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AAT3663 1A Linear Li-Ion Battery Charger for Single and Dual Cell Applications General Description The AAT3663 BatteryManagerTM is a member of AnalogicTech's Total Power Management ICTM family. This device is an integrated single/dual cell Lithium-Ion (Li-Ion) / polymer battery charger IC designed to operate from USB ports or an AC adapter inputs up to an input voltage of 13.2V. AAT3663 precisely regulates battery charge voltage and current for 4.2V and 8.4V Li-Ion battery cells. The battery charging current is user programmed up to 1A by an external resistor. Battery charge state is continuously monitored for fault conditions. A Digital Thermal Loop Control maintains the maximum possible battery charging current for the optimum set of input to output power dissipation and ambient temperature conditions. In the event of an over-current, over-voltage, shortcircuit, or over-temperature fault condition, the device will automatically shut down, thus protecting the charger and the battery under charge. Two status monitor output pins are provided to indicate the battery charge status by directly driving external LEDs. Additionally, an open-drain powersource detection output (ADPP#) is provided to report presence of an input power supply The AAT3663 is available in a thermally enhanced, space-saving, 14-pin 3x3 mm TDFN package and is specified for operation over the -40C to +85C temperature range. Features * * * * * * * * * * * * * * * * BatteryManagerTM 4.0V ~ 13.2V Input Voltage Range Compatible with USB or AC Adapter Sources Programmable Fast Charge Current from 100mA to 1A Programmable Charge Termination Current Digital Thermal Loop Charge Reduction Less Than 0.4A Battery Leakage Current Programming Charge Timer Battery Temperature Sensing Battery Temp Sense Open Circuit Detection Automatic Recharge Sequencing Automatic Trickle Charge for Battery Pre-Conditioning Automatic Charge Termination Shutdown/Sleep Mode Less than 1A Shutdown Current Over-Voltage and Over-Current Protection Power On Reset and Soft Start 3x3mm 14-pin TDFN Package Applications * * * * * * BluetoothTM Headset Cell Phones Digital Still Cameras MP3 Players Personal Data Assistants (PDAs) Other Li-Ion Battery Powered Devices Typical Application ON/OFF EN BATS VIN IN BAT BATT+ 10F BATTTEMP STAT1 STAT2 ADPP# GND TS TERM ISET CT CT RSET R TERM Battery Pack AAT3663 3663.2007.10.1.0 1 AAT3663 1A Linear Li-Ion Battery Charger for Single and Dual Cell Applications Pin Description Pin # 1 2 3 4 5 6 7 8, 9 10 11 12 13 Symbol EN CT ISET GND TS BATS BAT IN STAT1 STAT2 ADPP# TERM Type I I I I/O I/O I O I O O O I Function Enable pin, Active high with internal pull-down. If not used, pull high to the IN pin to continuously enable the charger IC when input power is applied. Charge timer programming pin. A 0.1F ceramic capacitor should be connected between this pin and GND. Connect directly to GND to disable the timer function. Charge current programming pin. Connect a resistor between this pin and GND to program the constant fast charge current. IC ground connection. Connect this pin to power ground. Battery temperature sense input. Connect the Li-Ion battery pack NTC resistor terminal to this pin. Battery voltage sense pin. Connect this pin directly to the positive battery terminal. If this function is not used, connect to the BAT pin directly. Battery charge output pin. Connect to the positive battery terminal. Power supply input pin. Connect the input USB port or Adapter power source to this pin Charge status pin, open-drain output. Connect the STAT1 LED with a series ballast resistor between IN and this pin. Charge status pin, open-drain output. Connect the STAT2 LED with a series ballast resistor between IN and this pin. Input supply power-good status pin, open-drain output. Connect the ADPP# status LED with a series ballast resistor between IN and this pin. Charge termination current programming input pin. Connect a resistor between this pin and GND to program the charge termination current. When TERM is open, the termination current is 10% (default sertting) of the set maximum charge current. No connection. 14 N/C Pin Configuration TDFN33-14 (Top View) EN CT ISET GND TS BATS BAT 1 2 3 4 5 6 7 14 13 12 11 10 9 8 N/C TERM ADPP# STAT2 STAT1 IN IN 2 3663.2007.10.1.0 AAT3663 1A Linear Li-Ion Battery Charger for Single and Dual Cell Applications Absolute Maximum Ratings1 Symbol VIN VN VN TJ TLEAD Description IN Continuous Voltage STAT1, STAT2, ADPP#, EN, BAT, BATS TS, CT, TERM, ISET Operating Junction Temperature Range Maximum Soldering Temperature (at Leads) Value -0.3 to 14 -0.3 to VIN + 0.3 -0.3 to 5.5 -40 to 150 300 Units V V V C C Thermal Information2 Symbol JA PD Description Maximum Thermal Resistance (TDFN3x3) Maximum Power Dissipation Value 50 2 Units C/W W AAT3663 Feature Options Product AAT3663-4.2-1 AAT3663-4.2-2 AAT3663-8.4-1 AAT3663-8.4-2 Number of Battery Cells Single Single Dual Dual Battery Temperature Sense For Use With Any NTC Thermistor For Use With 10k NTC Thermistor For Use With Any NTC Thermistor For Use With 10k NTC Thermistor 1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at conditions other than the operating conditions specified is not implied. Only one Absolute Maximum rating should be applied at any one time. 2. Mounted on a FR4 board. 