AIC AIC1781ACSTR Battery charge controller Datasheet

AIC1781A
Battery Charge Controller
n FEATURES
n DESCRIPTION
Fast Charge Control of NiMH/NiCd Batteries,
even with a Fluctuating Charging Current.
Fast Charge Termination by: ∆T / ∆t , −∆V ,
0 ∆V , Safety Timer, Maximum Temperature,
Maximum Voltage.
Linearly Adjustable ∆T / ∆t Detection Slope and
Safety Timer.
Adjustable Peak Voltage Timer for 0 ∆V .
Battery Voltage Protection Range Selectable.
Selectable Battery Temperature Protection
Mode.
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 for
Eliminating Memory Effect.
Quick and Easy Testing for Production.
16-pin DIP or SO Packages.
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n APPLICATIONS
Battery Fast Chargers for:
Mobile Phones.
l Notebook and Laptop Personal Computers.
l Portable Power Tools and Toys.
l Portable Communication Equipments.
l Portable Video & Stereo Equipments.
(-0.25%), 0 ∆V detection (peak
voltage timer) and ∆T / ∆t detection are the
Detection
primary methods employed by the AIC1781A 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 AIC1781A
utilizes the combination of these two methods to
achieve reliable decision of ending fast charge and
prevent misacting caused by using −∆V detection
example of charging curve of a battery charged by
a fluctuating current from a NiMH battery charger,
which uses the AIC1781A controller IC to achieve
optimal charging. This technique, in cooperating
with the 0 ∆V detection (peak voltage timer), is
particularly suitable for NiMH batteries, whose
100
1.55
voltage drop is hardly significant yet temperature
rises rapidly. The ∆T / ∆t or −∆V detection
80
1.45
Cell Voltage
60
1.35
40
1.25
Temperature (°C)
Charge Current = 600 mA
Cell Capacity = 550 mA
NiMH Battery
Cell Voltage (V)
designed for intelligent charging of NiMH or NiCd
batteries without the risk of overcharge. −∆V
alone under certain conditions. Fig. 1 shows an
l
circuitry
may
be
disabled
independently
for
different applications, such as system-integrated
chargers, chargers with varying charge current, or
battery
packs
lack
of
temperature
sensing
thermistor.
Temperature
1.15
The AIC1781A fast charge controller IC is
20
0
10
20
30
40
50
60
The
Charge Time (min.)
safety
timer
period,
mode
of
battery
temperature protection, battery voltage protection
Fig. 1
Battery Charging Characteristics Resulting from
an
AIC1781A-Controlled
Charger
with
Fluctuating Charging Current
Analog Integrations Corporation
range, pulsed trickle charge duty, and LED display
a
mode
are
all
adjustable
4F, 9 Industry E. 9th Rd, Science-Based Industrial Park, Hsinchu, Taiwan
TEL: 886-3-5772500
FAX: 886-3-5772510
www.analog.com.tw
or
selectable.
DS-1781AP-01
011604
1
AIC1781A
Discharge-before-charge function is included to
production test time.
