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. l l l l l l l l l l l l 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