bq2406x www.ti.com SLUS689A – JUNE 2006 – REVISED OCTOBER 2006 1A SINGLE-CHIP Li-Ion/Li-Pol CHARGE MANAGEMENT IC WITH THERMAL REGULATION FEATURES • • • • • • • • • • • • • DESCRIPTION Ideal for Low-Dropout Designs for Single-Cell Li-Ion or Li-Pol Packs in Space Limited Applications Integrated Power FET and Current Sensor for up to 1-A Charge Applications Reverse Leakage Protection Prevents Battery Drainage ±0.5% Voltage Regulation Accuracy Thermal Regulation Maximizes Charge Rate Charge Termination by Minimum Current and Time Precharge Conditioning With Safety Timer Status Outputs for LED or System Interface Indicate Charge, Fault, and Power Good Outputs Short-Circuit and Thermal Protection Automatic Sleep Mode for Low Power Consumption Small 3×3 mm MLP Package Selectable Battery Insertion and Battery Absent Detection Input Overvoltage Protection – 6.5 V and 10.5 V Options The bq2406x series are highly integrated Li-Ion and Li-Pol linear chargers, targeted at space-limited portable applications. The bq2406x series offers a variety of safety features and functional options, while still implementing a complete charging system in a small package. The battery is charged in three phases: conditioning, constant or thermally regulated current, and constant voltage. Charge is terminated based on minimum current. An internal programmable charge timer provides a backup safety feature for charge termination and is dynamically adjusted during the thermal regulation phase. The bq2406x automatically re-starts the charge if the battery voltage falls below an internal threshold; sleep mode is set when the external input supply is removed. Multiple versions of this device family enable easy design of the bq2406x in cradle chargers or in the end equipment, while using low cost or high-end AC adapters. Pin Out (Top View) bq24061 IN 10 OUT TMR 2 9 BAT STAT1 3 8 CE STAT2 4 7 PG VSS 5 6 ISET APPLICATIONS • • 1 PDA, MP3 Players, Digital Cameras Internet Appliances and Handheld Devices TYPICAL APPLICATION CIRCUIT Li-lon or Li-Pol Battery Pack bq24061 Input Power 1 RTMR 4.7 mF 1.5 kW 1.5 kW 2 IN OUT TMR BAT 49.9 kW 3 4 5 STAT1 CE STAT2 PG VSS ISET Pack+ 10 4.7 mF 9 + Pack- 8 7 6 RSET 1.13 kW Typical Application for Charging Between 350 mA and 1 A. Charge Enable and Input Power Status Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. UNLESS OTHERWISE NOTED this document contains PRODUCTION DATA information current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 2006, Texas Instruments Incorporated bq2406x www.ti.com SLUS689A – JUNE 2006 – REVISED OCTOBER 2006 These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. AVAILABLE OPTIONS Charge Input Over Voltage Voltage Termination Enable Safety Timer Enable Power Good Status IC Enable Pack Temp Pack Voltage Detection (Absent) Devices (1) (2) (3) Marking 4.2 V 6.5 V TMR pin TMR pin PG pin No TS pin With timer enabled bq24060 BPG 4.2 V 6.5 V TMR pin TMR pin PG pin CE pin No With timer enabled bq24061 BPH 4.2 V 6.5 V TE pin TMR pin No CE pin No With termination enabled bq24063 Preview 4.2 V 10.5 V TMR pin TMR pin PG pin No TS pin With timer enabled bq24064 BSA (1) (2) (3) The bq2406x are only available taped and reeled. Add suffix R to the part number for quantities of 3,000 devices per reel (e.g., bq24060BPGR). Add suffix T to the part number for quantities of 250 devices per reel (e.g., bq24060DRCT). This product is RoHS compatible, including a lead concentration that does not exceed 0.1% of total product weight, and is suitable for use in specified lead-free soldering processes. In addition, this product uses package materials that do not contain halogens, including bromine (Br) or antimony (Sb) above 0.1% of total product weight. For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI Web site at www.ti.com. ABSOLUTE MAXIMUM RATINGS (1) bq2406x –0.3 V to 18 V (2) Supply voltage (IN with respect to Vss) Input voltage on IN, STATx, PG, TS, CE, TE, TMR (all with respect to Vss) –0.3 V to V(IN) Input voltage on OUT, BAT, ISET (all with respect to Vss) –0.3 V to 7 V Output sink current (STATx) + PG 15 mA Output current (OUT pin) 1.5 A TA Operating free-air temperature range –40°C to 155°C Tstg Storage temperature range –65°C to 150°C TJ Junction temperature range –40°C to 150°C (1) (2) Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under recommended operating conditions is not implied. Exposure to absolute–maximum–rated conditions for extended periods may affect device reliability The bq2406x device can withstand up to 26 V for a maximum of 87 hours. RECOMMENDED OPERATING CONDITIONS MIN V(IN) Supply voltage range Battery absent detection not functional V(IN) Supply voltage range Battery absent detection functional TJ Junction temperature RTMR 33K ≤ RTMR≤ 100K TYP MAX UNIT V 3.5 4.35 4.35 16.5 V 0 125 °C DISSIPATION RATINGS (1) (1) 2 PACKAGE θJC (°C/W) θJA (°C/W) 10-pin DRC 3.21 46.87 This data is based on using the JEDEC High-K board and the exposed die pad is connected to a Cu pad on the board. This is connected to the ground plane by a 2×3 via matrix. Submit Documentation Feedback bq2406x www.ti.com SLUS689A – JUNE 2006 – REVISED OCTOBER 2006 ELECTRICAL CHARACTERISTICS over recommended operating, TJ = 0 –125°C range, See the Application Circuits section, typical values at TJ = 25°C (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT 1.5 3.0 V 130 mV POWER DOWN THRESHOLD – UNDERVOLTAGE LOCKOUT V(UVLO) V(IN) = 0 V, increase V(OUT): 0 → 3 V OR V(OUT) = 0 V, increase V(IN): 0 → 3 V, CE = LO (1) Power down threshold INPUT POWER DETECTION, CE = HI or LOW, V(IN) > 3.5 V VIN(DT) Input power detection threshold V(IN) detected at [V(IN) – V(OUT)] > VIN(DT) VHYS(INDT) Input power detection hysteresis Input power not detected at [V(IN)– V(OUT)] < [VIN(DT)– VHYS(INDT)] 30 TDGL(INDT1) Deglitch time, input power detected status PG:HI → LO, Thermal regulation loop not active, RTMR = 50 KΩ or V(TMR) = OPEN 1.5 TDGL(NOIN) Delay time, input power not detected status PG: LO →HI after TDGL(NOIN) TDLY(CHGOFF) Charger off delay Charger turned off after TDLY(CHGOFF), Measured from PG: LO → HI; Timer reset after TDLY(CHGOFF) mV 28 3.5 ms 10 µs 32 ms INPUT OVERVOLTAGE PROTECTION V(OVP) Input overvoltage detection threshold V(IN) increasing VHYS(OVP) Input overvoltage hysteresis V(IN) decreasing TDGL(OVDET) Input overvoltage detection delay TDGL(OVNDET) Input overvoltage not detected delay bq24060/61/63 bq24064 6.2 6.5 7.0 10.2 10.5 11.7 V bq24060/61/63 0.1 0.2 bq24064 0.3 0.5 CE = HI or LO, Measured from V(IN) > V(OVP) to PG: LO → HI; VIN increasing 10 100 µs CE = HI or LO, Measured from V(IN) < V(OVP) to PG: HI → LO; V(IN) decreasing 10 100 µs V QUIESCENT CURRENT V(IN) = 6 V 100 V(IN) = 16.5 V 300 200 ICC(CHGOFF) IN pin quiescent current, charger off Input power detected, CE = HI ICC(CHGON) IN pin quiescent current, charger on Input power detected, CE = LO, VBAT = 4.5 V 4 6 mA IBAT(DONE) Battery leakage current after termination into IC Input power detected, charge terminated, CE = LO 1 5 µA IBAT(CHGOFF) Battery leakage current into IC, charger off Input power detected, CE = HI OR input power not detected, CE = LO 1 5 µA µA TS PIN COMPARATOR V(TS1) Lower voltage temperature threshold Hot detected at V(TS) < V(TS1); NTC