AIC1781 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. l l l l l l l l l l l l (-0.25%), 0 V detection (peak voltage timer) and T / t detection are the primary methods employed by the AIC1781 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 AIC1781 utilizes the combination of these two methods to achieve reliable decision of ending fast charge and prevent misaction caused by using -V detection alone of charging curve of a battery charged by a 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. fluctuating current from a NiMH battery charger l which uses the AIC1781 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 voltage drop is hardly significant yet temperature rises rapidly. The T / t or -V detection 100 1.55 Charge Current = 600 mA Cell Capacity = 550 mA NiMH Battery 80 1.45 Cell Voltage 60 1.35 40 1.25 circuitry Temperature (C) Cell Voltage (V) for intelligent charging of NiMH or NiCd batteries without the risk of overcharge. -V detection under certain conditions. Fig. 1 shows an example n APPLICATIONS 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 AIC1781 fast charge controller IC is designed The safety timer period, mode of battery 20 0 10 20 30 40 50 60 temperature protection, battery voltage protection Charge Time (min.) range, pulsed trickle charge duty, and LED display Fig. 1 Battery Charging Characteristics Resulting from an AIC1781-Controlled Charger with Fluctuating Charging Current Analog Integrations Corporation mode a are all adjustable selectable. Discharge-before-charge function is included to 4F, 9 Industry E. 9th Rd, Science-Based Industrial Park, Hsinchu, Taiwan TEL: 886-3-5772500 or FAX: 886-3-5772510 www.analog.com.tw DS-1781-01 012102 1 AIC1781 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. n TYPICAL APPLICATION CIRCUIT D1 R2 1K D2 L1 IN4148 C4 220F 3 C1 4 BOOST DE IS C10 47nF 91K Q1 MPS2222A 3 4 + 5 FB 470P GND VCC 6 BAT1 C3 220F AIC1563 LED1 VTS VCC GND LED2 DIS 680 RX R7 R14 200K + RY C6 0.1F C11 100F C8 7 R6 8 50K 0.1F DSW ICON VBT R15 5 RS 0.3/1W 6 CF 2 C7 0.1F 4.7F 1N5819 IN4148 7 C9 R9 D4 D3 8 DC PEAK + THERMISTOR 2 1 ADJ SEL1 SEL3 SEL2 MODE TMR R11 LED2 LED3 R12 100K U2 YELLOW 0.1F **BATTERY 1 PB SW R10 100K R8 300K C5 U1 R4 20/5W IN5819 + 1F R5 120/0.5W 390K 270 LED1 220H C2 SW1 R3 R1 GREEN RED R16 R17 680 680 16 15 14 13 12 11 10 9 AIC1781 100K U3 VIN 11~15V 78L05 VOUT VIN + R13 470K Q2 MMBT2222A + C12 GND 1F C13 10F **3~5 NiMH/NiCd cells. Note: Charge Current=0.3/RS Ampere Safety Timer: 80min Battery Charge Circuit for Fluctuating Charging Current Application n ORDERING INFORMATION AIC1781CXXX PIN CONFIGURATION PACKING TYPE TR: TAPE & REEL TB: TUBE PACKAGE TYPE N: PLASTIC DIP S: SMALL OUTLINE Example: AIC1781CSTR a in SO-16 Package & Tape & Reel Packing Type (CN is not available in TR packing type) TOP VIEW 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 2 AIC1781 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 ........................................ ... ... ... ... .............. 0C~ 70C Storage Temperature Range ................................................ ... ... ... ...... -65C~ 150C n TEST CIRCUIT VCC VOLTAGE SOURCE - PEAK DSW VBT ICON DIS LED2 R3 + YELLOW R1 + 560 R4 GREEN 560 560 - ORANGE VTS LED1 RED 560 AIC1781 VOLTAGE SOURCE R5 VCC GND ADJ SEL1 VCC SEL3 SEL2 VCC TMR MODE VCC VCC VCC (5V) VCC V1 (0.95V) V2 (3V) 100K R2 n ELECTRICAL CHARACTERISTICS (TA=25C, VCC=5V, unless otherwise specified.) PARAMETER SYMBOL MIN. TYP. MAX. UNIT Supply Voltage VCC 4.5 5.0 5.5 V Supply Current ICC Voltage Protection Limit TEST CONDITIONS Battery Low During Initial Timer After Initial Timer (SEL3>3V) (SEL3<2V) Battery High (SEL3>3V) (SEL3<2V) VBT 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 V 3 AIC1781 n ELECTRICAL CHARACTERISTICS (Continued) PARAMETER TEST CONDITIONS SYMBOL Temperature High Temperature Sense Limit Output impedance of DIS Pin MAX. 1.35 1.45 1.55 3.5 3.6 3.70 140 250 25 50 M ZDIS LED1, LED2, ICON pins ON OFF Output Impedance TYP. Source Current Capability SEL3 pin DSW pin Input Impedance MODE, PEAK, SEL1, SEL2 pins UNIT V VTS Temperature Low MIN. 1 ISEL3 IDSW VBT, VTS, ADJ pins 5.5 16 A 300 K 1 Recommended External Resistor of TMR pin RTMR M 2 100 -V Detection Level w.r.t.