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AIC1782
Dual-Battery Charge Controller
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 Selectable. 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.
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 sequence gives priority to battery pack A, represented 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 condition. -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
100
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.
1.55
Charge Current = 600m A Cell Capaci ty = 550m A Ni MH B attery
misaction caused by using -V detection alone
Temperature (C)
Cell Voltage (V)
1.45
80
under certain conditions. Fig. 1 shows an example of charging curve of a battery charged by a fluctuating 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 applications, such as system-integrated chargers, chargers with varying charge current, or battery packs lack of temperature sensing thermistor.
Cell Voltage
1.35 60
1.25
40
Temperature
1.15 0 10 20 30 40 50 60 20
Charge Time (min.)
Fig. 1
Battery Charging Characteristics Resulted from an AIC1782-Controlled Charger with a Fluctuating Charging Current
Analog Integrations Corporation DS-1782-00
4F, 9, Industry E. 9th Rd, Science Based Industrial Park, Hsinchu Taiwan, ROC TEL: 886-3-5772500 FAX: 886-3-5772510
www.analog.com.tw
1
AIC1782
The safety timer period, mode of battery temperature protection, battery voltage protection range, pulsed trickle charge duty, and LED display mode are all adjustable or selectable. Discharge-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
R1 + R3 100K C1 4.7F R2 R27 4.7K R28 R34 1K A1012 Q6 R29 150 R30 220 L1 200H + D1 1N5821 RS 0.1/2W C11 220F A1012 Q2 R22 470 R23 330 4.7K D6 1N4148 R6 R7 + 1N5820 D4 VCC(5V) R21 2.7K Q1 D468 R5 20/5W R32 680 4 THERMISTOR BATTERY B B2 R10 B C5 0.1F R11 + C6 100F C7 0.1F R13 VCC(5V) 5 R12 6 7 R14 8 100K THERMISTOR BATTERY A B1 VCC(5V) R16 9 ATS R15 R17 10 LEA1 680 ICOA LEA2 1N5820 D5 R37 3.9K R35 1.5K Q7 D468 C2 0.1F
D7
R8 100K C3 4.7F R4 390 C4 0.1F VCC 5V
1 ABV DSW ICOB 2
20 SW1 19 R20 680 LED4
1N4148
VIN
LED5 + 2.2F C12
D8 1N4148 1M R36 3
BBV
LEB2 18
AIC1782 DIS LEB1 17 R19 680 LED3
SC SE TC C10 1nF GND
BST VCC(5V) IS VCC + VIN 78L05 C9 100F R33 47K D2 1N4148
Q3 3904
GND 16 BTS VCC SEL1 15 14
FB
AIC1563 1N4148 D3 R25 470
A1012 Q4
ADJ SEL3 TMR
SEL2
R26 330
VCC(5V) R24 2.7K
MODE
13
Q5 3904
12 11 R18 LED2 680
A
C8 0.1F
LED1
Battery Charger for Dual NiMH and NiCd Battery
2
AIC1782
ORDERING INFORMATION
AIC1782 XX ORDER NUMBER PACKAGE TYPE N: PLASTIC DIP S: SMALL OUTLINE TEMPERATURE RANGE C= 0C~70C AIC1782 CN (PLASTIC DIP)
ABV BBV
PIN CONFIGURATION
1 2 20 DSW 19 ICOB 18 LEB2 17 LEB1 16 GND 15 SEL1 14 SEL2 13 MODE 12 ICOA 11 LEA2
DIS 3 BTS VCC ADJ 4 5 6
AIC1782 CS (PLASTIC SO)
SEL3 7 TMR 8 ATS 9
LEA1 10
ABSOLUTE MAXIMUM RATINGS
Supply Voltage ................................................................................................... 5.5V ........................................................................... 5.5V ............................................... 20mA -65C~ 150C DC Voltage Applied on any Pin
Sink Current of ICOA Pin, LEA1 and LEA2 Pins ............................................... 20mA Sink Current of ICOB Pin, LEB1 and LEB2 Pins Operating Temperature Range ................................................................... 0C~ 70C
Storage Temperature Range ................................................................