thermistor 29 30 31 %V(IN) V(TS2) Upper voltage temperature threshold Cold detected at V(TS) > V(TS2); NTC thermistor 60 61 62 %V(IN) Hysteresis Temp OK at V(TS) > [ V(TS1) + VHYS(TS) ] OR V(TS) < [ V(TS2)– VHYS(TS) ] 2 %V(IN) VIL Input (low) voltage V(CE) increasing VIH Input (high) voltage V(CE) decreasing VHYS(TS) CE INPUT 0 1 2.0 V V STAT1, STAT2 AND PG OUTPUTS , V(IN) ≥ VO(REG) + V(DO-MAX) VOL Output (low) saturation voltage Ioutput = 5 mA (sink) 0.5 V THERMAL SHUTDOWN T(SHUT) Temperature trip Junction temperature, temp rising T(SHUTHYS) Thermal hysteresis Junction temperature (1) 155 °C 20 °C Specified by design, not production tested. Submit Documentation Feedback 3 bq2406x www.ti.com SLUS689A – JUNE 2006 – REVISED OCTOBER 2006 ELECTRICAL CHARACTERISTICS (Continued) over recommended operating, TJ = 0–125°C range, See the Application Circuits section, typical values at TJ = 25°C (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT VOLTAGE REGULATION, V(IN) ≥ VO(REG) + V(DO-MAX), I(TERM) < I(OUT) < IO(OUT), CHARGER ENABLED, NO FAULT CONDITIONS DETECTED VO(REG) Output voltage VO(TOL) Voltage regulation accuracy V(DO) Dropout voltage, V(IN) – V(OUT) bq24060/61/63/64 4.20 TA = 25°C –0.5% V 0.5% –1% 1% I(OUT) = 1 A 750 mV 1000 mA V CURRENT REGULATION , V(IN) > V(OUT) > V(DO-MAX), CHARGER ENABLED, NO FAULT CONDITIONS DETECTED IO(OUT) Output current range V(BAT) > V(LOWV), IO(OUT) = I(OUT) = K(SET)× V(SET)/RSET 100 V(SET) Output current set voltage V(ISET) = V(SET), V(LOWV) < V(BAT) ≤ VO(REG) 2.45 2.50 2.55 K(SET) Output current set factor 100 mA ≤ IO(OUT)≤ 1000 mA 315 335 355 315 372 430 RISET External resistor range 10 mA ≤ IO(OUT) < 100 mA mA kW Volts Resistor connected to ISET pin 0.7 10 kΩ VOLTAGE AND CURRENT REGULATION TIMING, V(IN) > V(OUT) + V(DO-MAX), CHARGER ENABLED, NO FAULT CONDITIONS DETECTED, RTMR = 50K or V(TMR) = OPEN; Thermal regulation loop not active TPWRUP(CHG) Input power detection to full charge current time delay Measured from PG:HI → LO to I(OUT) > 100 mA, CE = LO, IO(OUT) = 1 A, V(BAT) = 3.5 V 25 35 ms TPWRUP(EN) Charge enable to full charge current delay Measured from CE:HI → LO to I(OUT) >100 mA, IO(OUT) = 1A, V(BAT)= 3.5 V, V(IN) = 4.5 V, Input power detected 25 35 ms TPWRUP(LDO) Input power detection to voltage regulation delay, LDO mode set, no battery or load connected Measured from PG:HI → LO to V(OUT) > 90% of charge voltage regulation; V(TMR) = OPEN, LDO mode set, no battery and no load at OUT pin, CE = LO 25 35 ms PRECHARGE AND OUTPUT SHORT-CIRCUIT CURRENT REGULATION, V(IN)–V(OUT) > V(DO-MAX) , V(IN) ≥ 4.5V, CHARGER ENABLED, NO FAULT CONDITIONS DETECTED, RTMR = 50K or V(TMR)=OPEN; Thermal regulation loop not active V(LOWV) Precharge to fast-charge transition V(BAT) increasing threshold 2.8 2.95 3.15 V(SC) Precharge to short-circuit transition threshold V(BAT) decreasing 1.2 1.4 1.6 V(SCIND) Short-circuit indication V(BAT) decreasing 1.6 1.8 2.0 IO(PRECHG) Precharge current range V(SC) < VI(BAT) < V(LOWV), t < T(PRECHG) IO(PRECHG) = K(SET)× V(PRECHG)/R(ISET) 10 V(PRECHG) Precharge set voltage V(ISET) = V(PRECHG), V(SC) < VI(BAT) < V(LOWV), t < T(PRECHG) Output shorted regulation current VSS≤ V(BAT)≤ V(SCI), IO(SHORT) = I(OUT), V(BAT)= VSS, Internal pullup resistor IO(SHORT) VPOR < VIN < 6.0 V V V 100 mA mV 225 250 280 15 22 30 mA 6.0 V < VIN < VOVP 25 TEMPERATURE REGULATION (Thermal regulation™), CHARGER ENABLED, NO FAULT CONDITIONS DETECTED 4 TJ(REG) Temperature regulation limit V(IN) = 5.5 V, V(BAT) = 3.2 V, Fast charge current set to 1A I(MIN_TJ(REG)) Minimum current in thermal regulation V(LOWV) < V(BAT) < VO(REG), 0.7kΩ < RISET < 3.5kΩ Submit Documentation Feedback 101 112 125 °C 200 250 mA bq2406x www.ti.com SLUS689A – JUNE 2006 – REVISED OCTOBER 2006 ELECTRICAL CHARACTERISTICS (Continued) over recommended operating, TJ = 0–125°C range, See the Application Circuits section, typical values at TJ = 25°C (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT CHARGE TERMINATION DETECTION, VO(REG) = 4.2 V, CHARGER ENABLED, NO FAULT CONDITIONS DETECTED, Thermal regulation LOOP NOT ACTIVE, RTMR = 50K or TMR pin OPEN I(TERM) Termination detection current range V(BAT) > V(RCH), I(TERM) = K(SET)× V(TERM)/RISET V(TERM) Charge termination detection set voltage (1) V(BAT) > V(RCH) TDGL(TERM) Deglitch time, termination detected 10 100 mA 225 250 275 mV V(ISET) decreasing 15 25 35 ms BATTERY RECHARGE THRESHOLD V(RCH) Recharge threshold detection [VO(REG)–V(BAT) ] > V(RCH) 75 100 135 mV TDGL(RCH) Deglitch time, recharge detection V(BAT) decreasing 15 25 35 ms TIMERS, CE = LO, CHARGER ENABLED, NO FAULT CONDITIONS DETECTED, V(TMR) < 3 V, TIMERS ENABLED T(CHG) Charge safety timer range T(CHG) = K(CHG)× RTMR ; thermal loop not active K(CHG) Charge safety timer constant V(BAT) > V(LOWV) 0.08 T(PCHG) Pre-charge safety timer range T(PCHG) = K(PCHG)× T(CHG) ; Thermal regulation loop not active 1080 K(PCHG) Pre-charge safety timer constant V(BAT) < V(LOWV) 0.08 0.1 0.12 Charge timer and termination enable threshold [Charge timer AND termination disabled] at V(TMR) bq24060/61/64 > VTMR(OFF) 2.5 3.0 3.5 V Charge timer enable threshold [Charge timer disabled] at V(TMR) > VTMR(OFF) TMR pin source current V(TMR) = 3.5 V, V(IN) = 4.5 V 1 6 µA 1 3.2 mA VTMR(OFF) ITMR 3 0.1 10 hours 0.12 hr/kΩ 3600 sec bq24063 BATTERY DETECTION THRESHOLDS IDET(DOWN) Battery detection current (sink) 2 V < V(BAT) < VO(REG) IDET(UP) Battery detection current (source) 2 V < V(BAT) < VO(REG) T(DETECT) Battery detection time 2 V < V(BAT) < VO(REG), Thermal regulation loop not active; RTMR = 50 kΩ, IDET(down) or IDET (UP) 2 IO(PRECHG) 85 120 150 ms –12 –10 –8 mA TIMER FAULT RECOVERY I(FAULT) Fault Current (source) V(OUT) < V(RCH) CHARGE OVERCURRENT DETECTION, V(IN) ≥ 4.5 V, CHARGER ENABLED ICH(OI) Charge overcurrent detection threshold V(ISET) = VSS TDGL(OI) Overcurrent detection delay time Measured from V(ISET) = VSS to IO(OUT) = 0 (1) 2 A 100 µs The voltage on the ISET pin is compared to the V(TERM) voltage to determine when the termination should occur. Submit Documentation Feedback 5 bq2406x www.ti.com SLUS689A – JUNE 2006 – REVISED OCTOBER 2006 DEVICE INFORMATION PIN ASSIGNMENT VSS STAT 2 STAT 1 TMR IN VSS STAT 2 STAT 1 TMR IN VSS STAT 2 STAT 1 TMR IN 5 4 3 2 1 5 4 3 2 1 5 4 3 2 1 bq24060/64 DRC (TOP VIEW) bq24063 DRC (TOP VIEW) bq24061 DRC (TOP VIEW) 6 7 8 9 10 6 7 8 9 10 6 7 8 9 10 ISET PG TS BAT OUT ISET PG CE BAT OUT ISET CE TE BAT OUT TERMINAL FUNCTIONS, REQUIRED COMPONENTS TERMINAL NO. NAME DESCRIPTION AND REQUIRED COMPONENTS bq24061 bq24063 IN 1 1 1 I Charge Input Voltage and internal supply. Connect a 1- µF (minimum) capacitor from IN to VSS. CIN≥ COUT TMR 2 2 2 I Safety Timer Program Input, timer disabled if floating. Connect a resistor to VSS pin to program safety timer timeout value STAT1 3 3 3 O Charge Status Output 1 (open-collector, seeTable 3) STAT2 4 4 4 O Charge Status Output 2 (open-collector, see Table 3) VSS 5 5 5 I Ground ISET 6 6 6 O Charge current set point, resistor connected from ISET to VSS sets charge current value. Connect a 0.47-µF capaciator from BAT to ISET. PG 7 7 — O Power Good status output (open-collector), active low CE — 8 7 I Charge enable Input. CE = LO enables charger. CE = HI disables