* Peak Value 1000 K -0.25 % * w.r.t.: with respect to n TYPICAL PERFORMANCE CHARACTERISTICS (TA=25C, R2=100K, VCC=5V, refer to Test Circuit) 1.21 81.0 Safety Timer (min.) Supply Current (mA) 1.18 1.12 1.06 80.5 80.0 79.5 1.00 79.0 4.4 4.6 4.8 5.0 5.2 5.4 4.4 4.6 Fig. 2 Supply Current vs. Supply Voltage 4.8 5.0 5.2 5.4 VCC (V) VCC (V) Fig. 3 Safety Timer vs. Supply Volatge 4 AIC1781 n TYPICAL PERFORMANCE CHARACTERISTICS (Continued) 4.8 1.26 Supply Current (mA) Frequency (Hz) 4.6 4.4 4.2 1.14 1.02 4.0 3.8 0.9 4.4 4.6 4.8 5.0 5.2 0 5.4 20 Fig. 4 40 60 80 Temperature (C) VCC (V) LED Flashing Frequency vs. Supply Voltage Fig. 5 Supply Current vs. Temperature 5.0 82.0 Frequency (Hz) Safety Timer (min.) 4.6 81.0 4.2 80.0 3.8 79.0 0 20 40 60 3.4 0 80 20 Temperature(C) Fig. 6 40 60 80 Temperature(C) Safety Timer vs. Temperature Fig. 7 2.74 LED Flashing Frequency vs. Temperature 2.03 VBT (V) VBT (V) 2.70 2.01 2.66 1.99 1.98 2.62 0 20 40 60 80 0 20 Fig. 8 VBT (High) Limit vs. Temperature (SEL3>3V) 40 60 80 Temperature (C) Temperature (C) Fig. 9 VBT (High) Limit vs. Temperature (SEL3<2V) 5 AIC1781 n TYPICAL PERFORMANCE CHARACTERISTICS (Continued) 0.163 Output Impedance() 29 VBT (V) 0.162 0.161 0.160 0.159 27 25 0.158 23 0 20 40 60 80 0 20 Temperature (C) Fig. 10 40 60 80 Temperature (C) VBT (Low) Limit vs. Temperature (During Initial Timer) Fig. 11 Output Impedance vs. Temperature (LED1,LED2,ICON pins) 1.48 3.62 1.46 VTS (V) VTS (V) 3.61 3.60 1.44 3.59 3.58 0 20 40 60 1.42 80 0 Temperature (C) Fig. 12 20 40 60 80 Temperature (C) VTS (High) Limit vs. Temperature Fig. 13 VTS (Low) Limit vs. Temperature 1.24 0.700 0.695 VBT(V) VBT (V) 1.22 0.690 1.20 0.685 1.18 0 20 40 60 Temperature (C) Fig. 14 VBT (Low) Limit vs. Temperature (SEL3>3V, After Initial Timer) 80 0 20 40 60 80 Temperature (C) Fig. 15 VBT (Low) Limit vs. Temperature (SEL3<3V, After Initial Timer) 6 AIC1781 n BLOCK DIAGRAM PEAK MODE Peak Voltage Timer Control SEL3 MODE Selection GND VCC Bandgap Reference & Voltage Regulator Battery Voltage & Temperature Portection Setting SEL2 LED`s Display & Trickle Pulse Duty Setting ADJ T/t Detection Setting LED2 Oscillator LED1 Charge Control SEL1 TMR Display Control Unit ICON State Machine Charge Control Unit DIS Battery Temp. Protection 13-bit A/D VTS Battery Voltage Protection Discharge Control Unit DSW VBT n PIN DESCRIPTIONS PIN 1: PEAK- Tri-level input, determining the PIN 2: VBT- The battery cell temperature is period of peak voltage timer. represented as a voltage input (See 0V cut-off section in to the AIC1781 at this pin. The application informations.) acceptable voltage range of Divided battery voltage input to sense the battery voltage. PIN 3: DIS- PIN 4: VTS- Push-pull output, used VTS pin is 0.29VCC to 0.72VCC. The battery temperature is regarded as too high if the to voltage of VTS pin is lower control an external transistor to than 0.29VCC, and is otherwise discharge the battery. DIS is regarded as too low if the active high when the AIC1781 voltage of VTS pin is higher enters discharge mode. than 0.72VCC. 7 AIC1781 PIN 5: VCC- Power supply input at 5V10%. PIN 6: ADJ- For adjusting the slope of T/t. PIN 11: SEL1- The same as Pin 10. Acceptable voltage range for PIN 12: GND- Power ground. this pin is approximately 0.28V to 3.8V. If voltage higher than PIN 13: LED1 & VCC-0.3V, PIN 14: LED2- Open-drained outputs used to the function of T/t detection is disabled. indicate the battery charging status. Two modes of display PIN 7: SEL3- Determine acceptable are available, depending on voltage range of VBT pin and the the setting of SEL1 and SEL2 mode pins. of temperature protection function. PIN 8: TMR- PIN 15: ICON- Open-drained output, used to Determine the period of safety control the charging current to timer with an external resistor the battery. connected to GND. PIN 9: MODE- Determine the mode of operation for the AIC1781. PIN 10: SEL2 - Tri-level inputs, that jointly control the LED display mode PIN 16: DSW- Controlling discharge- the function before- of charge. (See discharge- before- charge subsection in application informations). and the duty of trickle charge after the completion of fast charge. 