get rid of memory effect of NiCd batteries without
the risk of overdischarging. Test mode is provided
for charger manufactures to dramatically reduce
n TYPICAL APPLICATION CIRCUIT
D1
R2
1K
D2
L1
IN4148
C4
220µF
3
C1
4
BOOST
DE
IS
CF
+
5
FB
470P
MPS2222A
680
4
VTS
6
C3
RX
R7
RY
R14
200K
+
C6
0.1µF
C11
100µF
C8
0.1µF
7
R6
8
50K
R11
DSW
ICON
LED2
DIS
VCC
220µF
AIC1563
47nF
91K
Q1
3
BAT1
VCC
GND
C10
VBT
R15
5
RS 0.3/1W
6
2
C7
0.1µF
4.7µF
1N5819
IN4148
7
C9
R9
D4
D3
8
DC
PEAK
+
THERMISTOR
2
1
LED1
GND
ADJ
SEL1
SEL3
SEL2
TMR
MODE
LED2
LED3
R12
100K
U2
YELLOW
0.1µF
**BATTERY
1
PB SW
R10
100K
R8
300K
C5
U1
R4
20/5W
IN5819
+
1µF
R5 120/0.5W
390K
270
LED1
220µH
C2
SW1
R3
R1
GREEN
RED
R16
R17
680
680
16
15
14
13
12
11
10
9
AIC1781A
100K
U3
VIN
11~15V
VIN
+
C12
R13
470K
78L05
VOUT
Q2
MMBT2222A
+
GND
1µF
C13
10µF
**3~5 NiMH/NiCd cells.
Note: Charge Current=0.3/RS Ampere
Safety Timer: 80min
Battery Charge Circuit for Fluctuating Charging Current Application
2
AIC1781A
n ORDERING INFORMATION
AIC1781AXXXX
PIN CONFIGURATION
PACKING TYPE
TR: TAPE & REEL
TB: TUBE
TOP VIEW
PACKAGE TYPE
N: PLASTIC DIP
S: SMALL OUTLINE
C: COMMERCIAL
P: LEAD FREE COMMERCIAL
(Available for PS only)
Example: AIC1781CSTR
à in SO-16 Package & Tape & Reel Packing Type
(CN is not available in TR packing type)
PEAK
1
16
DSW
VBT
2
15
ICON
DIS
3
14
LED2
VTS
4
13
LED1
VCC
5
12
GND
ADJ
6
11
SEL1
SEL3
7
10
SEL2
TMR
8
9
MODE
AIC1781PSTR
à in SO-16 Lead Free Package & Tape & Reel
Packing Type
n ABSOLUTE MAXIMUM RATINGS
Supply Voltage
............................................… … … … ........................................ 5.5V
DC Voltage Applied on any pin ......................… … … … … ...................................... 5.5V
Sink current of ICON pin, LED1 and LED2 pin .......................… … … .................. 20mA
Operating Temperature Range .....................................… … … … … .............. 0°C~ 70°C
Storage Temperature Range .............................................… … … … ......
-65°C~ 150°C
n TEST CIRCUIT
VCC
VOLTAGE
SOURCE
-
PEAK
DSW
VBT
ICON
DIS
LED2
R3
+
YELLOW
R1
+
560
R4
GREEN
560
560
-
ORANGE
VTS
LED1
VCC
RED
560
AIC1781A
VOLTAGE SOURCE
R5
GND
VCC
VCC (5V)
VCC
V1 (0.95V)
V2 (3V)
100K
ADJ
SEL1
VCC
SEL3
SEL2
VCC
TMR
MODE
VCC
R2
3
AIC1781A
n ELECTRICAL CHARACTERISTICS (TA=25°C, VCC=5V, unless otherwise specified.)
SYMBOL
MIN.
TYP.
MAX.
UNIT
Supply Voltage
VCC
4.5
5.0
5.5
V
Supply Current
ICC
PARAMETER
TEST CONDITIONS
Battery Low
During Initial Timer
After Initial Timer
(SEL3>3V)
(SEL3<2V)
Battery High
(SEL3>3V)
(SEL3<2V)
Voltage Protection Limit
VBT
Temperature High
Temperature Sense Limit
Temperature Low
Output impedance of DIS Pin
VTS
1.1
mA
0.11
0.16
0.21
0.63
1.1
0.69
1.2
0.75
1.30
2.6
2.7
2.80
1.9
2.0
2.10
1.35
1.45
1.55
3.5
3.6
3.70
50
100
Ω
25
50
Ω
V
V
ZDIS
LED1, LED2, ICON pins
Output Impedance
ON
OFF
1
SEL3 pin
ISEL3
5.5
DSW pin
IDSW
90
Source Current Capability
MODE, PEAK, SEL1,
SEL2 pins
Input Impedance
MΩ
µA
300
VBT, VTS, ADJ pins
KΩ
1
MΩ
Recommended External
RTMR
Resistor of TMR pin
-∆V Detection
Peak Value
Level
w.r.t.*
2
100
-0.25
1000
KΩ
%
* w.r.t.: with respect to
4
AIC1781A
n TYPICAL PERFORMANCE CHARACTERISTICS
(TA=25°C, R2=100KΩ, VCC=5V,
refer to Test Circuit)
81.5
81.0
Safety Timer (min)
Supply Current (mA)
1.08
1.02
0.96
0.90
80.5
80.0
79.5
79.0
78.5
0.84
4.4
4.6
4.8
5.0
5.2
78.0
4.4
5.4
4.6
4.8
VCC (V)
Fig. 2 Supply Current vs. Supply Voltage
5.4
5.6
1.05
Supply Current (mA)
Frequency (Hz)
5.2
Fig. 3 Safety Timer vs. Supply Voltage
4.4
4.2
4.0
3.8
3.6
4.4
4.6
4.8
5.0
5.2
5.4
1.00
0.95
0.90
0.85
0.80
0
5.6
20
40
60
80
Temperature (°C)
VCC (V)
Fig. 4 LED Flashing Frequency vs.