charger. TE — — 8 I Termination enable Input. TE = LO enables termination detection and battery absent detection. TE = HI disables termination detection and battery absent detection. TS 8 — — I Temperature Sense Input, connect to battery pack thermistor. Connect an external resistive divider to program temperature thresholds. BAT 9 9 9 I Battery Voltage Sense Input. Connect to the battery positive terminal. Connect a 200-Ω resistor from BAT to OUT. OUT 10 10 10 O Charge current output. Connect to the battery positive terminal. Connect a 1µF (minimum) capacitor from OUT to VSS. Exposed Thermal Pad 6 I/O bq24060/64 Pad Pad Pad There is an internal electrical connection between the exposed thermal pad and Vss pin of the IC. The exposed thermal pad must be connected to the same potential as the VSS pin on the printed circuit board. Do not use the thermal pad as the primary ground input for the IC. VSS pin must be connected to ground at all times. Submit Documentation Feedback bq2406x www.ti.com SLUS689A – JUNE 2006 – REVISED OCTOBER 2006 TYPICAL OPERATING CHARACTERISTICS Measured using the typical application circuit shown previously. THERMAL LOOP OPERATION WITH POWERPAD ATTACHED THERMAL LOOP AND DTC OPERATION 1.75 1.6 6 1.50 1.4 5 1.25 4 1 12 10 IBAT 0.75 3 VISET 2 Battery Current - A Safety Timer Battery Current - A Voltage - V VIN 1.2 8 1 0.8 0 1.50 2 t - Time - s 2.50 2 0.2 0 1 4 0.4 0.25 0.50 IBAT 0.6 0.50 1 0 6 0 0 0 3 TCHG - Safety Timer - Hrs 7 0.50 Figure 1. 1 1.50 2 t - Time - s 2.50 3 Figure 2. PACK REMOVAL TRANSIENT 5 4.75 INPUT OVP RECOVERY TRANSIENTS 1 8 0.8 7 2 1.80 0.2 IBAT 3.75 0 Voltage - V 0.4 4 VIN 6 Battery Current - A 4.25 5 1.40 1.20 1 4 IBAT 3 0.80 0.60 3.50 2 VPG -0.2 3.25 3 0 0.5 1 1.5 t - Time - mS 2 1 -0.4 2.5 0.40 0.20 0 0 0 5 Figure 3. 10 15 20 25 30 35 t - Time - mS 40 45 50 Figure 4. PG DEGLITCH TIME 9 8 7 VIN Voltage - V Battery Voltage - V 0.6 Charge Current - A 1.60 VBAT 4.50 6 5 4 VPG 3 2 1 0 0 1 2 3 t - Time - mS 4 5 Figure 5. Submit Documentation Feedback 7 bq2406x www.ti.com SLUS689A – JUNE 2006 – REVISED OCTOBER 2006 TYPICAL OPERATING CHARACTERISTICS (continued) Measured using the typical application circuit shown previously. FAST-CHARGE CURRENT vs BATTERY VOLTAGE FAST-CHARGE CURRENT vs BATTERY VOLTAGE 52.5 1000 104.5 995 52 104 990 51.5 103.5 103 85°C 102.5 25°C 102 101.5 0°C 985 980 970 85°C 965 101 960 955 2.20 2.40 2.60 Battery Voltage - V 2.80 3.20 3.40 3.60 3.80 Battery Voltage - V 85°C 49 3 4 3.20 3.40 3.60 Battery Voltage - V 3.80 4 Figure 8. LOW CHARGE RATE KSET LINEARITY vs CHARGE CURRENT BATTERY REGULATION VOLTAGE vs INPUT VOLTAGE 4.202 350 400 390 0°C 4.200 345 380 4.198 Battery Voltage - V 85°C 370 85°C 350 0°C 340 KSET - A/A 340 KSET - A/A 50 49.5 Figure 7. HIGH CHARGE RATE KSET LINEARITY vs CHARGE CURRENT 330 50.5 48 47.5 Figure 6. HIGH CHARGE RATE 360 25°C 0°C 51 48.5 950 3 3 25°C 0°C 975 100.5 100 2 Charge Current - mA 105 Charge Current - mA Charge Current - mA PRE-CHARGE CURRENT vs BATTERY VOLTAGE 25°C 0°C 335 25°C 330 25°C 4.196 4.194 4.192 4.190 320 325 300 25 35 45 55 65 75 85 95 105 115 125 Battery Charge Current - 320 0 100 200 300 400 500 600 700 800 900 1000 Battery Charge Current - mA Figure 9. 2.0 < V(BAT) < 3.0 V Figure 10. 3.0 < V(BAT) < 4.0 V DROPOUT VOLTAGE vs TEMPERATURE 0.400 V(DO) - Droput Voltage - V 0.375 0.350 0.325 0.300 0.275 0.250 0.225 0.200 -15 5 25 45 65 85 TA - Temperature - °C 105 Figure 12. 8 85°C 4.188 310 Submit Documentation Feedback 125 4.186 4.5 6.5 8.5 10.5 12.5 Input Voltage - V Figure 11. 14.5 16.5 bq2406x www.ti.com SLUS689A – JUNE 2006 – REVISED OCTOBER 2006 FUNCTIONAL DESCRIPTION The charge current is programmable using external components (RISET resistor). The charge process starts when an external input power is connected to the system, the charger is enabled by CE = LO and the battery voltage is below the recharge threshold, V(BAT) < V(RCH). When the charge cycle starts a safety timer is activated, if the safety timer function is enabled. The safety timer timeout value is set by an external resistor connected to TMR pin. When the charger is enabled two control loops modulate the battery switch drain to source impedance to limit the BAT pin current to the programmed charge current value (charge current loop) or to regulate the BAT pin voltage to the programmed charge voltage value (charge voltage loop). If V(BAT) < V(LOWV) (3 V typical) the BAT pin current is internally set to 10% of the programmed charge current value. A typical charge profile is shown below, for an operation condition that does not cause the IC junction temperature to exceed TJ(REG), (112°C typical). VO(REG) PreConditioning Phase Voltage Regulation and Charge Termination Phase Current Regulation Phase DONE IO(OUT) FAST-CHARGE CURRENT Battery Current, I(BAT) Battery Voltage, V(BAT) v(LOWV) Charge Complete Status, Charger Off IO(PRECHG), I(TERM) PRE-CHARGE CURRENT AND TERMINATION THRESHOLD T(PRECHG) T(CHG) DONE Figure 13. Charging Profile With TJ(REG) If the operating conditions cause the IC junction temperature to exceed TJ(REG), the charge cycle is modified, with the activation of the integrated thermal control loop. The thermal control loop is activated when an internal voltage reference, which is inversely proportional to the IC junction temperature, is lower than a fixed, temperature stable internal voltage. The thermal loop overrides the other charger control loops and reduces the charge current until the IC junction temperature returns to TJ(REG), effectively regulating the IC junction temperature. Submit Documentation Feedback 9 bq2406x www.ti.com SLUS689A – JUNE 2006 – REVISED OCTOBER 2006 IN VREF VTJ Thermal Loop BATTERY SWITCH I(BAT) OUT I(BAT) / K(SET) ISET V(BAT) VO(REG) System Voltage Regulation Loop BAT Figure 14. Thermal Regulation Circuit A modified charge cycle, with the thermal loop active, is shown in Figure 15. VO(REG) PreConditioning Phase Thermal Regulation Phase Current Regulation Phase Voltage Regulation and Charge Termination Phase DONE IO(OUT) Battery Current, I(BAT) FAST-CHARGE CURRENT PRE-CHARGE CURRENT AND TERMINATION THRESHOLD Battery Voltage, V(BAT) Charge Complete Status, Charger Off VO(LOWV) IO(PRECHG),I(TERM) T(THREG) temperature , Tj T(PRECHG) T(CHG) Figure 15. Charge Profile, Thermal Loop Active 10 Submit Documentation Feedback DONE bq2406x www.ti.com SLUS689A – JUNE 2006 – REVISED OCTOBER 2006 FUNCTIONAL BLOCK DIAGRAM BACKGATE BIAS V(IN) I(OUT) OUT IN V(OUT) PRE_CHARGE IOUT) / K(SET) ISET VO(REG) V(ISET) I(DETECT) V(IN) V(SET) V(PRECHG) I(FAULT ) TJ BATTERY ABSENT DETECTION AND SHORT RECOVERY T J(REG) CHG ENABLE V(IN) Dynamically Controlled Oscillator V(SET) , V(PRECHG) + - V OC TDGL(CHOVC) Deglitch TMR + V(IN) VTMR(OFF) TDGL(INDT) Deglitch Over_current + + V(IN) - V(OUT)+VIN(DT ) Input Power Detected TS Timer Fault + V(IN) Timer V(IN) Disable + V(OVP) BAT + V (RCH) - TDGL(OVP) Deglitch Input Over-Voltage TDGL(RCH) Deglitch Recharge Precharge + V(LOW) V (TERM ) V(ISET) POR Suspend Thermal Shutdown Internal Voltage References CE CHARGE CONTROL, TIMER and DISPLAY LOGIC + - REFERENCE AND BIAS PG STAT1 TDGL(TERM) Deglitch Terminate STAT2 VSS Submit Documentation Feedback 11 bq2406x www.ti.com SLUS689A – JUNE 2006 – REVISED OCTOBER 2006 