AIC1782

Dual-Battery Charge Controller

Analog Integrations Corporation 4F, 9, Industry E. 9th Rd, Science Based Industrial Park, Hsinchu Taiwan, ROC

www.analog.com.tw

DS-1782-00

TEL: 886-3-5772500 FAX: 886-3-5772510

FEATURES

Quick and Easy Testing for Production.

Sequential Charging Control of Two
NiMH/NiCd Battery Packs.

Reliable Sequential Fast Charge Control of
Dual NiMH and/or NiCd Battery Packs, even
with a Fluctuating Charging Current.

Fast Charge Termination by:

T / t ,

-V,

0 V

, Safety Timer, Maximum Temperature,

Maximum Voltage.

Safety Timer and

T / t Detection Slope

Linearly Adjustable.

Battery Voltage Protection Range Selectable.

Mode of Battery Temperature Protection Se-
lectable.

Protection against Battery Voltage and Battery
Temperature Faults.

Selectable LED Display Mode for Battery
Status.

Five Pulsed Trickle Charge Modes.

Discharge-before-Charge Function Available to
Eliminate Memory Effect.

20-pin DIP or SO Packages.

APPLICATIONS

Dual-Battery Fast Chargers for:

Mobile Phones.

Notebook and Laptop Personal Computers.

Portable Power Tools and Toys.

Portable Communication Equipments.

Portable Video & Stereo Equipments.

1.15

1.25

1.35

1.45

1.55

100

atur

e (

C h a r g e C u r r e n t = 6 0 0 m A
C e l l C a p a c i t y = 5 5 0 m A
N i M H B a t t e r y

C e l l V o l t a g e

l
l
V

l
t
age (

)

C h a r g e T i m e ( mi n . )

T e m p e r a t u r e

Fig. 1 Battery Charging Characteristics Resulted from

an AIC1782-Controlled Charger with a Fluc-
tuating Charging Current

DESCRIPTION

The AIC1782 fast charge controller is designed
for intelligent sequential charging of dual NiMH
and NiCd batteries without the risk of malfunction.
After powered on, the AIC1782 charging se-
quence gives priority to battery pack A, repre-
sented by input signals of ATS and ABV pins,
over battery pack B, represented by BTS and
BBV pin signals. The AIC1782 automatically
switches charging current to charge the standby
battery pack after the battery pack being charged
finishes its charging or encounters a fault condi-
tion.

-V (-0.25%) detection, 0 V

(peak voltage

timer) detection, and

T / t detection are the

primary methods employed by the AIC1782 to
terminate fast charge. The fast charge can also
be cut off by maximum battery voltage and
maximum battery temperature detection along
with the safety timer to prevent charging under
fault conditions of the charging system or the
battery itself

Both

T / t and

-V detection methods have

been proved powerful in terminating fast charging
for NiMH and NiCd batteries. The AIC1782 utilizes
the combination of these two methods to achieve
reliable decision of ending fast charge and prevent
misaction caused by using

-V detection alone

under certain conditions. Fig. 1 shows an example
of charging curve of a battery charged by a fluc-
tuating current from a NiMH battery charger which
uses the AIC1782 controller IC to achieve optimal
charging. The

T / t or

-V detection circuitry

may be disabled independently for different appli-
cations, such as system-integrated chargers,
chargers with varying charge current, or battery
packs lack of temperature sensing thermistor.

AIC1782

The safety timer period, mode of battery tem-
perature protection, battery voltage protection
range, pulsed trickle charge duty, and LED dis-
play mode are all adjustable or selectable. Dis-
charge-before-charge function is included to get

rid of memory effect of NiCd batteries without the
risk of overdischarging. Test mode is provided for
charger manufactures to dramatically reduce
production test time.