3663.2007.10.1.0 3 AAT3663 1A Linear Li-Ion Battery Charger for Single and Dual Cell Applications Electrical Characteristics VIN = 5V, TA = -25 to +85C; Unless otherwise noted, typical values are at TA = 25C Symbol Operation VIN Description Conditions Min 4.0 3 Typ Max 13.2 4 Units V V mV mV mA A A A Input Voltage Range Under Voltage Lockout Threshold VUVLO UVLO Hysteresis Adapter Present Indicator Threshold VADPP_TH Voltage, VIN - VBAT IOP Operating Current ISHUTDOWN Shutdown Current ILEAKAGE Leakage Current from BAT Pin ENLEAKAGE EN Pin Leakage Voltage Regulation VBAT_EOC VBAT_EOC/ VBAT_EOC VMIN End of Charge Voltage Regulation End of Charge Voltage Accuracy Preconditioning Voltage Threshold Rising Edge 150 VIN > VUVLO Charge Current = 100mA VBAT = 4.25V, EN = GND VBAT = 4V, IN = Open VEN = 5V AAT3663-4.2 AAT3663-8.4 4.158 8.316 50 0.35 0.4 0.4 0.6 4.2 8.4 0.5 AAT3663-4.2 AAT3663-8.4 AAT3663-4.2 2.5 5.0 2.6 5.2 VBAT_EOC - 0.1 VBAT_EOC - 0.2 100 RISET = 1.74K (for 1A), VBAT = 3.6V RISET = 17.8K (for 0.1A), VBAT = 3.6V Constant Current Mode, VBAT = 3.6V RTERM = 40k TERM pin open RTERM = 13.3 k, ICH_CC 800mA VIN = 5V 1.6 STAT Pin Sinks 4mA 0.4 0.4 8 5 5 8 900 80 1000 100 2 900 0.6 10 10 10 1000 1100 2.7 5.4 100 1 1 2 4.242 8.484 V % V VRCH Battery Recharge Voltage Threshold AAT3663-8.4 V Current Regulation ICC_RANGE Charge Current Programmable Range ICH_CC VISET KISET VTERM ICH_TRK ICH_TERM Constant-Current Mode Charge Current ISET Pin Voltage Charge Current Set Factor: ICH_CC/ISET TERM Pin Voltage Trickle-Charge Current Charge Termination Current Threshold mA mA 120 V V 15 15 12 % ICH_CC % ICH_CC % ICH_CC m Charging Devices RDS(ON) Charging Transistor ON Resistance Logic Control / Protection Input High Threshold VEN Input Low Threshold VSTAT Output Low Voltage ISTAT STAT Pin Current Sink Capability 330 500 V V mA 4 3663.2007.10.1.0 AAT3663 1A Linear Li-Ion Battery Charger for Single and Dual Cell Applications Electrical Characteristics VIN = 5V, TA = -25 to +85C; Unless otherwise noted, typical values are at TA = 25C Symbol Description Conditions ADPP# Pin Sinks 4mA AAT3663-4.2 AAT3663-8.4 CT = 100nF, VIN = 5V CT = 100nF, VIN = 5V CT = 100nF, VIN = 5V AAT3663-2 Only Threshold, AAT3663-2 Only Hysteresis, AAT3663-2 Only Threshold, AAT3663-2 Only Hysteresis, AAT3663-2 Only Threshold, AAT3663-1 Only Hysteresis, AAT3663-1 Only Threshold, AAT3663-1 Only Hysteresis, AAT3663-1 Only 71 316 2.30 29.1 58.2 4.4 8.8 105 TC/8 3 3 75 331 25 2.39 25 30 2 60 2 115 85 100 140 15 Min Typ Max 0.4 8 Units V mA V %VCS Hour Hour Hour A mV mV %VIN %VIN C C C C Logic Control / Protection VADDP# Output Low Voltage IADPP# ADDP# Current Sink Capability VOVP VOCP TK TC TV ITS TS1 TS2 VTS1 VTS2 TLOOP_IN TLOOP_OUT TREG TSHDN Over-Voltage Protection Threshold Over-Current Protection Threshold Trickle Charging Time-Out Trickle and Constant Current Mode Time-Out Constant Voltage Mode Time-Out Current Source from TS Pin TS Hot Temperature Fault TS Cold Temperature Fault High Temperature Threshold Low Temperature Threshold Digital Thermal Loop Entering Threshold Digital Thermal Loop Exiting Threshold Digital Thermal Loop Regulation Over-Temperature Shutdown 79 346 2.48 30.9 61.8 Threshold Hysteresis 3663.2007.10.1.0 5 AAT3663 1A Linear Li-Ion Battery Charger for Single and Dual Cell Applications Typical Characteristics Operating Current vs ISET Resistor 2000 Constant Charging Current vs. Set Resistor Values Constant Charge Current (mA) 10000 Operating Current (A) 1800 1600 1400 1200 1000 800 600 400 200 0 1 10 100 Preconditioning Mode Constant Current Mode 1000 100 10 1 1 10 100 RSET (k) RSET (k) End of Charge Voltage Accuracy vs. Input Voltage (VBAT_EOC = 4.2V) 0.100 End of Charge Voltage vs. Temperature 4.220 4.215 End of Charge Voltage Accuracy (%) 0.075 Battery Voltage (V) 0.050 0.025 0.000 -0.025 -0.050 -0.075 -0.100 4 5 6 7 8 9 10 11 12 13 14 4.210 4.205 4.200 4.195 4.190 4.185 4.180 -40 -15 10 35 60 85 Input Voltage (V) Temperature (C) Recharge Threshold Voltage vs. Input Voltage 4.120 4.115 4.14 4.13 Recharge Voltage vs. Temperature (VIN = 5V; RSET = 8.87k) Battery Voltage (V) 4.110 4.105 4.100 4.095 4.090 4.085 4.080 4 5 6 7 8 9 10 11 12 13 14 Battery Voltage (V) 4.12 4.11 4.10 4.09 4.08 4.07 4.06 -40 -15 10 35 60 85 Input Voltage (V) Temperature (C) 6 3663.2007.10.1.0 AAT3663 1A Linear Li-Ion Battery Charger for Single and Dual Cell Applications Typical Characteristics Constant Charging Current vs. VBAT (RSET = 8.87k) 240 Constant Charging Current vs. Battery Voltage 1200 Charging Current (mA) 210 180 150 120 90 60 30 0 2.3 2.5 2.7 2.9 3.1 3.3 VIN = 13.2V 1000 1.78K 2.21K 3.57K 8.87K VIN = 7.5V VIN = 5V ICH (mA) VIN = 9.5V VIN = 12V 800 600 400 200 0 2.5 3.5 3.7 3.9 4.1 4.3 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 VBAT (V) Battery Voltage (V) Preconditioning Threshold Voltage vs. Input Voltage 2.70 2.68 Preconditioning Threshold Voltage vs. Temperature 2.70 2.68 Battery Voltage (V) 2.66 2.64 2.62 2.60 2.58 2.56 2.54 2.52 2.50 4 5 6 7 8 9 10 11 12 13 14 Battery Voltage (V) 2.66 2.64 2.62 2.60 2.58 2.56 2.54 2.52 2.50 -40 -15 10 35 60 85 Input Voltage (V) Temperature (C) Preconditioning Charge Current vs. Input Voltage 120 100 80 Temperature Sense Output Current vs. Temperature 79 78 RSET = 1.78k RSET = 2.21k ITS (A) RSET = 3.57k RSET = 8.87k ICH_TRK (mA) 80 60 40 20 0 4 77 76 75 74 73 72 71 70 5 6 7 8 9 10 11 12 13 14 -40 -15 10 35 60 85 Input Voltage (V) Temperature (C) 3663.2007.10.1.0 7 AAT3663 1A Linear Li-Ion Battery Charger