Supply Voltage
Fig.5 Supply Current vs. Temperature
82
5.0
81
4.8
Frequency (Hz)
Safety Timer (min)
5.0
VCC (V)
80
79
78
77
76
4.6
4.4
4.2
4.0
3.8
3.6
75
0
20
40
60
Temperature (°C)
Fig. 6 Safety Timer vs. Temperature
80
3.4
-20
0
20
40
60
80
Temperature (°C)
Fig. 7 LED Flashing Frequency vs. Temperature
5
AIC1781A
n TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
2.80
2.28
2.76
VBT (V)
VBT (V)
2.16
2.72
2.68
2.04
2.64
1.92
2.60
0
Fig. 8
20
40
60
80
0
Temperature (°C)
VBT (High) Limit vs. Temperature
(SEL3>3V)
Fig. 9
0.20
Output Impedance (O)
VBT (V)
0.16
0.14
60
80
30
27
24
0.12
0
Fig.10
20
40
60
21
80
Temperature (°C)
VBT (Low) Limit vs. Temperature
(During Initial Timer)
0
20
40
60
80
Temperature (°C)
Fig.11 Output Impedance vs. Temperature
(LED1, LED2, ICON Pins)
4.0
1.55
3.8
1.50
VTS (V)
VBT (V)
40
Temperature (°C)
VBT (High) Limit vs. Temperature
(SEL3<2V)
33
0.18
3.6
1.45
3.4
3.2
20
1.40
0
20
40
60
Fig.12
Temperature (°C)
VTS (Low Temp) Limit vs.
Temperature
80
1.35
0
20
40
60
80
Temperature (°C)
Fig.13 VTS (High Temp) Limit vs.
Temperature
6
AIC1781A
1.5
0.84
1.4
VBT (V)
VBT (V)
0.80
0.76
0.72
0.68
1.3
1.2
1.1
0.64
0
20
40
60
1.0
80
0
Temperature (°C)
Fig. 14 VBT (Low) Limit vs. Temperature
(SEL3>3V, After Initial Timer)
20
40
60
80
Fig.15
Temperature (°C)
VBT (Low) Limit vs. Temperature
(SEL3<2V, After Initial Timer)
VCC
TMR
n BLOCK DIAGRAM
PEAK
Peak Voltage
Timer Control
SEL3
MODE
MODE
Selection
GND
Bandgap
Reference &
Voltage
Regulator
Battery Voltage &
Temperature
Portection Setting
SEL2
LED‘s Display
& Trickle Pulse
Duty Setting
ADJ
∆T/∆t Detection
Setting
Battery Temp.
Protection
VTS
Oscillator
LED1
Charge Control
SEL1
LED2
Display
Control
Unit
ICON
State Machine
Charge
Control Unit
DIS
13-bit
A/D
Battery
Voltage
Protection
Discharge
Control Unit
DSW
VBT
7
AIC1781A
n PIN DESCRIPTIONS
PIN 1: PEAK- Tri-level input, determining the
PIN 8: TMR-
period of peak voltage timer.
timer with an external resistor
(See 0∆V cut-off section in
application informations.)
PIN 2: VBT-
connected to GND.
PIN 9: MODE- Determine
Push-pull
output,
used
PIN 10: SEL2 - Tri-level
AIC1781A
when
enters
discharge
PIN 4: VTS-
inputs,
that
jointly
after the completion of fast
charge.
the
mode.
of
and the duty of trickle charge
discharge the battery. DIS is
high
mode
control the LED display mode
to
control an external transistor to
active
the
operation for the AIC1781A.
Divided battery voltage input to
sense the battery voltage.
PIN 3: DIS-
Determine the period of safety
PIN 11: SEL1- The same as Pin 10.
PIN 12: GND-
Power ground.
The battery cell temperature is
represented as a voltage input
PIN 13: LED1 &
to the AIC1781A at this pin.
PIN 14: LED2- Open-drained outputs used to
The acceptable voltage range
indicate the battery charging
of VTS pin is 0.29VCC to
status. Two modes of display
0.72VCC.
battery
are available, depending on
temperature is regarded as too
the setting of SEL1 and SEL2
high if the voltage of VTS pin is
pins.
The
lower than 0.29VCC, and is
otherwise regarded as too low
if the voltage of VTS pin is
higher than 0.72VCC.
PIN 15: ICON- Open-drained output, used to
control the charging current to
the battery.
PIN 16: DSW- Controlling
the
function
of
PIN 5: VCC-
Power supply input at 5V±10%.