APPLICATION CIRCUITS The typical application diagrams shown here are configured for 750 mA fast charge current, 75 mA pre-charge current, 5 hour safety timer and 30 min pre-charge timer. Li-Ion or Li-Pol Battery Pack bq24060/64 Input Power 1 RTMR C3 4.7 mF R1 R2 1.5 kW 1.5 kW 2 OUT 10 IN TMR BAT 9 STAT 1 TS 8 STAT 2 PG 49.9 kW RED 3 Pack+ R8 + C2 200 W 2.2 mF C1 4 GREEN 5 0.47 mF 7 ISET 6 Vss Pack- RT1 10 kW RT2 33.2 kW R ISET 1.13 kW Power Good Li-Ion or Li-Pol Battery Pack bq24061 Input Power 1 RTMR C3 4.7 mF R1 1.5 kW R2 1.5 kW 2 IN 3 RED GREEN 4 5 10 OUT TMR 49.9 kW CE STAT 2 PG Pack+ R8 9 BAT STAT 1 Vss TEMP + C2 200 W 1 mF Pack- 8 C1 7 0.47 mF 6 ISET RSET 1.13 kW Charge Enable and Power Good Li-Ion or Li-Pol Battery Pack bq24063 Input Power 1 RTMR C3 4.7 mF R1 1.5 kW R2 1.5 kW 2 IN TMR 49.9 kW RED GREEN 3 4 5 OUT BAT Pack+ R8 9 C2 1 mF 200 W TE STAT 2 CE ISET + Pack- 8 STAT 1 Vss 10 C1 7 0.47 mF 6 RSET 1.13 kW Charge and Termination Enable NOTE: Temp window set between 0°C and 45°C for application w/TS pin. Figure 16. Application Circuits OPERATING MODES Power Down The bq2406x family is in a power-down mode when the input power voltage (IN) is below the power-down threshold V(PDWN). During the power down mode all IC functions are off, and the host commands at the control pins are not interpreted. The integrated power mosfet connected between IN and OUT pins is off, the status output pins STAT1 and STAT2 are set to high impedance mode and PG output is set to the high impedance state. 12 Submit Documentation Feedback bq2406x www.ti.com SLUS689A – JUNE 2006 – REVISED OCTOBER 2006 Sleep Mode The bq2406x enters the sleep mode when the input power voltage (IN) is above the power down threshold V(PDWN) but still lower than the input power detection threshold, V(IN) < V(OUT) + VIN(DT). During the sleep mode the charger is off, and the host commands at the control pins are not interpreted. The integrated power mosfet connected between IN and OUT pins is off, the status output pins STAT1 and STAT2 are set to the high impedance state and the PG output indicates input power not detected. The sleep mode is entered from any other state, if the input power (IN) is not detected. Overvoltage Lockout The input power is detected when the input voltage V(IN) > V(OUT) + VIN(DT). When the input power is detected the bq2460x transitions from the sleep mode to the power-on-reset mode. In this mode of operation an internal timer T(POR) is started and internal blocks are reset (power-on-reset). Until the timer expires the STAT1 and STAT2 outputs indicate charger OFF, and the PG output indicates the input power status as not detected. At the end of the power-on-reset delay the internal comparators are enabled, and the STAT1, STAT2 and PG pins are active. Stand-By Mode In the bq24061/63 the stand-by mode is started at the end of the power-on-reset phase, if the input power is detected and CE = HI. In the stand-by mode selected blocks in the IC are operational, and the control logic monitors system status and control pins to define if the charger will set to on or off mode. The quiescent current required in stand-by mode is 100 µA typical. If the CE pin is not available the bq2406x enters the begin charge mode at the end of the power-on-reset phase. Begin Charge Mode All blocks in the IC are powered up, and the bq2406x is ready to start charging the battery pack. A new charge cycle is started when the control logic decides that all conditions required to enable a new charge cycle are met. During the begin charge phase all timers are reset, after that the IC enters the charging mode. Charging Mode When the charging mode is active the bq2406x executes the charging algorithm, as described in the operational flow chart, Figure 17. Suspend Mode The suspend mode is entered when the pack temperature is not within the valid temperature range. During the suspend mode the charger is set to off, but the timers are not reset. The normal charging mode resumes when the pack temperature is within range. LDO Mode Operation The LDO Mode (TMR pin open circuit) disables the charging termination circuit, disables the battery detect routine and holds the safety timer clock in reset. This is often used for operation without a battery or in production testing. This mode is different than a typical LDO since it has different modes of operation, and delivers less current at lower output voltages. See Figure 24 for the output current versus the output voltage. Note that a load on the output prior to powering the device may keep the part in short-circuit mode. Also, during normal operation, exceeding the programmed fast charge level causes the output to drop, further restricting the output power, and soon ends up in short-circuit mode. Operation with a battery or keeping the average load current below the programmed current level prevents this type of latch up. The out pin current can be monitored via the ISET pin. If in LDO mode without a battery present, It is recommended that a 200-Ω feedback resistor, R8, be used, see Figure 16. Submit Documentation Feedback 13 bq2406x www.ti.com SLUS689A – JUNE 2006 – REVISED OCTOBER 2006 STATE MACHINE DIAGRAM CHARGING RECHARGE DETECTION No V(TS) >V(TS2) OR V(TS) < V( TS1) VI(BAT ) < V(RCH ) Yes Suspend Set Charge Off, Stop timers, Keep timer count, STATn=Hi-Z V(TS) < V(TS2) AND V(TS) > V( TS1) V(OUT) <V(SC) Enable IO(SHORT) current T (PRCH) OFF ANY STATE No VDETECT ENABLED ANY STATE Yes V(OUT) <V(LOWV) Reset T(CHG) Regulate IO(PRECHG) T(PRCH) ON Indicate ChargeIn-Progress Yes No Enable I(DETECT) for t(DETECT) No Yes Reset T(PRCH) T (CHG) ON Battery Present VI(BAT) <V(LOWV) No GO TO Begin Charge Indicate ChargeIn-Progress Yes BATTERY DETECTION No OR Timers disabled Regulate Current or Voltage Apply IO(PRECHG) for t(DETECT) No Yes Yes No T(CHG) Expired? T (PRCH) Expired? VI(BAT ) > V(RCH ) No OR timers disabled Yes ANY STATE V(OUT) <V( LOWV) Yes AND timers enabled Yes AND Timers enabled Battery Absent Charge Off T(DETECT) Fault Yes V(OUT) <V(LOWV) Fault Condition V(TS) >V (TS2) OR V(TS) < V (TS1) Suspend Set Charge Off, Stop timers, Keep timer count, STATn=Hi-Z V(TS) >V(TS2) OR V(TS) < V(TS1) No OR termination disabled ANY STATE V(TS) < V(TS2) AND V(TS) > V(TS1) Indicate Fault No ITERM detection? V(OUT) > V(RCH)? Stand-by /CE=HI OR V(IN)>V( OVP) STATn set to HI-Z, update /PG status, enable control logic Yes AND termination enabled Yes /CE=LO AND [V(BAT)+V(INDT) ] < V(IN) < V( OVP) No Enable IFAULT current Termination No Indicate Termination Yes T (POR) Expired? Yes No Power-on-reset Turn off charger , STATn and PG set to HI-Z, reset timers Begin Charge Disable IFAULT current Reset ALL TImers V(IN) > V(POR) AND V(IN) > V(OUT)+VIN(DT) FAULT RECOVERY Sleep [V(IN) -V(OUT)] < [VIN(DT) - VHYS(INDT) ] Turn off charger , STATn , /PG set to HI-Z , monitor input power Done Turn off charger , Indicate Charge done Reset timers V(IN) > V(POR) V(IN) < V (POR) Power down All IC functions off STATn and PG set to HI-Z START -UP ANY STATE Figure 17. Operational Flow Chart 14 V(OUT) > V(RCH )? Submit Documentation Feedback bq2406x www.ti.com SLUS689A – JUNE 2006 – REVISED OCTOBER 2006 CONTROL LOGIC OVERVIEW An external host can enable or disable the charging