TEST CIRCUIT
Voltage Source
-
+
ABV BBV R1 560 DIS
DSW ICOB LEB2 R3 560 R4 560 R5 560 RED GREEN ORANGE
Voltage Source
-
+
YELLOW
-
+
BTS VCC ADJ SEL3
LEB1 GND
Voltage Source VCC (5V) VCC V1 (0.95V) V2 (3V) 100K R2
AIC1782
VCC SEL1 VCC SEL2 VCC MODE R8 560 ORANGE
TMR
-
+
ATS
ICOA
Voltage Source RED VCC R6 560 LEA1 LEA2
R7 560
GREEN
3
AIC1782
ELECTRICAL CHARACTERISTICS
fied.)
PARAMETER Supply Voltage Supply Current Battery Low Before Initial Timer After Initial Timer (SEL3>3V) Voltage Protection Limit (SEL3<2V) Battery High (SEL3>3V) (SEL3<2V) Temperature Sense Limit Output impedance of DIS Pin LEA1, LEA2, LEB1, LEB2, ICOA, ICOB pins ON OFF SEL3 pin DSW pin MODE, SEL1, SEL2 pins Input Impedance ABV, BBV, ATS, BTS, ADJ pins RTM
R
(Ta=25C, VCC=5V, unless otherwise speci
TEST CONDITIONS
SYMBOL VCC ICC VABV VBBV
MIN. 4.5
TYP. 5 1.1
MAX. 5.5
UNIT V mA
0.11 0.63 1.1
0.16 0.69 1.2
0.21 0.75 1.3 V
2.6 1.9 VATS VBTS ZDIS 1.35 3.5
2.7 2.0 1.45 3.6 140
2.8 2.1 1.55 3.7 250 V
Temperature High Temperature Low
Output Impedance
25 1 ISEL3 IDSW 5.5 16
50
M A A
Source Current Capability
300 1 2 100 1000
K M K
Recommended External Resistor of TMR pin -V detection level w.r.t.* Peak Value *: with respected to
-0.25
%
4
AIC1782
TYPICAL
1.18 81.0
PERFORMANCE CHARACTERISTICS
Supply Current vs Supply Voltage
(Ta=25C, R2=100K,
VCC=5V, refer to Test Circuit)
Safety Timer vs Supply Volatge
Supply Current (mA)
1.12
Safety Timer (min.)
4.4 4.6 4.8 5.0 5.2 5.4
80.5
80.0
1.06
79.5
1.00 79.0 4.4 4.6 4.8 5.0 5.2 5.4
VCC (V)
VCC (V)
Safety Timer vs Temperature
82.0
1.26
Supply Current vs Temperature
Supply Current (mA)
0 20 40 60 80
Safety Timer (min.)
81.0
1.14
1.02
80.0
0.90
79.0
0
20
Temperature(C)
Temperature (C)
40
60
80
ABV and BBV (High) Limit vs Temperature (SEL3>3V)
2.74
2.03
ABV and BBV (High) Limit vs Temperature (SEL3<2V)
2.02
ABV, BBV (V)
ABV, BBV (V)
0 20 40 60 80
2.70
2.66
2.00
2.62
1.98
Temperature (C)
0
20
40
60
80
Temperature (C)
5
AIC1782
TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
ABV and BBV (Low) Limit vs Temperature (Before Initial Timer)
0.163
Output Impedance vs Temperature (LEA's, LEB's, ICO's pins)
29
Output Impedance()
0.162
ABV, BBV (V)
27
0.160
25
0.158 0 20 40 60 80
23 0 20 40 60 80
Temperature (C)
Temperature(C)
ABV and BBV (Low ) limits vs Temperature (SEL3<2V, After Initial Timer)
0.710
ABV and BBV (Low) limits vs Temperature (SEL3>3V, After Initial Timer)
1.22 0.705
ABV, BBV (V)
1.21
1.20
1.19
0
20
40
60
80
ABV, BBV (V)
0.700
0.695
0.690
0
20
40
60
80
Temperature (C)
Temperature (C)
ATS and BTS (High) Limit vs Temperature
1.48 3.62
ATS and BTS (Low) Limit vs Temperature
ATS, BTS (V)
20 40 60 80
ATS, BTS (V)
3.61
1.46
3.60
1.44
3.59
3.58
0
1.42 0 20 40 60 80
Temperature (C)
Temperature (C)
6
AIC1782
BLOCK DIAGRAM
GND VCC TMR LEB2 LEB1 LEA2
MODE
MODE Selection
Bandgap Reference & Voltage Regulator
Oscillator Timing Control Unit Display Control Unit
LEA1
SEL3
Battery Voltage & Temperature Protection Setting LED Display& Trickle Charge Duty Setting
ICOB
SEL1 SEL2
Charge Control State Machine
Charge Control Unit
ICOA
ADJ
T/t Detection Setting Battery Temperature Protection 13-bit A/D Battery Voltage Protection + Discharge Control Unit
DIS DSW
CHARGE END
ATS
BTS
ABV
BBV
PIN DESCRIPTIONS
PIN 1: ABV - Divided battery voltage input to sense the battery voltage of pack A. PIN 5: VCC PIN 2: BBV - Divided battery voltage input to sense the battery voltage of pack B. PIN 3: DIS - Push-pull output, used to control an external transistor to discharge the battery of pack B. DIS is active high when function of discharge is enabled. PIN 7: SEL3 range of BTS pin is 0.29 VCC to 0.72 VCC. - Power supply input at 5V 10%. - For adjusting the slope of T / t . Acceptable voltage range for this pin is approximately 0.28V to 3.8V. If voltage higher than VCC - 0.3V, function of T / t detection is disabled. - Determining the acceptable voltage range of ABV and BBV pins and mode of temperature protection function.