PIN 6: ADJ-
For adjusting the slope of ∆T/∆t.
(See discharge- before- charge
Acceptable voltage range for
subsection
this pin is approximately 0.28V
informations).
discharge-
beforein
charge.
application
to 3.8V. If voltage higher than
VCC-0.3V,
the
function
of
∆T/∆t detection is disabled.
PIN 7: SEL3-
Determine
the
acceptable
voltage range of VBT pin and
mode
of
temperature
protection function.
8
AIC1781A
n APPLICATION INFORMATIONS
discharge is finished. The application circuit is
l THE AIC1781A OPERATION
included in TYPICAL APPLICATION CIRCUIT.
Power-on and Battery Pre-qualifying
When power is first applied to the AIC1781A, all
internal digital circuit blocks of the AIC1781A are
reset by the internal power-on-reset circuitry and
output LEDs (depending on the setting of SEL1 and
SEL2 pins) flash 3 times to indicate the initiation of
power-on. The internal control unit then examines
the battery condition through the VBT and VTS
pins.
Fast Charge
After the battery passes fault checks and required
discharging of the battery is completed, fast
charging begins while initial timer and safety timer
of the AIC1781A start counting. Functions of -∆V
detection, peak voltage timer, ∆T/∆t detection,
and maximum battery voltage are, however,
disabled temporarily until the initial timer period in
the initial stage of a charge cycle elapses. The
The acceptable limits of VBT pin is determined by
the input voltage of SEL3 pin and the acceptable
temperature sense voltage window for VTS pin is
0.29 VCC to 0.72 VCC. If the voltage of VBT pin fails
to fall within the predetermined acceptable limits,
the AIC1781A enters a charge-suspending mode, in
initial timer period is equal to 1/80 of safety timer.
Since the low limit of acceptable VBT voltage is
only about 0.16V during the initial timer period,
even deeply discharged batteries can easily qualify
to be fast charged subsequently.
which all the internal circuitry remains in reset state.
In the course of fast charge, the AIC1781A
If the voltage of VTS pin is outside the 0.29 VCC to
constantly monitors the voltages at VBT and VTS
0.72 VCC window, action of AIC1781A is determined
pins. The fast charge process is switched to trickle
by the input voltage of SEL3 pin.
charge when any one of the following situations is
encountered, which are explained below:
Discharge-Before-Charge
The
AIC1781A
l Negative delta voltage (-∆V)
provides
discharge-before-charge
to
the
function
precondition
of
NiCd
l Peak voltage timer (0 ∆V )
l Delta temperature/ delta time (∆T/∆t)
batteries which suffer from memory effect. This
l Maximum charge time
function
l Maximum battery voltage
can
only
be
activated
after
the
pre-qualification of battery voltage and temperature,
l Maximum battery temperature
yet before the charge completion is registered for
the fast charge cycle.
To trigger this function, DSW pin has to be biased
to GND for over 0.18 second. After discharge
begins, LED1 and LED2 pins are both off, ICON
pin is on, and DIS pin goes high to activate an
external circuit to discharge the battery until the
voltage of VBT pin falls 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. Fast charge will automatically start after
-∆V Cutoff
The AIC1781A makes a voltage sampling at VBT
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
VBT pin, the fast charge cycle is terminated.
0∆V Cutoff
If the battery voltage stays at its peak value or
decreases very slowly for the duration determined
9
AIC1781A
by the peak voltage timer, which is in turn
duty cycle is controlled by the setting of SEL1 and
determined by PEAK pin voltage, the fast charge
SEL2 pins.
action is terminated.
The
functions
and
charging
states
control
∆T/∆t Cutoff
mentioned above are illustrated in the function flow
The ∆T/∆t detection of the AIC1781A is performed
chart of AIC1781A (Fig. 16)
by sensing the decrease of VTS pin voltage in a
specific timer interval dictated by the safety timer.
l DESIGN GUIDE
The fast charging terminates when the decrease of
VTS pin voltage in 56 seconds exceeds the
Selecting Peak Voltage Timer (0∆V)
predetermined value set by ADJ pin input. This time
The voltage of PEAK pin along with safety timer
interval of 56 seconds is based on the assumption
determines the period of peak voltage timer. It can
that voltage of VTS pin is sampled once for every 8
be selected according to the following table:
seconds, which is also determined by safety timer.
Functioning of -∆V detection and peak voltage timer
TABLE 1
(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 VCC
PEAK PIN
PEAK VOLTAGE TIMER
VCC
1.5% of safety timer
Floating
3.7% of safety timer
GND
6% of safety timer
- 0.3V.