process using a dedicated control pin, CE. A low-level signal on this pin enables the charge, and a high-level signal disables the charge. The bq2460x is in stand-by mode with CE = HI. When the charger function is enabled (CE = LO) a new charge is initiated. Table 1 describes the charger control logic operation, in bq2460x versions without the TS pin the pack temp status is internally set to OK. Table 1. Control Logic Functionality bq2460X OPERATION MODE CE INPUT POWER TIMER FAULT (latched) OUTPUT SHORT CIRCUIT TERMINATION (latched) PACK TEMP THERMAL SHUTDOWN POWER DOWN CHARGER POWER STAGE POWER DOWN LO Low X X X X X Yes OFF SLEEP X Not Detected X X X X X No OFF STANDBY HI Detected X X X X X No OFF SEE STATE DIAGRAM LO Detected X Yes X X X No LO Detected No No Yes X X No LO Detected Yes No No X X No IFAULT LO Detected No No Yes Absent TJ < TSHUT No IDETECT LO Detected No No No Hot or Cold TJ < TSHUT No OFF LO Detected No No No Ok TJ < TSHUT No OFF LO Over Voltage No No No Ok TJ < TSHUT No OFF LO Detected No No No Ok TJ < TSHUT No ON CHARGING OFF In both STANDBY and SUSPEND modes the charge process is disabled. In the STANDBY mode all timers are reset; in SUSPEND mode the timers are held at the count stored when the suspend mode was set. The timer fault, termination and output short circuit variables shown in the control logic table are latched in the detection circuits, outside the control logic. Refer to the timers, termination and short circuit protection sections for additional details on how those latched variables are reset. TEMPERATURE QUALIFICATION (Applies only to versions with TS pin option) The bq2406x devices continuously monitor the battery temperature by measuring the voltage between the TS and VSS pins. The IC compares the voltage on the TS pin against the internal V(TS1) and V(TS2) thresholds to determine if charging is allowed. Once a temperature outside the V(TS1) and V(TS2) thresholds is detected the IC immediately suspends the charge. The IC suspends charge by turning off the power FET and holding the timer value (i.e., timers are NOT reset). Charge is resumed when the temperature returns to the normal range. Submit Documentation Feedback 15 bq2406x www.ti.com SLUS689A – JUNE 2006 – REVISED OCTOBER 2006 VIN Charge Suspend VC(TS2) 0.6* VIN Normal Temperature Charge Range VC(TS1) 0.3* VIN Charge Suspend Figure 18. Battery Temperature Qualification With NTC Thermistor The external resistors RT1 and RT2 (see application diagram) enable selecting a temperature window. If RTC and RTH are the thermistor impedances for the Cold and Hot thresholds the values for RT1 and RT2 can be calculated as follows, for a NTC (negative temperature coefficient) thermistor. Solve for RT2 first and substitute into RT1 equation. 2.5 R TCRTH R T2 + RTC * 3.5 RTH (1) R T1 + 7 R THRT2 3 ƪRTH ) RT2ƫ (2) Applying a fixed voltage, 1/2 Vin (50% resistor divider from Vin to ground), to the TS pin to disable the temperature sensing feature. INPUT OVERVOLTAGE DETECTION, POWER GOOD STATUS OUTPUT The input power detection status for pin IN is shown at the open collector output pin PG. Table 2. Input Power Detection Status INPUT POWER DETECTION (IN) PG STATE NOT DETECTED High impedance DETECTED, NO OVERVOLTAGE LO DETECTED, OVERVOLTAGE High impedance The bq2406x detects an input overvoltage when V(IN) > V(OVP). When an overvoltage protection is detected the charger function is turned off and the bq2460x is set to standby mode of operation. The OVP detection is not latched, and the IC returns to normal operation when the fault condition is removed. CHARGE STATUS OUTPUTS The open-collector STAT1 and STAT2 outputs indicate various charger operations as shown in Table 3. These status pins can be used to drive LEDs or communicate to the host processor. Note that OFF indicates the open-collector transistor is turned off. When termination is disabled (TMR pin floating or TE = Hi, bq24063) the Done state is not available; the status LEDs indicate fast charge if VBAT > VLOWV and precharge if VBAT < VLOWV. The available output current is a function of the OUT pin voltage, See Figure 24. 16 Submit Documentation Feedback bq2406x www.ti.com SLUS689A – JUNE 2006 – REVISED OCTOBER 2006 Table 3. Charge Status Charge State (1) STAT1 STAT2 Precharge in progress ON ON Fast charge in progress ON OFF Done (termination enabled only) OFF ON OFF OFF Charge Suspend (temperature) Timer Fault Charger off Selected Input power overvoltage detected Battery absent Batteryshort (1) Pulse loading on the OUT pin may cause the IC to cycle between Done and charging states (LEDs Flashing) BATTERY CHARGING: CONSTANT CURRENT PHASE The bq2406x family offers on-chip current regulation. The current regulation is defined by the value of the resistor connected to ISET pin. During a charge cycle the fast charge current IO(OUT) is applied to the battery if the battery voltage is above the V(LOWV) threshold (2.95 V typical): V(SET) KSET) I(OUT) + I O(OUT) + RISET (3) Where K(SET) is the output current set factor and V(SET) is the output current set voltage. During a charge cycle if the battery voltage is below the V(LOWV) threshold a pre-charge current I(PRECHG) is applied to the battery. This feature revives deeply discharged cells. V(PRECHG) KSET) I O(OUT) I(OUT) + I (PRECHG) + X 10 RISET (4) Where K(SET) is the output current set factor and V(PRECHG) is the precharge set voltage. At low constant current charge currents, less than 350 mA, it is recommended that a 0.47-µF capacitor be placed between the ISET and BAT pins to insure stability, see Figure 16. CHARGE CURRENT TRANSLATOR When the charge function is enabled internal circuits generate a current proportional to the charge current at the ISET pin. This current, when applied to the external charge current programming resistor RISET generates an analog voltage that can be monitored by an external host to calculate the current sourced from the OUT pin. R ISET V(ISET) + I(OUT) K(SET) (5) BATTERY VOLTAGE REGULATION The battery pack voltage is sensed through the BAT pin, which is tied directly to the positive side of the battery pack. The bq2406x monitors the battery pack voltage between the BAT and VSS pins. When the battery voltage rises to VO(REG) threshold the voltage regulation phase begins and the charging current begins to taper down. The voltage regulation threshold VO(REG) is fixed by an internal IC voltage reference. Submit Documentation Feedback 17 bq2406x www.ti.com SLUS689A – JUNE 2006 – REVISED OCTOBER 2006 PRE-CHARGE TIMER The bq2406x family activates an internal safety timer during the battery pre-conditioning phase. The charge safety timer time-out value is set by the external resistor connected to TMR pin, RTMR and the timeout constants K(PCHG) and T(CHG) : T(PCHG) = K(PCHG)× T(CHG) The pre-charge timer operation is detailed in Table 4. Table 4. Pre-Charge Timer Operational Modes bq2460X MODE V(OUT) > V(LOWV) PRE-CHARGE TIMER MODE STANDBY (CE = Hi) X RESET CHARGING Yes RESET SUSPEND (TS out of range) Yes RESET SUSPEND (TS out of range) No Hold CHARGING, TMR PIN NOT OPEN No COUNTING, EXTERNAL PROGRAMMED RATE X RESET CHARGING, TMR PIN OPEN In SUSPEND mode the pre-charge timer is put on hold (i.e., pre-charge timer is not