Product Folder Order Now Support & Community Tools & Software Technical Documents bq24157 SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 bq24157 Fully Integrated Switch-Mode Charger With USB Compliance and USB-OTG Support 1 Features * * * 1 * * * * * * * * * * * * * Power Up System without Battery Charge Faster than Linear Chargers High-Accuracy Voltage and Current Regulation - Input Current Regulation Accuracy: 5% (100 mA and 500 mA) - Charge Voltage Regulation Accuracy: 0.5% (25C), 1% (0C to 125C) - Charge Current Regulation Accuracy: 5% Input Voltage Based Dynamic Power Management (VIN DPM) Bad Adaptor Detection and Rejection Safety Limit Register for Maximum Charge Voltage and Current Limiting High-Efficiency Mini-USB/AC Battery Charger for Single-Cell Li-Ion and Li-Polymer Battery Packs 20-V Absolute Maximum Input Voltage Rating 6.5-V Maximum Operating Input Voltage Built-In Input Current Sensing and Limiting Integrated Power FETs for Up To 1.55-A Charge Rate Programmable Charge Parameters through I2CTM Compatible Interface (up to 3.4 Mbps): - Input Current Limit - VIN DPM Threshold - Fast-Charge/Termination Current - Charge Regulation Voltage (3.5 V to 4.44 V) - Low Charge Current Mode Enable/Disable - Termination Enable/Disable Support up to 1.55A Charge Current using 55 m Sensing Resistor Synchronous Fixed-Frequency PWM Controller Operating at 3 MHz With 0% to 99.5% Duty Cycle Automatic High Impedance Mode for Low Power Consumption Robust Protection - Reverse Leakage Protection Prevents Battery Drainage - Thermal Regulation and Protection - Input/Output Overvoltage Protection * * * * Status Output for Charging and Faults USB Friendly Boot-Up Sequence Automatic Charging Boost Mode Operation for USB OTG - Input Voltage Range (from Battery): 3.2 V to 4.5 V 2.1 mm x 2 mm 20-Pin WCSP Package * 2 Applications * * * Mobile and Smart Phones MP3 Players Handheld Devices 3 Description The bq24157 is a compact, flexible, high-efficiency, USB-friendly switch-mode charge management device for single-cell Li-ion and Li-polymer batteries used in a wide range of portable applications. The charge parameters can be programmed through an I2C interface. The IC integrates a synchronous PWM controller, power MOSFETs, input current sensing, high-accuracy current and voltage regulation, and charge termination, into a small WCSP package. Device Information(1) PART NUMBER bq24157 PACKAGE BODY SIZE (NOM) WCSP (20-Pin) 2.1 mm x 2.0 mm (1) For all available packages, see the orderable addendum at the end of the datasheet. Typical Application Circuit LO 1.0 mH VBUS VBUS CIN 1 mF RSNS SW U1 bq24157 VBAT CO1 CBOOT 22 mF 33 nF C IN 4.7 mF PMID + 0.1 mF CSIN 10 kW 10 kW 10 kW 2 I C BUS SCL SCL SDA PACK- CSOUT SDA STAT STAT OTG 10 kW PACK+ CCSIN PGND VAUX HOST BOOT CD OTG CD CCSOUT VREF CVREF 0.1 mF 1 mF 10 kW Copyright (c) 2016, Texas Instruments Incorporated 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA. bq24157 SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 www.ti.com Table of Contents 1 2 3 4 5 6 7 8 Features .................................................................. Applications ........................................................... Description ............................................................. Revision History..................................................... Description (Continued) ........................................ Device Comparisons ............................................. Pin Configuration and Functions ......................... Specifications......................................................... 8.1 8.2 8.3 8.4 8.5 8.6 8.7 9 1 1 1 2 4 4 5 6 Absolute Maximum Ratings ..................................... 6 ESD Ratings ............................................................ 6 Recommended Operating Conditions....................... 6 Thermal Information .................................................. 6 Electrical Characteristics........................................... 7 Timing Requirements ................................................ 9 Typical Characteristics ............................................ 10 Detailed Description ............................................ 12 9.1 9.2 9.3 9.4 Overview ................................................................. Functional Block Diagrams ..................................... Operational Flow Chart ........................................... Feature Description................................................. 12 13 15 16 9.5 Device Functional Modes........................................ 18 9.6 Programming .......................................................... 23 9.7 Register Description................................................ 27 10 Application and Implementation........................ 30 10.1 Application Information.......................................... 30 10.2 Typical Performance Curves................................. 34 11 Power Supply Recommendations ..................... 36 11.1 System Load After Sensing Resistor .................... 36 12 Layout................................................................... 38 12.1 Layout Guidelines ................................................. 38 12.2 Layout Example .................................................... 39 13 Device and Documentation Support ................. 40 13.1 13.2 13.3 13.4 13.5 13.6 Documentation Support ....................................... Receiving Notification of Documentation Updates Community Resources.......................................... Trademarks ........................................................... Electrostatic Discharge Caution ............................ Glossary ................................................................ 40 40 40 40 40 40 14 Mechanical, Packaging, and Orderable Information ........................................................... 40 14.1 Package Summary................................................ 41 4 Revision History NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Revision D (July 2016) to Revision E Page * Changed Output voltage (with respect to PGND) - SW MIN value From: -0.7 To: -2 in the Absolute Maximum Ratings ... 6 * Deleted graphs "Cycle by Cycle Current Limiting in Charge Mode" and "PWM Charging Waveform" from the Typical Characteristics ...................................................................................................................................................................... 10 * Deleted list item "Default charge current will be 550 mA, if 68-m sensing resistor is used, since default LOW_CHG = 0." following Table 8 .......................................................................................................................................................... 28 Changes from Revision B (October 2013) to Revision C Page * Added ESD Ratings table, Timing Requirements table, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information sections..................................... 1 * Changed Features From: Integrated Power FETs for Up To 1.25-A To: Integrated Power FETs for Up To 1.55-A ............. 1 * Changed the ICHARGE(MAX) row of the Device Comparisons table............................................................................................ 4 * Changed capacitor from 10-nF to 33-nF for BOOT pin in the Pin Functions table ............................................................... 5 * Changed Note 1 in the Electrical Characteristics table From: "While in 15-min mode" To: "While in DEFAULT mode"....... 7 * Deleted "t15M, 15 minute safety timer" in the Electrical Characteristics table ......................................................................... 7 * Changed Figure 3 "15 Minute Mode" To: "DEFAULT Mode" and "32 S Mode" To" HOST Mode"...................................... 10 * Changed Figure 8 text note From: "32S mode" To: "HOST MODE" .................................................................................. 10 * Changed Figure 14............................................................................................................................................................... 15 * Added Battery Detection at Power Up in DEFAULT Mode ................................................................................................. 18 * Changed section 15-Minute Safety Timer To: DEFAULT Mode ......................................................................................... 18 * Added Figure 26 and Figure 27............................................................................................................................................ 34 * Changed section title From: Design considerations and potential issues: To: Design Requirements and Potential Issues: .................................................................................................................................................................................. 36 2 Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 bq24157 www.ti.com SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 Changes from Revision A (March 2013) to Revision B * Page Changed Table 8 Memory location: 05, Bit B5 Function description from "....(default 0)" to ".....(default 1) ....................... 28 Changes from Original (September 2012) to Revision A Page * Deleted capacitor CO2 from the Typical Application Circuit ................................................................................................... 1 * Deleted capacitor CO2 from Figure 23 ................................................................................................................................. 30 Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 3 bq24157 SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 www.ti.com 5 Description (Continued) The IC charges the battery in three phases: conditioning, constant current and constant voltage. The input current is automatically limited to the value set by the host. Charge is terminated based on battery voltage and user-selectable minimum current level. A safety timer with reset control provides a safety backup for I2C interface. During normal operation, The IC automatically restarts the charge cycle if the battery voltage falls below an internal threshold and automatically enters sleep mode or high impedance mode when the input supply is removed. The charge status can be reported to the host using the I2C interface. During the charging process, the IC monitors its junction temperature (TJ) and reduces the charge current once TJ increases to about 125C. To support USB OTG device, bq24157 can provide VBUS (5.05 V) by boosting the battery voltage. The IC is available in 20-pin WCSP package. 