8 AIC1781 n APPLICATION INFORMATIONS discharge is finished. The application circuit is l THE AIC1781 OPERATION included in TYPICAL APPLICATION CIRCUIT. Power-on and Battery Pre-qualifying When power is first applied to the AIC1781, all internal digital circuit blocks of the AIC1781 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 AIC1781 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 AIC1781 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 AIC1781 constantly If the voltage of VTS pin is outside the 0.29 VCC to monitors the voltages at VBT and VTS pins. The 0.72 VCC window, action of AIC1781 is determined fast charge process is switched to trickle charge by the input voltage of SEL3 pin. when any one of the following situations is encountered, which are explained below: Discharge-Before-Charge The AIC1781 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 AIC1781 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. 0V Cutoff If the battery voltage stays at its peak value or decreases very slowly for the duration determined 9 AIC1781 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 AIC1781 is performed chart of AIC1781 (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 (0V) 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 AIC1781 measures the battery voltage through connected from TMR pin to GND. Safety timer, -V VBT pin, which is connected to battery positive sampling rate, and T/t sampling rate will be terminal through a resistor-divider network, as longer if the resistor value is larger. When the value shown in Fig. 17. The input voltage of SEL3 pin of the resistor is 100K, 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 AIC1781 guards against the maximum limits + C5 2 VBT 100K C6 0.1F action is terminated. 4.7F safety timer period is finished, the fast charge AIC1781 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 AIC1781 Battery Temperature Measurement TABLE 2 The AIC1781 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 (K) RB (K) 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(K) RB (K) 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 0.1F 4 Thermistor number of battery cells are as below: 5 VCC Rx For SEL3 < (VCC/2) -0.4V, the suggested divider VTS AIC1781 Ry 12 GND Fig. 18 Battery Temperature Sense Circuit with a Negative Temperature Coefficient (NTC) Thermistor 11 AIC1781 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 Yes If Discharge Enabled 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 AIC1781 12 AIC1781 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 = -10C TH (C) RTL= The resistance of thermistor at lower limit of temperature protection. Substitution and rearranging the equations yield Rx= 2.061 x RTL x RTH Rx (K) Ry (K) 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 x RTL x 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 = 0C TH (C) Rx(K) Ry (K) 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 AIC1781. The calculation of ADJ pin voltage is shown in the following procedure followed by an example. 13 AIC1781 Procedure (a) First, determine the temperature protection limits TH and TL. Then, substitute TH & TL into the following equation: V TS 0.72 V CC - 0.29 V CC 0.43 V CC = = TBASE TH - TL TH - TL (b) Determine the safety timer to obtain the value of tBASE . 56(sec.) tBASE(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 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 0C to 60C is as below. TABLE 7 ADJ Pin Voltage (TL=0C, TH=60C) T / t 0.75 S.T. (a) Let TH=50C, TL=0C, VCC =5V. We have VTS 0.43 x 5 = 0.043V/ C = TBASE 50 - 0 which means that VTS decreases 43mV as (C/min.) (C/min.) (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 (a) SEL3 > VCC - 0.3V Acceptable VBT Range: Before initial timer: 0.16V~2.7V temperature rises 1C. After initial timer: 0.69V~2.7V (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 1 T/t = = 0.0166 60 (d) VADJ =25 x 0.043x 0.0166 x 56 = 1(V) If the temperature range is from 0C to 50C, Temperature Protection Mode: Entering charge-suspending conditions should be set as tabulated below. ADJ pin Voltage (TL=0C, TH=50C) S.T. 40 min. (2C) 0.75 1.0 1.25 (C/min.) (C/min.) (C/min.) 0.37 0.5 0.63 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. the voltage of VADJ under different setting T / t 1.25 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: Example TABLE 6 1.0 (b) VCC - 1.4V> SEL3 > V cc - 0.4V 2 Acceptable VBT Range: Before initial timer: 0.16V~2.7V After initial timer: 0.69V~2.7V Temperature Protection Mode: 14 AIC1781 If temperature is too high, battery charging is 800 regarded as completed. If temperature is too low, function of T/t detection is disabled, just (c) RTMR (K) as thermistor is not existing. 