TYPICAL APPLICATION CIRCUIT

R35

D468

20/5W

R32

680

LED5

1M
R36

4.7

µF

100K

C2
0.1

µF

4.7

µF

R8 100K

C4
0.1

µF

1.5K

R37
3.9K

R4
390

D8
1N4148

2.2

µF

C12

Q7
D468

VCC 5V

LED2

LED3

LED4

LED1

1N5820

1N4148

3904

1N4148

1N5821

200

µH

C9
100

µF

C6
100

µF

C11

220

µF

A1012

R28

4.7K

R27

4.7K

R20

680

R19

680

R18

680

R17

680

R14

100K

R13

R34

R25

470

R22

470

0.1/2W

R29
150

R16

R15

R11

R12

R10

R24
2.7K

R21

2.7K

R33

47K

R26

330

R23

330

R30

220

0.1

µF

0.1

µF

0.1

µF

C10

1nF

TTE

AIC1782

SEL1

MODE

ICOA

LEA2

LEA1

ATS

TMR

SEL3

ADJ

VCC

SEL2

GND

BTS

DIS

LEB1

LEB2

ICOB

BBV

DSW

ABV

(5V)

I
ST

(5V)

78L05

AIC1563

VCC

BST

GND

TTE

SW1

Battery Charger for Dual NiMH and NiCd Battery

AIC1782

ORDERING INFORMATION

PACKAGE TYPE
N: PLASTIC DIP
S: SMALL OUTLINE

TEMPERATURE RANGE
C= 0

°C~70°C

ORDER NUMBER

AIC1782 CN

PIN CONFIGURATION

AIC1782 XX

(PLASTIC DIP)

AIC1782 CS

(PLASTIC SO)

ABV

BBV

DIS

BTS

VCC

ADJ

SEL3

SEL1

SEL2

LEB1

GND

TMR

DSW

ICOB

LEB2

MODE

ICOA

LEA2

ATS

LEA1

ABSOLUTE MAXIMUM RATINGS

Supply Voltage

................................................................................................... 5.5V

DC Voltage Applied on any Pin

........................................................................... 5.5V

Sink Current of ICOA Pin, LEA1 and LEA2 Pins ............................................... 20mA

Sink Current of ICOB Pin, LEB1 and LEB2 Pins ............................................... 20mA

Operating Temperature Range

................................................................... 0

°C~ 70°C

Storage Temperature Range ................................................................

-65

°C~ 150°C

TEST CIRCUIT

ABV

DSW

BBV

ICOB

DIS

LEB2

BTS

LEB1

VCC

GND

ADJ

SEL1

SEL3

SEL2

TMR

MODE

ATS

ICOA

LEA1

LEA2

V2 (3V)

V1 (0.95V)

(5V)

GREEN

ORANGE

AIC1782

YELLOW

Voltage Source

100K

560

Voltage Source

Voltage

Source

560

GREEN

ORANGE

560

RED

560

RED

AIC1782

ELECTRICAL CHARACTERISTICS

(Ta=25

°
°
°
°C, V

=5V, unless otherwise speci-

fied.)

PARAMETER

TEST CONDITIONS

SYMBOL

MIN.

TYP.

MAX.

UNIT

Supply Voltage

4.5

5.5

Supply Current

1.1

Battery Low

ABV

Before Initial Timer

BBV

0.11

0.16

0.21

After Initial Timer

(SEL3>3V)

0.63

0.69

0.75

(SEL3<2V)

1.1

1.2

1.3

Battery High

(SEL3>3V)

2.6

2.7

2.8

Voltage Protection Limit

(SEL3<2V)

1.9

2.0

2.1

Temperature High

ATS

1.35

1.45

1.55

Temperature Sense
Limit

Temperature Low

BTS

3.5

3.6

3.7

Output impedance of DIS
Pin

DIS

140

250

LEA1, LEA2, LEB1,
LEB2, ICOA, ICOB pins

Output Impedance

ON
OFF

Source Current
Capability

SEL3 pin
DSW pin

SEL3

DSW

5.5

µA
µA

MODE, SEL1, SEL2
pins

300

Input Impedance

ABV, BBV, ATS, BTS,
ADJ pins

Recommended External
Resistor of TMR pin

100

1000

-V detection level w.r.t.*

Peak Value

-0.25

*: with respected to

AIC1782

TYPICAL PERFORMANCE CHARACTERISTICS

(Ta=25

°
°
°
°C, R2=100K

=5V, refer to Test Circuit)