6 Device Comparisons PART NUMBER bq24157 VOVP (V) 6.5 D4 Pin Definition OTG ICHARGE(MAX) at POR in default mode with R(SNS) = 68 m (55 m) and OTG=High on bq24157(mA) 325 (402) ICHARGE(MAX) in HOST mode with R(SNS) = 68 m (55 m) and Safety Limit Register increased from default (A) (1) 1.25 (1.55) Output regulation voltage at POR (V) 3.54 Boost Function Yes 100 mA (OTG=LOW); 500 mA (OTG=High) Input Current Limit in Default Mode Battery Detection at Power Up No I2C Address 6AH PN1 (bit4 of 03H) 1 PN0 (bit3 of 03H) 0 Safety Timer and WD Timer Disabled 100 ms Power Up Delay (1) 4 No See Application Section for explanation and calculations on using different sense resistors. Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 bq24157 www.ti.com SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 7 Pin Configuration and Functions Pin Layout (20-Bump YFF Package) bq24157 (Top View) A1 A2 A3 A4 VBUS VBUS BOOT SCL B3 B4 PMID B1 PMID B2 PMID SDA C1 C2 C3 C4 SW SW SW STAT D1 D2 D3 D4 PGND PGND PGND OTG E1 E2 E3 E4 CD VREF CSOUT CSIN Pin Functions PIN I/O DESCRIPTION A3 I/O Bootstrap capacitor connection for the high-side FET gate driver. Connect a 33-nF ceramic capacitor (voltage rating 10 V) from BOOT pin to SW pin. CD E2 I Charge disable control pin. CD=0, charge is enabled. CD=1, charge is disabled and VBUS pin is high impedance to GND. CSIN E1 I Charge current-sense input. Battery current is sensed across an external sense resistor. A 0.1-F ceramic capacitor to PGND is required. CSOUT E4 I Battery voltage and current sense input. Bypass it with a ceramic capacitor (minimum 0.1 F) to PGND if there are long inductive leads to battery. OTG D4 I Boost mode enable control or input current limiting selection pin. When OTG is in active status, the device is forced to operate in boost mode. It has higher priority over I2C control and can be disabled using the control register. At POR while in default mode, the OTG pin is used as the input current limiting selection pin. The I2C register is ignored at startup. When OTG=High, IIN_LIMIT = 500mA and when OTG = Low, IIN_LIMIT = 100mA. NAME NO. BOOT PGND D1, D2, D3 PMID B1, B2, B3 I/O SCL A4 I I2C interface clock. Connect a 10-k pullup resistor to 1.8V rail (VAUX= VCC_HOST) SDA B4 I/O I2C interface data. Connect a 10-k pullup resistor to 1.8V rail (VAUX= VCC_HOST) STAT C4 O Charge status pin. Pull low when charge in progress. Open drain for other conditions. During faults, a 128-s pulse is sent out. STAT pin can be disabled by the EN_STAT bit in control register. STAT can be used to drive a LED or communicate with a host processor. C1, C2, C3 O Internal switch to output inductor connection. VBUS A1, A2 I/O Charger input voltage. Bypass it with a 1-F ceramic capacitor from VBUS to PGND. It also provides power to the load during boost mode . VREF E3 O Internal bias regulator voltage. Connect a 1F ceramic capacitor from this output to PGND. External load on VREF is not recommended. SW Power ground Connection point between reverse blocking FET and high-side switching FET. Bypass it with a minimum of 3.3-F capacitor from PMID to PGND. Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 5 bq24157 SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 www.ti.com 8 Specifications 8.1 Absolute Maximum Ratings (1) (2) over operating free-air temperature range (unless otherwise noted) MIN MAX UNIT -2 20 V SCL, SDA, OTG, SLRST, CSIN, CSOUT, CD -0.3 7 V PMID, STAT -0.3 20 V Supply voltage (with respect to PGND (3)) VBUS; VPMID VBUS -0.3 V Input voltage (with respect to PGND (3)) Output voltage (with respect to PGND (3)) VREF 7 V BOOT -0.7 20 V SW -2 (4) 20 V Voltage difference between CSIN and CSOUT inputs (V(CSIN) - V(CSOUT) ) 7 V Voltage difference between BOOT and SW inputs (V(BOOT) - V(SW) ) -0.3 7 V Voltage difference between VBUS and PMID inputs (V(VBUS) - V(PMID) ) -7 0.7 V -0.7 20 Voltage difference between PMID and SW inputs (V(PMID) - V(SW) ) Output sink STAT Output Current (average) SW V 10 mA 1.55 (2) A TA Operating free-air temperature range -30 85 C TJ Junction temperature -40 125 C Tstg Storage temperature range -45 150 C (1) (2) (3) (4) 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 voltage values are with respect to the network ground terminal unless otherwise noted. Duty cycle for output current should be less than 50% for 10- year life time when output current is above 1.25A. All voltages are with respect to PGND if not specified. Currents are positive into, negative out of the specified terminal, if not specified. Consult Packaging Section of the data sheet for thermal limitations and considerations of packages. 20 ns duration 8.2 ESD Ratings VALUE V(ESD) (1) (2) Electrostatic discharge Human body model (HBM), per ANSI/ESDA/JEDEC JS-001, all pins (1) 2000 Charged device model (CDM), per JEDEC specification JESD22-C101, all pins (2) 500 UNIT V JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process. JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process. 8.3 Recommended Operating Conditions MIN VBUS Supply voltage, bq24157 TJ Operating junction temperature range (1) NOM MAX UNIT 4 6 (1) V -40 125 C The inherent switching noise voltage spikes should not exceed the absolute maximum rating on either the BOOST or SW pins. A tight layout minimizes switching noise. 8.4 Thermal Information THERMAL METRIC (1) bq24157 YFF (20 Pins) UNIT RJA Junction-to-ambient thermal resistance 85 C/W RJC(top) Junction-to-case (top) thermal resistance 25 C/W RJB Junction-to-board thermal resistance 55 C/W JT Junction-to-top characterization parameter 4 C/W JB Junction-to-board characterization parameter 50 C/W RJC(bot) Junction-to-case (bottom) thermal resistance n/a C/W (1) 6 For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report. Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 bq24157 www.ti.com SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 8.5 Electrical Characteristics Circuit of Figure 23, VBUS = 5 V, HZ_MODE = 0, OPA_MODE = 0 (CD = 0), TJ = -40C to 125C, TJ = 25C for typical values (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT INPUT CURRENTS VBUS > VBUS(min), PWM switching I(VBUS) VBUS supply current control 10 VBUS > VBUS(min), PWM NOT switching 0C < TJ < 85C, CD=1 or HZ_MODE=1 Ilgk Leakage current from battery to VBUS pin 0C < TJ < 85C, V(CSOUT) = 4.2 V, High Impedance mode, VBUS = 0 V Battery discharge current in High Impedance mode, (CSIN, CSOUT, SW pins) 0C < TJ < 85C, V(CSOUT) = 4.2 V, High Impedance mode, V = 0 V, SCL, SDA, OTG = 0 V or 1.8 V mA 5 15 23 A 5 A 23 A V VOLTAGE REGULATION V(OREG) Output regulation voltage programable range Operating in voltage regulation, programmable TA = 25C Voltage regulation accuracy 3.5 4.44 -0.5% 0.5% -1% 1% 550 1250 mA 350 mA CURRENT REGULATION (FAST CHARGE) IO(CHARGE) Output charge current programmable range V(LOWV) V(CSOUT) < V(OREG), VBUS > V(SLP), R(SNS) = 68 m, LOW_CHG=0, Programmable Low charge current VLOWV VCSOUT < VOREG, VBUS >VSLP, RSNS= 68 m, LOW_CHG=1, OTG=High Regulation accuracy of the voltage across R(SNS) (for charge current regulation) V(IREG) = IO(CHARGE) x R(SNS) 37.4 mV V(IREG)< 44.2mV 44.2 mV V(IREG) 325 -3.5% 3.5% -3% 3% 3.4 3.7 WEAK BATTERY DETECTION V(LOWV) Weak battery voltage threshold programmable range2 (1) Adjustable using I2C control Weak battery voltage accuracy -5% Hysteresis for V(LOWV) Battery voltage falling V 5% 100 mV CD, OTG and SLRST PIN LOGIC LEVEL VIL Input low threshold level VIH Input high threshold level I(bias) Input bias current 0.4 V 1.0 A 1.3 V Voltage on control pin is 5 V CHARGE TERMINATION DETECTION I(TERM) Termination charge current programmable range Regulation accuracy for termination current across R(SNS) V(IREG_TERM) = IO(TERM) x R(SNS) V(CSOUT) > V(OREG) - V(RCH), VBUS > V(SLP), R(SNS) = 68 m, Programmable 50 400 3.4 mV V(IREG_TERM) 6.8 mV -15% 15% 6.8 mV < V(IREG_TERM) 17 mV -10% 10% 17 mV < V(IREG_TERM) 27.2 mV -5.5% 5.5% mA BAD ADAPTOR DETECTION VIN(min) ISHORT Input voltage lower limit BAD ADAPTOR DETECTION 3.6 Hysteresis for VIN(min) Input voltage rising 100 Current source to GND During bad adaptor detection 20 3.8 30 4 V 200 mV 40 mA INPUT BASED DYNAMIC POWER MANAGEMENT VIN_DPM Input Voltage DPM threshold programmable range VIN DPM threshold accuracy 4.2 4.76 -3% 1% V INPUT CURRENT LIMITING IIN = 100 mA IIN_LIMIT Input current limiting threshold IIN = 500 mA (1) TJ = 0C - 125C 88 93 98 TJ = -40C -125C 86 93 98 TJ = 0C - 125C 450 475 500 TJ = -40C -125C 440 475 500 mA mA While in DEFAULT mode, if a battery that is charged to a voltage higher than this voltage is inserted, the charger enters Hi-Z mode and awaits I2C commands. Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 7 bq24157 SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 www.ti.com Electrical Characteristics (continued) Circuit of Figure 23, VBUS = 5 V, HZ_MODE = 0, OPA_MODE = 0 (CD = 0), TJ = -40C to 125C, TJ = 25C for typical values (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT VREF BIAS REGULATOR VREF VBUS >VIN(min) or V(CSOUT) > VBUS(min), I(VREF) = 1 mA, C(VREF) = 1 F Internal bias regulator voltage 2 VREF output short current limit 6.5 30 V mA BATTERY RECHARGE THRESHOLD V(RCH) Recharge threshold voltage Below V(OREG) 100 120 150 mV STAT OUTPUTS VOL(STAT) Low-level output saturation voltage, STAT pin IO = 10 mA, sink current High-level leakage current for STAT Voltage on STAT pin is 5 V 0.55 V 1 A I2C BUS LOGIC LEVELS AND TIMING CHARACTERISTICS VOL Output low threshold level IO = 10 mA, sink current 0.4 V VIL Input low threshold level V(pull-up) = 1.8 V, SDA and SCL 0.4 V VIH Input high threshold level V(pull-up) = 1.8 V, SDA and SCL I(BIAS) Input bias current V(pull-up) = 1.8 V, SDA and SCL 1 A f(SCL) SCL clock frequency 1.2 V 3.4 MHz BATTERY DETECTION Battery detection current before charge done (sink current) (2) I(DETECT) Begins after termination detected, V(CSOUT) V(BATREG) -0.5 mA SLEEP COMPARATOR V(SLP) Sleep-mode entry threshold, VBUS - VCSOUT 2.3 V V(CSOUT) V(BATREG), VBUS falling V(SLP_EXIT) Sleep-mode exit hysteresis 0 40 100 mV 2.3 V V(CSOUT) V(BATREG) 140 200 260 mV 3.55 UNDERVOLTAGE LOCKOUT (UVLO) UVLO IC active threshold voltage VBUS rising - Exits UVLO 3.05 3.3 UVLO(HYS) IC active hysteresis VBUS falling below UVLO - Enters UVLO 120 150 Voltage from BOOT pin to SW pin During charge or boost operation Internal top reverse blocking MOSFET onresistance IIN(LIMIT) = 500 mA, Measured from VBUS to PMID 180 250 Internal top N-channel Switching MOSFET onresistance Measured from PMID to SW, VBOOT - VSW= 4V 120 250 Internal bottom N-channel MOSFET onresistance Measured from SW to PGND 110 210 V mV PWM f(OSC) 6.5 Oscillator frequency 3.0 Frequency accuracy D(MAX) Maximum duty cycle D(MIN) Minimum duty cycle Synchronous mode to non-synchronous mode transition current threshold (2) -10% V m MHz 10% 99.5% 0 Low-side MOSFET cycle-by-cycle current sensing 100 mA CHARGE MODE PROTECTION VOVP_IN_USB VOVP ILIMIT VSHORT ISHORT (2) 8 Input VBUS OVP threshold voltage VBUS threshold to turn off converter during charge 6.3 6.5 6.7 Output OVP threshold voltage V(CSOUT) threshold over V(OREG) to turn off charger during charge 110 117 121 V(OVP) hysteresis Lower limit for V(CSOUT) falling from above V(OVP) Cycle-by-cycle current limit for charge Charge mode operation 1.8 2.4 3.0 Trickle to fast charge threshold V(CSOUT) rising 2.0 2.1 2.2 VSHORT hysteresis V(CSOUT) falling below VSHORT Trickle charge charging current V(CSOUT) VSHORT) V %V OREG 11 100 20 30 A V mV 40 mA Bottom N-channel FET always turns on for ~30 ns and then turns off if current is too low. Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 bq24157 www.ti.com SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 Electrical Characteristics (continued) Circuit of Figure 23, VBUS = 5 V, HZ_MODE = 0, OPA_MODE = 0 (CD = 0), TJ = -40C to 125C, TJ = 25C for typical values (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT BOOST MODE OPERATION FOR VBUS (OPA_MODE = 1, HZ_MODE = 0) VBUS_B Boost output voltage (to VBUS pin) 2.5V < V(CSOUT) < 4.5 V Boost output voltage accuracy Including line and load regulation IBO Maximum output current for boost VBUS_B = 5.05 V, 2.5 V < V(CSOUT) < 4.5 V, TJ= 0C - 125C IBLIMIT Cycle by cycle current limit for boost VBUS_B = 5.05 V, 2.5 V < V(CSOUT) < 4.5 V VBUSOVP Overvoltage protection threshold for boost (VBUS Threshold over VBUS to turn off converter during pin) boost VBATMAX VBATMIN 5.05 3% 200 mA 1.0 5.8 VBUS falling from above VBUSOVP Maximum battery voltage for boost (CSOUT pin) V(CSOUT) rising edge during boost VBATMAX hysteresis V(CSOUT) falling from above VBATMAX 200 During boosting 2.5 Before boost starts 2.9 Boost output resistance at high-impedance mode (From VBUS to PGND) A 6.0 VBUSOVP hysteresis Minimum battery voltage for boost (CSOUT pin) V -3% 6.2 V 162 4.75 CD = 1 or HZ_MODE = 1 4.9 mV 5.05 V mV V 3.05 V 217 k PROTECTION TSHTDWN) Thermal trip 165 Thermal hysteresis TCF Thermal regulation threshold 10 Charge current begins to reduce C 120 8.6 Timing Requirements MIN NOM MAX UNIT WEAK BATTERY DETECTION Deglitch time for weak battery threshold Rising voltage, 2-mV over drive, tRISE = 100 ns 30 ms Both rising and falling, 2-mV overdrive, tRISE, tFALL = 100 ns 30 ms Deglitch time for VBUS rising above VIN(min) Rising voltage, 2-mV overdrive, tRISE = 100 ns 30 ms Detection Interval Input power source detection 2 s CHARGE TERMINATION DETECTION Deglitch time for charge termination BAD ADAPTOR DETECTION tINT BATTERY RECHARGE THRESHOLD Deglitch time V(CSOUT) decreasing below threshold, tFALL = 100 ns, 10-mV overdrive 130 ms 262 ms 30 ms 140 ms BATTERY DETECTION tDETECT Battery detection time SLEEP COMPARATOR Deglitch time for VBUS rising above V(SLP) + V(SLP_EXIT) Rising voltage, 2-mV overdrive, tRISE = 100 ns UNDERVOLTAGE LOCKOUT (UVLO) Power up delay Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 9 bq24157 SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 www.ti.com 8.7 Typical Characteristics Using circuit shown in Figure 23, TA = 25C, unless otherwise specified. VSW 5 V/div VBUS 2 V/div VSW 2 V/div IBUS 20 mA/div IBAT 200 mA/div 10 ms/div VBUS = 5 V at 8 mA, ICHG = 550 mA VBAT = 3.2V, Iin_limit = 100 mA, 500 mS/div Vin = 5 V, ICHG = 1550mA Figure 1. Poor Source Detection VBAT = 3. 2V, No Input Current Limit, Figure 2. Charge Current Ramp Up VBUS 1 V/div OTG 2 V/div DEFAULT Mode HOST Mode IBUS 0.2 A/div IBAT 0.1 A/div Write Command 1 S/div VBUS = 5 V, VBAT = 3.1V, Iin_limit = 100/500mA (OTG Control, DEFAULT Mode), Iin_limit = 100 mA (I2C Control, HOST Mode) 0.5 mS/div VBUS = 5 V at 500 mA, VIN_DPM = 4.52 V Figure 3. Input Current Control VBAT = 3.5V, ICHG = 1550 mA, Figure 4. VIN Based DPM 94 93 VBUS 2 V/div Vbat = 4.2 V 92 Vbat = 3.6 V 91 VPMID 200 mV/div, 5.02 V Offset Efficiency - % 90 89 88 87 VSW 5 V/div 86 85 Vbat = 3 V 84 83 IBUS 0.2 A/div 82 81 80 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Charge Current - A Figure 5. Charger Efficiency 10 5 mS/div 1.1 1.2 1.3 1.4 1.5 VBUS = 5.05 V VBAT = 3.5 V RLOAD (at VBUS) = 1 k to 0.5 Figure 6. VBUS Overload Waveforms (BOOST Mode) Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 bq24157 www.ti.com SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 Typical Characteristics (continued) VBUS 0.5 V/div, 4.5 V Offset VBUS 100 mV/div, 5.05 V Offset OTG 2 V/div VBAT 0.2 V/div, 3.5 V Offset VSW 5 V/div VSW 5 V/div IBAT 0.1 A/div IL 0.5 A/div 100 mS/div VBUS = 5.05 V 10 mS/div VBAT = 3.5 V IBUS = 217 mA VBUS = 4.5 V (Charge Mode)/5.1 V (Boost Mode), VBAT = 3.5V, IIN_LIM = 500 mA, (HOST Mode) Figure 8. BOOST to Charge Mode Transition (OTG Control) Figure 7. Load Step Down Response (BOOST Mode) 5.09 95 IBUS = 100 mA IBUS = 200 mA 5.08 5.07 5.06 85 VBUS - V Efficiency (%) 90 80 5.05 IBUS = 50 mA 5.04 5.03 VBAT = 2.7 V 75 VBAT = 3.6 V 5.02 VBAT = 4.2 V 70 0 50 100 150 5.01 2.6 200 2.8 3 3.2 3.4 3.6 3.8 4 4.2 VBAT - V Load Current at VBUS (mA) Figure 10. Line Regulation for BOOST Figure 9. BOOST Efficiency 5.09 5.08 5.07 VBUS 5.06 5.05 5.04 5.03 5.02 VBAT = 2.7 V 5.01 VBAT = 3.6 V VBAT = 4.2 V 5 0 50 100 150 200 Load Current at VBUS (mA) Figure 11. Load Regulation for BOOST Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 11 bq24157 SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 www.ti.com 9 Detailed Description 9.1 Overview For a current restricted power source, such as a USB host or hub, a high efficiency converter is critical to fully use the input power capacity for quickly charging the battery. Due to the high efficiency for a wide range of input voltages and battery voltages, the switch mode charger is a good choice for high speed charging with less power loss and better thermal management than a linear charger. The bq24157 are highly integrated synchronous switch-mode chargers, featuring integrated FETs and small external components, targeted at extremely space-limited portable applications powered by 1-cell Li-Ion or Lipolymer battery pack. Furthermore, bq24157 also has bi-directional operation to achieve boost function for USB OTG support. The bq24157 have three operation modes: charge mode, boost mode, and high impedance mode. In charge mode, the IC supports a precision Li-ion or Li-polymer charging system for single-cell applications. In boost mode, the IC boosts the battery voltage to VBUS for powering attached OTG devices. In high impedance mode, the IC stops charging or boosting and operates in a mode with very low current from VBUS or battery, to effectively reduce the power consumption when the portable device is in standby mode. Through I2C communication with a host, referred to as "HOST" control/mode, the IC achieves smooth transition among the different operation modes. Even when no I2C communication is available, the IC starts in default mode. During default mode operation, the charger will still charge the battery but using each register's default values. 12 Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 bq24157 www.ti.com SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 9.2 Functional Block Diagrams PMID bq24157 PMID V PMID PMID NMOS VBUS NMOS SW VBUS VBUS SW Q2 Q1 VREF 1 PWM Controller OSC Charge Pump - CBC Current Limiting Q3 I LIMIT - - I IN _ LIMIT - + V IN _ DPM - T CF + TJ - V BUS + V UVLO - V BUS + V IN(MIN) - VBUS + V OVP_IN - TJ + VOUT + V OVP - V CSIN + CSOUT V OREG - CSIN IOCHARGE VREF I SHORT PWM _ CHG VBUS UVLO LINEAR Poor Input Source REFERNCES & BIAS CHARGE CONTROL TIMER and DISPLAY LOGIC Thermal Shutdown * _CHG VREF VBUS OVP - T SHTDWN V OUT + + SW NMOS VREF BOOT VREF 1 V PMID VOUT Battery OVP STAT V BAT VBUS VOREG - VRCH PGND PGND VOUT VOUT VCSIN I TERM + - * Sleep CD + - + - * Recharge * ( I2 C Control ) Decoder DAC PGND VBAT + VSHORT - OTG (bq 24153 /8) SLRST(bq24156) Termination SCL SDA Charge * PWMMode * Signal Deglitched Figure 12. Function Block Diagram of bq2415x in Charge Mode Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 13 bq24157 SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 www.ti.com Functional Block Diagrams (continued) PMID bq24157 PMID V PMID PMID NMOS VBUS NMOS SW SW SW V BUS VBUS Q2 Q1 VREF 1 Charge Pump OSC PWM Controller CBC Current Limiting Q3 PFM Mode I BO - + + VBUS_B + I BLIMIT - VREF REFERNCES & BIAS PWM _ BOOST V BUS + V BUSOVP - TJ + TSHTDWN - VOUT + VBATMAX - NMOS 75 mA VBUS OVP VREF BOOT VREF 1 VPMID CSIN Thermal Shutdown * Battery OVP V OUT CHARGE CONTROL, TIMER and DISPLAY LOGIC CSOUT STAT CD PGND PGND V BAT + VBATMIN - * * Low Battery OTG ( I2 C Control) Decoder DAC Signal Deglitched PGND SCL SDA Figure 13. Function Block Diagram of bq2415x in Boost Mode 14 Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 bq24157 www.ti.com SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 9.3 Operational Flow Chart Power Up V BUS > V UVLO V POR Load I 2 C Registers with Default Value CSOUT < V LOWV High Impedance Mode or Host No Controlled Operation Mode Yes Disable Charge /CE = LOW Charge Configure Mode /CE = HIGH Any Charge State Disable Charge Wait Mode Delay TINT Indicate Power not Good Yes No Enable I SHORT V CSOPUT <V SHORT ? Yes V BUS < V IN ( MIN ) ? Indicate Short Circuit condition No No Regulate Input Current , Charge Current or Voltage Indicate Charge- In Progress VBUS < V IN ( MIN ) ? Yes Yes Turn Off Charge No Enable I DETECT for t DETECT No Battery Removed V CSOUT < VOREG V RCH ? Yes Wait Mode Delay T INT Reset Charge Parameters Yes No VCSOUT < V SHORT ? Charge Complete Indicate DONE No No Yes Termination Enabled I TERM detected and VCSOUT >V OREG -V RCH ? V CSOUT < V OREG VRCH ? Yes Figure 14. Operational Flow Chart of bq2415x in Charge Mode Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 15 bq24157 SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 www.ti.com 9.4 Feature Description 9.4.1 Input Voltage Protection 9.4.1.1 Input Overvoltage Protection The IC provides a built-in input overvoltage protection to protect the device and other components against damage if the input voltage (Voltage from VBUS to PGND) goes too high. When an input overvoltage condition is detected, the IC turns off the PWM converter, sets fault status bits, and sends out a fault pulse from the STAT pin. Once VBUS drops below the input overvoltage exit threshold, the fault is cleared and charge process resumes. 