bq24133 SLUSAF7B – DECEMBER 2010 – REVISED MAY 2011 www.ti.com 1.6-MHz Synchronous Switch-Mode Li-Ion and Li-Polymer Stand-Alone Battery Charger with Integrated MOSFETs and Power Path Selector Check for Samples: bq24133 FEATURES APPLICATIONS • • • • • • • • 1 • • • • • • • • • 1.6MHz Synchronous Switch-Mode Charger with 2.5A Integrated N-MOSFETs Up to 92% Efficiency 30V Input Rating with Adjustable Over-Voltage Protection – 4.5V to 17V Input Operating Voltage Battery Charge Voltage – 1, 2, or 3-Cell with 4.2V/Cell High Integration – Automatic Power Path Selector Between Adapter and Battery – Dynamic Power Management – Integrated 20-V Switching MOSFETs – Integrated Bootstrap Diode – Internal Loop Compensation – Internal Digital Soft Start Safety – Thermal Regulation Loop Throttles Back Current to Limit Tj = 120°C – Thermal Shutdown – Battery Thermistor Sense Hot/Cold Charge Suspend & Battery Detect – Input Over-Voltage Protection with Programmable Threshold – Cycle-by-Cycle Current Limit Accuracy – ±0.5% Charge Voltage Regulation – ±5% Charge Current Regulation – ±6% Input Current Regulation Less than 15μA Battery Current with Adapter Removed Less than 1.5mA Input Current with Adapter Present and Charge Disabled Small QFN Package – 3.5mm × 5.5mm QFN-24 Pin Tablet PC Netbook and Ultra-Mobile Computers Portable Data Capture Terminals Portable Printers Medical Diagnostics Equipment Battery Bay Chargers Battery Back-Up Systems DESCRIPTION The bq24133 is highly integrated stand-alone Li-ion and Li-polymer switch-mode battery charger with two integrated N-channel power MOSFETs. It offers a constant-frequency synchronous PWM controller with high accuracy regulation of input current, charge current, and voltage. It closely monitors the battery pack temperature to allow charge only in a preset temperature window. It also provides battery detection, pre-conditioning, charge termination, and charge status monitoring. The thermal regulation loop reduces charge current to maintain the junction temperature of 120°C during operation. The bq24133 charges a one, two, or three cell Li-Ion battery in three phases: precondictioning, constant current, and constant voltage. Charge is terminated when the current reaches 10% of the fast charge rate. A programmable charge timer offers a safety back up. The bq24133 automatically restarts the charge cycle if the battery voltage falls below an internal threshold, and enters a low-quiescent current sleep mode when the input voltage falls below the battery voltage. The bq24133 features Dynamic Power Management (DPM) to reduce the charge current when the input power limit is reached to avoid over-loading the adapter. A highly-accurate current-sense amplifier enables precise measurement of input current from adapter to monitor overall system power. 1 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. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 2010–2011, Texas Instruments Incorporated bq24133 SLUSAF7B – DECEMBER 2010 – REVISED MAY 2011 www.ti.com 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. DESCRIPTION (CONTINUED) The bq24133 provides power path selector gate driver ACDRV/CMSRC on input NMOS pair ACFET (Q1) and RBFET (Q2), and BATDRV on a battery PMOS device (Q3). When the qualified adapter is present, the system is directly connected to the adapter. Otherwise, the system is connected to the battery. In addition, the power path prevents battery from boosting back to the input. The bq24170/172 charges the battery from a DC source as high as 17V, including a car battery. The input over-voltage limit is adjustable through the OVPSET pin. The AVCC, ACP, and ACN pins have a 30V rating. When a high voltage DC source is inserted, Q1/Q2 remain off to avoid high voltage damage to the system. For 1 cell applications, if the battery is not removable, the system can be directly connected to the battery to simplify the power path design and lower the cost. With this configuration, the battery can automatically supplement the system load if the adapter is overloaded. The bq24133 is available in a 24-pin, 3.5mmx5.5 mm thin QFN package. SW 1 24 2 23 3 22 4 21 5 20 6 19 AGND 7 18 8 17 9 16 10 15 14 12 13 ISET 11 VREF PVCC PVCC AVCC ACN ACP CMSRC ACDRV STAT TS TTC SW RGY PACKAGE (TOP VIEW) PGND PGND BTST REGN BATDRV OVPSET ACSET SRP SRN CELL PIN FUNCTIONS PIN NO. 2 NAME TYPE DESCRIPTION 1,24 SW P Switching node, charge current output inductor connection. Connect the 0.047-µF bootstrap capacitor from SW to BTST. 2,3 PVCC P Charger input voltage. Connect at least 10-µF ceramic capacitor from PVCC to PGND and place it as close as possible to IC. 4 AVCC P IC power positive supply. Place a 1-µF ceramic capacitor from AVCC to AGND and place it as close as possible to IC. Place a 10-Ω resistor from input side to AVCC pin to filter the noise. For 5V input, a 5-Ω resistor is recommended. 5 ACN I Adapter current sense resistor negative input. A 0.1-µF ceramic capacitor is placed from ACN to ACP to provide differential-mode filtering. An optional 0.1-µF ceramic capacitor is placed from ACN pin to AGND for common-mode filtering. 6 ACP P/I Adapter current sense resistor positive input. A 0.1-µF ceramic capacitor is placed from ACN to ACP to provide differential-mode filtering. A 0.1-µF ceramic capacitor is placed from ACP pin to AGND for common-mode filtering. 7 CMSRC O Connect to common source of N-channel ACFET and reverse blocking MOSFET (RBFET). Place 4-kΩ resistor from CMSRC pin to the common source of ACFET and RBFET to control the turn-on speed. The resistance between ACDRV and CMSRC should be 500-kΩ or bigger. Copyright © 2010–2011, Texas Instruments Incorporated bq24133 SLUSAF7B – DECEMBER 2010 – REVISED MAY 2011 www.ti.com PIN FUNCTIONS (continued) PIN NO. NAME TYPE DESCRIPTION 8 ACDRV O AC adapter to system switch driver output. Connect to 4-kΩ resistor then to the gate of the ACFET N-channel power MOSFET and the reverse conduction blocking N-channel power MOSFET. Connect both FETs as common-source. The internal gate drive is asymmetrical, allowing a quick turn-off and slower turn-on in addition to the internal break-before-make logic with respect to the BATDRV. 9 STAT O Open-drain charge status pin with 10-kΩ pull up to power rail. The STAT pin can be used to drive LED or communicate with the host processor. It indicates various charger operations: LOW when charge in progress. HIGH when charge is complete or in SLEEP mode. Blinking at 0.5Hz when fault occurs, including charge suspend, input over-voltage, timer fault and battery absent. 10 TS I Temperature qualification voltage input. Connect a negative temperature coefficient thermistor. Program the hot and cold temperature window with a resistor divider from VREF to TS to AGND. The temperature qualification window can be set to 5-40°C or wider. The 103AT thermistor is recommended. 11 TTC I Safety Timer and termination control. Connect a capacitor from this node to AGND to set the fast charge safety timer(5.6min/nF). Pre-charge timer is internally fixed to 30 minutes. Pull the TTC to LOW to disable the charge termination and safety timer. Pull the TTC to HIGH to disable the safety timer but allow the charge termination. 