for Single and Dual Cell Applications Typical Characteristics Constant Charge Current vs. Input Voltage 240 2.40 Shutdown Current vs. Input Voltage Shutdown Current (A) Charge Current (mA) 230 220 210 200 190 180 170 160 4 5 6 7 8 10 11 12 13 14 2.10 1.80 1.50 1.20 0.90 0.60 0.30 0.00 4 5 6 7 8 9 10 11 12 85C 25C VBAT = 3V VBAT = 3.5V -40C VBAT = 3.9V VBAT = 4.1V 13 14 Input Voltage (V) Input Voltage (V) Input High Threshold vs. Input Voltage 1.60 1.40 1.20 Input Low Threshold vs. Input Voltage 1.60 1.40 1.20 VEN(H) (V) -40C 1.00 0.80 0.60 0.40 4 5 6 7 8 9 10 11 12 13 14 VEN(L) (V) -40C 1.00 0.80 0.60 0.40 4 5 6 7 8 9 10 11 12 13 14 25C 85C 25C 85C Input Voltage (V) Input Voltage (V) Charging Transistor On Resistance vs. Input Voltage 600 500 Termination Current to Constant Current Ratio (%) vs. Termination Resistance 50 45 85C RDS(ON) (m) 400 300 200 100 0 4.0 4.4 4.8 5.2 5.6 6.0 6.4 6.8 7.2 7.6 8.0 8.4 ICH_TERM/ICH_CC (%) 40 35 30 25 20 15 10 5 0 0 10 20 30 40 50 60 25C -40C Input Voltage (V) RTERM (k) 8 3663.2007.10.1.0 AAT3663 1A Linear Li-Ion Battery Charger for Single and Dual Cell Applications Typical Characteristics CT Pin Capacitance vs. Counter Timeout 1.0 0.9 Capacitance (F) 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 Preconditioning + Constant Current Timeout or Constant Voltage Timeout Preconditioning Timeout Timeout (h) 3663.2007.10.1.0 9 AAT3663 1A Linear Li-Ion Battery Charger for Single and Dual Cell Applications Functional Block Diagram Reverse Blocking IN Current Compare Charge Control CV/ Precharge BAT BATS ISET TERM Constant Current UVLO Over-Temp Protect Power Detection Thermal Loop ADPP# Charge Status STAT 1 STAT 2 EN 75A AAT3663-2 Only TS Window Comparator GND Watchdog Timer CT Functional Description The AAT3663 is a high performance battery charger designed to charge single/dual cell Lithium-Ion or Lithium-Polymer batteries with up to 1000mA of current from an external power source. It is a highly integrated stand-alone charging solution, with the least external components required for complete functionality. The AAT3663 precisely regulates end of charge battery voltage and current for single cell 4.2V and dual cell 8.4V lithium-ion/polymer battery with a programmable constant current range from 100mA to 1A for fast charging applications. The system has a default charge termination current set to 10 percent of the programmed fast charge constant. The charge termination current may also be user programmed by an external resistor. During battery charging, the device temperature will rise. In some cases with adapter (ADP) charging, the power dissipation in the charge regulation pass device may cause the junction temperature to rise and approach the internal thermal shutdown threshold. Excessive power dissipation is caused by the high input adapter voltage versus the low output battery cell voltage difference at a given constant charge current. 10 In the event of an internal over-temperature condition caused by excessive ambient operating temperature or excessive power dissipation conditions, the AAT3663 enables a digitally controlled thermal loop system that will reduce the charging current to prevent thermal shutdown. The digital thermal loop will maintain the maximum possible battery charging current for a given set of input to output power dissipation and ambient temperature conditions. The digital thermal loop control is dynamic in the sense that it will continue to adjust the battery charging current as operating conditions change. The digital thermal loop will reset and resume normal operation when the power dissipation or over-temperature conditions are removed. In the event of an over-voltage, over-current or overtemperature false condition beyond the limits of the digital thermal loop system, the device will automatically shut down, thus protecting the charging device, control system, and the battery under charge. AAT3663 provides two status monitor pins, STAT1 and STAT2. These pins are open drain MOSFET switches intended to directly drive external LEDs to indicate the battery charging state. A third status pin is prided to 3663.2007.10.1.0 AAT3663 1A Linear Li-Ion Battery Charger for Single and Dual Cell Applications indicate the presence of power on the input supply pin. This open drain MOSFET switch may be used to either power a display LED or to alert a system microcontroller for the presence on input power. Constant Current Charging Trickle charging continues until the battery voltage reaches the VMIN threshold. At this point, the AAT3663 begins constant-current fast charging. The current level for this mode is programmed using a single resistor from the ISET pin to ground. Programmed current can be set at a minimum 100mA up to a maximum 1A. Battery Charging Operation Figure 1 illustrates the entire battery charging profile and operation, which consists of three phases: 1. Preconditioning (Trickle) Charge 2. Constant Current Charge 3. Constant Voltage Charge When power is initially applied or when a battery pack is connected to the BAT pin, battery charging commences after the AAT3663 checks several conditions in order to maintain a safe charging environment. The input supply must be above the minimum operating voltage (UVLO) and the enable pin must be high (internally pulled down). When the battery is connected to the BAT pin the AAT3663 checks the condition of the battery and determines which charging