PIN 6: ADJ
PIN 4: BTS - The battery cell temperature of pack B is represented as a voltage input to the AIC1782 at this pin. The acceptable voltage
7
AIC1782
PIN 8: TMR - Determining the period of safety timer with an external resistor connected to GND. - 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 VCC to 0.72 VCC. PIN 15: SEL1 - Tri-level inputs, that jointly control the LED display mode and the duty of trickle charge after the completion of fast charge. - Power ground.
PIN 9: ATS
PIN 16: GND
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 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. - Controlling the function of discharge-before-charge of the battery pack B. (See discharge-before-charge subsection in application informations).
PIN 20: DSW
PIN 13: MODE - Determining the mode of operation for the AIC1782. PIN 14: SEL2 &
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 output of LED`s (depending on the setting of SEL1 and SEL2 pins) flash 3 times to indicate the initiation of power-on. If both battery pack A and B are present when VCC 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 Discharge-Before-Charge The AIC1782 controls the initiation of a charge action and checks for acceptable battery voltage and temperature prior to fast charging. If the voltage of ABV or BBV fail to fall within the predetermined acceptable limits, the corresponding battery pack enters a chargingsuspending mode. If the voltage of ATS or BTS is outside the 0.29 VCC to 0.72 VCC window, action to AIC1782 is determined by the input voltage of SEL3 pin. acceptable limits of ABV and BBV are determined by the input voltage of SEL3 pin and the acceptable temperature sense voltage window for ATS and BTS are 0.29 VCC to 0.72 VCC.
8
AIC1782
The AIC1782 provides the function of discharge-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 temperature, yet before the charge completion is registered for fast charge cycle of pack B. To trigger this function, DSW pin has to be biased 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 activate 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 battery remains in a waiting state until the first battery 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 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 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 subsequently. In the course of fast charge, the AIC1782 constantly monitors the battery voltage and temperature through ABV (or BBV) and ATS (or BTS) pins. The fast charge process is registered 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. 0V Cutoff If the battery voltage stays at its peak value or decreases very slowly for the duration determined by the peak voltage timer, which is in turn equal 3.7% of safety timer, the fast charge action is terminated. T/t Cutoff The T / t detection of the AIC1782 is performed by sensing the decrease of ATS (or BTS) pin voltage in a specific timer interval dictated by the safety timer. The fast charging terminates when the decrease of ATS (or BTS) pin voltage in 56 seconds exceeds the predetermined value set by ADJ pin input. This time interval of 56 seconds is based on the assumption that voltage of ATS (or BTS) pin is sampled once for every 8 seconds, which is also determined by safety timer.