12 VREF P 3.3V reference voltage output. Place a 1-μF ceramic capacitor from VREF to AGND pin close to the IC. This voltage could be used for programming ISET and ACSET and TS pins. It may also serve as the pull-up rail of STAT pin and CELL pin. 13 ISET I Fast charge current set point. Use a voltage divider from VREF to ISET to AGND to set the fast charge current: ICHG = VISET 20 ´ RSR The pre-charge and termination current is internally as one tenth of the charge current. The charger is disabled when ISET pin voltage is below 40mV and enabled when ISET pin voltage is above 120mV. 14 CELL I Cell selection pin. Set CELL pin LOW for 1-cell, Float for 2-cell (0.8V-1.8V), and HIGH for 3-cell with a fixed 4.2V per cell. 15 SRN I Charge current sense resistor negative input. A 0.1-μF ceramic capacitor is placed from SRN to SRP to provide differential-mode filtering. A 0.1-μF ceramic capacitor is placed from SRN pin to AGND for common-mode filtering. 16 SRP I/P Charge current sense resistor, positive input. A 0.1-μF ceramic capacitor is placed from SRN to SRP to provide differential-mode filtering. A 0.1-μF ceramic capacitor is placed from SRP pin to AGND for common-mode filtering. 17 ACSET I Input current set point. Use a voltage divider from VREF to ACSET to AGND to set this value: IDPM = VACSET 20 ´ R AC 18 OVPSET I Valid input voltage set point. Use a voltage divider from input to OVPSET to AGND to set this voltage. The voltage above internal 1.6V reference indicates input over-voltage, and the voltage below internal 0.5V reference indicates input under-voltage. In either condition, charge terminates, and input NMOS pair ACFET/RBFET turn off. LED driven by STAT pin keeps blinking, reporting fault condition. 19 BATDRV O Battery discharge MOSFET gate driver output. Connect to 1kohm resistor to the gate of the BATFET P-channel power MOSFET. Connect the source of the BATFET to the system load voltage node. Connect the drain of the BATFET to the battery pack positive node. The internal gate drive is asymmetrical to allow a quick turn-off and slower turn-on, in addition to the internal break-before-make logic with respect to ACDRV. 20 REGN P PWM low side driver positive 6V supply output. Connect a 1-μF ceramic capacitor from REGN to PGND pin, close to the IC. Generate high-side driver bootstrap voltage by integrated diode from REGN to BTST. 21 BTST P PWM high side driver positive supply. Connect the 0.047-µF bootstrap capacitor from SW to BTST. 22,23 PGND P Power ground. Ground connection for high-current power converter node. On PCB layout, connect directly to ground connection of input and output capacitors of the charger. Only connect to AGND through the Thermal Pad underneath the IC. Thermal Pad AGND P Exposed pad beneath the IC. Always solder Thermal Pad to the board, and have vias on the Thermal Pad plane star-connecting to AGND and ground plane for high-current power converter. It dissipates the heat from the IC. Copyright © 2010–2011, Texas Instruments Incorporated 3 bq24133 SLUSAF7B – DECEMBER 2010 – REVISED MAY 2011 www.ti.com TYPICAL APPLICATIONS Q2 Q1 RAC: 20m System 12V Adapter C12: 0.1µ RIN 2 C11: 0.1µ C4: 10µ CIN 2.2? R11 4.02k VBAT ACN ACP CMSRC R12 4.02k D1 VREF R2 232k VREF R4 100k R1 10 BATDRV bq24133 ISET C1 1µ RT 103AT R8 5.23k R9 30.1k R10 1.5k VREF D3 VBAT C8 0.1? C9, C10 10? 10? C6 1? PGND C3: 0.1? VREF C7 0.1? REGN AVCC OVPSET R7 100k C5 0.047? BTST ACSET R6 1000k L: 3.3?H RSR:10m SW VREF R3 32.4k R5 32.4kk Q3 R14 1k ACDRV C2: 1µ D2 PVCC SRP TTC SRN TS CELL Float THERMAL STAT PAD Figure 1. Typical Application Schematic (12V input, 2 cell battery 8.4V, 2A charge current, 0.2A pre-charge/termination current, 2A DPM current, 18V input OVP, 0 – 45°C TS) 4 Copyright © 2010–2011, Texas Instruments Incorporated bq24133 SLUSAF7B – DECEMBER 2010 – REVISED MAY 2011 www.ti.com RevFET Q4 RAC: 20m Adapter Or USB System 0.1µ 0.1µ PVCC ACN ACP CMSRC 1µ VREF Selectable input current limit R5B 8.06k ILIM_500mA R11 5 VREF BATDRV ACDRV 3.3?H VBAT bq24133 ISET 0.047? R3 32.4k R5A 32.4k RSR: 10m SW VREF R2 100k R4 100k 4.7µ BTST ACSET REGN 0.1? 0.1? 10? 10? D1 D Optional 1? R6 845k C1 1µ AVCC PGND OVPSET R7 100k RT 103AT SRP VREF R8 6.81k R10 1.5k R9 133k VREF D3 TTC SRN TS CELL THERMAL STAT PAD Figure 2. Typical Application Schematic wth Single Cell Unremovable Battery (USB or adapter with input OVP 15V, up to 2A charge current, 0.2A pre-charge current, 2A adapter current or 500mA USB current, 5 – 40°C TS, system connected before sense resistor) ORDERING INFORMATION (1) PART NUMBER bq24133 (1) PART MARKING bq24133 PACKAGE 24-Pin 3.5mm×5.5mm QFN ORDERING NUMBER QUANTITY bq24133RGYR 3000 bq24133RGYT 250 For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI website at www.ti.com. Copyright © 2010–2011, Texas Instruments Incorporated 5 bq24133 SLUSAF7B – DECEMBER 2010 – REVISED MAY 2011 www.ti.com ABSOLUTE MAXIMUM RATINGS over operating free-air temperature range (unless otherwise noted) (1) (2) VALUE Voltage range (with respect to AGND) AVCC, ACP, ACN, ACDRV, CMSRC, STAT –0.3 to 30 PVCC –0.3 to 20 BTST –0.3 to 26 BATDRV, SRP, SRN –0.3 to 20 UNIT V –2 to 20 SW OVPSET, REGN, TS, TTC, CELL –0.3 to 7 VREF, ISET, ACSET –0.3 to 3.6 PGND –0.3 to 0.3 SRP–SRN, ACP-ACN –0.5 to 0.5 V Junction temperature range, TJ –40 to 155 °C Storage temperature range, Tstg –55 to 155 °C Maximum difference voltage (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. All voltages are with respect to GND if not specified. Currents are positive into, negative out of the specified terminal. Consult Packaging Section of the data book for thermal limitations and considerations of packages. THERMAL INFORMATION bq24133 THERMAL METRIC (1) RGY UNITS 24 PINS θJA Junction-to-ambient thermal resistance (2) ψJT Junction-to-top characterization parameter (3) 0.4 ψJB Junction-to-board characterization parameter (4) 31.2 (1) (2) (3) (4) 35.7 °C/W For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953. The junction-to-ambient thermal resistance under natural convection is obtained in a simulation on a JEDEC-standard, high-K board, as specified in JESD51-7, in an environment described in JESD51-2a. The junction-to-top characterization parameter, ψJT, estimates the junction temperature of a device in a real system and is extracted from the simulation data for obtaining θJA, using a procedure described in JESD51-2a (sections 6 and 7). The junction-to-board characterization parameter, ψJB, estimates the junction temperature of a device in a real system and is extracted from the simulation data for obtaining θJA , using a procedure described in JESD51-2a (sections 6 and 7). RECOMMENDED OPERATING CONDITIONS Input voltage VIN Output voltage VOUT Output current (RSR 10mΩ) IOUT Maximum difference voltage MAX 4.5 17 UNIT V 13.5 V 0.6 2.5 A ACP - ACN –200 200 mV SRP–SRN –200 200 mV –40 85 °C Operation free-air temperature range, TA 6 MIN Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): bq24133 bq24133 SLUSAF7B – DECEMBER 2010 – REVISED MAY 2011 www.ti.com ELECTRICAL CHARACTERISTICS 4.5V ≤ V(PVCC, AVCC) ≤ 17V, –40°C < TJ + 125°C, typical values are at TA = 25°C, with respect to AGND (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNITS OPERATING CONDITIONS VAVCC_OP AVCC input voltage operating range during charging 4.5 17 V QUIESCENT CURRENTS Battery discharge current (sum of currents into AVCC, PVCC, ACP, ACN) IBAT Adapter supply current (sum of current into AVCC,ACP, ACN) IAC VAVCC > VUVLO, VSRN > VAVCC (SLEEP), TJ = 0°C to 85°C 15 BTST, SW, SRP, SRN, VAVCC > VUVLO, VAVCC > VSRN, ISET < 40mV, VBAT=12.6V, Charge disabled 25 BTST, SW, SRP, SRN, VAVCC > VUVLO, VAVCC > VSRN, ISET > 120mV, VBAT=12.6V, Charge done 25 VAVCC > VUVLO, VAVCC > VSRN, ISET < 40mV, VBAT=12.6V, Charge disabled 1.2 1.5 VAVCC > VUVLO, VAVCC > VSRN, ISET > 120mV, Charge enabled, no switching 2.5 5 VAVCC > VUVLO, VAVCC > VSRN, ISET > 120mV, Charge enabled, switching 15 (1) µA mA CHARGE VOLTAGE REGULATION VBAT_REG SRN regulation voltage Charge voltage regulation accuracy CELL to AGND, 1 cell, measured on SRN 4.2 V CELL floating, 2 cells, measured on SRN 8.4 V CELL to VREF, 3 cells, measured on SRN 12.6 V TJ = 0°C to 85°C –0.5% 0.5% TJ = –40°C to 125°C -0.7% 0.7% 0.12 0.5 CURRENT REGULATION – FAST CHARGE VISET ISET Voltage Range KISET Charge Current Set Factor (Amps of Charge RSENSE = 10mΩ Current per Volt on ISET pin) RSENSE = 10mΩ Charge Current Regulation Accuracy 5 A/V VSRP-SRN = 40 mV -5% VSRP-SRN = 20 mV -8% 8% VSRP-SRN = 5 mV -25% 25% VISET_CD Charge Disable Threshold ISET falling VISET_CE Charge Enable Threshold ISET rising IISET Leakage Current into ISET VISET = 2V 40 V 5% 50 100 mV 120 mV 100 nA INPUT CURRENT REGULATION KDPM Input DPM Current Set Factor (Amps of Input Current per Volt on ACSET) Input DPM Current Regulation Accuracy IACSET Leakage Current into ACSET pin RSENSE = 20mΩ 2.5 A/V VACP-ACN = 80 mV -6% 6% VACP-ACN = 40 mV -10% 10% VACP-ACN = 20 mV –15% 15% VACP-ACN = 5 mV –20% 20% VACSET = 2V 100 nA CURRENT REGULATION – PRE-CHARGE KIPRECHG Precharge current set factor Precharge current regulation accuracy (1) (2) 10% (2) Percentage of fast charge current VSRP-SRN = 4 mV –25% 25% VSRP-SRN = 2 mV –40% 40% Specified by design The minimum current is 120 mA on 10mΩ sense resistor. Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): bq24133 7 bq24133 SLUSAF7B – DECEMBER 2010 – REVISED MAY 2011 www.ti.com ELECTRICAL CHARACTERISTICS (continued) 4.5V ≤ V(PVCC, AVCC) ≤ 17V, –40°C < TJ + 125°C, typical values are at TA = 25°C, with respect to AGND (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNITS CHARGE TERMINATION KTERM Termination current set factor 10% (3) Percentage of fast charge current Termination current regulation accuracy VSRP-SRN = 4 mV –25% VSRP-SRN = 2 mV –40% tTERM_DEG Deglitch time for termination (both edges) tQUAL Termination qualification time VSRN > VRECH and ICHG < ITERM IQUAL Termination qualification current Discharge current once termination is detected 25% 40% 100 ms 250 ms 2 mA INPUT UNDER-VOLTAGE LOCK-OUT COMPARATOR (UVLO) VUVLO AC under-voltage rising threshold Measure on AVCC VUVLO_HYS AC under-voltage hysteresis, falling Measure on AVCC 3.4 3.6 3.8 300 V mV SLEEP COMPARATOR (REVERSE DISCHARGING PROTECTION) VSLEEP SLEEP mode threshold VAVCC – VSRN falling VSLEEP_HYS SLEEP mode hysteresis VAVCC – VSRN rising 200 mV tSLEEP_FALL_CD SLEEP deglitch to disable charge VAVCC – VSRN falling 1 ms tSLEEP_FALL_FETOFF SLEEP deglitch to turn off input FETs VAVCC – VSRN falling 5 ms tSLEEP_FALL Deglitch to enter SLEEP mode, disable VREF and enter low quiescent mode VAVCC – VSRN falling 100 ms tSLEEP_PWRUP Deglitch to exit SLEEP mode, and enable VREF VAVCC – VSRN rising 30 ms 50 90 150 mV ACN-SRN COMPARATOR VACN-SRN Threshold to turn on BATFET VACN-SRN falling VACN-SRN_HYS Hysteresis to turn off BATFET VACN-SRN rising 150 220 100 300 mV mV tBATFETOFF_DEG Deglitch to turn on BATFET VACN-SRN falling 2 ms tBATFETON_DEG Deglitch to turn off BATFET VACN-SRN rising 50 µs BAT LOWV COMPARATOR VLOWV Precharge to fast charge transition VLOWV_HYS Fast charge to precharge hysteresis CELL to AGND, 1 cell, measure on SRN 2.87 2.9 2.93 CELL floating, 2 cells, measure on SRN 5.74 5.8 5.86 CELL to VREF, 3 cells, measure on SRN 8.61 8.7 8.79 CELL to AGND, 1 cell, measure on SRN 200 CELL floating, 2 cells, measure on SRN 400 CELL to VREF, 3 cells, measure on SRN 600 V mV tpre2fas VLOWV rising deglitch Delay to start fast charge current 25 ms tfast2pre VLOWV falling deglitch Delay to start precharge current 25 ms RECHARGE COMPARATOR Recharge Threshold, below regulation voltage limit, VBAT_REG-VSRN VRECHG CELL to AGND, 1 cell, measure on SRN 70 100 130 CELL floating, 2 cells, measure on SRN 140 200 260 CELL to VREF, 3 cells, measure on SRN 210 300 390 mV tRECH_RISE_DEG VRECHG rising deglitch SRN decreasing below VRECHG 10 ms tRECH_FALL_DEG VRECHG falling deglitch SRN increasing above VRECHG 10 ms (3) 8 The minimum current is 120 mA on 10mΩ sense resistor. Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): bq24133 bq24133 SLUSAF7B – DECEMBER 2010 – REVISED MAY 2011 www.ti.com ELECTRICAL CHARACTERISTICS (continued) 4.5V ≤ V(PVCC, AVCC) ≤ 17V, –40°C < TJ + 125°C, typical values are at TA = 25°C, with respect to AGND (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNITS 1.65 V BAT OVER-VOLTAGE COMPARATOR VOV_RISE Over-voltage rising threshold As percentage of VBAT_REG 104% VOV_FALL Over-voltage falling threshold As percentage of VSRN 102% INPUT OVER-VOLTAGE COMPARATOR (ACOV) VACOV AC Over-Voltage Rising Threshold to turn off ACFET OVPSET rising VACOV_HYS AC over-voltage falling hysteresis OVPSET falling 50 mV tACOV_RISE_DEG AC Over-Voltage Rising Deglitch to turn off ACFET and Disable Charge OVPSET rising 1 µs tACOV_FALL_DEG AC Over-Voltage Falling Deglitch to Turn on ACFET OVPSET falling 30 ms 1.55 1.6 INPUT UNDER-VOLTAGE COMPARATOR (ACUV) VACUV AC Under-Voltage Falling Threshold to turn off ACFET OVPSET falling VACUV_HYS AC Under-Voltage Rising Hysteresis OVPSET rising 100 mV tACOV_FALL_DEG AC Under-Voltage Falling Deglitch to turn off ACFET and Disable Charge OVPSET falling 1 µs tACOV_RISE_DEG AC Under-Voltage Rising Deglitch to turn on OVPSET rising ACFET 30 ms ISET > 120mV, Charging 120 °C 0.45 0.5 0.55 V THERMAL REGULATION TJ_REG Junction Temperature Regulation Accuracy THERMAL SHUTDOWN COMPARATOR TSHUT Thermal shutdown rising temperature Temperature rising 150 °C TSHUT_HYS Thermal shutdown hysteresis Temperature falling 20 °C tSHUT_RISE_DEG Thermal shutdown rising deglitch Temperature rising 100 µs tSHUT_FALL_DEG Thermal shutdown falling deglitch Temperature falling 10 ms THERMISTOR COMPARATOR VLTF Cold Temperature Threshold, TS pin Voltage Rising Threshold Charger suspends charge. As percentage to VVREF VLTF_HYS Cold Temperature Hysteresis, TS pin Voltage Falling VHTF 72.5% 73.5% 74.5% As percentage to VVREF 0.2% 0.4% 0.6% Hot Temperature TS pin voltage rising Threshold As percentage to VVREF 46.6% 47.2% 48.8% VTCO Cut-off Temperature TS pin voltage falling Threshold As percentage to VVREF 44.2% 44.7% 45.2% tTS_CHG_SUS Deglitch time for Temperature Out of Range Detection VTS > VLTF, or VTS < VTCO, or VTS < VHTF tTS_CHG_RESUME Deglitch time for Temperature in Valid Range Detection 20 ms VTS < VLTF – VLTF_HYS or VTS >VTCO, or VTS > VHTF 400 ms 160% CHARGE OVER-CURRENT COMPARATOR (CYCLE-BY-CYCLE) VOCP_CHRG Charge Over-Current Rising Threshold, VSRP>2.2V Current as percentage of fast charge current VOCP_MIN Charge Over-Current Limit Min, VSRP<2.2V Measure VSRP-SRN 45 mV VOCP_MAX Charge Over-Current Limit Max, VSRP>2.2V Measure VSRP-SRN 75 mV HSFET OVER-CURRENT COMPARATOR (CYCLE-BY-CYCLE) IOCP_HSFET Current limit on HSFET Measure on HSFET 6 A CHARGE UNDER-CURRENT COMPARATOR (CYCLE-BY-CYCLE) VUCP Charge under-current falling threshold Measure on V(SRP-SRN) 1 5 9 Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): bq24133 mV 9 bq24133 SLUSAF7B – DECEMBER 2010 – REVISED MAY 2011 www.ti.com ELECTRICAL CHARACTERISTICS (continued) 4.5V ≤ V(PVCC, AVCC) ≤ 17V, –40°C < TJ + 125°C, typical values are at TA = 25°C, with respect to AGND (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNITS BAT SHORT COMPARATOR VBATSHT Battery short falling threshold Measure on SRN 2 VBATSHT_HYS Battery