9.4.1.2 Bad Adaptor Detection/Rejection Although not shown in Figure 14, at power-on-reset (POR) of VBUS, the IC performs the bad adaptor detection by applying a current sink to VBUS. If the VBUS is higher than VIN(MIN) for 30ms, the adaptor is good and the charge process begins. Otherwise, if the VBUS drops below VIN(MIN), a bad adaptor is detected. Then, the IC disables the current sink, sends a send fault pulse in FAULT pin and sets the bad adaptor flag (B2 - B0 = 011 for Register 00H). After a delay of TINT, the IC repeats the adaptor detection process, as shown in Figure 15 and Figure 16. Adpator V BUS VBUS ISHORT (30 mA) Adaptor Detection Control VIN_GOOD Deglitch 30ms PGND GND START VIN VIN(MIN) VIN_POOR Delay TINT Figure 15. Bad Adaptor Detection Circuit 16 Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 bq24157 www.ti.com SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 Feature Description (continued) Charge Command (Host Control or VBUS Ramps Up) Delay 10mS Enable Adaptor Detection Start 30ms Timer Enable Input Current Sink (30mA, to GND) No VBUS>VIN(MIN)? Yes 30ms Timer Expired? Yes No Bad Adaptor Detected Good Adaptor Detected Pulsing STAT Pin Set Bad Adaptor Flag Disable Adaptor Detection Charge Start Enable VIN Based DPM Delay TINT (2 Seconds) Figure 16. Bad Adaptor Detection Scheme Flow Chart 9.4.1.3 Sleep Mode The IC enters the low-power sleep mode if the VBUS pin voltage falls below the sleep-mode entry threshold, VCSOUT+VSLP, and VBUS is higher than the bad adaptor detection threshold, VIN(MIN). This feature prevents draining the battery during the absence of VBUS. During sleep mode, both the reverse blocking switch Q1 and PWM are turned off. 9.4.1.4 Input Voltage Based DPM (Special Charger Voltage Threshold) During the charging process, if the input power source is not able to support the programmed or default charging current, the VBUS voltage will decrease. Once the VBUS drops to VIN_DPM (default 4.52V), the charge current begins to taper down to prevent any further drop of VBUS. When the IC enters this mode, the charge current is lower than the set value and the special charger bit is set (B4 in Register 05H). This feature makes the IC compatible with adapters having different current capabilities. 9.4.2 Battery Protection 9.4.2.1 Output Overvoltage Protection The IC provides a built-in overvoltage protection to protect the device and other components against damage if the battery voltage goes too high, as when the battery is suddenly removed. When an overvoltage condition is detected, the IC turns off the PWM converter, sets fault status bits, and sends out a fault pulse from the STAT pin. Once V(CSOUT) drops to the battery overvoltage exit threshold, the fault is cleared and charge process resumes. Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 17 bq24157 SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 www.ti.com Feature Description (continued) 9.4.2.2 Battery Detection at Power Up in DEFAULT Mode bq24157 also has a unique battery detection scheme during the start up of the charger. At VBUS power up, bq24157 starts a 262-ms timer when exiting from short circuit mode to PWM charge mode. If the battery voltage is charged above the recharge threshold (VOREG-VRCH) when the 262-ms timer expired, bq2157 will not consider the battery present; then stop charging, and go to high impedance mode immediately. However, if the battery voltage is still below the recharge threshold when the 262-ms timer expires, the charging process will continue as normal battery charging process. 9.4.2.3 Battery Short Protection During the normal charging process, if the battery voltage is lower than the short-circuit threshold, VSHORT, the charger operates in short circuit mode with a lower charge rate of ISHORT. 9.4.2.4 Battery Detection in Host Mode For applications with removable battery packs, the IC provides a battery absent detection scheme to reliably detect insertion or removal of battery packs. During the normal charging process with host control, once the voltage at the CSOUT pin is above the battery recharge threshold, VOREG - VRCH, and the termination charge current is detected, the IC turns off the PWM charge and enables a discharge current, IDETECT, for a period of tDETECT, (262 ms typical) then checks the battery voltage. If the battery voltage is still above the recharge threshold after tDETECT, the battery is present. On the other hand, if the battery voltage is below the battery recharge threshold, the battery is absent. Under this condition, the charge parameters (such as input current limit) are reset to the default values and charge resumes after a delay of TINT. This function ensures that the charge parameters are reset whenever the battery is replaced. 9.4.3 DEFAULT Mode The bq24157 stays in default mode indefinitely until I2C communication begins. 9.4.4 USB Friendly Power Up The default control bits set the charging current and regulation voltage low as a safety feature to avoid violating USB spec and over-charging any of the Li-Ion chemistries, while the host has lost communication. The input current limiting is described below. 9.4.5 Input Current Limiting At Power Up The input current sensing circuit and control loop are integrated into the IC. When operating in default mode, the OTG pin logic level sets the input current limit to 100mA for a logic low and 500mA for a logic high. In host mode, the input current limit is set by the programmed control bits in register 01H. 9.5 Device Functional Modes 9.5.1 Charge Mode Operation 9.5.1.1 Charge Profile Once a good battery with voltage below the recharge threshold has been inserted and a good adapter is attached, the bq24157 enters charge mode. In charge mode, the IC has five control loops to regulate input voltage, input current, charge current, charge voltage and device junction temperature. During the charging process, all five loops are enabled and the one that is dominant takes control. The IC supports a precision Li-ion or Li-polymer charging system for single-cell applications. Figure 17 (a) indicates a typical charge profile without input current regulation loop. It is the traditional CC/CV charge curve, while Figure 17(b) shows a typical charge profile when input current limiting loop is dominant during the constant current mode. In this case, the charge current is higher than the input current so the charge process is faster than the linear chargers. The input voltage threshold for DPM loop, input current limits, charge current, termination current, and charge voltage are all programmable using I2C interface. 18 Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 bq24157 www.ti.com SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 Device Functional Modes (continued) Precharge Phase Current Regulation Phase Voltage Regulation Phase Regulation Voltage Regulation Current Charge Voltage V SHORT Charge Current Termination I SHORT Precharge (Linear Charge) Fast Charge (PWM Charge) (a) Precharge Phase Current Regulation Phase Voltage Regulation Phase Regulation voltage Charge Voltage VSHORT Charge Current Termination I SHORT Precharge (Linear Charge) Fast Charge (PWM Charge) (b) Figure 17. Typical Charging Profile for (a) without Input Current Limit, and (b) with Input Current Limit Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 19 bq24157 SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 www.ti.com Device Functional Modes (continued) 9.5.2 PWM Controller in Charge Mode The IC provides an integrated, fixed 3 MHz frequency voltage-mode controller to regulate charge current or voltage. This type of controller is used to improve line transient response, thereby, simplifying the compensation network used for both continuous and discontinuous current conduction operation. The voltage and current loops are internally compensated using a Type-III compensation scheme that provides enough phase margin for stable operation, allowing the use of small ceramic capacitors with a low ESR. The device operates between 0% to 99.5% duty cycles. The IC has back to back common-drain N-channel FETs at the high side and one N-channel FET at low side. The input N-FET (Q1) prevents battery discharge when VBUS is lower than VCSOUT. The second high-side N-FET (Q2) is the switching control switch. A charge pump circuit is used to provide gate drive for Q1, while a bootstrap circuit with an external bootstrap capacitor is used to supply the gate drive voltage for Q2. Cycle-by-cycle current limit is sensed through the FETs Q2 and Q3. The threshold for Q2 is set to a nominal 2.4A peak current. The low-side FET (Q3) also has a current limit that decides if the PWM Controller will operate in synchronous or non-synchronous mode. This threshold is set to 100mA and it turns off the low-side N-channel FET (Q3) before the current reverses, preventing the battery from discharging. Synchronous operation is used when the current of the low-side FET is greater than 100mA to minimize power losses. 9.5.3 Battery Charging Process At the beginning of precharge, while battery voltage is below the V(SHORT) threshold, the IC applies a short-circuit current, I(SHORT), to the battery. When the battery voltage is above VSHORT and below VOREG, the charge current ramps up to fast charge current, IOCHARGE, or a charge current that corresponds to the input current of IIN_LIMIT. The slew rate for fast charge current is controlled to minimize the current and voltage over-shoot during transient. Both the input current limit, IIN_LIMIT, and fast charge current, IOCHARGE, can be set by the host. Once the battery voltage reaches the regulation voltage, VOREG, the charge current is tapered down as shown in Figure 17. The voltage regulation feedback occurs by monitoring the battery-pack voltage between the CSOUT and PGND pins. In HOST mode, the regulation voltage is adjustable (3.5V to 4.44V) and is programmed through I2C interface. In 15-minute mode, the regulation voltage is fixed at 3.54V. The IC monitors the charging current during the voltage regulation phase. If termination is enabled, during the normal charging process with HOST control, once the voltage at the CSOUT pin is above the battery recharge threshold, VOREG - VRCH for the 32-ms (typical) deglitch period, and the termination charge current ITERM is detected, the IC turns off the PWM charge and enables a discharge current, IDETECT, for a period of tDETECT (262ms typical), then checks the battery voltage. If the battery voltage is still above the recharge threshold after tDETECT, the battery charging is complete. The battery detection routine is used to ensure termination did not occur because the battery was removed. After 40ms (typical) for synchronization purposes of the EOC state and the counter, the status bit and pin are updated to indicate charging has completed. The termination current level is programmable. To disable the charge current termination, the host can set the charge termination bit (I_Term) of charge control register to 0, refer to I2C section for detail. A * * * new charge cycle is initiated when one of the following conditions is detected: The battery voltage falls below the V(OREG) - V(RCH) threshold. VBUS Power-on reset (POR), if battery voltage is below the V(LOWV) threshold. CE bit toggle or RESET bit