4.4

4.6

4.8

5.0

5.2

5.4

1.00

1.06

1.12

1.18

Supply Current vs Supply Voltage

l
y

e
n

t

(mA

)

(V)

79.0

79.5

80.0

80.5

81.0

4.4

4.6

4.8

5.0

5.2

5.4

Safety Timer vs Supply Volatge

e
r

(
m

i
n
.
)

(V)

79.0

80.0

81.0

82.0

Safety Timer vs Temperature

a
fe

i
m

r
(

i
n

.
)

Temperature(

°C)

1.02

0.90

1.14

1.26

Supply Current vs Temperature

u
p

p
l
y
Cur

r
en

t (

)

Temperature (

°C)

2.74

2.62

2.66

2.70

ABV and BBV (High) Limit vs Temperature

(SEL3>3V)

(

)

Temperature (

°C)

2.02

2.03

1.98

2.00

ABV and BBV (High) Limit vs Temperature

(SEL3<2V)

ABV,

BBV

(
V

)

Temperature (

°C)

AIC1782

TYPICAL PERFORMANCE CHARACTERISTICS

(Continued)

ABV and BBV (Low) Limit vs Temperature

(Before Initial Timer)

ABV,

BBV (

)

0.158

0.160

0.162

0.163

Temperature (

°C)

Output Impedance vs Temperature

(LEA's, LEB's, ICO's pins)

u
t
put

pedanc

)

Temperature(

°C)

ABV and BBV (Low ) limits vs Temperature

(SEL3<2V, After Initial Timer)

ABV

,
BBV

(
V

)

Temperature (

°C)

1.20

1.21

1.22

1.19

ABV and BBV (Low) limits vs Temperature

(SEL3>3V, After Initial Timer)

V (

)

Temperature (

°C)

0.690

0.695

0.700

0.705

0.710

3.58

3.59

3.60

3.61

3.62

ATS and BTS (High) Limit vs Temperature

ATS,

(
V

)

Temperature (

°C)

1.42

1.44

1.46

1.48

ATS and BTS (Low) Limit vs Temperature

(
V

)

Temperature (

°C)

AIC1782

BLOCK DIAGRAM

LEB2 LEB1

LEA2

LEA1

ICOB

ICOA

Display
Control

Unit

TMR

Timing

Control Unit

GND VCC

Bandgap

Reference

& Voltage
Regulator

MODE

Selection

SEL3

Battery Voltage
& Temperature

Protection

Setting

SEL2

SEL1

LED Display&

Trickle Charge

Duty Setting

Charge Control

State Machine

CHARGE END

DSW

DIS

BBV

ATS

ADJ

Charge

Control Unit

T/t Detection

Setting

Battery Temperature

Protection

Battery Voltage

Protection

Discharge

Control Unit

13-bit A/D

Oscillator

BTS

ABV

PIN DESCRIPTIONS

PIN 1: ABV - Divided battery voltage input to

sense the battery voltage of
pack A.

PIN 2: BBV - Divided battery voltage input to

sense the battery voltage of
pack B.

PIN 3: DIS

- Push-pull output, used to con-

trol an external transistor to dis-
charge the battery of pack B.
DIS is active high when function
of discharge is enabled.

PIN 4: BTS - The battery cell temperature of

pack B is represented as a volt-
age input to the AIC1782 at this
pin. The acceptable voltage

range of BTS pin is 0.29 V

0.72 V

PIN 5: VCC

- Power supply input at 5V ±

10%.

6: ADJ

- For adjusting the slope of

T / t . Acceptable voltage

range for this pin is approxi-
mately 0.28V to 3.8V. If volt-
age higher than VCC - 0.3V,
function of

T / t detection is

disabled.

7: SEL3

- Determining the acceptable

voltage range of ABV and
BBV pins and mode of tem-
perature protection function.

AIC1782

8: TMR

- Determining the period of

safety timer with an external
resistor connected to GND.