short rising hysteresis Measure on SRN 200 mV V tBATSHT_DEG Deglitch on both edges 1 µs VBATSHT Charge Current during BATSHORT Percentage of fast charge current VVREF_REG VREF regulator voltage VAVCC > VUVLO, No load IVREF_LIM VREF current limit VVREF = 0 V, VAVCC > VUVLO 35 VREGN_REG REGN regulator voltage VAVCC > 10 V, ISET > 120 mV 5.7 IREGN_LIM REGN current limit VREGN = 0 V, VAVCC > 10 v, ISET > 120 mV 40 tprechrg Precharge Safety Timer Precharge time before fault occurs tfastchrg Fast Charge Timer Range Tchg=CTTC*KTTC 10% (4) VREF REGULATOR 3.267 3.3 3.333 90 V mA REGN REGULATOR 6.0 6.3 V 120 mA 1980 Sec TTC INPUT 1620 Fast Charge Timer Accuracy KTTC Timer Multiplier VTTC_LOW TTC Low Threshold ITTC TTC Source/Sink Current VTTC_OSC_HI TTC oscillator high threshold VTTC_OSC_LO TTC oscillator low threshold 1800 1 10 -10% 10% 5.6 TTC falling 45 50 hr min/nF 0.4 V 55 µA 1.5 V 1 V BATTERY SWITCH (BATFET) DRIVER RDS_BAT_OFF BATFET Turn-off Resistance VAVCC > 5V 100 Ω RDS_BAT_ON BATFET Turn-on Resistance VAVCC > 5V 20 kΩ VBATDRV_REG BATFET Drive Voltage VBATDRV_REG =VACN - VBATDRV when VAVCC > 5V and BATFET is on 7 V tBATFET_DEG BATFET Power-up Delay to turn off BATFET after adapter is detected 4.2 30 ms 60 µA 6 V AC SWITCH (ACFET) DRIVER IACFET ACDRV Charge Pump Current Limit VACDRV - VCMSRC = 5V VACDRV_REG Gate Drive Voltage on ACFET VACDRV - VCMSRC when VAVCC > VUVLO RACDRV_LOAD Maximum load between ACDRV and CMSRC 4.2 500 kΩ AC/BAT SWITCH DRIVER TIMING tDRV_DEAD Dead Time when switching between ACFET and BATFET Driver Dead Time µs 10 BATTERY DETECTION tWAKE Wake timer Max time charge is enabled IWAKE Wake current RSENSE = 10 mΩ tDISCHARGE Discharge timer Max time discharge current is applied IDISCHARGE IFAULT VWAKE Wake threshold with respect to VREG To detect battery absent during WAKE Measure on SRN 100 mV/cell VDISCH Discharge Threshold to detect battery absent during discharge Measure on SRN 2.9 V/cell (4) 10 500 50 125 ms 200 mA 1 sec Discharge current 8 mA Fault current after a timeout fault 2 mA The minimum current is 120 mA on 10mΩ sense resistor. Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): bq24133 bq24133 SLUSAF7B – DECEMBER 2010 – REVISED MAY 2011 www.ti.com ELECTRICAL CHARACTERISTICS (continued) 4.5V ≤ V(PVCC, AVCC) ≤ 17V, –40°C < TJ + 125°C, typical values are at TA = 25°C, with respect to AGND (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNITS 1360 1600 1840 kHz INTERNAL PWM fsw PWM Switching Frequency (5) tSW_DEAD Driver Dead Time RDS_HI High Side MOSFET On Resistance RDS_LO Low Side MOSFET On Resistance VBTST_REFRESH Bootstrap Refresh Comparator Threshold Voltage Dead time when switching between LSFET and HSFET no load 30 VBTST – VSW = 4.5 V 80 150 mΩ 95 160 mΩ VBTST – VSW when low side refresh pulse is requested, VAVCC=4.5V 3 VBTST – VSW when low side refresh pulse is requested, VAVCC>6V 4 ns V INTERNAL SOFT START (8 steps to regulation current ICHG) SS_STEP Soft start steps TSS_STEP Soft start step time 8 1.6 step 3 ms CHARGER SECTION POWER-UP SEQUENCING tCE_DELAY Delay from ISET above 120mV to start charging battery 1.5 s INTEGRATED BTST DIODE VF Forward Bias Voltage IF=120mA at 25°C VR Reverse breakdown voltage IR=2uA at 25°C 0.85 20 V V LOGIC IO PIN CHARACTERISTICS VOUT_LO STAT Output Low Saturation Voltage Sink Current = 5 mA 0.5 V VCELL_LO CELL pin input low threshold, 1 cell CELL pin voltage falling edge 0.5 V VCELL_MID CELL pin input mid threshold, 2 cells CELL pin voltage rising for MIN, falling for MAX 0.8 1.8 V VCELL_HI CELL pin input high threshold, 3 cells CELL pin voltage rising edge 2.5 (5) V Specified by design Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): bq24133 11 bq24133 SLUSAF7B – DECEMBER 2010 – REVISED MAY 2011 www.ti.com TYPICAL CHARACTERISTICS Table 1. Table of Graphs (1) FIGURE (1) DESCRIPTION Figure 3 AVCC, VREF, ACDRV and STAT Power Up (ISET=0) Figure 4 Charge Enable by ISET Figure 5 Current Soft Start Figure 6 Charge Disable by ISET Figure 7 Continuous Conduction Mode Switching Figure 8 Discontinuous Conduction Mode Switching Figure 9 BATFET to ACFET Transition during Power Up Figure 10 System Load Transient (Input Current DPM) Figure 11 Battery Insertion and Removal Figure 12 Battery to Ground Short Protection Figure 13 Battery to Ground Short Transition Figure 14 Efficiency vs Output Current (VOUT = 3.8 V) Figure 15 Efficiency vs Output Current (2-3 cell) All waveforms and data are measured on HPA715 EVM. ISET 500mV/div AVCC 10V/div REGN 5V/div VREF 2V/div STAT 10V/div ACDRV 5V/div IL 1A/div STAT 10V/div 20 ms/div Figure 3. Power Up (ISET = 0) 400 ms/div Figure 4. Charge Enable by ISET ISET 500mV/div PH 5V/div PH 5V/div IL 2A/div IOUT 0.5A/div 4 ms/div 2 ms/div Figure 5. Current Soft Start 12 Figure 6. Charge Disable by ISET Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): bq24133 bq24133 SLUSAF7B – DECEMBER 2010 – REVISED MAY 2011 www.ti.com PH 5V/div PH 5V/div IL 1A/div IL 1A/div 200 ns/div Figure 7. Continuous Conduction Mode Switching 200 ns/div Figure 8. Discontinuous Conduction Mode Switching AVCC 10V/div ACDRV 10V/div IIN 1A/div ISYS 2A/div VSYS 10V/div BATDRV 10V/div IOUT 1A/div 10 ms/div 200 ms/div Figure 9. BATFET to ACFET Transition During Powerup Figure 10. System Load Transient (Input current DPM) SRN 5V/div SRN 5V/div PH 10V/div PH 10V/div IL 1A/div IL 1A/div 400 ms/div Figure 11. Battery Insertion and Removal 2 ms/div Figure 12. Battery to Ground Short Protection Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): bq24133 13 bq24133 SLUSAF7B – DECEMBER 2010 – REVISED MAY 2011 www.ti.com EFFICIENCY vs OUTPUT CURRENT 95 VOUT = 3.8 V AVCC = 5 V 90 Efficiency - % SRN 5V/div PH 10V/div IL 1A/div AVCC = 9 V 85 80 75 4 ms/div 70 0 0.5 1 1.5 2 2.5 IOUT - Output Current - A Figure 13. Battery to Ground Short Transition Figure 14. EFFICIENCY vs OUTPUT CURRENT 95 90 Efficiency - % AVCC = 12 V, 2 cell AVCC = 15 V, 3 cell AVCC = 15 V, 2 cell 85 80 75 70 0 0.5 1 1.5 2 IOUT - Output Current - A 2.5 3 Figure 15. 14 Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): bq24133 bq24133 SLUSAF7B – DECEMBER 2010 – REVISED MAY 2011 www.ti.com FUNCTIONAL BLOCK DIAGRAM CMSRC+6V SLEEP bq24133 ACN-SRN VACN UVLO 3.6V ACOV UVLO AVCC ACDRV CHARGE PUMP VSRN+100mV SYSTEM POWER SELECTOR CONTROL 8 ACDRV 7 CMSRC ACN ACUV 4 19 BATDRV VSRN+90mV SLEEP ACN-6V 1.35V LOWV VREF 12 VREF LDO 2.05V RCHRG Thermal PAD AVCC CE BAT_OVP 2.184V REGN LDO 20 REGN 21 BTST EAI FBO SRN 2 PVCC 3 PVCC CELL 14 1V 2.1V LEVEL SHIFTER 1 SW IC TJ 20μA 120C ACP 6 ACN 5 EAO PWM PWM CONTROL 24 SW REGN 20xIAC 22 PGND 20X 23 PGND 5mV ACSET 17 CE UCP VSRP-VSRN OCP VSRP-VSRN 120mV 160%xVISET/20 ISET 13 Fast-Chrg IBAT_REG Pre-Chrg Selection VSW+4.2V REFRESH VBTST 20μA LOWV EN_CHARGE 9 STAT CE SRP 16 20xICHG RCHRG Charge Termination 20X SRN 15 Discharge 10%xVISET Discharge Termination Qualification IDISCHARGE IQUAL 2V Fault IFAULT ACOV BAT_SHORT STATE MACHINE LTF SUSPEND Timer Fault HTF 10 TS ACOV TCO ACUV 1.6V IC TJ 0.5V VREF VSRN Fast Charge Timer (TTC) Precharge Timer (30 mins) TTC 11 OVPSET 18 Termination Qualification ACUV TSHUT TSHUT SLEEP UVLO Figure 16. Functional Block Diagram Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): bq24133 15 bq24133 SLUSAF7B – DECEMBER 2010 – REVISED MAY 2011 www.ti.com DETAILED DESCRIPTION Regulation Voltage VRECH I CHRG Precharge Current Regulation Phase Fastcharge Current Regulation Phase Fastcharge Voltage Regulation Phase Termination Charge Current Charge Voltage VLOWV 10% ICHRG Precharge Timer