Maximum Safety Timer Cutoff
The maximum fast charge period is determined by
Battery Voltage Measurement
the safety timer, which is set by a resistor
The AIC1781A measures the battery voltage
connected from TMR pin to GND. Safety timer, -∆V
through VBT pin, which is connected to battery
sampling rate, and ∆T/∆t sampling rate will be
positive terminal through a resistor-divider network,
longer if the resistor value is larger. When the value
as shown in Fig. 17. The input voltage of SEL3 pin
of the resistor is 100KΩ, the safety timer period
determines the acceptable limit of divided battery
equals 80 minutes. This can be verified by biasing
voltage.
MODE pin to VCC and the measured frequency on
VBAT
DSW pin should be around 32.8 KHz. After the
RA
R5
Maximum Voltage and Temperature Cutoff
RB
The AIC1781A guards against the maximum limits
+
C5
2
VBT
100K
C6
0.1µF
action is terminated.
4.7µF
safety timer period is finished, the fast charge
AIC1781A
for battery voltage and temperature during fast
charging. If either of these limits is exceeded, fast
charge action is terminated.
Fig. 17
Battery Voltage Divider
Trickle Charge
For SEL3 > (VCC/2) + 0.4V, the suggested divider
There are five different selectable duty cycles for
resistance of RA and RB for the corresponding
trickle charge after the fast charge to prevent the
number of battery cells are as below:
loss of charge due to battery self-discharging. The
10
AIC1781A
Battery Temperature Measurement
TABLE 2
The AIC1781A employs a negative temperature
BATTERY
CELLS
RA/RB
2~4
2
240
120
battery’s temperature. The thermistor is inherently
3~6
3.3
300
91
nonlinear with respect to temperature. To reduce
4~8
4.9
300
62
5~10
6.4
300
47
6~12
7.8
310
39
8~16
10.8
390
36
RA (KΩ)
RB (KΩ)
coefficient
(NTC)
thermistor
to
measure
the
the effect of nonlinearity, a resistor-divider network
in parallel with the thermistor is recommended. A
typical application circuit is shown in Fig. 18.
VCC
VBAT
resistance of RA and RB for the corresponding
TABLE 3
BATTERY
CELLS
RA/RB
RA(KΩ)
RB (KΩ)
2
1
240
240
3
2
240
120
4
3
240
80
5
4
300
75
6
5
300
60
8
7
360
51
10
9
360
40
12
11
390
36
16
15
410
27
C7
0.1µF
4
Thermistor
number of battery cells are as below:
5
VCC
Rx
For SEL3 < (VCC/2) -0.4V, the suggested divider
VTS
AIC1781A
Ry
12
GND
Fig. 18 Battery Temperature Sense Circuit
with a Negative Temperature Coefficient
(NTC) Thermistor
11
AIC1781A
Power ON
LED Flash 3 Times
If
VBT in Normal
Range
No
Yes
Yes
If
VNTC<0.72 VCC
LED's Display Abnormal,
ICON ON,
Safety Timer Reset
No
If
SEL3>VCC-0.3V
or VCC/2-0.4V>SEL3
>1.4V
No
No
If
SEL3>VCC-0.3V
or VCC/2-0.4V>SEL3
>1.4V
Yes
∆T/∆t Disabled
No
Yes
If VNTC>0.29VCC
LED's Display,
Abnormal,
ICON ON,
Safety Timer Reset
Yes
No
If
Discharge
Finished
If
Discharge
Enabled
Yes
Battery Replacement
Yes
Yes
No
No
LED's Display Fast Charge, ICON OFF
Safety Timer Counts
If
Initial Timer
Finished
∆T/∆t Detector,
-∆V Detector,
Peak timer are all
Disabled
No
Yes
If
Peak Timer Period
has Finished
Yes
No
If
0.25% Decline of VBT
is Detected
Yes
No
If ∆T/ ∆ t
has Reached
LED's Display
Battery Fulll,
Fast Charge
Finished,
Trickle charge
Starts
Battery Replacement
Yes
Yes
No
No
No
If
Safety Timer Period
has Finished
Fig. 16
Yes
Function Flow Chart of AIC1781A
12
AIC1781A
65
5.9
34.0
The calculation for Rx and Ry in the circuit is as
66
5.7
31.6
following.
67
5.5
29.5
Ry//RTH
0.29 VCC =
x VCC
Rx + (Ry// RTH)
68
5.3
27.5
69
5.2
25.8
RTH= The resistance of thermistor at upper limit of
70
5.0
24.3
temperature protection.