PIN 9: ATS

- The battery cell temperature

of pack A is represented as a
voltage input to the AIC1782
at this pin. the acceptable
voltage range of ATS is 0.29
V

to 0.72 V

PIN 10: LEA1 &
PIN 11: LEA2

- Open-drained outputs used to

indicate the charging status of
the battery pack A.

PIN 12: ICOA - Open-drained output, used to

control the charging current of
the battery pack A.

PIN 13: MODE - Determining the mode of op-

eration for the AIC1782.

PIN 14: SEL2 &

15: SEL1

- Tri-level inputs, that jointly

control the LED display mode
and the duty of trickle charge
after the completion of fast
charge.

PIN 16: GND

- Power ground.

PIN 17: LEB1 &
PIN 18: LEB2

- Open-drained outputs used to

indicate the charging status of
battery pack B

PIN 19: ICOB

- Open-drained output, used to

control the charging current of
the battery pack B.

PIN 20: DSW

- Controlling the function of dis-

charge-before-charge of the
battery pack B. (See dis-
charge-before-charge sub-
section in application informa-
tions).

APPLICATION INFORMATIONS

THE AIC1782 OPERATION

Power-on and Battery Prequalifying

The AIC1782 is a sequential charger, initiating a
charge action on either battery pack A or B.
When power is first applied to the AIC1782, all
internal digital circuit of the AIC1782 are reset
by the internal power-on-reset circuitry, the out-
put of LED`s (depending on the setting of SEL1
and SEL2 pins) flash 3 times to indicate the ini-
tiation of power-on. If both battery pack A and B
are present when V

is applied to the AIC1782,

the charge action begins with battery pack A if
conditions are acceptable.

Condition of battery pack A is examined through
the ATS and ABV pins, while battery pack B is
examined through the BTS and BBV pins. The

acceptable limits of ABV and BBV are deter-
mined by the input voltage of SEL3 pin and the
acceptable temperature sense voltage window
for ATS and BTS are 0.29 V

to 0.72 V

CC.

The AIC1782 controls the initiation of a charge
action and checks for acceptable battery volt-
age and temperature prior to fast charging. If
the voltage of ABV or BBV fail to fall within the
predetermined acceptable limits, the corre-
sponding battery pack enters a charging-
suspending mode. If the voltage of ATS or BTS
is outside the 0.29 V

to 0.72 V

window, ac-

tion to AIC1782 is determined by the input volt-
age of SEL3 pin.

Discharge-Before-Charge

AIC1782

The AIC1782 provides the function of dis-
charge-before-charge to precondition NiCd
batteries which suffer from memory effect. This
function can only be activated for pack B after
the prequalification of battery voltage and tem-
perature, yet before the charge completion is
registered for fast charge cycle of pack B.

To trigger this function, DSW pin has to be bi-
ased to GND over 0.18 second. After discharge
begins, LEB1 and LEB2 pins are both OFF,
ICOB pin is ON, and DIS pin goes high to acti-
vate an external circuit to discharge the battery
pack B until the voltage of BBV pin fall below
0.9V (or 0.69V, depending on the input voltage
of SEL3 pin) or DSW pin is biased to GND for
over 0.18 second again. The application circuit
is included in TYPICAL APPLICATION
CIRCUIT.

Fast Charge

After the battery passes fault checks, charge
begins on either of the batteries, the other bat-
tery remains in a waiting state until the first bat-
tery terminates fast charge. The AIC1782 will
automatically switch to fast charge the second
battery. The battery pack A has the priority over
battery pack B only when power is first applied
to the AIC1782. When fast charging begins, the
initial and safety timer of the AIC1782 start
counting. Functions of -

V detection, Peak volt-

age timer,

T / t detection, and maximum

battery voltage are, however, disabled tempo-
rarily until the initial timer period in the initial
stage of a charge cycle elapses. The initial timer
period is equal to 1/80 of safety timer.

Since the low limit of acceptable ABV or BBV
voltage are only about 0.16V during the initial
timer period, even deeply discharged batteries
can easily qualify to be fast charged subse-
quently.