mode to apply. Constant Voltage Charging Constant current charging continues until such time that the battery voltage reaches the voltage regulation point VBAT_REG. When the battery voltage reaches VBAT_REG, the AAT3663 will transition to the constantvoltage mode. The regulation voltage is factory programmed to a nominal 4.2V for the AAT3663-4.2 option and to 8.4V for the AAT3663-8.4 option. Under default conditions with the TERM pin not connected (open circuit), constant voltage charging will continue until the charge current has reduced to 10% of the programmed current. Placing a resistor between the TERM pin and ground allows the user to program a desired termination current. After the charge cycle is complete, the AAT3663 turns off the series pass device and automatically goes into a power saving sleep mode. During this time the series pass device will block current in both directions therefore preventing the battery discharging through the IC. The AAT3663 will remain in sleep mode, until either the battery terminal voltage drops below the VRCH threshold, the charger EN pin is recycled or the charging power source is reconnected. In all cases the AAT3663 will monitor all battery parameters and resume charging in the appropriate mode. Battery Preconditioning If the battery voltage is below VMIN, the AAT3663 begins battery trickle charging by charging at 10% of the programmed constant-current. For example, if the programmed current is 500mA, then the trickle charge current is 50mA. Trickle charging is a recommended safety precaution for a deeply discharged cell and maximizes the charge cycle life of the battery. In addition, charger IC power dissipation for the internal series pass MOSFET is minimized when the input-output voltage differential is at its highest. This in turn allows the charging operation to commence over wider thermal and input to output voltage differential conditions. Preconditioning Trickle Charge Phase Charge Complete Voltage Regulated Current I = Max CC Constant Current Charge Phase Constant Voltage Charge Phase Constant Current Mode Voltage Threshold Trickle Charge and Termination Threshold I = CC / 10 Figure 1: Current and Voltage Profile During Charging Phases. 3663.2007.10.1.0 11 AAT3663 1A Linear Li-Ion Battery Charger for Single and Dual Cell Applications System Operation Flow Chart Power On Sleep Sleep Reset Mode Mode ADP Voltage Power Input S Voltage ADP > V ADPP VIN>VUVLO Yes No Enable Power Select EN=HIGH Yes No FAULT Shut Down Shut Down STAT1=Off Mode STAT2=Off Mode Yes Fault Fault Condition Monitoring Power Select OV, OT, V TS1 MIN BAT Yes Shut Down Shut Down Shut Down Mode Mode Mode Expire No VBAT IBAT >ITERM Yes Preconditioning Shut Down Shut Down (Trickle Charge) Mode Mode Set No No Recharge Test VRCH >V BAT Yes Current Phase Test VIN > VBAT_EOC Yes Constant Current Shut Down Charge Mode Mode Mode Shut Down V >V CH BAT No Device Temp. No Device Temp. Monitor Monitor TJ >115C TJ >110 C Yes Thermal Loop Shut Down Shut Down Current Reduction In C.C. Mode Mode Mode Voltage Phase Test IBAT >ITERM Yes Constant Voltage Shut Down Shut Down Charge Mode Mode Mode IBAT MIN >I No Mode Charge Charge Charge Completed Completed Completed 12 3663.2007.10.1.0 AAT3663 1A Linear Li-Ion Battery Charger for Single and Dual Cell Applications Application Information Adapter or USB Power Input Constant current charge levels up to 1A may be programmed by the user when powered from a sufficient input power source. The AAT3663 will operate over an input voltage range from 4.0V to 13.2V. The low input voltage capability of the AAT3663 permits charging single cell Li-Ion/Poly batteries from USB ports and lower voltage input power sources. The high 13.2V input rating of this device allows for the use of a wide range of input power sources for both single and dual cell Li-Ion/Poly applications. battery sense function inadvertently becoming an open circuit, the BATS pin may be terminated to the BAT pin using a 10k resistor. Under normal operation, the connection to the battery terminal will be close to 0; if the BATS connection becomes an open circuit, the 10k resistor will provide feedback to the BATS pin from the BAT connection with a voltage sensing accuracy loss of 1mV or less. Enable (EN) EN is a logic input (active high) to enable the charger, this function is internally pulled down to ground. When the device is initially enabled or if the EN pin is cycled low and then re-enabled, the charge control circuit will automatically reset and resume charging functions with the appropriate charging mode based on the battery charge state and measured battery voltage on the BATS pin. Adapter Input Charge Inhibit and Resume The AAT3663 has an under-voltage lockout (UVLO) and power on reset feature so that if the input supply to the IN pin drops below the UVLO threshold, the charger will suspend charging and shut down. When power is reapplied to the IN pin or the UVLO condition recovers, the system charge control will assess the state of charge on the battery cell and will automatically resume charging in the appropriate mode for the condition of the battery. Programming Charge Current The constant current mode charge level is user programmed with a set resistor (RSET) connected between the ISET pin and ground. The accuracy of the constant charge current, as well as the preconditioning trickle charge current, is dominated by the tolerance of