Ry//R TL
0.72 VCC =
x VCC
Rx + (Ry// R TL )
TABLE 5 Values of Rx and Ry at TL = -10°C
TH (°C)
RTL= The resistance of thermistor at lower limit of
temperature protection.
Substitution and rearranging the equations yield
Rx= 2.061 ×
RTL × RTH
Rx (KΩ)
Ry (KΩ)
45
11.4
95.6
46
11.0
85.0
47
10.6
76.2
48
10.2
68.9
49
9.8
62.8
RTL − RTH
5. 3 × RTL × RTH
50
9.5
57.5
51
9.1
52.9
RTL − 6. 3RTH
52
8.8
48.8
If temperature characteristic of the thermistor is like
53
8.5
45.3
that of SEMITEC 103AT-2, the resistance of Rx and
54
8.2
42.1
Ry is tabulated for different TL and TH as below.
55
7.9
39.4
56
7.6
36.8
57
7.4
34.6
58
7.1
32.5
59
6.9
30.7
Ry =
(Note: TL is lower temperature limit and TH is upper
temperature limit.)
TABLE 4 Values of Rx and Ry at TL = 0°C
TH (°C)
Rx(KΩ)
Ry (KΩ)
60
6.7
29.0
50
10.1
551.1
61
6.4
27.4
51
9.7
300.7
62
6.2
26.0
52
9.4
204.8
63
6.0
24.6
53
9.0
153.9
64
5.8
23.4
54
8.7
122.8
65
5.6
22.2
55
8.4
101.8
56
8.1
86.5
57
7.8
75.0
58
7.5
66.0
59
7.2
58.7
60
7.0
52.8
61
6.8
47.8
62
6.5
43.6
63
6.3
39.9
64
6.1
36.8
Setting the ADJ Pin Voltage
The slope of ∆T/∆t detection is determined by ADJ
pin voltage of the AIC1781A.
The calculation of ADJ pin voltage is shown in the
following procedure followed by an example.
13
AIC1781A
Procedure
(a) First, determine the temperature protection
limits TH and TL. Then, substitute TH & TL into
the following equation:
∆VTS
0.72V CC − 0.29V CC 0.43V CC
=
=
∆TBASE
TH − TL
TH − TL
(b) Determine the safety timer to obtain the value of
∆tBASE .
56(sec.)
∆tBASE(sec.) =
× Safety Timer (min .)
80(min .)
(c) Determine the expected slope of ∆T / ∆t at
which temperature rises y°C in x seconds and
fast charge is subsequently cut off.
∆T y
=
∆t
x
TABLE 6
ADJ pin Voltage (TL=0°C, TH=50°C)
∆T / ∆t
S.T.
Example
(a) Let TH=50°C, TL=0°C, VCC =5V. We have
∆VTS
0.43 × 5
= 0.043V/° C
=
∆TBASE
50 − 0
which means that VTS decreases 43mV as
temperature rises 1°C.
1.0
1.25
(°C/min.) (°C/min.) (°C/min.)
0.45
0.60
0.75
40 min. (2C)
80 min. (1C)
0.90
1.20
1.50
120 min. (0.67C)
1.35
1.80
2.25
160 min. (0.5C)
1.80
2.40
3.01
200 min. (0.4C)
2.25
3.01
3.76
240 min. (0.33C)
2.70
3.61
4.51
A similar table for temperature range from 0°C to
60°C is as below.
TABLE 7 ADJ Pin Voltage (TL=0°C, TH=60°C)
∆T / ∆t
S.T.
0.75
1.0
1.25
(°C/min.) (°C/min.) (°C/min.)
0.37
0.50
0.62
40 min. (2C)
(d) Calculate the value of VADJ
∆VTS ∆T
VADJ = 30 ×
×
× ∆tBASE
∆TBASE ∆t
0.75
80 min. (1C)
0.75
1.00
1.25
120 min. (0.67C)
1.12
1.50
1.88
160 min. (0.5C)
1.50
2.00
2.50
200 min. (0.4C)
1.88
2.50
3.13
240 min. (0.33C)
2.25
3.01
3.76
VBT Range and Temperature Protection
The acceptable voltage range of VBT pin and
mode of temperature protection function is
determined by the voltage of SEL3 pin, shown as
the following:
(b) If safety timer is equal to 80 minutes, ∆tBASE is
then 56 seconds.