Fast Charge Safety Timer Figure 17. Typical Charging Profile BATTERY VOLTAGE REGULATION The bq24133 offers a high accuracy voltage regulator on for the charging voltage. The bq24133 uses CELL pin to select number of cells with a fixed 4.2V/cell. Connecting CELL to AGND sets 1 cell output, floating CELL pin sets 2 cell output, and connecting to VREF sets 3 cell output. Table 2. bq24133 CELL Pin Settings CELL PIN VOLTAGE REGULATION AGND 4.2V Floating 8.4 V VREF 12.6 V BATTERY CURRENT REGULATION The ISET input sets the maximum charging current. Battery current is sensed by current sensing resistor RSR connected between SRP and SRN. The equation for charge current is: VISET ICHARGE = 20 ´ RSR (1) The valid input voltage range of ISET is up to 0.5V. With 10mΩ sense resistor, the maximum output current is 2.5A. The charger is disabled when ISET pin voltage is below 40mV and is enabled when ISET pin voltage is above 120mV. For 10mΩ current sensing resistor, the minimum fast charge current must be higher than 600mA. 16 Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): bq24133 bq24133 SLUSAF7B – DECEMBER 2010 – REVISED MAY 2011 www.ti.com Under high ambient temperature, the charge current will fold back to keep IC temperature not exceeding 120°C. BATTERY PRECHARGE CURRENT REGULATION On Power-up, if the battery voltage is below the VLOWV threshold, the bq24133 applies the pre-charge current to the battery. This pre-charge feature is intended to revive deeply discharged cells. If the VLOWV threshold is not reached within 30 minutes of initiating pre-charge, the charger turns off and a fault is indicated on the status pin. For bq24133, the pre-charge current is set as 10% of the fast charge rate set by ISET voltage. VISET IPRECHARGE = 200 ´ RSR (2) INPUT CURRENT REGULATION The total input current from an AC adapter or other DC sources is a function of the system supply current and the battery charging current. System current normally fluctuated as portions of the systems are powered up or down. Without Dynamic Power Management (DPM), the source must be able to supply the maximum system current and the maximum available charger input current simultaneously. By using DPM, the input current regulator reduces the charging current when the summation of system power and charge power exceeds the maximum input power. Therefore, the current capability of the AC adapter can be lowered, reducing system cost. Input current is set by the voltage on ACSET pin using the following equation: VACSET IDPM = 20 ´ R AC (3) The ACP and ACN pins are used to sense across RAC with default value of 20mΩ. However, resistors of other values can also be used. A larger sense resistor will give a larger sense voltage and higher regulation accuracy, at the expense of higher conduction loss. CHARGE TERMINATION, RECHARGE, AND SAFETY TIMERS The charger monitors the charging current during the voltage regulation phase. Termination is detected when the SRN voltage is higher than recharge threshold and the charge current is less than the termination current threshold, as calculated below: VISET ITERM = 200 ´ RSR (4) where VISET is the voltage on the ISET pin and RSR is the sense resistor. There is a 25ms deglitch time during transition between fast-charge and pre-charge. As a safety backup, the charger also provides an internal fixed 30 minutes pre-charge safety timer and a programmable fast charge timer. The fast charge time is programmed by the capacitor connected between the TTC pin and AGND, and is given by the formula: t TTC = CTTC ´ K TTC (5) Where CTTC is the capacitor connected to TTC and KTTC is the constant multiplier. A • • • new charge cycle is initiated when one of the following conditions occurs: The battery voltage falls below the recharge threshold A power-on-reset (POR) event occurs ISET pin toggled below 40mV (disable charge) and above 120mV (enable charge) Pull TTC pin to AGND to disable both termination and fast charge safety timer (reset timer). Pull TTC pin to VREF to disable the safety timer, but allow charge termination. Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): bq24133 17 bq24133 SLUSAF7B – DECEMBER 2010 – REVISED MAY 2011 www.ti.com POWER UP The charge uses a SLEEP comparator to determine the source of power on the AVCC pin, since AVCC can be supplied either from the battery or the adapter. With the adapter source present, if the AVCC voltage is greater than the SRN voltage, the charger exits SLEEP mode. If all conditions are met for charging, the charger then starts charge the battery (see the Enabling and Disabling Charging section). If SRN voltage is greater than AVCC, the charger enters low quiescent current SLEEP mode to minimize current drain from the battery. During SLEEP mode, the VREF output turns off and the STAT pin goes to high impedance. If AVCC is below the UVLO threshold, the device is disabled. INPUT UNDER-VOLTAGE LOCK-OUT (UVLO) The system must have a minimum AVCC voltage to allow proper operation. This AVCC voltage could come from either input adapter or battery, since a conduction path exists from the battery to AVCC through the high side NMOS body diode. When AVCC is below the UVLO threshold, all circuits on the IC are disabled. INPUT OVER-VOLTAGE/UNDER-VOLTAGE PROTECTION ACOV provides protection to prevent system damage due to high input voltage. In bq24133, once the voltage on OVPSET is above the 1.6V ACOV threshold or below the 0.5V ACUV threshold, charge is disabled and input MOSFETs turn off. The bq24133 provides flexibility to set the input qualification threshold. ENABLE AND DISABLE CHARGING The following conditions have to be valid before charging is enabled: • ISET pin above 120mV • Device is not in Under-Voltage-Lock-Out (UVLO) mode (i.e. VAVCC > VUVLO) • Device is not in SLEEP mode (i.e. VAVCC > VSRN) • OVPSET voltage is between 0.5V and 1.6V to qualify the adapter • 1.5s delay is complete after initial power-up • REGN LDO and VREF LDO voltages are at correct levels • Thermal Shut down (TSHUT) is not valid • TS fault is not detected • ACFET turns on (See System Power Selector for details) One of the following conditions stops on-going charging: • ISET pin voltage is below 40mV • Device is in UVLO mode • Adapter is removed, causing the device to enter SLEEP mode • OVPSET voltage indicates the adapter is not valid • REGN or VREF LDO voltage is overloaded • TSHUT temperature threshold is reached • TS voltage goes out of range indicating the battery temperature is too hot or too cold • ACFET turns off • TTC timer expires or pre-charge timer expires SYSTEM POWER SELECTOR The IC automatically switches adapter or battery power to the system load. The battery is connected to the system by default during power up or during SLEEP mode. When the adapter plugs in and the voltage is above the battery voltage, the IC exits SLEEP mode. The battery is disconnected from the system and the adapter is connected to the system after exiting SLEEP. An automatic break-before-make logic prevents shoot-through currents when the selectors switch. The ACDRV is used to drive a pair of back-to-back n-channel power MOSFETs between adapter and ACP with sources connected together to CMSRC. The n-channel FET with the drain connected to the ACP (Q2, RBFET) 18 Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): bq24133 bq24133 SLUSAF7B – DECEMBER 2010 – REVISED MAY 2011 www.ti.com provides reverse battery discharge protection, and minimizes system power dissipation with its