the set resistor used. For this reason, a 1% tolerance metal film resistor is recommended for the set resistor function. The constant charge current levels from 100mA to 1A may be set by selecting the appropriate resistor value from Table 1. Constant Charging Current (mA) 100 200 300 400 500 600 700 800 900 1000 Battery Connection and Battery Voltage Sensing Battery Connection A single or dual cell Li-Ion/Polymer battery should be connected between the BAT pin and ground. Battery Voltage Sensing The BATS pin is provided to employ an accurate voltage sensing capability to measure the positive terminal voltage at the battery cell being charged. This function reduces measured battery cell voltage error between the battery terminal and the charge control IC. The AAT3663 charge control circuit will base charging mode states upon the voltage sensed at the BATS pin. The BATS pin must be connected to the battery terminal for correct operation. If the battery voltage sense function is not needed, the BATS pin should be terminated directly to the BAT pin. If there is concern of the Set Resistor Value (k) 17.8 8.87 5.9 4.42 3.57 2.94 2.55 2.21 1.96 1.78 Table 1: RSET Values. 3663.2007.10.1.0 13 AAT3663 1A Linear Li-Ion Battery Charger for Single and Dual Cell Applications CC Mode Charge Current (mA) 10000 50 45 1000 ICH_TERM/ICH_CC (%) 40 35 30 25 20 15 10 5 100 10 1 1 10 100 0 0 10 20 30 40 50 60 RSET (k) RTERM (k) Figure 2: Constant Charging Current vs. RSET Resistor Values. If the desired charge current level is not listed in Table 1, the RSET resistor value can be found in Figure 2 and calculated by the following equation: RSET = K * Where: K = KI_SET = 900 VISET = 2V ICC = Fast charge constant current VISET ICC Figure 3: Charge Termination Current (% Value of the Programmed Fast Charge Current) vs. RTERM Resistance. If the desired charge termination current set resistor (RTERM) value is not shown in Figure 3, the value may be determined by the following equation: ICH_TERM = Where: ICH_TERM = Charge termination current level ICH_CC = Programmed fast charge constant current level RTERM = TERM resistor value 15A * RTERM * ICH_CC 2V Programmable Charge Termination Current The AAT3663 is designed with a default charge termination current set to 10 percent of the programmed fast charge constant current level. The charge termination current (ICH_TERM) may also be user programmed to a level other than 10% of the set fast charge current by connecting a set resistor (RTERM) between the TERM pin and ground. When the charge current under the constant voltage charging mode drops to the charge termination threshold the device halts charging and goes into a sleep mode. The charger will remain in the sleep mode until the battery voltage as sensed by the BATS pin decreases to a level below the battery recharge voltage threshold (VRCH). Charge termination current levels based on a percentage of the programmed fast charge current are shown in Figure 3. Battery Charge Status Indication The AAT3663 indicates the status of the battery under charge using three status LED driver outputs. These three LEDs can indicate simple functions such as input power present, no battery charge activity, battery charging, charge complete and charge fault. Status Indicator Display System charging status may be displayed using one or two LEDs in conjunction with the STAT1 and STAT2 pins on the AAT3663. These two pins are simple open drain N-channel MOSFET switches to connect the status LED cathodes to ground. It is not necessary to use both display LEDs if a user simply wants to have a single LED to show "charging" or "not charging". This can be accomplished 14 3663.2007.10.1.0 AAT3663 1A Linear Li-Ion Battery Charger for Single and Dual Cell Applications by just using the STAT1 pin and a single LED. Using two LEDs and both STAT pins simply gives the user more information for the various charging states. Refer to Table 2 for LED display definitions. The LED anodes should be connected to the charger power source input (IN pin). Event Description Charge enabled without battery Battery charging Charging completed Fault The required ballast resistor values can be estimated using the following formula: RBALLAST = Example: (VIN - VF(LED)) ILED STAT1 Flash1 ON OFF OFF STAT2 Flash1 OFF ON OFF RBALLAST = (5.0V - 2.0V) = 1.5k 2mA Note: Red LED forward voltage (VF) is typically 2.0V @ 2mA. Table 2: LED Status Indicator Truth Table. Digital Thermal Loop Control Due to the integrated nature of the linear charging control pass device for the adapter mode, a special thermal loop control system has been employed to maximize charging current under all operation conditions. The thermal management system measures the internal circuit die temperature and reduces the fast charge current when the device exceeds a preset internal temperature control threshold. Once the thermal loop control becomes active, the fast charge current is initially reduced by a factor of 0.28. The initial thermal loop current can be estimated by the following equation: ITLOOP = ICH_CC * 0.28 The thermal loop control re-evaluates the circuit die temperature every 1.5 seconds and adjusts the fast charge current back up in small steps to the full fast charge current level or until an equilibrium current is discovered and maximized for the given ambient temperature condition. The thermal loop controls the system charge level; therefore, the