(c) If fast charge should be terminated when
temperature rises 1°C in 60 seconds, then
1
∆T/∆t =
= 0.0166
60
(d) VADJ =30 x 0.043x 0.0166 x 56 = 1.2(V)
(a) SEL3 > VCC - 0.3V
Acceptable VBT Range:
Before initial timer: 0.16V~2.7V
After initial timer: 0.69V~2.7V
Temperature Protection Mode:
Entering
charge-suspending
mode
when
If the temperature range is from 0°C to 50°C,
temperature is either too low or too high,
the voltage of VADJ under different setting
same as abnormal battery voltage. Latch for
conditions should be set as tabulated below.
charge-suspending function is provided for
high temperature protection, but not for low
temperature protection.
14
AIC1781A
(b) VCC - 1.4V> SEL3 >
V cc
+ 0.4V
2
of the commonly chosen safety timer periods. Also
shown in the table are their corresponding
Acceptable VBT Range:
oscillator frequencies.
Before initial timer: 0.16V~2.7V
800
After initial timer: 0.69V~2.7V
If temperature is too high, battery charging is
regarded as completed. If temperature is too
low, function of ∆T/∆t detection is disabled, just
RTMR (KΩ)
600
Temperature Protection Mode:
as thermistor is not existing.
400
200
0
0
V cc
(c)
- 0.4V>SEL3 >1.4V
2
Fig. 19
After initial timer: 1.2V~2V
charge-suspending
mode
11
23
48
74
100
152
206
314
491
667
when
temperature is either too low or too high, same
battery
voltage.
Latch
for
charge-suspending function is provided for high
temperature
400
500
protection,
but
not
Safety Timer vs. RTMR
RTMR (KΩ)
Temperature Protection Mode:
abnormal
300
TABLE 8
Before initial timer: 0.16V~2V
as
200
Safety Timer (min.)
Acceptable VBT Range:
Entering
100
for
low
temperature protection.
(d) 0.3V> SEL3
Acceptable VBT Range:
OSC.
Freq.(KHz)
256
131
65.8
43.1
32.8
21.6
16.0
10.6
6.89
5.04
Safety timer
(min.)
10
20
40
60
80
120
160
250
380
520
Before initial timer: 0.16V~2V
After initial timer: 1.2V~2V
Selecting Mode of Operation
Temperature Protection Mode:
The AIC1781A provides three modes of operation:
If temperature is too high, battery charging is
normal, test, and AC mode determined by the
regarded as completed. If temperature is too
setting of MODE pin according to TABLE 9. The
low, function of ∆T/∆t detection is disabled, just
AIC1781A will operate normally when the MODE
as thermistor is not existing.
pin
is
left
floating
(a
0.1µF
capacitor
is
recommended to be tied to MODE pin if the charge
Setting the Period of Safety Timer
circuit works in a noisy environment). When the
The AIC1781A provides a method for linearly
MODE pin is biased to GND, the function of -∆V
adjusting the period of safety timer with an external
detection is disabled. When the MODE pin is
resistor connected from TMR pin to GND. The
biased to VCC, the AIC1781A enters the test mode.
relation between safety timer length and the
The test mode can be used to significantly reduce
external resistor (RTMR) is shown in Fig. 19. The
table following shows the resistor values for some
production test time. For relevant informations
please contact AIC directly.
15
AIC1781A
TABLE 9
The Operating Mode of AIC1781A
MODE pin
Mode
VCC
Test
Floating
AC
Power
ON
Function
Safety timer period scaled
down to 1/32....etc.
Normal Normal operation
GND
TYPE 2
–∆V detection disabled
The Mode of LED Display and Trickle Charge
The AIC1781A provides two LED display modes
and five-pulsed trickle charge modes. The
tri-level inputs, SEL1 and SEL2 pins, as in the
TABLE 6 determine the modes of LED display
Charge
Fault
Fast
Charging Completed Conditions
LED1
1Hz
ON
OFF
4Hz
Flashing
LED2
1Hz
4Hz
Flashing
ON
OFF
Charging Current Control
As shown in the typical application circuit, the
AIC1781A offers an open-drained output pin, ICON
pin, to control the charging current flow in fast
charge state and switch on to inhibit the charging
and trickle charge.
TABLE 10 Mode of LED Display and Trickle
Charge
current flow in fault conditions. When fast charge is
completed, the AIC1781A enters the trickle charge
mode. In trickle charge mode, the ICON pin output
SEL1
VCC
Floating
GND
Trickle Charge LED Display
Duty
Mode
SEL2
switches with predetermined duty cycle. Refer to
the table of trickle charge mode (TABLE 6), the
VCC
N/A
Type 1
Floating
1/32
Type 1
GND
1/64
Type 1
and SEL2 pins. The following table summarizes
VCC
1/128
Type 1
how ICON pin corresponds to various charging
Floating
1/256
Type 1
states.