14
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 VCC - 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 VCC 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 exceeded, 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 selfdischarging. 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. (c) (b) VCC - 1.4V> SEL3 > The acceptable battery voltage range of ABV and BBV pins and mode of temperature protection function is determined by the voltage of SEL3 pin, shown as the following: (a) SEL3 > VCC - 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 temperature is either too low or too high, same as abnormal battery voltage. Latch for chargesuspending function is provided for high temperature protection, but not for low temperature protection.
V cc - 0.4V 2
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.
V cc - 0.4V>SEL3 >1.4V 2
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.
DESIGN GUIDE
ABV/BBV Range and Temperature Protection
15
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 resistordivider network, as shown in Fig. 2. The acceptable limit of divided battery voltage is determined by the input voltage of SEL3 pin. Battery Temperature Measurement The AIC1782 employs a negative temperature
VBAT RA R6 + C5 100K 4.7F C6 0.1F ABV/BBV AIC1782
For SEL3 < (VCC/2) -0.4V, the suggested divider resistances of RA and RB for the corresponding number of battery cells are as below: BATTERY CELLS 2 3 4 5 6 8 10 12 16 RA/RB 1 2 3 4 5 7 9 11 15 RA(K) 240 240 240 300 300 360 360 390 410 RB (K) 240 120 80 75 60 51 40 36 27
coefficient (NTC) thermistor to measure the battery s temperature. The thermistor is inherently nonlinear with respect to temperature. To reduce the effect of nonlinearity, a resistordivider network in parallel with the thermistor is recommended. A typical application circuit is shown in Fig. 3.
VCC VBAT Rx 5 VCC ATS/BTS C7 0.1F
'
RB
Fig. 2 Battery Voltage Divider For SEL3 > (VCC/2) + 0.4V, the suggested divider resistances of RA and RB for the corresponding number of battery cells are as below: BATTERY CELLS 2~4 3~6 4~8 5~10 6~12 8~16 RA/RB 2 3.3 4.9 6.4 7.8 10.8 RA (K) 240 300 300 300 310 390 RB (K) 120 91 62 47 39 36
Thermistor
AIC1782
Ry 16 GND
Fig. 3 Battery Temperature Sense Circuit with a Negative Temperature Coefficient (NTC) Thermistor
16
AIC1782
The calculation for Rx and Ry in the circuit is as following.
67 68 69 70
5.5 5.3 5.2 5.0
29.5 27.5 25.8 24.3
Ry / /RTH 0.29 Vcc = x Vcc Rx + (Ry / / RTH) RTH= The resistance of thermistor at upper limit of temperature protection. Ry / /RTH 0.72 Vcc = x Vcc Rx + (Ry / / RTL) RTL= The resistance of thermistor at lower limit of temperature protection.
TABLE. 2 Values of Rx and Ry at TL = -10C
TH (C) 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65
Rx (K) 11.4 11.0 10.6 10.2 9.8 9.5 9.1 8.8 8.5 8.2 7.9 7.6 7.4 7.1 6.9 6.7 6.4 6.2 6.0 5.8 5.6
Ry (K) 95.6 85.0 76.2 68.9 62.8 57.5 52.9 48.8 45.3 42.1 39.4 36.8 34.6 32.5 30.7 29.0 27.4 26.0 24.6 23.4 22.2
Substitution and rearranging the equations yield Rx= 2.061 x
Ry = RTL x RTH RTL - RTH 5. 3 x RTL x RTH RTL - 6. 3RTH If temperature characteristic of the thermistor is like that of SEMITEC 103AT-2, the resistance 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 = 0C
TH (C) 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66
Rx(K) 10.1 9.7 9.4 9.0 8.7 8.4 8.1 7.8 7.5 7.2 7.0 6.8 6.5 6.3 6.1 5.9 5.7
Ry (K) 551.1 300.7 204.8 153.9 122.8 101.8 86.5 75.0 66.0 58.7 52.8 47.8 43.6 39.9 36.8 34.0 31.6
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:
17
AIC1782
V TS 0.72V CC - 0.29V CC 0.43V CC = = TBASE TH - TL TH - TL
TABLE. 3 ADJ Pin Voltage (TL=0C, TH=50C)
S.T.