reset), normal operation resumes when the timer returns to the normal operating mode (COUNTING). If V(BAT) does not reach the internal voltage threshold V(LOWV) within the pre-charge timer period a fault condition is detected, the charger is turned off and the pre-charge safety timer fault condition is latched. When the pre-charge timer fault latch is set the charger is turned off. Under those conditions a small current IFAULT is applied to the OUT pin, as long as input power (IN) is detected AND V(OUT) < V(LOWV), as part of a timer fault recovery protocol. This current allows the output voltage to rise above the pre-charge threshold V(LOWV), resetting the pre-charge timer fault latch when the pack is removed. Table 5 further details the pre-charge timer fault latch operation. Table 5. Pre-Charge Timer Latch Functionality PRE-CHARGE TIMER FAULT ENTERED WHEN PRE-CHARGE TIMER FAULT LATCH RESET AT CE rising edge or OVP detected Pre-charge timer timeout AND V(OUT) > V(LOW V) Input power removed (not detected) Timer function disabled THERMAL PROTECTION LOOP An internal control loop monitors the bq2406x junction termperature (TJ) to ensure safe operation during high power dissipations and or increased ambient temperatures. This loop monitors the bq2406x junction temperature and reduces the charge current as necessary to keep the junction temperature from exceeding, TJ(REG), (112°C, typical). The bq2406x's thermal loop control can reduce the charging current down to ~200mA if needed. If the junction temperature continues to rise, the IC will enter thermal shutdown. THERMAL SHUTDOWN AND PROTECTION Internal circuits monitor the junction temperature, TJ, of the die and suspends charging if TJ exceeds an internal threshold T(SHUT) (155°C typical). Charging resumes when TJ falls below the internal threshold T(SHUT) by approximately 20°C. 18 Submit Documentation Feedback bq2406x www.ti.com SLUS689A – JUNE 2006 – REVISED OCTOBER 2006 Thermal Regulation Normal Operation Thermal Shutdown 800 175 IBAT 700 Battery Current - mA 600 125 500 TJ Junction Temperature 400 100 300 75 200 TJ - Junction Temperature - °C 150 50 100 0 4 6 8 10 12 14 16 25 18 VI - Input Voltage - V Figure 19. Thermal Regulation Loop Performance and Thermal Shutdown DYNAMIC TIMER FUNCTION The charge and pre-charge safety timers are programmed by the user to detect a fault condition if the charge cycle duration exceeds the total time expected under normal conditions. The expected charge time is usually calculated based on the fast charge current rate. When the thermal loop is activated the charge current is reduced, and bq2406x activates the dynamic timer control, an internal circuit that slows down the safety timer's clock frequnency. The dynamic timer control circuit effectively extends the safety time duration for either the precharge or fast charge timer modes. This minimizes the chance of a safety timer fault due to thermal regulation. The bq2406x dynamic timer control (DTC) monitors the voltage at pin ISET during pre-charge and fast charge, and if in thermal regulation slows the clock frequency proportionately to the change in charge current. The time duration is based on a 224 ripple counter, so slowing the clock frequency is a real time correction. The DTC circuit changes the safety timers clock period based on the V(SET)/V(ISET) ratio (fast charge) or V(PRECHG)/V(SET) ratio (pre-charge). Typical safety timer multiplier values relative to the V(SET)/V(ISET) ratio is shown in Figure 20 and Figure 21. Submit Documentation Feedback 19 bq2406x www.ti.com SLUS689A – JUNE 2006 – REVISED OCTOBER 2006 CHARGE TIMER INTERNAL CLOCK PERIOD MULTIPLICATION FACTOR 5 4 3 2 1 0 0 1 5 4 3 2 V(SET)/V(ISET) - V Figure 20. Safety Timer Linearity Internal Clock Period Multiplication Factor 45 RTMR = 70 kW T(CHG) - Safety Timer - Hours 40 35 30 RTMR = 50 kW 25 20 RTMR = 30 kW 15 10 5 0 0 1 2 3 VSET/VISET - V 4 5 Figure 21. bq2406x Safety Timer Linearity for RTMR Values 20 Submit Documentation Feedback 6 bq2406x www.ti.com SLUS689A – JUNE 2006 – REVISED OCTOBER 2006 160 Core Oscillator Frequency - kHz 140 120 100 80 60 40 20 0 20 30 40 60 50 ITMR Current - mA 70 80 90 Figure 22. bq2406x Oscillator Linearity vs ITMR RTMR 30 KΩ – 100 KΩ CHARGE TERMINATION DETECTION AND RECHARGE The charging current is monitored the during the voltage regulation phase. Charge termination is indicated at the STATx pins (STAT1 = Hi-Z; STAT2 = Low ) once the charge current falls below the termination current threshold I(TERM). A deglitch period TDGL(TERM) is added to avoid false termination indication during transient events. Charge termination is not detected if the charge current falls below the termination threshold as a result of the thermal loop activation. Termination is also not detected when charger enters the suspend mode, due to detection of invalid pack temperature or internal thermal shutdown. Table 6 describes the termination latch functionality. Table 6. Termination Latch Functionality TERMINATION DETECTED LATCHED WHEN TERMINATION LATCH RESET AT CE rising edge or OVP detected I(OUT) < I(TERM) AND t > TDGL(TERM) AND V(OUT) > V(RCH) New charging cycle started; see state diagram Termination disabled The termination function is DISABLED: 1. In bq24060/61/64 the termination is disabled when the TMR pin is left open (floating). 2. In bq24063 leaving TMR pin open (floating) does NOT disable the termination. The only way to disable termination in the bq24063 is to set TE = HIGH. BATTERY ABSENT DETECTION – VOLTAGE MODE ALGORITHM The bq2406x provides a battery absent detection scheme to reliably detect insertion and/or removal of battery packs. The detection circuit applies an internal current to the battery terminal, and detects battery presence based on the terminal voltage behavior. Figure 23 has a typical waveform of the output voltage when the battery absent detection is enabled and no battery is connected: Submit Documentation Feedback 21 bq2406x www.ti.com SLUS689A – JUNE 2006 – REVISED OCTOBER 2006 5 VO - Output Voltage - V 4.50 4 3.50 3 2.50 2 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 t - Time - s Figure 23. Battery-Absent Detection Waveforms The battery absent detection function is disabled if the voltage at the BAT pin is held above the battery recharge threshold, V(RCH), after termination detection. When the voltage at the BAT pin falls to the recharge threshold, either by connection of a load to the battery or due to battery removal, the bq2406x begins a battery absent detection test. This test involves enabling a detection current, IDET(DOWN), for a period of T(DETECT) and checking to see if the battery voltage is below the pre-charge threshold, V(LOWV). Following this, the precharge current, IDET(UP) is applied for a period of T(DETECT) and the battery voltage checked again to be above the recharge threshold. Passing both of the discharge and charging tests (battery terminal voltage being below the pre-charge and above the recharge thresholds on the battery detection test) indicates a battery absent fault at the STAT1 and STAT2 pins. Failure of either test starts a new charge cycle. For the absent battery condition the voltage on the BAT pin rises and falls between the V(LOWV) and