AAT3663 will always provide the highest level of constant current in the fast charge mode possible for any given ambient temperature condition. Input Power Present Indicator The ADDP# pin provides an additional open drain N-channel MOSFET switch to indicate the presence of power applied to the charger input (IN pin). This function may either be used to control an addition status LED to give a visual indication when input power is applied. This open drain output may also be pulled high via a pull up resistor to provide an active low signal to a system microcontroller to indicate the presence of applied input power. Status Display LED Biasing The LED should be biased with as little current as necessary to create reasonable illumination; therefore, a ballast resistor should be placed between the LED cathode and the STAT pin. LED current consumption will add to the overall thermal power budget for the device package, hence it is good to keep the LED drive current to a minimum. 2mA should be sufficient to drive most low-cost green or red LEDs. It is not recommended to exceed 8mA for driving an individual status LED. 1. Flashing rate depends on output capacitance. 3663.2007.10.1.0 15 AAT3663 1A Linear Li-Ion Battery Charger for Single and Dual Cell Applications Protection Circuitry Programmable Timer Function The AAT3663 contains a watchdog timing circuit to shut down charging functions in the event of a defective battery cell not accepting a charge over a preset period of time. Typically, a 0.1F ceramic capacitor is connected between the CT pin and ground. When a 0.1F ceramic capacitor is used, the device will time out a shutdown condition if the trickle charge mode exceeds 25 minutes and a combined trickle charge plus constant current mode of 3 hours. When the device transitions to the constant voltage mode, the timing counter is reset and will time out after an additional 3 hours if the charge current does not drop to the charge termination level. The AAT3663 has a battery fault detector, which, when used in conjunction with a 0.1F capacitor on the CT pin, outputs a 1Hz signal with 50% duty cycle at the STAT1 pin in the event of a timeout while in the trickle charge mode. Mode Trickle Charge (TC) Time Out Trickle Charge (TC) + Constant Current (CC) Mode Time Out Constant Voltage (CV) Mode Time Out Ceramic capacitor materials, such as X7R and X5R types, are a good choice for this application. Over-Voltage Protection An over-voltage event is defined as a condition where the voltage on the BAT pin exceeds the maximum battery charge voltage and is set by the overvoltage protection threshold (VOVP). If an over-voltage condition occurs, the AAT3663 charge control will shut down the device until the voltage on the BAT pin drops below VOVP. The AAT3663 will resume normal charging operation after the overvoltage condition is removed. During an over-voltage event, the STAT LEDs will report a system fault. Over-Temperature Shutdown The AAT3663 has a thermal protection control circuit which will shut down charging functions once the internal die temperature exceeds the over-temperature shutdown threshold. Once the internal die temperature falls below the hysteresis, normal operation will resume the previous charging state. Time 25 minutes 3 hours 3 hours Battery Temperature Fault Monitoring There are two AAT3663 temperature sense options, The AAT3663-1 and AAT3663-2. The AAT3663-1 option allows of the use of any NTC resistor. For ease of use, the AAT3663-2 option is factory set to function with typical 10k NTC resistors and eliminates the need for a resistor divider pull up to the input power source. Regardless of the AAT3663 option selected, the internal system control checks battery temperature before starting the charge cycle and continues to monitor the battery temperature during all stages of the charging cycle. This is accomplished by monitoring the voltage at the TS pin. In general, the system is intended for use with negative temperature coefficient thermistors (NTC) which are typically integrated into the battery package. The voltage on the TS pin resulting from the resistive load and applied current, should stay within a window bounded by the TS1 and TS2 specification thresholds. Refer to the Electrical Characteristics table for the TS1 and TS2 limits for a selected AAT3663 option. If the battery becomes too hot during charge cycle due to an internal fault or excessive charge current, the NTC thermistor will heat up and reduce in value. This in turn will pull the TS pin 3663.2007.10.1.0 Table 3: Summary for a 0.1F Ceramic Capacitor Used for the Timing Capacitor. The CT pin is driven by a constant current source and will provide a linear response to increases in the timing capacitor value. Thus, if the timing capacitor were to be doubled from the nominal 0.1F value, the timeout periods would be doubled. If the programmable watchdog timer function is not needed, it can be disabled by terminating the CT pin to ground. The CT pin should not be left floating or unterminated, as this will cause errors in the internal timing control circuit. The constant current provided to charge the timing capacitor is very small, and this pin is susceptible to noise and changes in capacitance value. Therefore, the timing capacitor should be physically located on the printed circuit board layout as close as possible to the CT pin. Since the accuracy of the internal timer is dominated by the capacitance value, a 10% tolerance or better ceramic capacitor is recommended. 