In the course of fast charge, the AIC1782 con-
stantly monitors the battery voltage and tem-
perature through ABV (or BBV) and ATS (or
BTS) pins. The fast charge process is regis-
tered complete when any one of the following
situations is encountered, which are explained
below:

Negative delta voltage (-

V).

Peak voltage timer (0 V

Delta temperature/ delta time (

T / t ).

Maximum charge time.
Maximum battery voltage.
Maximum battery temperature.

V Cutoff

The AIC1782 makes a voltage sampling at ABV
(or BBV) pin every 4 seconds when safety timer
period is set equal to 80 minutes. If a negative
delta voltage of 0.25% compared to its peak
value is detected at ABV (or BBV) pin, the fast
charge cycle is terminated.

V Cutoff

If the battery voltage stays at its peak value or
decreases very slowly for the duration deter-
mined by the peak voltage timer, which is in turn
equal 3.7% of safety timer, the fast charge ac-
tion is terminated.

T/t Cutoff
The

T / t detection of the AIC1782 is per-

formed by sensing the decrease of ATS (or BTS)
pin voltage in a specific timer interval dictated
by the safety timer. The fast charging termi-
nates when the decrease of ATS (or BTS) pin
voltage in 56 seconds exceeds the predeter-
mined value set by ADJ pin input. This time in-
terval of 56 seconds is based on the assump-
tion that voltage of ATS (or BTS) pin is sampled
once for every 8 seconds, which is also deter-
mined by safety timer.

AIC1782

Functioning of -

V detection and peak voltage

timer (0 V

) can be disabled if the MODE pin is

biased to GND. Functioning of

T / t detection

can be disabled if the voltage of ADJ pin is
higher than V

- 0.3V.

Maximum Safety Timer Cutoff

The maximum fast charge period is determined
by the safety timer, which is set by a resistor
connected from TMR pin to GND. Safety timer,
-

V sampling rate, and

T / t sampling rate

will be longer if the resistor value is larger.
When the value of the resistor is 100K

, the

safety timer period equals 80 minutes. This can
be verified by biasing MODE pin to V

and the

measured frequency on DSW pin should be
around 32.8 KHz. After the safety timer period is
finished, the fast charge action is terminated.

Maximum Voltage and Temperature Cutoff

The AIC1782 guards against the maximum
limits for battery voltage and temperature during
fast charging. If either of these limits is ex-
ceeded, fast charge action is terminated.

Trickle Charge

There are five different selectable duty cycles
for trickle charge after the fast charge to prevent
the loss of charge due to battery self-
discharging. The setting of SEL1 and SEL2 pins
controls the duty cycle

This function can only

be activated on the following three situation:

Battery pack A is charge full and battery

pack B is abnormal.

Battery pack B is charge full and battery

pack A is abnormal.

Battery pack A and B are both charge full.

DESIGN GUIDE

ABV/BBV Range and Temperature Protec-
tion

The acceptable battery voltage range of ABV
and BBV pins and mode of temperature protec-
tion function is determined by the voltage of
SEL3 pin, shown as the following:

(a) SEL3 > V

- 0.3V

Acceptable ABV/BBV Range:

Before initial timer: 0.16V~2.7V
After initial timer: 0.69V~2.7V

Temperature Protection Mode:

Entering charge-suspending mode when tem-
perature is either too low or too high, same as
abnormal battery voltage. Latch for charge-
suspending function is provided for high tem-
perature protection, but not for low temperature
protection.

(b) V

- 1.4V> SEL3 >

- 0.4V

Acceptable ABV/BBV Range:

Before initial timer: 0.16V~2.7V
After initial timer: 0.69V~2.7V

Temperature Protection Mode:

If temperature is too high, battery charging
is regarded as completed. If temperature is
too low, function of

T / t detection is

disabled, just as thermistor is not existing.

(c)

- 0.4V>SEL3 >1.4V

Acceptable ABV/BBV Range:

Before initial timer: 0.16V~2 V
After initial timer:1.2V~2V

Temperature Protection Mode:

Entering charge-suspending mode when
temperature is either too low or too high,
same as abnormal battery voltage. Latch
for charge-suspending function is provided
for high temperature protection, but not for
low temperature protection.

