.00

e1.27 (TYP)

H5.80 6.20

L0.40 1.27