600 V cc - 0.4V>SEL3 >1.4V 2 400 200 Acceptable VBT Range: 0 Before initial timer: 0.16V~2V 0 After initial timer: 1.2V~2V charge-suspending Fig. 19 mode abnormal battery voltage. Latch for TABLE 8 RTMR (K) charge-suspending function is provided for high temperature protection, but not 300 400 500 Safety Timer vs. RTMR when temperature is either too low or too high, same as 200 Safety Timer (min.) Temperature Protection Mode: Entering 100 for low temperature protection. (d) 0.3V> SEL3 Acceptable VBT Range: 11 OSC. Freq.(KHz) 262.4 Safety timer (min.) 10 23 131.2 20 48 65.6 40 74 43.7 60 100 32.8 80 Before initial timer: 0.16V~2V 152 21.9 120 After initial timer: 1.2V~2V 206 16.4 160 314 10.9 240 491 7.3 360 667 5.5 480 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. Selecting Mode of Operation The AIC1781 provides three modes of operation: Setting the Period of Safety Timer normal, test, and AC mode determined by the The AIC1781 provides a method for linearly setting of MODE pin according to TABLE 9. The adjusting the period of safety timer with an external AIC1781 will operate normally when the MODE pin resistor connected from TMR pin to GND. The is left floating (a 0.1F capacitor is recommended relation between safety timer length and the to be tied to MODE pin if the charge circuit works external resistor (RTMR) is shown in Fig. 19. The in a noisy environment). When the MODE pin is table following shows the resistor values for some biased to GND, the function of -V detection is of the commonly chosen safety timer periods. Also shown in the table are their corresponding oscillator frequencies. disabled. When the MODE pin is biased to VCC, the AIC1781 enters the test mode. The test mode can be used to significantly reduce production test time. For relevant informations please contact AIC directly. 15 AIC1781 TABLE 9 The Operating Mode of AIC1781 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 AIC1781 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 AIC1781 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 AIC1781 enters the trickle charge mode. In trickle charge mode, the ICON pin output SEL1 VCC Floating GND SEL2 Trickle Charge LED Display Duty Mode 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 AIC1781 provides two open-drained outputs, Fig. 20 shows the timing diagram for externally LED1 and LED2, to indicate the battery charging controlled PEAK, ADJ, VBT, VTS, SEL1 and status. Refer to the table of LED display mode SEL2 pin voltages of a recommended AIC1781 (TABLE 10), depending on the setting of SEL1 test scheme, utilizing TEST mode function. and SEL2 pins, the outputs of LED1 and LED2 Output waveforms of LED1, LED2 and ICON of a pins are shown in the following table: properly functioning AIC1781 are also shown in TYPE 1 the figure. Fast Charge Fault Power Completed Conditions ON Charging LED1 1Hz ON OFF OFF LED2 OFF OFF ON OFF 16 AIC1781 n TIMING DIAGRAM VCC, SEL3, MODE=5V, (DSW FREQ.=820KHz, 25 TIMES of 32.8K) Power Init. ON -V TEST PEAK TIMER TEST 5V PEAK -V DISALBE 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 2mV Step/100mS 1.993V (-0.35%) 4V 4V 2V 2V 1.96V 0V 1.85V (-2.15%) (-2.5%) 2V 2mV Step/100mS OFF OFF OFF OFF 4V 4V 2V VTS 2V 1.997V ON ON ON LED1 OFF 3.2KHz LED2 ON OFF ICON ON OFF OFF ON SEL1 SEL2 TIME ON ON Floating Floating VCC Floating 0.1 0.14 0.12 0.28 0.2 0.12 3 4 0.32 GND Floating Floating GND 0.32 0.12 5 6 0.32 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 AIC1781 in Test Mode 17 AIC1781 n PHYSICAL DIMENSIONS l 16 LEAD PLASTIC DIP (unit: mm) D 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 E1 E A2 A1 C L e eB b eB -- 10.92 L 2.92 3.81 16 LEAD PLASTIC SO (300 mil) (unit: mm) D E H A B SYMBOL 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 A1 l e 2.54(TYP) c L 1.27(TYP) H 10.00 10.65 L 0.40 1.27 18