AIC1782

(d) 0.3V> SEL3

Acceptable ABV/BBV Range:

Before initial timer: 0.16V~2 V
After initial timer:1.2V~2V

Temperature Protection Mode:

If temperature is too high, battery charging
is regarded as completed. If temperature is
too low, function of

T / t detection is

disabled, just as thermistor is not existing.

Battery Voltage Measurement

The AIC1782 measures the battery voltage
through ABV and BBV pins, which is connected
to battery positive terminal through a resistor-
divider network, as shown in Fig. 2. The ac-
ceptable limit of divided battery voltage is de-
termined by the input voltage of SEL3 pin.

BAT

7
µ

100K

1
µ

AIC1782

ABV/BBV

Fig. 2 Battery Voltage Divider

For SEL3 > (VCC/2) + 0.4V, the suggested di-
vider resistances of RA and RB for the corre-
sponding number of battery cells are as below:

BATTERY

CELLS

RA/RB

RA (K

) RB (K)

2~4

240

120

3~6

3.3

300

4~8

4.9

300

5~10

6.4

300

6~12

7.8

310

8~16

10.8

390

For SEL3 < (V

/2) -0.4V, the suggested divider

resistances of RA and RB for the corresponding
number of battery cells are as below:

BATTERY

CELLS

RA/RB

RA(K

)

RB (K

)

240

120

240

300

360

390

410

Battery Temperature Measurement

The AIC1782 employs a negative temperature
coefficient (NTC) thermistor to measure the
battery

temperature. The thermistor is inher-

ently nonlinear with respect to temperature. To
reduce the effect of nonlinearity, a resistor-
divider network in parallel with the thermistor is
recommended. A typical application circuit is
shown in Fig. 3.

BAT

1
µ

VCC

GND

h
er

i
s
t
or

ATS/BTS

AIC1782

Fig. 3 Battery Temperature Sense Circuit

with a Negative Temperature Coef-
ficient (NTC) Thermistor

AIC1782

The calculation for Rx and Ry in the circuit is as
following.

0.29 Vcc

Ry / /R

Rx (Ry / / R

)

Vcc

= The resistance of thermistor at upper limit

of temperature protection.

0.72 Vcc

Ry / /R

Rx (Ry / / R )

Vcc

= The resistance of thermistor at lower limit

of temperature protection.

Substitution and rearranging the equations yield

Rx= 2.061

Ry =

5. 3

6. 3R

If temperature characteristic of the thermistor
is like that of SEMITEC 103AT-2, the resis-
tance of Rx and Ry is tabulated for different
TL and TH as below.

(note: TL is lower temperature limit and TH is
upper temperature limit.)

TABLE. 1 Values of Rx and Ry at TL = 0

°
°
°
°C

TH (

°C)

Rx(K

)

Ry (K

)

10.1

551.1

9.7

300.7

9.4

204.8

9.0

153.9

8.7

122.8

8.4

101.8

8.1

86.5

7.8

75.0

7.5

66.0

7.2

58.7

7.0

52.8

6.8

47.8

6.5

43.6

6.3

39.9

6.1

36.8

5.9

34.0

5.7

31.6

5.5

29.5

5.3

27.5

5.2

25.8

5.0

24.3

TABLE. 2 Values of Rx and Ry at TL = -10

°
°
°
°C

TH (

°C)

Rx (K

)

Ry (K

)

11.4

95.6

11.0

85.0

10.6

76.2

10.2

68.9

9.8

62.8

9.5

57.5

9.1

52.9

8.8

48.8

8.5

45.3

8.2

42.1

7.9

39.4

7.6

36.8

7.4

34.6

7.1

32.5

6.9

30.7

6.7

29.0

6.4

27.4

6.2

26.0

6.0

24.6

5.8

23.4

5.6

22.2

Setting the ADJ Pin Voltage

The slope of

T / t detection is determined by

ADJ pin voltage of the AIC1782.

The calculation of ADJ pin voltage is shown in
the following procedure followed by an example.