T / t
(b) Determine the safety timer to obtain the value of tBASE . 56(sec. ) t BASE(sec.) = x Safety Timer (min. ) 80(min. ) (c) Determine the expected slope of T / t at which temperature rises yC in x seconds and fast charge is subsequently cut off. T y = t x
(d) Calculate the value of VADJ V TS T V ADJ = 25 x x x t BASE TBASE t
Example
40 min. (2C) 80 min. (1C) 120 min. (0.67C) 160 min. (0.5C) 200 min. (0.4C) 240 min. (0.33C)
0.75 1.0 1.25 (C/min.) (C/min.) (C/min.) 0.37 0.5 0.63 0.75 1.12 1.5 1.87 2.25 1.0 1.5 2.0 2.5 3.0 1.25 1.87 2.5 3.12 3.75
A similar table for temperature range from 0C to 60C is as below.
TABLE. 4 TH=60C) ADJ Pin Voltage (TL=0C,
S.T.
T / t
0.75 1.0 1.25 (C/min.) (C/min.) (C/min.) 0.31 0.62 0.94 1.25 1.56 1.87 0.42 0.84 1.25 1.67 2.08 2.5 0.52 1.05 1.56 2.08 2.60 3.12
40 min. (2C) 80 min. (1C) 120 min. (0.67C) 160 min. (0.5C) 200 min. (0.4C) 240 min. (0.33C)
(a) Let TH=50C, TL=0C, VCC =5V. We have V TS TBASE 50 - 0 which means that VTS decreases 43mV as temperature rises 1C. (b) If safety timer is equal to 80 minutes, tBASE is then 56 seconds. (c) If fast charge should be terminated when temperature rises 1C in 60 seconds, then T / t = 1 = 0. 0166 60 = 0. 43 x 5 = 0. 043 V / C
Setting the Period of Safety Timer The AIC1782 provides a method for linearly
adjusting the period of safety timer with an external resistor connected from TMR pin to GND. The relation between safety timer length and the external resistor (RTMR) is shown in Fig. 4. The table following shows the resistor values for some of the commonly chosen safety timer periods. Also shown in the table is their corresponding oscillator frequencies.
(d) VADJ =25 x 0.043 x 0.0166 x 56 = 1(V) If the temperature range is from 0C to 50C, the voltage of VADJ under different setting conditions should be set as tabulated below.
18
AIC1782
800
ABLE. 5 The Operating Mode of AIC1782
MODE pin
600
Mode Test
Function Safety timer period scaled down to 1/32.... etc.
-V detection disabled
VCC
RTMR (K)
400
Floating
200
Normal Normal operation AC
GND
0 0 100 200 300 400 500
The Mode of LED Display and Trickle Charge
Safety Timer (min.)
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. Charge 6 Mode of LED Display and Trickle
Fig. 4 Safety Timer vs RTMR
RTMR (K) 11 23 48 74 100 152 206 314 491 667
Osc.Freq. (KHz) 262.4 131.2 65.6 43.7 32.8 21.9 16.4 10.9 7.3 5.5
Safety timer (min.) 10 20 40 60 80 120 160 240 360 480
SEL1
SEL2 VCC
Trickle Charge Duty N/A 1/32 1/64 1/128 1/256 N/A 1/32 1/64 1/128
LED Display Mode Type 1 Type 1 Type 1 Type 1 Type 1 Type 2 Type 2 Type 2 Type 2
VCC
Floating GND VCC
Selecting Mode of Operation The AIC1782 provides three modes of opera-
Floating
Floating GND VCC
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 0.1F 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 - V detection is disabled. When the MODE pin is biased to VCC, the AIC1782 enters the test mode. The test mode can be used to significantly reduce production test time. For relevant informations please contact AIC directly.