VO(REG) thresholds indefinitely. See the operation flowchart for more details on this algorithm. If it is desired to power a system load without a battery, it is recommended to float the TMR pin which puts the charger in LDD mode (disables termination). The battery absent detection function is disabled when the termination is disabled. The bq2406x provides a small battery leakage current, IBAT(DONE) (1 µA typical), after termination to pull down the BAT pin voltage in the event of battery removal. If the leakage on the OUT pin is higher than this pulldown current, then the voltage at the pin remains above termination and a battery-absent state will not be detected. This problem is fixed with the addition of a pulldown resistor of 2 MΩ to 4 MΩ from the OUT pin to VSS. A resistor too large (< 2 MΩ) can cause the OUT pin voltage to drop below the V(LOWV) threshold before the recharge deglitch (typical 25 ms) expires, causing a fault condition. In this case the bq2406x provides a fault current (typical 750 µA) to pull the pin above the termination threshold. CHARGE SAFETY TIMER As a safety mechanism the bq2406x has a user-programmable timer that monitors the total fast charge time. This timer (charge safety timer) is started at the beginning of the fast charge period. The safety charge timeout value is set by the value of an external resistor connected to the TMR pin (RTMR); if pin TMR is left open (floating) the charge safety timer is disabled. The charge safety timer time-out value is calculated as follows: T(CHG) = [K(CHG)× R(TMR)] The safety timer operation modes are shown in Table 7 22 Submit Documentation Feedback bq2406x www.ti.com SLUS689A – JUNE 2006 – REVISED OCTOBER 2006 Table 7. Charge Safety Timer Operational Modes bq2460X V(OUT) > V(LOWV) CHARGE SAFETY TIMER MODE STANDBY X RESET CHARGING No RESET SUSPEND No RESET SUSPEND Yes SUSPEND CHARGING, TMR PIN NOT OPEN Yes COUNTING X RESET CHARGING, TMR PIN OPEN In SUSPEND mode the charge safety timer is put on hold (i.e., charge safety timer is not reset), normal operation resumes when the TS fault is removed and the timer returns to the normal operating mode (COUNTING). If charge termination is not reached within the timer period a fault condition is detected. Under those circumstances the LED status is updated to indicate a fault condition and the charger is turned off. When the charge safety timer fault latch is set and the charger is turned off a small current IFAULT is applied to the OUT pin, as long as input power (IN) is detected AND V(OUT) < V(RCHG), as part of a timer fault recovery protocol. This current allows the output voltage to rise above the recharge threshold V(RCHG) if the pack is removed, and assures that the charge safety timer fault latch is reset if the pack is removed and re-inserted. Table 8 further details the charge safety timer fault latch operation. Table 8. Charge Safety Timer Latch Functionality CHARGE SAFETY TIMER FAULT ENTERED CHARGE SAFETY TIMER FAULT LATCH RESET AT CE rising edge, or OVP detected V(OUT) > V(LOW V) Input power removed (not detected) New charging cycle started; see state diagram SHORT CIRCUIT PROTECTION The internal comparators monitor the battery voltage and detect when a short circuit is applied to the battery terminal. If the voltage at the BAT pin is less than the internal threshold V(scind) (1.8 V typical), the STAT pins indicate a fault condition (STAT1 = STAT2 = Hi-Z). When the voltage at the BAT pin falls below a second internal threshold V(sc) (1.4 V typical), the charger power stage is turned off. A recovery current, I(short) (22 mA typical), is applied to the BAT pin, enabling detection of the short circuit removal. The battery output current versus battery voltage is shown in the graph, Figure 24 1200 RISET at 840 W Battery Current - mA 1000 800 600 400 200 0 4 3.5 3 2.5 2 1.5 1 0.5 0 Battery Voltage - V Figure 24. bq2406x Short Circuit Behavior Submit Documentation Feedback 23 bq2406x www.ti.com SLUS689A – JUNE 2006 – REVISED OCTOBER 2006 See the application section for additional details on start-up operation with V(BAT) < V(SC). STARTUP WITH DEEPLY DEPLETED BATTERY CONNECTED The bq2406x charger furnishes the programmed charge current if a battery is detected. If no battery is connected the bq2406x operates as follows: • The output current is limited to 22 mA (typical), if the voltage at BAT pin is below the short circuit detection threshold V(SC), 1.8 V typical. • The output current is regulated to the programmed pre-charge current if V(SC) < V(BAT) < V(LOWV). • The output current is regulated to the programmed fast charge current If V(BAT) > V(LOWV) AND voltage regulation is not reached. The output voltage collapses if no battery is present and the end equipment requires a bias current larger that the available charge current. 24 Submit Documentation Feedback bq2406x www.ti.com SLUS689A – JUNE 2006 – REVISED OCTOBER 2006 APPLICATION INFORMATION SELECTING INPUT AND OUTPUT CAPACITOR In most applications, all that is needed is a high-frequency decoupling capacitor on the input power pin. A 1-µF ceramic capacitor, placed in close proximity to the IN pin and GND pad, works fine. In some applications, depending on the power supply characteristics and cable length, it may be necessary to increase the input filter capacitor to avoid exceeding the IN pin maximum voltage rating during adapter hot plug events. The bq2406x only requires a small output capacitor for loop stability. A 0.47 µF ceramic capacitor placed between the BAT and ISET pad is typically sufficient. bq2406x CHARGER DESIGN EXAMPLE Requirements • Supply voltage = 5 V • Safety timer duration of 5 hours for fast charge • Fast charge current of approximately 750 mA • Battery temp sense is not used Calculations Program the charge current for 750 mA: RISET = [V(SET)× K(SET) / I(OUT)] from electrical characteristics table. . . V(SET) = 2.5 V from electrical characteristics table. . . K(SET) = 335 RISET = [2.5 V × 335 / 0.75 A] = 1.12 kΩ Selecting the closest standard value, use a 1.13 kΩ resistor connected between ISET (pin 6) and ground. Program 5-hour safety timer timeout: R(TMR) = [T(CHG) / K(CHG)] from the electrical characteristics table. . . K(CHG) = 0.1 hr / kΩ K(TMR) = [5 hrs / (0.1 hr / kΩ)] = 50 kΩ Selecting the closest standard value, use a 49.9 kΩ resistor connected between TMR (pin 2) and ground. Disable the temp sense function: A constant voltage between VTS1 and VTS2 on the TS input disables the temp sense function. from electrical characteristics table. . . V(TS1) = 30% × VIN from electrical characteristics table. . . V(TS2) = 61% × VIN A constant voltage of 50% × Vin disables the temp sense function, so a divide-by-2 resistor divider connected between Vin and ground can be used. Two 1-mΩ resistors keeps the power dissipated in this divider to a minimum. For a 0–45°C range with a Semitee 103AT thermistor, the thermistor values are 4912 at 450°C and 2728k at 0°C. RT1 (top resisotr) and RT2 (bottom resistor) are calculated as follows: Submit Documentation Feedback 25 bq2406x www.ti.com SLUS689A – JUNE 2006 – REVISED OCTOBER 2006 APPLICATION INFORMATION (continued) R T2 + R T1 + 2.5 R TCRTH RTC * 3.5 RTH 7 R THRT2 3 ƪRTH ) RT2ƫ + + 2.5 (27.28k) (4.912k) + 