Procedure

(a) First, determine the temperature protection

limits TH and TL. Then, substitute TH & TL
into the following equation:

AIC1782

0.72V

0.29V

TH TL

0.43V

TH TL

BASE

(b) Determine the safety timer to obtain the

value of

BASE

(sec.) =

56(sec.)

Safety Timer

BASE

(min.)

T / t at

which temperature rises y

°C in x seconds

and fast charge is subsequently cut off.

y
x

(d) Calculate the value of V

ADJ

BASE

Example

(a) Let TH=50

°C, TL=0°C, V

=5V. We have

0. 43

0. 043 V / C

BASE

which means that V

decreases 43mV

as temperature rises 1

°C.

(b) If safety timer is equal to 80 minutes,

BASE

is then 56 seconds.

temperature rises 1

°C in 60 seconds, then

T / t =

0.0166

(d) V

ADJ

=25 x 0.043 x 0.0166 x 56 = 1(V)

If the temperature range is from 0

°C to

°C, the voltage of V

ADJ

under different

setting conditions should be set as tabulat-
ed below.

TABLE. 3 ADJ Pin Voltage (TL=0

°
°
°
°C, TH=50°°°°C)

T / t

S.T.

0.75

(

°C/min.)

1.0

(

°C/min.)

1.25

(

°C/min.)

40 min. (2C)

0.37

0.5

0.63

80 min. (1C)

0.75

1.0

1.25

120 min. (0.67C)

1.12

1.5

1.87

160 min. (0.5C)

1.5

2.0

2.5

200 min. (0.4C)

1.87

2.5

3.12

240 min. (0.33C)

2.25

3.0

3.75

A similar table for temperature range from 0

°C

to 60

°C is as below.

TABLE. 4 ADJ Pin Voltage (TL=0

°
°
°
°C,

TH=60

°
°
°
°C)

T / t

S.T.

0.75

(

°C/min.)

1.0

(

°C/min.)

1.25

(

°C/min.)

40 min. (2C)

0.31

0.42

0.52

80 min. (1C)

0.62

0.84

1.05

120 min. (0.67C)

0.94

1.25

1.56

160 min. (0.5C)

1.25

1.67

2.08

200 min. (0.4C)

1.56

2.08

2.60

240 min. (0.33C)

1.87

2.5

3.12

Setting the Period of Safety Timer
The AIC1782 provides a method for linearly
adjusting the period of safety timer with an ex-
ternal resistor connected from TMR pin to GND.
The relation between safety timer length and
the external resistor (R

TMR

) is shown in Fig. 4.

The table following shows the resistor values for
some of the commonly chosen safety timer pe-
riods. Also shown in the table is their corre-
sponding oscillator frequencies.

AIC1782

100

200

300

400

500

200

400

600

800

)

Safety Timer (min.)

Fig. 4 Safety Timer vs R

TMR

TMR

)

Osc.Freq.

(KHz)

Safety timer

(min.)

262.4

131.2

65.6

43.7

100

32.8

152

21.9

120

206

16.4

160

314

10.9

240

491

7.3

360

667

5.5

480

Selecting Mode of Operation
The AIC1782 provides three modes of opera-
tion: normal, test, and AC mode, determined by
the setting of MODE pin according to TABLE 5.
The AIC1782 will operate normally when the
MODE pin is left floating (a 0.1

µF capacitor is

recommended to be tied to MODE pin if the
charge circuit works in a noisy environment).
When the MODE pin is biased to GND, the
function of

detection is disabled. When

the MODE pin is biased to V

, the AIC1782

enters the test mode. The test mode can be
used to significantly reduce production test time.
For relevant informations please contact AIC di-
rectly.

ABLE. 5 The Operating Mode of AIC1782

MODE pin

Mode

Function

Test

Safety timer period
scaled down to 1/32....
etc.

Floating

Normal Normal operation

GND

V detection disabled

The Mode of LED Display and Trickle Charge
The AIC1782 provides two LED display modes
and five pulsed trickle charge modes. The
modes of LED display and trickle charge are
determined by the tri-level inputs, SEL1 and
SEL2 pins, as in the TABLE 6.