GND
Floating GND
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:
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AIC1782
TYPE 1
Power On LEA1/ LEB1 LEA2/ LEB2
TYPE 2
Wait ON ON
Charge ON OFF
Full OFF ON
Abnormal OFF OFF
ICOA/ ICOB
Power Wait Fast Charge Fault ON ON Charging Completed Conditions ON ON OFF See pin 14 & 15 ON
1HZ OFF
Test Mode
Power On LEA1/ LEB1 LEA2/ LEB2 1HZ 1HZ
Wait 1HZ 1HZ
Charge ON 4HZ
Full OFF ON
Abnormal 4HZ OFF
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. Output waveforms of LEA1, LEA2, LEB1, LEB2, ICOA and ICOB of a properly functioning AIC1782 are also shown in the figure. For detailed information please consult with AIC staffs directly.
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 current 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 predetermined duty cycle. Refer to the table of trickle charge mode (TABLE 6), the duty cycle is determined by the setting of SEL1 and SEL2 pins. The following table summarizes how ICOA and ICOB pins correspond to various charging states.
20
AIC1782
TIMING DIAGRAM
VCC, SEL3, MODE=5V, (DSW FREQ.=820KHz, 25 TIMES of 32.8K)
Power Init. PEAK TIMER TEST ON ADJ
-V TEST
-V DISALBE TEST 1.12V
T/t TEST
SAFETY TIMER TEST
5V
3V (-0.15%) 2V 1.95V
(A):ABV (B):BBV
<2.1V 2V (-0.15%) 1.997V 1.993V (-0.35%) 4V 2V 1.96V (-2.15%) 2V 1.997V 1.9V 2V 2mV Step/100mS
1.997V
1.5V
(A):ATS (B):BTS
4V 2V
4V <2.1V 2V 1.85V (-2.5%) OFF ON 3.2KHz ON 2mV Step/100mS
4V 2V
0V
OFF
(A):LEA1 (B):LEB1 (A):LEA2 (B):LEB2 (A):ICOA (B):ICOB SEL1 SEL2 TIME (A) (SEC.) STAGE
0.1
OFF
OFF
ON OFF
ON ON
ON OFF ON OFF
ON
OFF
VCC Floating
0.14 0.12 1 2 0.74 0.26 3 0.12 4
Floating Floating
0.32 0.32 5 0.12 6 0.32
Floating GND
0.97 0.5 7
GND Floating
0.24 0.4 8
GND GND
1.32 9
Floating
Floating 0.1 0.02 10 5.89 5.99 6.01
0 0.14 0.26 TIME (B) (SEC.) STAGE 6.01
0.1 0.14 0.12 11 12 0.74
1
0.26 13
1.26 1.38
1.17
2.02 2.14
Delay 0.3 14
2.46
3.43
0.5 15
3.93 4.17
0.24 0.4 16
4.57
6.11 6.25 6.37
7.21 7.47
7.77
8.27 8.51
8.91
Fig. 5 Timing Diagram of AIC1782 in Test Mode
21
AIC1782
PHYSICAL DIMENSIONS
20 LEAD PLASTIC DIP (unit: mm)
D
SYMBOL A1
E1
MIN 0.381 2.92 0.35 0.20 24.89 7.62 6.09 -- 2.92
MAX -- 4.96 0.56 0.36 26.93 8.26 7.12 10.92 3.81
A2 b
E
C D E
C
A1 A L eB b e
E1 e eB L
2.54(TYP)
20 LEAD PLASTIC SO (300 mil) (unit: mm)
D
SYMBOL A A1
E H
MIN 2.35 0.10 0.33 0.23 12.60 7.40 1.27(TYP) 10.00 0.40
MAX 2.65 0.30 0.51 0.32 13.00 7.60 10.65 1.27
B C D E
e
A
e H
L
B
C
L
A1
22

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