is set (Host controlled) 9.5.4 Thermal Regulation and Protection To prevent overheating of the chip during the charging process, the IC monitors the junction temperature, TJ, of the die and begins to taper down the charge current once TJ reaches the thermal regulation threshold, TCF. The charge current is reduced to zero when the junction temperature increases approximately 10C above TCF. In any state, if TJ exceeds TSHTDWN, the IC suspends charging. In thermal shutdown mode, PWM is turned off and all timers are frozen. Charging resumes when TJ falls below TSHTDWN by approximately 10C. 20 Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 bq24157 www.ti.com SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 Device Functional Modes (continued) 9.5.5 Charge Status Output, STAT Pin The STAT pin is used to indicate operation conditions. STAT is pulled low during charging when EN_STAT bit in control register (00H) is set to "1". Under other conditions, STAT pin behaves as a high impedance (open-drain) output. Under fault conditions, a 128-s pulse will be sent out to notify the host. The status of STAT pin at different operation conditions is summarized in Table 1. The STAT pin can be used to drive an LED or communicate to the host processor. Table 1. STAT Pin Summary CHARGE STATE STAT Charge in progress and EN_STAT=1 Low Other normal conditions Open-drain Charge mode faults: Timer fault, sleep mode, VBUS or battery overvoltage, poor input source, VBUS UVLO, no battery, thermal shutdown 128-s pulse, then open-drain Boost mode faults: Timer fault, over load, VBUS or battery overvoltage, low battery voltage, thermal shutdown 128-s pulse, then open-drain 9.5.6 Control Bits in Charge Mode 9.5.6.1 CE Bit (Charge Mode) The CE bit in the control register is used to disable or enable the charge process. A low logic level (0) on this bit enables the charge and a high logic level (1) disables the charge. 9.5.6.2 RESET Bit The RESET bit in the control register is used to reset all the charge parameters. Writing `1" to the RESET bit will reset all the charge parameters to default values except the safety limit register, and RESET bit is automatically cleared to zero once the charge parameters get reset. It is designed for charge parameter reset before charge starts and it is not recommended to set the RESET bit while charging or boosting are in progress. 9.5.6.3 OPA_Mode Bit OPA_MODE is the operation mode control bit. When OPA_MODE = 0, the IC operates as a charger if HZ_MODE is set to "0", refer to Table 2 for detail. When OPA_MODE=1 and HZ_MODE=0, the IC operates in boost mode. Table 2. Operation Mode Summary OPA_MODE HZ_MODE OPERATION MODE 0 0 Charge (no fault) Charge configure (fault, Vbus > UVLO) High impedance (Vbus < UVLO) 1 0 Boost (no faults) Any fault go to charge configure mode X 1 High impedance 9.5.7 Control Pins in Charge Mode 9.5.7.1 CD Pin (Charge Disable) The CD pin is used to disable the charging process. When the CD pin is low, charge is enabled. When the CD pin is high, charge is disabled and the charger enters high impedance (Hi-Z) mode. 9.5.8 BOOST Mode Operation In host mode, when OTG pin is high (and OTG_EN bit is high thereby enabling OTG functionality) or the operation mode bit (OPA_MODE) is set to 1, the device operates in boost mode and delivers the power to VBUS from the battery. In normal boost mode converts the battery voltage to VBUS-B (about 5.05V) and delivers a current as much as IBO (about 200mA) to support other USB OTG devices connected to the USB connector. Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 21 bq24157 SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 www.ti.com 9.5.8.1 PWM Controller in Boost Mode Similar to charge mode operation, in boost mode, the IC provides an integrated, fixed 3 MHz frequency voltagemode controller to regulate output voltage at PMID pin (VPMID). The voltage control loop is internally compensated using a Type-III compensation scheme that provides enough phase margin for stable operation with a wide load range and battery voltage range. In boost mode, the input N-FET (Q1) prevents battery discharge when VBUS pin is over loaded. Cycle-by-cycle current limit is sensed through the internal sense FET for Q3. The cycle-by-cycle current limit threshold for Q3 is set to a nominal 1.0-A peak current. Synchronous operation is used in PWM mode to minimize power losses. 9.5.8.2 Boost Start Up To prevent the inductor saturation and limit the inrush current, a soft-start control is applied during the boost start up. 9.5.8.3 PFM Mode at Light Load In boost mode, under light load conditions, the IC operates in pulse skipping mode (PFM mode) to reduce the power loss and improve the converter efficiency. During boosting, the PWM converter is turned off once the inductor current is less than 75mA; and the PWM is turned back on only when the voltage at PMID pin drops to about 99.5% of the rated output voltage. A unique pre-set circuit is used to make the smooth transition between PWM and PFM mode. 9.5.8.4 Protection in Boost Mode 9.5.8.4.1 Output Overvoltage Protection The IC provides a built-in over-voltage protection to protect the device and other components against damage if the VBUS voltage goes too high. When an over-voltage condition is detected, the IC turns off the PWM converter, resets OPA_MODE bit to 0, sets fault status bits, and sends out a fault pulse from the STAT pin. Once VBUS drops to the normal level, the boost starts after host sets OPA_MODE to "1" or OTG pin stays in active status. 9.5.8.4.2 Output Overload Protection The IC provides a built-in over-load protection to prevent the device and battery from damage when VBUS is over loaded. Once the over load condition is detected, Q1 operates in linear mode to limit the output current. If the over load condition lasts for more than 30ms, the over-load fault is detected. When an over-load condition is detected, the IC turns off the PWM converter, resets OPA_MODE bit to 0, sets fault status bits and sends out fault pulse in STAT pin. The boost will not start until the host clears the fault register. 9.5.8.4.3 Battery Overvoltage Protection During boosting, when the battery voltage is above the battery over voltage threshold, VBATMAX, or below the minimum battery voltage threshold, VBATMIN, the IC turns off the PWM converter, resets OPA_MODE bit to 0, sets fault status bits and sends out fault pulse in STAT pin. Once the battery voltage goes above VBATMIN, the boost will start after the host sets OPA_MODE to "1" or OTG pin stays in active status. 9.5.8.5 STAT Pin in Boost Mode During normal boosting operation, the STAT pin behaves as a high impedance (open-drain) output. Under fault conditions, a 128-s pulse is sent out to notify the host. 9.5.9 High Impedance (Hi-Z) Mode In Hi-Z mode, the charger stops charging and enters a low quiescent current state to conserve power. Taking the CD pin high causes the charger to enter Hi-Z mode. When in default mode and the CD pin is low, the charger automatically enters Hi-Z mode if 1. VBUS > UVLO and a battery with VBAT > VLOWV is inserted, or 2. VBUS falls below UVLO. When in HOST mode and the CD is low, the charger can be placed into Hi-Z mode if the HZ-MODE control bit is set to "1" and OTG pin is not in active status. 22 Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 bq24157 www.ti.com SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 In order to exit Hi-Z mode, the CD pin must be low, VBUS must be higher than UVLO and the HOST must write a "0" to the HZ-MODE control bit. 9.6 Programming 9.6.1 Serial Interface Description I2C is a 2-wire serial interface developed by Philips Semiconductor (see I2C-Bus Specification, Version 2.1, January 2000). The bus consists of a data line (SDA) and a clock line (SCL) with pull-up structures. When the bus is idle, both SDA and SCL lines are pulled high. All the I2C compatible devices connect to the I2C bus through open drain I/O pins, SDA and SCL. A master device, usually a microcontroller or a digital signal processor, controls the bus. The master is responsible for generating the SCL signal and device addresses. The master also generates specific conditions that indicate the START and STOP of data transfer. A slave device receives and/or transmits data on the bus under control of the master device. The IC works as a slave and is compatible with the following data transfer modes, as defined in the I2C-Bus Specification: standard mode (100 kbps), fast mode (400 kbps), and high-speed mode (up to 3.4 Mbps in write mode). The interface adds flexibility to the battery charge solution, enabling most functions to be programmed to new values depending on the instantaneous application requirements. Register contents remain intact as long as supply voltage remains above 2.2 V (typical). I2C is asynchronous, which means that it runs off of SCL. The device has no noise or glitch filtering on SCL, so SCL input needs to be clean. Therefore, it is recommended that SDA changes while SCL is LOW. The data transfer protocol for standard and fast modes is the same; therefore, they are referred to as F/S-mode in this document. The protocol for high-speed mode is different from the F/S-mode, and it is referred to as HSmode. The bq24157B device supports 7-bit addressing only. The device 7-bit address is defined as `1101010' (6AH). 9.6.1.1 F/S Mode Protocol The master initiates data transfer by generating a start condition. The start condition is when a high-to-low transition occurs on the SDA line while SCL is high, as shown in Figure 18. All I2C-compatible devices should recognize a start condition. DATA CLK S P START Condition STOP Condition Figure 18. START and STOP Condition The master then generates the SCL pulses, and transmits the 8-bit address and the read/write direction bit R/W on the SDA line. During all transmissions, the master ensures that data is valid. A valid data condition requires the SDA line to be stable during the entire high period of the clock pulse (see Figure 19). All devices recognize the address sent by the master and compare it to their internal fixed addresses. Only the slave device with a matching address generates an acknowledge (see Figure 19) by pulling the SDA line low during the entire high period of the ninth SCL cycle. Upon detecting this acknowledge, the master knows that communication link with a slave has been established. Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 23 bq24157 SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 www.ti.com Programming (continued) DATA CLK Data Line Stable; Data Valid Change of Data Allowed Figure 19. Bit Transfer on the Serial Interface The master generates further SCL cycles to either transmit data to the slave (R/W bit 1) or receive data from the slave (R/W bit 0). In either case, the receiver needs to acknowledge the data sent by the transmitter. So an acknowledge signal can either be generated by the master or by the slave, depending on which one is the receiver. The 9-bit valid data sequences consisting of 8-bit data and 1-bit acknowledge can continue as long as necessary. To signal the end of the data transfer, the master generates a stop condition by pulling the SDA line from low to high while the SCL line is high (see Figure 21). This releases the bus and stops the communication link with the addressed slave. All I2C compatible devices must recognize the stop condition. Upon the receipt of a stop condition, all devices know that the bus is released, and they wait for a start condition followed by a matching address. If a transaction is terminated prematurely, the master needs to send a STOP condition to prevent the slave I2C logic from getting stuck in a bad state. Attempting to read data from register addresses not listed in this section will result in FFh being read out. Data Output by Transmitter Not Acknowledge Data Output by Receiver Acknowledge SCL From Master 1 8 2 9 Clock Pulse for Acknowledgement START Condition Figure 20. Acknowledge on the I2C BusTM 24 Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 bq24157 www.ti.com SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 Programming (continued) Recognize START or REPEATED START Condition Recognize STOP or REPEATED START Condition Generate ACKNOWLEDGE Signal P SDA Acknowledgement Signal From Slave MSB Sr Address R/W SCL S or Sr ACK ACK Sr or P Clock Line Held Low While Interrupts are Serviced Figure 21. Bus Protocol 9.6.1.2 H/S Mode Protocol When the bus is idle, both SDA and SCL lines are pulled high by the pull-up devices. The master generates a start condition followed by a valid serial byte containing HS master code 00001XXX. This transmission is made in F/S-mode at no more than 400 Kbps. No device is allowed to acknowledge the HS master code, but all devices must recognize it and switch their internal setting to support 3.4-Mbps operation. The master then generates a repeated start condition (a repeated start condition has the same timing as the start condition). After this repeated start condition, the protocol is the same as F/S-mode, except that transmission speeds up to 3.4 Mbps are allowed. A stop condition ends the HS-mode and switches all the internal settings of the slave devices to support the F/S-mode. Instead of using a stop condition, repeated start conditions should be used to secure the bus in HS-mode. If a transaction is terminated prematurely, the master needs sending a STOP condition to prevent the slave I2C logic from getting stuck in a bad state. Attempting to read data from register addresses not listed in this section results in FFh being read out. 9.6.1.3 I2C Update Sequence The IC requires a start condition, a valid I2C address, a register address byte, and a data byte for a single update. After the receipt of each byte, the IC acknowledges by pulling the SDA line low during the high period of a single clock pulse. A valid I2C address selects the IC. The IC performs an update on the falling edge of the acknowledge signal that follows the LSB byte. For the first update, the IC requires a start condition, a valid I2C address, a register address byte, a data byte. For all consecutive updates, The IC needs a register address byte, and a data byte. Once a stop condition is received, the IC releases the I2C bus, and awaits a new start conditions. Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 25 bq24157 SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 www.ti.com Programming (continued) S SLAVE ADDRESS R/W A REGISTER ADDRESS A DATA A/A P Data Transferred (n Bytes + Acknowledge) `0' (Write) From master to IC A A From IC to master S Sr P = Acknowledge (SDA LOW) = Not acknowledge (SDA HIGH) = START condition = Repeated START condition = STOP condition (a) F/S-Mode F/S-Mode S F/S-Mode HS-Mode HS-MASTER CODE A Sr SLAVE ADDRESS R/W A REGISTER ADDRESS A DATA A/A Data Transferred (n Bytes + Acknowledge) `0' (write) P HS-Mode Continues Sr Slave A. (b) HS- Mode Figure 22. Data Transfer Format in F/S Mode and H/S Mode 9.6.1.4 Slave Address Byte MSB X LSB 1 1 0 1 0 1 1 The slave address byte is the first byte received following the START condition from the master device. 9.6.1.5 Register Address Byte MSB 0 LSB 0 0 0 0 D2 D1 D0 Following the successful acknowledgment of the slave address, the bus master will send a byte to the IC, which contains the address of the register to be accessed. The IC contains five 8-bit registers accessible via a bidirectional I2C-bus interface. Among them, four internal registers have read and write access; and one has only read access. 26 Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 bq24157 www.ti.com SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 9.7 Register Description Table 3. Status/Control Register (Read/Write) Memory Location: 00, Reset State: x1xx 0xxx BIT NAME READ/WRITE FUNCTION B7 (MSB) TMR_RST/OTG Read/Write Write: TMR_RST function, write "1" to reset the safety timer (auto clear) Read: OTG pin status, 0-OTG pin at Low level, 1-OTG pin at High level B6 EN_STAT Read/Write 0-Disable STAT pin function, 1-Enable STAT pin function (default 1) B5 STAT2 Read Only B4 STAT1 Read Only B3 BOOST Read Only 1-Boost mode, 0-Not in boost mode B2 FAULT_3 Read Only B1 FAULT_2 Read Only B0 (LSB) FAULT_1 Read Only Charge mode: 000-Normal, 001-VBUS OVP, 010-Sleep mode, 011-Bad Adaptor or VBUS<VUVLO, 100-Output OVP, 101-Thermal shutdown, 110-Timer fault, 111-No battery Boost mode: 000-Normal, 001-VBUS OVP, 010-Over load, 011-Battery voltage is too low, 100-Battery OVP, 101-Thermal shutdown, 110-Timer fault, 111-NA 00-Ready, 01-Charge in progress, 10-Charge done, 11-Fault Table 4. Control Register (Read/Write) Memory Location: 01, Reset State: 0011 0000 BIT NAME READ/WRITE B7 (MSB) Iin_Limit_2 Read/Write FUNCTION B6 Iin_Limit_1 Read/Write 00-USB host with 100-mA current limit, 01-USB host with 500-mA current limit, 10USB host/charger with 800-mA current limit, 11-No input current limit B5 V(LOWV_2) (1) Read/Write Weak battery voltage threshold: 200mV step (default 1) B4 V(LOWV_1) (1) Read/Write Weak battery voltage threshold: 100mV step (default 1) TE Read/Write 1-Enable charge current termination, 0-Disable charge current termination (default 0) B2 CE Read/Write 1-Charger is disabled, 0-Charger enabled (default 0) B1 HZ_MODE Read/Write 1-High impedance mode, 0-Not high impedance mode (default 0) B0 (LSB) OPA_MODE Read/Write 1-Boost mode, 0-Charger mode (default 0) B3 (1) The range of the weak battery voltage threshold (V(LOWV)) is 3.4 V to 3.7 V with an offset of 3.4 V and steps of 100 mV (default 3.7 V, using bits B4-B5). Table 5. Control/Battery Voltage Register (Read/Write) Memory Location: 02, Reset State: 0000 1010 * BIT NAME READ/WRITE B7 (MSB) VO(REG5) Read/Write Battery Regulation Voltage: 640 mV step (default 0) FUNCTION B6 VO(REG4) Read/Write Battery Regulation Voltage: 320 mV step (default 0) B5 VO(REG3) Read/Write Battery Regulation Voltage: 160 mV step (default 0) B4 VO(REG2) Read/Write Battery Regulation Voltage: 80 mV step (default 0) B3 VO(REG1) Read/Write Battery Regulation Voltage: 40 mV step (default 1) B2 VO(REG0) Read/Write Battery Regulation Voltage: 20 mV step (default 0) B1 OTG_PL Read/Write 1-OTG Boost Enable with High level, 0-OTG Boost Enable with Low level (default 1); not applicable to OTG pin control of current limit at POR in default mode B0 (LSB) OTG_EN Read/Write 1-Enable OTG Pin in HOST mode, 0-Disable OTG pin in HOST mode (default 0), not applicable to OTG pin control of current limit at POR in default mode Charge voltage range is 3.5 V to 4.44 V with the offset of 3.5 V and steps of 20 mV (default 3.54 V), using bits B2-B7. Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 27 bq24157 SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 www.ti.com Table 6. Vender/Part/Revision Register (Read only) Memory Location: 03, Reset State: 0101 000x BIT NAME READ/WRITE FUNCTION B7 (MSB) Vender2 Read Only Vender Code: bit 2 (default 0) B6 Vender1 Read Only Vender Code: bit 1 (default 1) B5 Vender0 Read Only Vender Code: bit 0 (default 0) B4 PN1 Read Only B3 PN0 Read Only B2 Revision2 Read Only B1 Revision1 Read Only B0 (LSB) Revision0 Read Only For I2C Address 6AH: 01-NA, 10-bq24157, 11-NA. 011: Revision 1.0; 001: Revision 1.1; 100-111: Future Revisions Table 7. Battery Termination/Fast Charge Current Register (Read/Write) Memory Location: 04, Reset State: 0000 0001 (1) (2) * BIT NAME READ/WRITE B7 (MSB) Reset Read/Write Write: 1-Charger in reset mode, 0-No effect, Read: always get "0" FUNCTION B6 VI(CHRG3) (1) Read/Write Charge current sense voltage: 27.2 mV step B5 VI(CHRG2) (1) Read/Write Charge current sense voltage: 13.6 mV step B4 VI(CHRG1) (1) Read/Write Charge current sense voltage: 6.8 mV step B3 VI(CHRG0) (1) Read/Write NA B2 VI(TERM2) (2) Read/Write Termination current sense voltage: 13.6 mV step (default 0) B1 VI(TERM1) (2) Read/Write Termination current sense voltage: 6.8 mV step (default 0) B0 (LSB) VI(TERM0) (2) Read/Write Termination current sense voltage: 3.4 mV step (default 1) See Table 12 See Table 11 Charge current sense voltage offset is 37.4 mV and default charge current is 550 mA, if 68-m sensing resistor is used and LOW_CHG=0. Table 8. Special Charger Voltage/Enable Pin Status Register Memory location: 05, Reset state: 000X X100 * 28 BIT NAME READ/WRITE B7 (MSB) NA Read/Write NA FUNCTION B6 NA Read/Write NA B5 LOW_CHG Read/Write 0 - Normal charge current sense voltage at 04H (default 1), 1 - Low charge current sense voltage of 22.1 mV B4 DPM_STATUS Read Only 0 - DPM mode is not active, 1 - DPM mode is active B3 CD_STATUS Read Only 0 - CD pin at LOW level, 1 - CD pin at HIGH level B2 VSREG2 Read/Write Special charger voltage: 320 mV step (default 1) B1 VSREG1 Read/Write Special charger voltage: 160 mV step (default 0) B0 (LSB) VSREG0 Read/Write Special charger voltage: 80 mV step (default 0) Special charger voltage offset is 4.2 V and default special charger voltage is 4.52 V. Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 bq24157 www.ti.com SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 Table 9. Safety Limit Register (READ/WRITE, Write only once after reset!) Memory location: 06, Reset state: 01000000 BIT * * * FUNCTION VMCHRG3 Read/Write Maximum charge current sense voltage: 54.4 mV step (default 0) B6 VMCHRG2 (1) Read/Write Maximum charge current sense voltage: 27.2 mV step (default 1) B5 VMCHRG1 (1) Read/Write Maximum charge current sense voltage: 13.6 mV step (default 0) VMCHRG0 (1) B4 * READ/WRITE (1) B7 (MSB) (1) NAME Read/Write Maximum charge current sense voltage: 6.8 mV step (default 0) B3 VMREG3 Read/Write Maximum battery regulation voltage: 160 mV step (default 0) B2 VMREG2 Read/Write Maximum battery regulation voltage: 80 mV step (default 0) B1 VMREG1 Read/Write Maximum battery regulation voltage: 40 mV step (default 0) B0 (LSB) VMREG0 Read/Write Maximum battery regulation voltage: 20 mV step (default 0) (2) Refer to Table 12 Maximum charge current sense voltage offset is 37.4 mV (550 mA), default at 64.6 mV (950 mA) and the maximum charge current option is 1.55 A (105.4 mV), if 55-m sensing resistor is used. Maximum battery regulation voltage offset is 4.2V (default at 4.2 V) and maximum battery regulation voltage option is 4.44V. Memory location 06H resets only when V(CSOUT) drops below either 1) V(SHORT) threshold (typ. 2.05 V) if VBUS > V(UVLO) or 2) the digital reset threshold of 2.4 V typical if VBUS < V(UVLO). Programmed values in the safety limit register exclude higher values from memory locations 02 (battery regulation voltage), and from memory location 04 (fast charge current) from being successfully written. If host accesses (write command) to some other register before Safety limit register, the safety default values are used. Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 29 bq24157 SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 www.ti.com 10 Application and Implementation NOTE Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI's customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality. 10.1 Application Information The bq24157 is a compact, flexible, high-efficiency, USB-friendly, switch-mode charge management solution for single-cell Li-ion and Li-polymer batteries used in a wide range of portable applications. The bq24157 integrates a synchronous PWM controller, power MOSFETs, input current sensing, high-accuracy current and voltage regulation, and charge termination, into a small DSBGA package. The charge parameters can be programmed through an I2C interface. 10.1.1 Typical Application VBUS = 5 V, ICHARGE = 1250 mA, VBAT = 3.5 to 4.44 V (adjustable). LO 1.0 mH VBUS VBUS CIN VBAT SW CO1 CBOOT U1 bq24157 1 mF RSNS 22 mF 33 nF C IN 4.7 mF BOOT PMID PACK+ + CCSIN PGND VAUX 0.1 mF CSIN 10 kW 10 kW 10 kW 10 kW 2 I C BUS SLRST 10 kW SDA STAT SLRST CD PACK- CSOUT SCL SCL SDA STAT CCSOUT VREF CVREF CD 0.1 mF 1 mF 10 kW HOST Figure 23. I2C Controlled 1-Cell USB Charger Application Circuit with USB OTG Support. 10.1.1.1 Design Requirements Use the following typical application design procedure to select external components values for the bq24157 device. Specification Test Condition Input DC voltage, VIN Input voltage from AC adapter input Input current Maximum input current from AC adapter input Charge current Battery charge current Output regulation voltage Voltage applied at VBAT Operating junction temperature range, TJ 30 MIN TYP MAX 4 5 6 V 0.1 0.1 to 0.5 1.5 A 0.325 0.7 1.55 A 0 3 to 4.2 4.44 V 125 C 0 Submit Documentation Feedback UNIT Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 bq24157 www.ti.com SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 10.1.1.2 Detailed Design Procedure Systems Design Specifications: * VBUS = 5 V * VBAT = 4.2 V (1-Cell) * I(charge) = 1.25 A * Inductor ripple current = 30% of fast charge current 1. Determine the inductor value (LOUT) for the specified charge current ripple: VBAT (VBUS - VBAT) VBUS f D IL L OUT = , the worst case is when battery voltage is as close as to half of the input voltage. LOUT = 2.5 (5 - 2.5) 5 (3 106 ) 1.25 0.3 (1) LOUT = 1.11 H Select the output inductor to standard 1 H. Calculate the total ripple current with using the 1-H inductor: DIL = DIL = VBAT (VBUS - VBAT) VBUS f LOUT (2) 2.5 (5 - 2.5) 5 (3 106 ) (1 10-6 ) (3) IL = 0.42 A Calculate the maximum output current: DIL ILPK = IOUT + 2 ILPK = 1.25 + (4) 0.42 2 (5) ILPK = 1.46 A Select 2.5mm by 2mm 1-H 1.5-A surface mount multi-layer inductor. The suggested inductor part numbers are shown as following. Table 10. Inductor Part Numbers (1) PART NUMBER INDUCTANCE SIZE MANUFACTURER LQM2HPN1R0MJ0 1 H 2.5 x 2.0 mm Murata MIPS2520D1R0 1 H 2.5 x 2.0 mm FDK MDT2520-CN1R0M 1 H 2.5 x 2.0 mm TOKO CP1008 1 H 2.5 x 2.0 mm Inter-Technical (1) See Third-Party Products Disclaimer spacer 2. Determine the output capacitor value (COUT) using 40 kHz as the resonant frequency: fo = 1 2p COUT = COUT = LOUT COUT (6) 1 4p2 f02 LOUT 1 (7) 4p2 (40 103 )2 (1 10-6 ) (8) Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 31 bq24157 SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 www.ti.com COUT = 15.8 F Select two 0603 X5R 6.3V 10-F ceramic capacitors in parallel i.e., Murata GRM188R60J106M. 3. Determine the sense resistor using the following equation: V(RSNS) R(SNS) = I(CHARGE) (9) The maximum sense voltage across the sense resistor is 85 mV. In order to get a better current regulation accuracy, V(RSNS) should equal 85mV, and calculate the value for the sense resistor. 85mV R(SNS) = 1.25A (10) R(SNS) = 68 m This is a standard value. If it is not a standard value, then choose the next close value and calculate the real charge current. Calculate the power dissipation on the sense resistor: P(RSNS) = I(CHARGE) 2 x R(SNS) P(RSNS) = 1.252 x 0.068 P(RSNS) = 0.106 W Select 0402 0.125-W 68-m 2% sense resistor, i.e. Panasonic ERJ2BWGR068. 4. Measured efficiency and total power loss with different inductors are shown in Figure 24. SW node and inductor current waveform are shown in Figure 34. Battery Charge Efficiency 90 TA = 25C VBUS = 5 V VBAT = 3 V 89 TA = 25C VBUS = 5 V VBAT = 3 V 700 600 87 Loss (mW) Efficiency (%) 88 Battery Charge Loss 800 86 85 84 82 500 600 700 800 400 300 FDK TOKO Inter-Technical muRata 83 500 FDK TOKO Inter-Technical muRata 200 100 900 1000 1100 1200 1300 500 Charge Current (mA) 600 700 800 900 1000 1100 1200 1300 Charge Current (mA) Figure 24. Measured Efficiency and Power Loss 32 Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 bq24157 www.ti.com SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 10.1.2 Charge Current Sensing Resistor Selection Guidelines Both the termination current range and charge current range depend on the sensing resistor (RSNS). The termination current step (IOTERM_STEP) can be calculated using Equation 11: IO(TERM_STEP) = VI(TERM0) R(SNS) (11) Table 11 shows the termination current settings for three sensing resistors. Table 11. Termination Current Settings for 55-m, 68-m, 100-m Sense Resistors BIT VI(TERM) (mV) I(TERM) (mA) R(SNS) = 55m I(TERM) (mA) R(SNS) = 68m I(TERM) (mA) R(SNS) = 100m VI(TERM2) 13.6 247 200 136 VI(TERM1) 6.8 124 100 68 VI(TERM0) 3.4 62 50 34 Offset 3.4 62 50 34 For example, with a 68-m sense resistor, V(ITERM2) = 1, V(ITERM1) = 0, and V(ITERM0) = 1, ITERM = [ (13.6 mV x 1) + (6.8 mV x 0) + (3.4 mV x 1) + 3.4 mV ] / 68 m = 200 mA + 0 + 50 mA + 50 mA = 300 mA. The charge current step (IO(CHARGE_STEP)) is calculated using Equation 12: IO(CHARGE_STEP) = VI(CHRG0) R(SNS) (12) Table 12 shows the charge current settings for three sensing resistors. Table 12. Charge Current Settings for 55-m, 68-m and 100-m Sense Resistors BIT VI(REG) (mV) IO(CHARGE) (mA) R(SNS) = 55m IO(CHARGE) (mA) R(SNS) = 68m IO(CHARGE) (mA) R(SNS) = 100m VI(CHRG3) 27.2 495 400 272 VI(CHRG2) 13.6 247 200 136 VI(CHRG1) 6.8 124 100 68 VI(CHRG0) N/A N/A N/A N/A Offset 37.4 680 550 374 For example, with a 68-m sense resistor, V(CHRG3) = 1, V(CHRG2) = 1, V(ICHRG1) = 1, ICHRG = [ (27.2 mV x 1) + (13.6 mV x 1) + (6.8 mV x 1) + 37.4 mV ] / 68 m = 400 mA + 200 + 100 + 550 mA = 1250 mA. 10.1.3 Output Inductor and Capacitance Selection Guidelines The IC provides internal loop compensation. With the internal loop compensation, the highest stability occurs when the LC resonant frequency, fo, is approximately 40 kHz (20 kHz to 80 kHz). Equation 13 can be used to calculate the value of the output inductor, LOUT, and output capacitor, COUT. fo = 1 2p LOUT COUT (13) To reduce the output voltage ripple, a ceramic capacitor with the capacitance between 4.7 F and 47 F is recommended for COUT, see the application section for components selection. VBUS = 5 V, ICHARGE = 1250 mA, VBAT = 3.5 V to 4.44 V (Adjustable). Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 33 bq24157 SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 www.ti.com 10.2 Typical Performance Curves Using circuit shown in Figure 23, TA = 25C, unless otherwise specified. VBUS 2 V/div VBAT 2 V/div VSW 5 V/div VSW 5 V/div IBAT 0.5 A/div IBAT 0.5 A/div Battery Inserted Battery Removed 10 ms/div VBUS = 0-5V, VBAT = 3.5V, Iin_limit = 500mA, ICHG = 550mA, 1 S/div Voreg = 4.2V 32S mode VBUS = 5 V VBAT = 3.4 V Iin_limit = 500 mA Figure 26. Battery Insertion/Removal (HOST Mode) Figure 25. Adapter Insertion VBUS 10 mV/div, 5.05 V Offset VBUS 5 V/div VBAT 10 mV/div, 3.5 V Offset VBAT 2 V/div VSW 2V/div IL 100 mA/div IBUS 50 mA/div 100 mS/div VBUS = 5 V 100 nS/div No Battery Connected VBUS = 5.05 V, VBUS 100 mV/div, 5.05 V Offset VBUS 200 mV/div, 5.05 V Offset VBAT 100 mV/div, 3.5 V Offset VBAT 200 mV/div, 3.5 V Offset VSW 5 V/div IL 0.2 A/div IBAT 500 mV/div 100 s/div 5 mS/div VBUS = 5.05 V, VBAT = 3.5V, IBUS = 42 mA Figure 29. BOOST Waveform (PFM Mode) 34 IBUS = 217 mA Figure 28. BOOST Waveform (PWM Mode) Figure 27. Battery Detection at Power Up VSW 2 V/div VBAT = 3.5V, VBUS = 5.05, VBAT = 3.5V, IBUS = 0-360 mA Figure 30. Load Step Up Response (BOOST Mode) Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 bq24157 www.ti.com SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 Typical Performance Curves (continued) VBUS 200 mV/div, 5.05 V Offset VBUS 100 mV/div 5.05 V Offset VBAT 200 mV/div, 3.5 V Offset VBAT 0.2 V/div 3.5 V Offset VSW 5 V/div VSW 5 V/div IBAT 500 mV/div IBAT 0.1 A/div 100 mS/div 100 s/div VBUS = 5.05 V, VBAT = 3.5V, IBUS = 0-217 mA Figure 31. Load Step Up Response (BOOST Mode) VBUS = 5.05, VBAT = 3.5V, IBUS = 360-0 mA Figure 32. Load Step Down Response (BOOST Mode) Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 35 bq24157 SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 www.ti.com 11 Power Supply Recommendations 11.1 System Load After Sensing Resistor One of the simpler high-efficiency topologies connects the system load directly across the battery pack, as shown in Figure 33. The input voltage has been converted to a usable system voltage with good efficiency from the input. When the input power is on, it supplies the system load and charges the battery pack at the same time. When the input power is off, the battery pack powers the system directly. SW VBUS L1 VIN + - Isys Isns Rsns bq2415x C1 PMID Ichg + PGND C4 C3 System Load BAT C2 Figure 33. System Load After Sensing Resistor 11.1.1 The Advantages: 1. When the AC adapter is disconnected, the battery pack powers the system load with minimum power dissipation. Consequently, the time that the system runs on the battery pack can be maximized. 