low-RDSON. The other n-channel FET with drain connected to adapter input (Q1, ACFET) separates battery from adapter, and provides a limited dI/dt when connecting the adapter to the system by controlling the FET turn-on time. The /BATDRV controls a p-channel power MOSFET (Q3, BATFET) placed between battery and system with drain connected to battery. Before the adapter is detected, the ACDRV is pulled to CMSRC to keep ACFET off, disconnecting the adapter from system. /BATDRV stays at ACN-6V (clamp to ground) to connect battery to system if all the following conditions are valid: • VAVCC > VUVLO (battery supplies AVCC) • VACN < VSRN + 200 mV After the device comes out of SLEEP mode, the system begins to switch from battery to adapter. The AVCC voltage has to be 300mV above SRN to enable the transition. The break-before-make logic keeps both ACFET and BATFET off for 10us before ACFET turns on. This prevents shoot-through current or any large discharging current from going into the battery. The /BATDRV is pulled up to ACN and the ACDRV pin is set to CMSRC + 6V by an internal charge pump to turn on n-channel ACFET, connecting the adapter to the system if all the following conditions are valid: • VACUV < VOVPSET < VACOV • VAVCC > VSRN + 300 mV When the adapter is removed, the IC turns off ACFET and enters SLEEP mode. BATFET keeps off until the system drops close to SRN. The BATDRV pin is driven to ACN - 6V by an internal regulator to turn on p-channel BATFET, connecting the battery to the system. Asymmetrical gate drive provides fast turn-off and slow turn-on of the ACFET and BATFET to help the break-before-make logic and to allow a soft-start at turn–on of both MOSFETs. The delay time can be further increased, by putting a capacitor from gate to source of the power MOSFETs. CONVERTER OPERATION The bq24133 employs a 1.6MHz constant-frequency step-down switching regulator. The fixed frequency oscillator keeps tight control of the switching frequency under all conditions of input voltage, battery voltage, charge current, and temperature, simplifying output filter design and keeping it out of the audible noise region. A type III compensation network allows using ceramic capacitors at the output of the converter. An internal saw-tooth ramp is compared to the internal error control signal to vary the duty-cycle of the converter. The ramp height is proportional to the AVCC voltage to cancel out any loop gain variation due to a change in input voltage, and simplifies the loop compensation. Internal gate drive logic allows achieving 97% duty-cycle before pulse skipping starts. AUTOMATIC INTERNAL SOFT-START CHARGER CURRENT The charger automatically soft-starts the charger regulation current every time the charger goes into fast-charge to ensure there is no overshoot or stress on the output capacitors or the power converter. The soft-start consists of stepping-up the charge regulation current into 8 evenly divided steps up to the programmed charge current. Each step lasts around 1.6ms, for a typical rise time of 12.8ms. No external components are needed for this function. CHARGE OVER-CURRENT PROTECTION The charger monitors top side MOSFET current by high side sense FET. When peak current exceeds MOSFET limit, it will turn off the top side MOSFET and keep it off until the next cycle. The charger has a secondary cycle-to-cycle over-current protection. It monitors the charge current, and prevents the current from exceeding 160% of the programmed charge current. The high-side gate drive turns off when either over-current condition is detected, and automatically resumes when the current falls below the over-current threshold. Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): bq24133 19 bq24133 SLUSAF7B – DECEMBER 2010 – REVISED MAY 2011 www.ti.com CHARGE UNDER-CURRENT PROTECTION After the recharge, if the SRP-SRN voltage decreases below 5mV, the low side FET will be turned off for the rest of the switching cycle. During discontinuous conduction mode (DCM), the low side FET will only turn on for a short period of time when the boostrap capacitor voltage drops below 4V to provide refresh charge for the capacitor. This is important to prevent negative inductor current from causing any boost effect in which the input voltage increases as power is transferred from the battery to the input capacitors. This can lead to an over-voltage on the AVCC node and potentially cause damage to the system. BATTERY DETECTION For applications with removable battery packs, IC provides a battery absent detection scheme to reliably detect insertion or removal of battery packs. The battery detection routine runs on power up, or if battery voltage falls below recharge threshold voltage due to removing a battery or discharging a battery. POR or RECHARGE Apply 8mA discharge current, start 1s timer VSRN < VBATOWV No 1s timer expired Yes No Yes Battery Present, Begin Charge Disable 8mA discharge current Enable 125mA charge current, start 0.5s timer VSRN > VRECH No 0.5s timer expired Yes Yes Disable 125mA charge current No Battery Present, Begin Charge Battery Absent Figure 18. Battery Detection Flowchart 20 Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): bq24133 bq24133 SLUSAF7B – DECEMBER 2010 – REVISED MAY 2011 www.ti.com Once the device has powered up, a 8-mA discharge current is applied to the SRN terminal. If the battery voltage falls below the LOWV threshold within 1 second, the discharge source is turned off, and the charger is turned on at low charge current (125mA). If the battery voltage gets up above the recharge threshold within 500ms, there is no battery present and the cycle restarts. If either the 500ms or 1 second timer time out before the respective thresholds are hit, a battery is detected and a charge cycle is initiated. Battery Absent Battery Absent VBAT_RE VRECH Battery Present VLOW Figure 19. Battery Detect Timing Diagram Care must be taken that the total output capacitance at the battery node is not so large that the discharge current source cannot pull the voltage below the LOWV threshold during the 1 second discharge time. The maximum output capacitances can be calculated according to the following equations: IDISCH ´ tDISCH CMAX = (4.1 V - 2.9 V) ´ Number of cells (6) Where CMAX is the maximum output capacitance, IDISCH is the discharge current, tDISCH is the discharge time. Example For a 3-cell Li+ charger, IDISCH = 8mA, tDISCH = 1 second. 8 mA ´ 1 sec CMAX = = 2.2 mF 1.2 V ´ 3 (7) Based on these calculations, no more than 2200 µF should be allowed on the battery node for proper operation of the battery detection circuit. BATTERY SHORT PROTECTION When SRN pin voltage is lower than 2V it is considered as battery short condition during charging period. The charger will shut down immediately for 1ms, then soft start back to the charging current the same as precharge current. This prevents high current may build in output inductor and cause inductor saturation when battery terminal is shorted during charging. The converter works in non-synchronous mode during battery short. BATTERY OVER-VOLTAGE PROTECTION The converter will not allow the high-side FET to turn-on until the battery voltage goes below 102% of the regulation voltage. This allows one-cycle response to an over-voltage condition – such as occurs when the load is removed or the battery is disconnected. A total 6mA current sink from SRP/SRN to AGND allows discharging the stored output inductor energy that is transferred to the output capacitors. If battery over-voltage condition lasts for more than 30ms, charge is disabled. Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): bq24133 21 bq24133 SLUSAF7B – DECEMBER 2010 – REVISED MAY 2011 www.ti.com TEMPERATURE QUALIFICATION The controller continuously monitors battery temperature by measuring the voltage between the TS pin and AGND. A negative temperature coefficient thermistor (NTC) and an external voltage divider typically develop this voltage. The controller compares this voltage against its internal thresholds to determine if charging is allowed. To initiate a charge cycle, the battery temperature must be within the VLTF to VHTF thresholds. If battery temperature is outside of this range, the controller suspends charge and waits until the battery temperature is within the VLTF to VHTF range. During the charge cycle the battery temperature must be within the VLTF to VTCO thresholds. If battery temperature is outside of this range, the controller suspends charge and waits until the battery temperature is within the VLTF to VHTF range. The controller suspends charge by turning off the PWM charge MOSFETs. Figure 20 summarizes the operation. TEMPERATURE RANGE TO INITIATE CHARGE TEMPERATURE RANGE DURING A CHARGE CYCLE VREF VREF CHARGE SUSPENDED CHARGE SUSPENDED VLTF VLTFH VLTF VLTFH CHARGE at full C CHARGE at full C VHTF VTCO CHARGE SUSPENDED CHARGE SUSPENDED AGND AGND Figure 20. TS Pin, Thermistor Sense Thresholds Assuming a 103AT NTC thermistor on the battery pack as shown in Figure 21, the values of RT1 and RT2 can be determined by using Equation 8 and Equation 9: æ 1 1 ö VVREF ´ RTHCOLD ´ RTHHOT ´ ç ÷ è VLTF VTCO ø RT2 = æV ö æV ö RTHHOT ´ ç VREF - 1÷ - RTHCOLD ´ ç VREF - 1÷ V V è LTF ø è TCO ø (8) VVREF -1 VLTF RT1 = 1 1 + RT2 RTHCO LD (9) Select 0°C to 45°C range for Li-ion or Li-polymer battery, RTHCOLD = 27.28 kΩ RTHHOT = 4.911 kΩ RT1 = 5.23 kΩ RT2 = 30.1 kΩ After select closest standard resistor value, by calculating the thermistor resistance at temperature threshold, the final temperature range can be gotten from thermistor datasheet temperature-resistance table. 22 Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): bq24133 bq24133 SLUSAF7B – DECEMBER 2010 – REVISED MAY 2011 www.ti.com VREF bq24133 RT1 TS RT2 RTH 103AT Figure 21. TS Resistor Network MOSFET SHORT CIRCUIT AND INDUCTOR SHORT CIRCUIT PROTECTION The IC has a short circuit protection feature. Its cycle-by-cycle current monitoring feature is achieved through monitoring the voltage drop across Rdson of the MOSFETs. The charger will be latched off, but the ACFET keep on to power the system. The only way to reset the charger from latch-off status is remove adapter then plug adapter in again. Meanwhile, STAT is blinking to report the fault condition. THERMAL REGULATION AND SHUTDOWN PROTECTION The QFN package has low thermal impedance, which provides good thermal conduction from the silicon to the ambient, to keep junctions temperatures low. The internal thermal regulation loop will fold back the charge current to keep the junction temperature from exceeding 120°C. As added level of protection, the charger converter turns off and self-protects whenever the junction temperature exceeds the TSHUT threshold of 150°C. The charger stays off until the junction temperature falls below 130°C. TIMER FAULT RECOVERY The IC provides a recovery method to deal with timer fault conditions. The following summarizes this method: Condition 1: The battery voltage is above the recharge threshold and a timeout fault occurs. Recovery Method: The timer fault will clear when the battery voltage falls below the recharge threshold, and battery detection will begin. A POR or taking ISET below 40mV will also clear the fault. Condition 2: The battery voltage is below the recharge threshold and a timeout fault occurs. Recovery Method: Under this scenario, the IC applies the fault current to the battery. This small current is used to detect a battery removal condition and remains on as long as the battery voltage stays below the recharge threshold. If the battery voltage goes above the recharge threshold, the IC disabled the fault current and executes the recovery method described in Condition 1. A POR or taking ISET below 40mV will also clear the fault. INDUCTOR, CAPACITOR, AND SENSE RESISTOR SELECTION GUIDELINES The IC provides internal loop compensation. With this scheme, the best stability occurs when the LC resonant frequency, fo, is approximately 15kHz – 25kHz for the IC. 1 fo = 2p LC (10) Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): bq24133 23 bq24133 SLUSAF7B – DECEMBER 2010 – REVISED MAY 2011 www.ti.com Table 3 provides a summary of typical LC components for various charge currents. Table 3. Typical Values as a Function of Charge Current CHARGE CURRENT 1A 2A Output inductor L 6.8 µH 3.3 µH Output capacitor C 10 µF 20 µF CHARGE STATUS OUTPUTS The open-drain STAT outputs indicate various charger operations as listed in Table 4. These status pins can be used to drive LEDs or communicate with the host processor. Note that OFF indicates that the open-drain transistor is turned off. Table 4. STAT Pin Definition CHARGE STATE Charge in progress (including recharging) ON Charge complete, Sleep mode, Charge disabled OFF Charge suspend, Input over-voltage, Battery over-voltage, timer fault, , battery absent 24 STAT Submit Documentation Feedback BLINK Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): bq24133 bq24133 SLUSAF7B – DECEMBER 2010 – REVISED MAY 2011 www.ti.com APPLICATION INFORMATION INDUCTOR SELECTION The bq24133 has a 1600-kHz switching frequency to allow the use of small inductor and capacitor values. Inductor saturation current should be higher than the charging current (ICHG) plus half the ripple current (IRIPPLE): ISAT ³ ICHG +(1/2)IRIPPLE (11) Inductor ripple current depends on input voltage (VIN), duty cycle (D = VOUT/VIN), switching frequency (fs), and inductance (L): V ´ D ´ (1 - D) IRIPPLE = IN fs × L (12) The maximum inductor ripple current happens with D = 0.5 or close to 0.5. Usually inductor ripple is designed in the range of 20% to 40% of the maximum charging current as a trade-off between inductor size and efficiency for a practical design. INPUT CAPACITOR The input capacitor should have enough ripple current rating to absorb input switching ripple current. The worst case RMS ripple current is half of the charging current when duty cycle is 0.5. If the converter does not operate at 50% duty cycle, then the worst case capacitor RMS current ICIN occurs where the duty cycle is closest to 50% and can be estimated by the following equation: ICIN = ICHG ´ D ´ (1 - D) (13) A low ESR ceramic capacitor such as X7R or X5R is preferred for the input decoupling placed as close as possible to the drain of the high-side MOSFET and source of the voltage rating of the capacitor must be higher than the normal input voltage level. capacitor is preferred for a 15V input voltage. A 20μF capacitance is suggested for current. capacitor and should be low-side MOSFET. The A 25V rating or higher a typical 2.5A charging OUTPUT CAPACITOR The output capacitor also should have enough ripple current rating to absorb output switching ripple current. The output capacitor RMS current ICOUT is given as: I ICOUT = RIPPLE » 0.29 ´ IRIPPLE 2 ´ 3 (14) The output capacitor voltage ripple can be calculated as follows: DVO = VOUT æ V ç 1 - OUT 2 ç VIN 8LCfs è ö ÷ ÷ ø (15) At certain input/output voltages and switching frequencies, the voltage ripple can be reduced by increasing the output filter LC. The bq24133 has an internal loop compensator. To achieve good loop stability, the resonant frequency of the output inductor and output capacitor should be designed between 15 kHz and 25 kHz. The preferred ceramic capacitor has a 25V or higher rating, X7R or X5R. INPUT FILTER DESIGN During adapter hot plug-in, the parasitic inductance and the input capacitor from the adapter cable form a second order system. The voltage spike at the AVCC pin may be beyond the IC maximum voltage rating and damage the IC. The input filter must be carefully designed and tested to prevent an over-voltage event on the AVCC pin. There are several methods to damping or limiting the over-voltage spike during adapter hot plug-in. An electrolytic capacitor with high ESR as an input capacitor can damp the over-voltage spike well below the IC maximum pin voltage rating. A high current capability TVS Zener diode can also limit the over-voltage level to an IC safe level. However, these two solutions may not be lowest cost or smallest size. Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): bq24133 25 bq24133 SLUSAF7B – DECEMBER 2010 – REVISED MAY 2011 www.ti.com A cost effective and small size solution is shown in Figure 22. R1 and C1 are composed of a damping RC network to damp the hot plug-in oscillation. As a result, the over-voltage spike is limited to a safe level. D1 is used for reverse voltage protection for the AVCC pin. C2 is the AVCC pin decoupling capacitor and it should be placed as close as possible to the AVCC pin. R2 and C2 form a damping RC network to further protect the IC from high dv/dt and high voltage spike. The C2 value should be less than the C1 value so R1 can dominant the equivalent ESR value to get enough damping effect for hot plug-in. R1 and R2 must be sized enough to handle in-rush current power loss according to the resistor manufacturer’s datasheet. The filter component values always need to be verified with a real application and minor adjustments may be needed to fit in the real application circuit. If the input is 5V (USB host or USB adapter), then D1 can be saved. R2 has to be 5Ω or higher to limit the current if the input is reversely inserted. D1 R2(1206) 4.7 - 30 W R1(2010) 2W Adapter Connector AVCC pin C1 2.2 mF C2 0.1 - 1 mF Figure 22. Input Filter INPUT ACFET AND RBFET SELECTION N-type MOSFETs are used as input ACFET(Q1) and RBFET(Q2) for better cost effective and small size solution, as shown in Figure 22. Normally, there are around 50uF capacitor totally connected at PVCC node --- 10uF capacitor for buck converter of bq24133 and 40uF capacitor for system side. There is a surge current during Q1 turn-on period when a valid adapter is inserted. Decreasing the turn-on speed of Q1 can limit this surge current in desirable range by selecting a MOSFET with relative bigger CGD and/or CGS. At the case Q1 turn on too fast, we need add external CGD and/or CGS. For example, 4.7nF CGD and 47nF CGS are adopted on EVM while using NexFET CSD17313 as Q1. RIN 2 CIN 2. ? 2.2? Q2 Q1 ADAPTER SYS RSNS C4 1m RGS 499k CGS CGD R11 4.02k R12 4.02k CSYS 40? PVCC CMSRC ACDRV Figure 23. Input ACFET and RBFET PCB LAYOUT The switching node rise and fall times should be minimized for minimum switching loss. Proper layout of the components to minimize the high frequency current path loop (see Figure 24) is important to prevent electrical and magnetic field radiation and high frequency resonant problems. The following is a PCB layout priority list for proper layout. Layout of the PCB according to this specific order is essential. 1. Place input capacitor as close as possible to the PVCC supply and ground connections and use the shortest copper trace connection. These parts should be placed on the same layer of the PCB instead of on different layers and using vias to make this connection. 2. Place the inductor input terminal as close as possible to the SW terminal. Minimize the copper area of this trace to lower electrical and magnetic field radiation but make the trace wide enough to carry the charging current. Do not use multiple layers in parallel for this connection. Minimize parasitic capacitance from this 26 Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): bq24133 bq24133 SLUSAF7B – DECEMBER 2010 – REVISED MAY 2011 www.ti.com 3. 4. 5. 6. 7. 8. 9. area to any other trace or plane. The charging current sensing resistor should be placed right next to the inductor output. Route the sense leads connected across the sensing resistor back to the IC in the same layer, close to each other (minimize loop area) and do not route the sense leads through a high-current path (see Figure 25 for Kelvin connection for best current accuracy). Place decoupling capacitor on these traces next to the IC. Place output capacitor next to the sensing resistor output and ground. Output capacitor ground connections need to be tied to the same copper that connects to the input capacitor ground before connecting to system ground. Route analog ground separately from power ground and use a single ground connection to tie charger power ground to charger analog ground. Just beneath the IC use analog ground copper pour but avoid power pins to reduce inductive and capacitive noise coupling. Use the thermal pad as a single ground connection point to connect analog ground and power ground together, or use a 0-Ω resistor to tie analog ground to power ground. A star-connection under the thermal pad is highly recommended. It is critical that the exposed thermal pad on the backside of the IC package be soldered to the PCB ground. Ensure that there are sufficient thermal vias directly under the IC, connecting to the ground plane on the other layers. Decoupling capacitors should be placed next to the IC pins and make trace connection as short as possible. The number and physical size of the vias should be enough for a given current path. SW L1 R1 High Frequency VIN Current Path C1 VBAT BAT PGND C3 C2 Figure 24. High Frequency Current Path Current Direction R SNS Current Sensing Direction To SRP and SRN pin Figure 25. Sensing Resistor PCB Layout Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): bq24133 27 bq24133 SLUSAF7B – DECEMBER 2010 – REVISED MAY 2011 www.ti.com REVISION HISTORY Changes from Revision A (March 2011) to Revision B Page • Added 30V Input Rating with Adjustable Over-Voltage Protection ....................................................................................... 1 • Added new paragraph to Description (Continued) ............................................................................................................... 2 • Changed Voltage range (with respect to AGND) pins in ABSOLUTE MAXIMUM RATINGS table ..................................... 6 • Added paragraph at the end of INPUT FILTER DESIGN section ...................................................................................... 26 28 Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): bq24133 PACKAGE OPTION ADDENDUM www.ti.com 19-Apr-2011 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Qty Eco Plan (2) Lead/ Ball Finish MSL Peak Temp (3) BQ24133RGYR ACTIVE VQFN RGY 24 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR BQ24133RGYT ACTIVE VQFN RGY 24 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR Samples (Requires Login) (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. 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