16 AAT3663 1A Linear Li-Ion Battery Charger for Single and Dual Cell Applications voltage below than the TS1 threshold, and indicate a battery cell temperature fault. The charging process will then be suspended until the over-temperature condition is removed, at which time charging will resume. Conversely, if the battery under charge is exposed to extreme cold ambient temperature condition, the NTC thermistor may increase in value and push the voltage on the TS pin above the TS2 threshold. In such a case, the charge cycle will be suspended and will not resume until the cold fault condition is removed. Both TS1 and TS2 temperature fault conditions will be report by the STAT1 and STAT2 LEDs. AAT3663-1 Option the AAT3663-1 option utilizes an internal battery temperature sensing system comprised of two comparators which establish a voltage window for safe operation. The thresholds for the TS operating window are bounded by the TS1 and TS2 specifications. Referring to the electrical characteristics table in this datasheet, the TS1 threshold = 0.30 * VIN and the TS2 threshold = 0.6 * VIN. Refer to Figure 4 for external resistor and NTC thermistor connections. If the use of the battery temperature sense function is not required, it may be disabled by terminating the TS pin to IN and ground using a 10k resistor divider network. If circuit power dissipation is a concern, the two terminating resistor values may be increased to 100k. VIN AAT3663-2 Option Most of the commonly used NTC thermistors in LiIon/Polymer battery packs are approximately 10k at room temperature (25C). The AAT3663-2 TS pin has been specifically designed to source 75A of current to the 10k NTC thermistor. The applied constant current source and fixed internal TS1 and TS2 voltage thresholds eliminate the need for a resistor divider on the TS pin. Simply connect the 10k NTC resistor between the TS pin and ground. If the TS function is not needed for the AAT3663-2, it may be left open (not connected). Thermal Considerations The AAT3663 is offered in a 3x3mm TDFN package which can provide up to 2.0W of power dissipation when it is properly bonded to a printed circuit board and has a maximum thermal resistance of 50C/W. Many considerations should be taken into account when designing the printed circuit board layout, as well as the placement of the charger IC package in proximity to other heat generating devices in a given application. The ambient temperature around the charger IC will also have an effect on the thermal limits of the battery charging operation. The maximum limits that can be expected for a given ambient condition can be estimated by the following discussion. IN AAT3663-4.2-1 or AAT3663-8.4-1 RT 0.6xV IN Battery Cold Fault TS Battery Pack Battery Hot Fault RNTC T 0.30xVIN Figure 4: External Resistor and NTC Thermistor Application Circuit. 3663.2007.10.1.0 17 AAT3663 1A Linear Li-Ion Battery Charger for Single and Dual Cell Applications First, the maximum power dissipation for a given situation should be calculated: Where: By substitution, we can derive the maximum charge current before reaching the thermal limit condition which will activate digital thermal loop operation. The maximum charge current is the key factor when designing battery charger applications. In general, the worst case condition is when the greatest input to output voltage drop occurs across the charger IC. Specifically when battery voltage is charged up just above the preconditioning voltage threshold and the charger enters into the constant current fast charging mode. Under this condition, the device will suffer the maximum possible power dissipation since both the voltage difference across the device and the charge current will be at their respective maximums. Figure 6 shows the safe fast charge current operating region for different ambient temperatures. Exceeding these limits will drive the charge control into digital thermal loop operation. When under digital thermal loop operation, the device will remain active and continue to charge the battery at a reduced current level for the given ambient condition. 1000 0.50 800 0.00 0 25 50 75 100 PD(MAX) = (TJ - TA) JA PD(MAX) = Maximum Power Dissipation (W) JA = Package Thermal Resistance (C/W) TJ = Thermal Loop Entering Threshold (C) [115C] TA = Ambient Temperature (C) Figure 5 shows the relationship between maximum power dissipation and ambient temperature of AAT3663 2.50 2.00 PD(MAX) (W) 1.50 1.00 ICC(MAX) (mA) TA = 85C TA = 60C 600 TA = 45C TA = 25C TA (C) 400 Figure 5: Maximum Power Dissipation Before Entering Thermal Loop. Next, the power dissipation can be calculated by the following equation: 200 0 4 5 6 7 8 9 10 11 12 13 VIN (V) ICH(MAX) = (PD(MAX) - VIN * IOP) VIN - VBAT Figure 6: Maximum Charging Current Before the Digital Thermal Loop Becomes Active. (TJ - TA) - V * I IN OP JA ICH(MAX) = VIN - VBAT Where: PD VIN VBAT ICH IOP = Total Power Dissipation by the Device = Input Voltage = Battery Voltage as Seen at the BAT Pin = Constant Charge Current Programmed for the Application = Quiescent Current Consumed by the Charger IC for Normal Operation [0.5mA] Capacitor Selection Input Capacitor In general, it is a good design practice to place a decoupling capacitor between the IN pin and ground. An input capacitor in the range of 1F to 22F is recommended. If