GND
N/A
Type 2
VCC
1/32
Type 2
Floating
1/64
Type 2
GND
1/128
Type 2
duty cycle is determined by the setting of SEL1
Power
Fast
Charge
Fault
ON
Charging Completed Conditions
ICON
ON
OFF
See pin 10
& 11
ON
Display the Battery Charging Status
Test Mode
The
open-drained
Fig. 20 shows the timing diagram for externally
outputs, LED1 and LED2, to indicate the battery
controlled PEAK, ADJ, VBT, VTS, SEL1 and
charging status. Refer to the table of LED display
SEL2 pin voltages of a recommended AIC1781A
mode (TABLE 10), depending on the setting of
test scheme, utilizing TEST mode function.
SEL1 and SEL2 pins, the outputs of LED1 and
Output waveforms of LED1, LED2 and ICON of a
LED2 pins are shown in the following table:
properly functioning AIC1781A are also shown in
TYPE 1
the figure.
AIC1781A
provides
two
Fast
Charge
Fault
Power
Completed
Conditions
ON
Charging
LED1
1Hz
ON
OFF
OFF
LED2
OFF
OFF
ON
OFF
16
AIC1781A
n TIMING DIAGRAM
VCC, SEL3, MODE=5V, (DSW FREQ.=820KHz, 25 TIMES of 32.8K)
Power Init.
ON
5V
PEAK
∆T/∆t INITIAL TIMER
-∆V TEST
PEAK TIMER TEST
SAFETY TIMER TEST
∆T/∆t TEST
0V
5V
1.12V
ADJ
3V
<2.1V
(-0.15%)
2V (-0.15%)
1.997V
2V
1.95V
1.997V
2V
1.9V
VBT
1.5V
1.993V
(-0.35%)
4V
4V
2V
2V
1.97V
0V
1.85V
(-2.15%)
OFF
4V
4V
2V
VTS
2mV
Step/100mS
(-2.5%)
2V
2mV
Step/100mS
OFF
OFF
OFF
ON
ON
ON
LED1
OFF
3.2KHz
LED2
ON
ON
OFF
ICON
ON
OFF
OFF
ON
SEL1
SEL2
TIME
ON
Floating
Floating
VCC
Floating
0.1
0.14 0.12
0.28
0.2
0.12
3
4
0.32
Floating
GND
0.32
0.12
5
6
0.32
GND
Floating
0.5
0.7
0.24
GND
GND
0.4
2.14
8
9
Floating
Floating
0.1
0.02
(SEC.)
STAGE
1
2
0 0.14 0.26
0.54
0.74 0.86
1.18
Fig. 20
1.5
7
1.62
1.94
2.64
3.14 3.38
3.78
10
5.92 6.02
6.04
Timing Diagram of AIC1781A in Test Mode
17
AIC1781A
n PHYSICAL DIMENSIONS (unit: mm)
l
16 LEAD PLASTIC SO (300 mil) (CS) (PS)
D
E
H
A1
A
l
MIN
MAX
A
2.35
2.65
A1
0.10
0.30
B
0.33
0.51
C
0.23
0.32
D
10.10
10.50
E
7.40
7.60
e
e
B
SYMBOL
L
c
1.27(TYP)
H
10.00
10.65
L
0.40
1.27
16 LEAD PLASTIC DIP (CN)
D
E1
E
A2
SYMBOL
MIN
MAX
A1
0.381
—
A2
2.92
4.96
b
0.35
0.56
C
0.20
0.36
D
18.66
19.69
E
7.62
8.26
E1
6.09
7.12
A1
C
L
eB
b
e
e
2.54(TYP)
eB
—
10.92
L
2.92
3.81
Note:
Information provided by AIC is believed to be accurate and reliable. However, we cannot assume responsibility for use of any
circuitry other than circuitry entirely embodied in an AIC product; nor for any infringement of patents or other rights of third
parties that may result from its use. We reserve the right to change the circuitry and specifications without notice.
Life Support Policy: AIC does not authorize any AIC product for use in life support devices and/or systems. Life support devices
or systems are devices or systems which, (I) are intended for surgical implant into the body or (ii) support or sustain life, and
whose failure to perform, when properly used in accordance with instructions for use provided in the labeling, can be reasonably
expected to result in a significant injury to the user.
18
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