TABLE. 6 Mode of LED Display and Trickle
Charge

SEL1

SEL2

Trickle

Charge

Duty

LED

Display

Mode

Floating
GND

N/A

1/32
1/64

Type 1
Type 1
Type 1

Floating

Floating
GND

1/128
1/256

N/A

Type 1
Type 1
Type 2

GND

Floating
GND

1/32
1/64

1/128

Type 2
Type 2
Type 2

Displaying the Battery Charging Status

The AIC1782 provides four open-drained outputs,
in which LEA1 and LEA2 are used to indicate the
battery charging status of pack A, yet LEB1 and
LEB2 are used to indicate battery charging status
of pack B. Refer to the table of LED display mode
(TABLE 6), depending on the setting of SEL1 and
SEL2 pins, the outputs of LEA1, LEA2, LEB1, and
LEB2 pins are shown in the following table:

AIC1782

TYPE 1

Power

Wait Charge Full Abnormal

LEA1/

LEB1

1HZ

OFF

LEA2/

LEB2

OFF

TYPE 2

Power

Wait Charge Full Abnormal

LEA1/

LEB1

1HZ

OFF

4HZ

LEA2/

LEB2

1HZ

4HZ

OFF

Charging Current Control

As shown in the typical application circuit, the
AIC1782 offers two open-drained output pins,
ICOA and ICOB pins, to control the charging cur-
rent of battery pack A and pack B. When fast
charge is completed, the AIC1782 enters the
trickle charge mode. In trickle charge mode, the
ICOA or ICOB pins output switch with predeter-
mined duty cycle. Refer to the table of trickle
charge mode (TABLE 6), the duty cycle is deter-
mined by the setting of SEL1 and SEL2 pins. The
following table summarizes how ICOA and ICOB
pins correspond to various charging states.

Power

Wait

Fast

Charging

Charge

Completed

Fault

Conditions

ICOA/

ICOB

OFF

See pin 14

& 15

Test Mode

Fig. 5 shows the timing diagram for externally
controlled ADJ, ABV, BBV, ATS, BTS, SEL1 and
SEL2 pin voltages of a recommended AIC1782
test scheme, utilizing TEST mode function. Out-
put waveforms of LEA1, LEA2, LEB1, LEB2,
ICOA and ICOB of a properly functioning
AIC1782 are also shown in the figure. For de-
tailed information please consult with AIC staffs
directly.

AIC1782

TIMING DIAGRAM

SAFETY TIMER TEST

T/t TEST

PEAK TIMER TEST

Power

Init.

GND
GND

GND

Floating

VCC

Floating

Floating
Floating

(-0.15%)

(-2.5%)

OFF

2mV
Step/100mS

1.993V
(-0.35%)

1.96V

1.9V

1.997V

1.5V

(-2.15%)

1.85V

1.12V

OFF

3.2KHz

OFF

VCC, SEL3, MODE=5V, (DSW FREQ.=820KHz, 25 TIMES of 32.8K)

V DISALBE TEST

V TEST

1.32

0.4

0.12

0.74

0.12

0.02

0.32

0.97

0.32

0.26

0.24

0.1

0.5

0.12

5.89

5.99

6.01

4.57

4.17

3.93

3.43

2.46

2.14

1.26

2.02

1.17

1.38

0.26

0.14

Floating

GND

Floating
Floating

OFF

<2.1V

0.4

Delay 0.3

0.74

0.12

0.26

0.24

0.5

8.91

8.51

8.27

7.77

7.47

7.21

(A):ICOA
(B):ICOB

(A):ABV
(B):BBV

ADJ

(A):LEA2
(B):LEB2

(A):LEA1
(B):LEB1

(A):ATS
(B):BTS

TIME (A)

(SEC.)

STAGE

SEL1
SEL2

TIME (B)

(SEC.)

STAGE

6.11

6.37

6.25

0.14

0.1

6.01

0.1

Fig. 5 Timing Diagram of AIC1782 in Test Mode

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