the source supply is unregulated, it may be necessary to increase the capacitance to keep the input voltage above the under-voltage lockout threshold during device enable and when battery charging is initiated. If the AAT3663's input is to be used in a system with an external power supply source, such as a typical AC-to-DC wall adapter, 18 3663.2007.10.1.0 AAT3663 1A Linear Li-Ion Battery Charger for Single and Dual Cell Applications then a CIN capacitor in the range of 10F should be used. A larger input capacitor in this application will minimize switching or power transient effects when the power supply is "hot plugged" in. Output Capacitor The AAT3663 only requires a 1F ceramic capacitor on the BAT pin to maintain circuit stability. This value should be increased to 10F or more if the battery connection is made any distance from the charger output. If the AAT3663 is to be used in applications where the battery can be removed from the charger, such as desktop charging cradles, an output capacitor 10F or greater is recommended to reduce the effect of the charger cycling on and off when no battery is present. Printed Circuit Board Layout Considerations For the best results, it is recommended to physically place the battery pack as close as possible to the AAT3663 BAT pin. To minimize voltage drops on the PCB, keep the high current carrying traces adequately wide. For maximum power dissipation of the AAT3663 3x3mm 14-pin TDFN package, the metal substrate should be solder bonded to the board. It is also recommended to maximize the substrate contact to the PCB ground plane layer to further increase local heat dissipation. Refer to the AAT3663 evaluation board for a good layout example. Figure 7: AAT3663 Evaluation Board Top (Component) Side Layout. Figure 8: AAT3663 Evaluation Board Bottom Side Layout. 3663.2007.10.1.0 19 AAT3663 1A Linear Li-Ion Battery Charger for Single and Dual Cell Applications JP1 ENABLE JP4 VIN Green Red Red LED D3 LED D2 LED D1 1 U1 TDFN33-14 AAT3663 R4 2k R7 (see note) JP3 5 EN ADPP# STAT1 STAT2 IN IN GND TS TERM BATS BAT ISET EP CT TS JP2 12 11 10 8 9 4 R5 2k 13 6 7 3 2 VIN 4V - 13.2V R6 2k BAT C2 10F C1 10F GND C3 0.1F R2 R1 10k 1.74k R3 10k GND C1 1206 X7R 10F 16V GRM31CR71C106KAC7L C2 0805 X7R 10F 10V GRM21BR71A106KE51L Note: R2 = 10k is set the termination current, 7.5% from the constant charging current R7 = 10k (for -1 option) R7 = open (for -2 option) Figure 9: AAT3663 Evaluation Board Schematic Diagram. 20 3663.2007.10.1.0 AAT3663 1A Linear Li-Ion Battery Charger for Single and Dual Cell Applications Ordering Information Battery Cell Voltage Option Single Cell (4.2V) Single Cell (4.2V) Dual Cell (8.4V) Dual Cell (8.4V) Battery Temperature Sense For Use With Any NTC Thermistor For Use With 10k NTC Thermistor For Use With Any NTC Thermistor For Use With 10k NTC Thermistor Package TDFN33-14 TDFN33-14 TDFN33-14 TDFN33-14 Marking1 ZZXYY Part Number (Tape and Reel)2 AAT3663IWO-4.2-1-T1 AAT3663IWO-4.2-2-T1 AAT3663IWO-8.4-1-T1 AAT3663IWO-8.4-2-T1 All AnalogicTech products are offered in Pb-free packaging. The term "Pb-free" means semiconductor products that are in compliance with current RoHS standards, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. For more information, please visit our website at http://www.analogictech.com/pbfree. 1. XYY = assembly and date code. 2. Sample stock is generally held on part numbers listed in BOLD. 3663.2007.10.1.0 21 AAT3663 1A Linear Li-Ion Battery Charger for Single and Dual Cell Applications Package Information TDFN33-14 Detail "A" Index Area 3.000 0.050 3.000 0.050 1.650 0.050 Top View Bottom View 0.425 0.050 0.750 0.050 0.000 Side View Pin 1 Indicator (Optional) Detail "A" All dimensions in millimeters. 1. The leadless package family, which includes QFN, TQFN, DFN, TDFN and STDFN, has exposed copper (unplated) at the end of the lead terminals due to the manufacturing process. A solder fillet at the exposed copper edge cannot be guaranteed and is not required to ensure a proper bottom solder connection. (c) Advanced Analogic Technologies, Inc. AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech product. No circuit patent licenses, copyrights, mask work rights, or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifications or to discontinue any product or service without notice. Except as provided in AnalogicTech's terms and conditions of sale, AnalogicTech assumes no liability whatsoever, and AnalogicTech disclaims any express or implied warranty relating to the sale and/or use of AnalogicTech products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right. In order to minimize risks associated with the customer's applications, adequate design and operating safeguards must be provided by the customer to minimize inherent or procedural hazards. Testing and other quality control techniques are utilized to the extent AnalogicTech deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed. AnalogicTech and the AnalogicTech logo are trademarks of Advanced Analogic Technologies Incorporated. All other brand and product names appearing in this document are registered trademarks or trademarks of their respective holders. Advanced Analogic Technologies, Inc. 3230 Scott Boulevard, Santa Clara, CA 95054 Phone (408) 737-4600 Fax (408) 737-4611 22 3663.2007.10.1.0 0.180 0.050 0.400 BSC + 0.100 - 0.000 0.203 REF 2.500 0.050 |
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