2. It reduces the number of external path selection components and offers a low-cost solution. 3. Dynamic power management (DPM) can be achieved. The total of the charge current and the system current can be limited to a desired value by setting the charge current value. When the system current increases, the charge current drops by the same amount. As a result, no potential over-current or over-heating issues are caused by excessive system load demand. 4. The total input current can be limited to a desired value by setting the input current limit value. USB specifications can be met easily. 5. The supply voltage variation range for the system can be minimized. 6. The input current soft-start can be achieved by the generic soft-start feature of the IC. 11.1.2 Design Requirements and Potential Issues: 1. If the system always demands a high current (but lower than the regulation current), the battery charging never terminates. Thus, the battery is always charged, and its lifetime may be reduced. 2. Because the total current regulation threshold is fixed and the system always demands some current, the battery may not be charged with a full-charge rate and thus may lead to a longer charge time. 3. If the system load current is large after the charger has been terminated, the IR drop across the battery impedance may cause the battery voltage to drop below the refresh threshold and start a new charge cycle. The charger would then terminate due to low charge current. Therefore, the charger would cycle between charging and terminating. If the load is smaller, the battery has to discharge down to the refresh threshold, resulting in a much slower cycling. 4. In a charger system, the charge current is typically limited to about 30mA, if the sensed battery voltage is below 2V short circuit protection threshold. This results in low power availability at the system bus. If an external supply is connected and the battery is deeply discharged, below the short circuit protection threshold, the charge current is clamped to the short circuit current limit. This then is the current available to the system during the power-up phase. Most systems cannot function with such limited supply current, and the battery supplements the additional power required by the system. Note that the battery pack is already at the depleted condition, and it discharges further until the battery protector opens, resulting in a system shutdown. 5. If the battery is below the short circuit threshold and the system requires a bias current budget lower than the 36 Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 bq24157 www.ti.com SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 System Load After Sensing Resistor (continued) short circuit current limit, the end-equipment will be operational, but the charging process can be affected depending on the current left to charge the battery pack. Under extreme conditions, the system current is close to the short circuit current levels and the battery may not reach the fast-charge region in a timely manner. As a result, the safety timers flag the battery pack as defective, terminating the charging process. Because the safety timer cannot be disabled, the inserted battery pack must not be depleted to make the application possible. 6. If the battery pack voltage is too low, highly depleted, totally dead or even shorted, the system voltage is clamped by the battery and it cannot operate even if the input power is on. Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 37 bq24157 SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 www.ti.com 12 Layout 12.1 Layout Guidelines It is important to pay special attention to the PCB layout. The following provides some guidelines: * To obtain optimal performance, the power input capacitors, connected from input to PGND, should be placed as close as possible to the pin. The output inductor should be placed close to the IC and the output capacitor connected between the inductor and PGND of the IC. The intent is to minimize the current path loop area from the SW pin through the LC filter and back to the PGND pin. To prevent high frequency oscillation problems, proper layout to minimize high frequency current path loop is critical. (See Figure 34.) The sense resistor should be adjacent to the junction of the inductor and output capacitor. Route the sense leads connected across the RSNS back to the IC, close to each other (minimize loop area) or on top of each other on adjacent layers (do not route the sense leads through a high-current path). (See Figure 35.) * Place all decoupling capacitors close to their respective IC pins and close to PGND (do not place components such that routing interrupts power stage currents). All small control signals should be routed away from the high current paths. * The PCB should have a ground plane (return) connected directly to the return of all components through vias (two vias per capacitor for power-stage capacitors, two vias for the IC PGND, one via per capacitor for smallsignal components). A star ground design approach is typically used to keep circuit block currents isolated (high-power/low-power small-signal) which reduces noise-coupling and ground-bounce issues. A single ground plane for this design gives good results. With this small layout and a single ground plane, there is no ground-bounce issue, and having the components segregated minimizes coupling between signals. * The high-current charge paths into VBUS, PMID and from the SW pins must be sized appropriately for the maximum charge current in order to avoid voltage drops in these traces. The PGND pins should be connected to the ground plane to return current through the internal low-side FET. * Place 4.7F input capacitor as close to PMID pin and PGND pin as possible to make high frequency current loop area as small as possible. Place 1F input capacitor as close to VBUS pin and PGND pin as possible to make high frequency current loop area as small as possible (see Figure 36). L1 VBUS SW R1 V BAT High Frequency BAT V IN PMID C1 Current Path PGND C3 C2 Figure 34. High Frequency Current Path 38 Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 bq24157 www.ti.com SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 12.2 Layout Example Charge Current Direction R SNS To Inductor To Capacitor and battery Current Sensing Direction To CSIN and CSOUT pin Figure 35. Sensing Resistor PCB Layout VBUS PMID SW Vin+ 1F Vin- 4.7F PGND Figure 36. Input Capacitor Position and PCB Layout Example Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 39 bq24157 SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 www.ti.com 13 Device and Documentation Support 13.1 Documentation Support 13.1.1 Third-Party Products Disclaimer TI'S PUBLICATION OF INFORMATION REGARDING THIRD-PARTY PRODUCTS OR SERVICES DOES NOT CONSTITUTE AN ENDORSEMENT REGARDING THE SUITABILITY OF SUCH PRODUCTS OR SERVICES OR A WARRANTY, REPRESENTATION OR ENDORSEMENT OF SUCH PRODUCTS OR SERVICES, EITHER ALONE OR IN COMBINATION WITH ANY TI PRODUCT OR SERVICE. 13.2 Receiving Notification of Documentation Updates To receive notification of documentation updates, navigate to the device product folder on ti.com. In the upper right corner, click on Alert me to register and receive a weekly digest of any product information that has changed. For change details, review the revision history included in any revised document. 13.3 Community Resources The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of Use. TI E2ETM Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help solve problems with fellow engineers. Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and contact information for technical support. 13.4 Trademarks E2E, NanoFree are trademarks of Texas Instruments. I2C is a trademark of NXP B.V. Corporation. 13.5 Electrostatic Discharge Caution 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. 13.6 Glossary SLYZ022 -- TI Glossary. This glossary lists and explains terms, acronyms, and definitions. 14 Mechanical, Packaging, and Orderable Information The following pages include mechanical, packaging, and orderable information. This information is the most current data available for the designated devices. This data is subject to change without notice and revision of this document. For browser-based versions of this data sheet, refer to the left-hand navigation. 40 Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 bq24157 www.ti.com SLUSB80E - SEPTEMBER 2012 - REVISED JANUARY 2018 14.1 Package Summary CHIP SCALE PACKAGE (Top Side Symbol For bq24157) WCSP PACKAGE (Top View) TIYMLLLLS bq24157A A1 A2 A3 A4 B1 B2 B3 B4 C1 C2 C3 C4 D1 D2 D3 D4 E1 E2 E3 E4 D E 0-Pin A1 Marker, TI-TI Letters, YM- Year Month Date Code, LLLL-Lot Trace Code, S-Assembly Site Code 14.1.1 Chip Scale Packaging Dimensions The bq24157 device is available in a 20-bump chip scale package (YFF, NanoFreeTM). The package dimensions are: D E Max = 2.17mm Max = 2.03 mm Min = 2.11 mm Min = 1.97 mm Submit Documentation Feedback Copyright (c) 2012-2018, Texas Instruments Incorporated Product Folder Links: bq24157 41 PACKAGE OPTION ADDENDUM www.ti.com 18-Dec-2017 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish MSL Peak Temp (2) (6) (3) Op Temp (C) Device Marking (4/5) BQ24157YFFR ACTIVE DSBGA YFF 20 3000 Green (RoHS & no Sb/Br) SNAGCU Level-1-260C-UNLIM BQ24157A BQ24157YFFT ACTIVE DSBGA YFF 20 250 Green (RoHS & no Sb/Br) SNAGCU Level-1-260C-UNLIM BQ24157A (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) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based flame retardants must also meet the <=1000ppm threshold requirement. (3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. (5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Device Marking for that device. (6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish value exceeds the maximum column width. 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. 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. Addendum-Page 1 Samples PACKAGE OPTION ADDENDUM www.ti.com 18-Dec-2017 Addendum-Page 2 PACKAGE MATERIALS INFORMATION www.ti.com 18-Dec-2017 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) BQ24157YFFR DSBGA YFF 20 3000 180.0 8.4 BQ24157YFFT DSBGA YFF 20 250 180.0 8.4 Pack Materials-Page 1 B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant 2.2 2.35 0.8 4.0 8.0 Q1 2.2 2.35 0.8 4.0 8.0 Q1 PACKAGE MATERIALS INFORMATION www.ti.com 18-Dec-2017 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) BQ24157YFFR DSBGA YFF 20 3000 182.0 182.0 20.0 BQ24157YFFT DSBGA YFF 20 250 182.0 182.0 20.0 Pack Materials-Page 2 D: Max = 2.172 mm, Min =2.112 mm E: Max = 2.03 mm, Min = 1.97 mm IMPORTANT NOTICE Texas Instruments Incorporated (TI) reserves the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. 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