33.2k; 27.28k * 3.5(4.912k) 7 (4.921k) (33.2k) + 10k 3 [4.921k ) 33.2k] (6) PIN COMPONENTS IN In most applications, the minimum input capacitance needed is a 0.1 µF ceramic decoupling capacitor near the input pin connected to ground (preferably to a grond plane through vias). The recommended amount of input capacitance is 1 µF or at least as much as on the output pin. This added capacitance helps with hot plug transients, input inductance and initial charge transients. OUT There is no minimum value for capacitance for this output, but it is recommended to connect a 1 µF ceramic capacitor between OUT and ground. This capacitance helps with termination, and cycling frequency between charge done and refresh charge when no battery is present. It also helps cancel out any battery lead inductance for long leaded battery packs. It is recommended to put as much ceramic capacitance on the input as the output so as not to cause a drop out of the input when charging is initiated. ISET/BAT For stability reasons, it may be necessary to put a 0.47-µF capacitor between the ISET and BAT pin.. STAT1/2 and PG Optional (LED STATUS – See below, Processor Monitored; or no status) STAT1 Connect the cathode of a red LED to the open-collector STAT1 output, and connect the anode of the red LED to the input supply through a 1.5 kΩ resistor that limits the current. STAT2 Connect the cathode of a green LED to the open-collector STAT2 output, and connect the anode of the green LED to the input supply through a 1.5 kΩ resistor that limits the current. PG Connect the cathode of an LED to the open-collector PG output, and connect the anode of the LED to the input supply through a 1.5 kΩ resistor to limit the current. THERMAL CONSIDERATIONS The bq2406x family is packaged in a thermally enhanced MLP package. The package includes a thermal pad to provide an effective thermal contact between the IC and the printed circuit board (PCB). Full PCB design guidelines for this package are provided in the application note entitled: QFN/SON PCB Attachment Application Note (SLUA271). The most common measure of package thermal performance is thermal impedance (θJA ) measured (or modeled) from the chip junction to the air surrounding the package surface (ambient). The mathematical expression for θJA is: T * TA q(JA) + J P (7) Where: TJ = chip junction temperature TA = ambient temperature P = device power dissipation Factors that can greatly influence the measurement and calculation of θJA include: • Whether or not the device is board mounted • Trace size, composition, thickness, and geometry • Orientation of the device (horizontal or vertical) • Volume of the ambient air surrounding the device under test and airflow 26 Submit Documentation Feedback bq2406x www.ti.com SLUS689A – JUNE 2006 – REVISED OCTOBER 2006 APPLICATION INFORMATION (continued) • Whether other surfaces are in close proximity to the device being tested The device power dissipation, P, is a function of the charge rate and the voltage drop across the internal PowerFET. It can be calculated from the following equation when a battery pack is being charged : P = [V(IN) – V(OUT)] × I(OUT) Due to the charge profile of Li-Ion batteries the maximum power dissipation is typically seen at the beginning of the charge cycle when the battery voltage is at its lowest. See the charging profile, Figure 13 . If the board thermal design is not adequate the programmed fast charge rate current may not be achieved under maximum input voltage and minimum battery voltage, as the thermal loop can be active effectively reducing the charge current to avoid excessive IC junction temperature. USING ADAPTERS WITH LARGE OUTPUT VOLTAGE RIPPLE Some low cost adapters implement a half rectifier topology, which causes the adapter output voltage to fall below the battery voltage during part of the cycle. To enable operation with low cost adapters under those conditions the bq2406x family keeps the charger on for at least 30 msec (typical) after the input power puts the part in sleep mode. This feature enables use of external low cost adapters using 50 Hz networks. The backgate control circuit prevents any reverse current flowing from the battery to the adapter terminal during the charger off delay time. Note that the PG pin is not deglitched, and it indicates input power loss immediately after the input voltage falls below the output voltage. If the input source frequently drops below the output voltage and recovers, a small capacitor can be used from PG to VSS to prevent /PG flashing events. PCB LAYOUT CONSIDERATIONS It is important to pay special attention to the PCB layout. The following provides some guidelines: • To obtain optimal performance, the decoupling capacitor from IN to GND (thermal pad) and the output filter capacitors from OUT to GND (thermal pad) should be placed as close as possible to the bq2406x, with short trace runs to both IN, OUT and GND (thermal pad). • All low-current GND connections should be kept separate from the high-current charge or discharge paths from the battery. Use a single-point ground technique incorporating both the small signal ground path and the power ground path. • The high current charge paths into IN pin and from the OUT pin must be sized appropriately for the maximum charge current in order to avoid voltage drops in these traces. • The bq2406x family are packaged in a thermally enhanced MLP package. The package includes a thermal pad to provide an effective thermal contact between the IC and the printed circuit board (PCB); this thermal pad is also the main ground connection for the device. Connect the thermal pad to the PCB ground connection. Full PCB design guidelines for this package are provided in the application note entitled: QFN/SON PCB Attachment Application Note (SLUA271). Submit Documentation Feedback 27 PACKAGE OPTION ADDENDUM www.ti.com 2-Oct-2006 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Eco Plan (2) Qty BQ24060DRCR ACTIVE SON DRC 10 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR BQ24060DRCRG4 ACTIVE SON DRC 10 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR BQ24060DRCT ACTIVE SON DRC 10 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR BQ24060DRCTG4 ACTIVE SON DRC 10 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR BQ24061DRCR ACTIVE SON DRC 10 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR BQ24061DRCRG4 ACTIVE SON DRC 10 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR BQ24061DRCT ACTIVE SON DRC 10 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR BQ24061DRCTG4 ACTIVE SON DRC 10 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR BQ24064DRCR ACTIVE SON DRC 10 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR BQ24064DRCRG4 ACTIVE SON DRC 10 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR BQ24064DRCT ACTIVE SON DRC 10 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR BQ24064DRCTG4 ACTIVE SON DRC 10 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR Lead/Ball Finish MSL Peak Temp (3) (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. Addendum-Page 1 PACKAGE OPTION ADDENDUM www.ti.com 2-Oct-2006 In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. 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