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  • RT9511

    1DS9511-01 April 2011 www.richtek.com

    Fully Integrated Battery Charger with TwoStep-Down ConvertersGeneral DescriptionThe RT9511 is a fully integrated low cost solution with asingle-cell Li-Ion battery charger and two high efficiencystep-down DC/DC converters ideal for portableapplications.

    The Battery Charger is capable of being powered up fromAC adapter and USB (Universal Serial Bus) port inputswhich can automatically detect and select the AC adapterand the USB port as the power source for the charger.The Battery Charger enters sleep mode when bothsupplies are removed. The Battery Charger optimizes thecharging task by using a control algorithm includingpreconditioning mode, fast charge mode and constantvoltage mode. The charging task is terminated as thecharge current drops below the preset threshold. The USBcharge current can be selected from preset ratings100mAand 500mA, while the AC adapter charge current can beprogrammed up to 1A with an external resister. The internalthermal feedback circuitry regulates the die temperatureto optimize the charge rate for all ambient temperatures.The Battery Charger features 18V and 7V maximum ratingvoltages for AC adapter and USB port inputs respectively.The other features are external programmed safety timer,under voltage protection, over voltage protection for ACadapter supply, battery temperature monitoring and chargestatus indicator.

    The high-efficiency step-down DC/DC converter is capableof delivering 1A output current over a wide input voltagerange from 2.5V to 5.5V, the step-down DC/DC converteris ideally suited for portable electronic devices that arepowered from 1-cell Li-ion battery or from other powersources such as cellular phones, PDAs and hand-helddevices. Two operating modes are available including :PWM/Low-Dropout autoswitch and shut-down modes. TheInternal synchronous rectifier with low RDS(ON) dramaticallyreduces conduction loss at PWM mode. No externalSchottky diode is required in practical application.

    The RT9511 is available in a WQFN -24L 4x4 package.

    FeaturesBattery Charger Automatic Input Supplies Selection 18V Maximum Rating for AC Adapter Integrated Selectable 100mA and 500mA USBCharge Current Internal Integrated Power FETs Charge Status Indicator External Capacitor Programmable Safety Timer Under Voltage Protection Over Voltage Protection Automatic Recharge Feature Battery Temperature Monitoring Thermal Feedback Optimizing Charge Rate Power Path Controller

    Step-Down DC/DC Converter Adjustable Output from 0.6V to VIN 1A Output Current 95% Efficiency No Schottky Diode Required 1.5MHz Fixed-Frequency PWM Operation

    Small 24-Lead WQFN PackageRoHS Compliant and Halogen Free

    ApplicationsMP3/MP4 PlayerGPSDigital Photo FrameHand held Device

    Marking InformationFor marking information, contact our sales representativedirectly or through a Richtek distributor located in yourarea.

  • RT9511

    2DS9511-01 April 2011www.richtek.com

    Typical Application Circuit

    Pin Configurations(TOP VIEW)

    WQFN-24L 4x4

    GNDEN1

    VDD1LX1

    GNDFB2

    ISE

    TU

    GN

    DE

    N2

    VD

    D2

    ISE

    TALX2

    BATTTSTIMER

    NC

    SYS

    FB1

    ACIN

    US

    B

    GND

    1

    2

    3

    4

    5

    6

    7 8 9 10 1211

    18

    17

    16

    15

    14

    13

    21 20 1924 2223

    25 EN

    BAT_ON

    AC_O

    N

    CH

    G_S

    Ordering Information

    Note :

    Richtek products are :

    } RoHS compliant and compatible with the current require-

    ments of IPC/JEDEC J-STD-020.

    } Suitable for use in SnPb or Pb-free soldering processes.

    RT9511

    23

    22

    BATT

    TIMER

    SYS

    16

    17

    18

    11

    ACIN

    ISETA

    TS

    15

    19

    20 USB

    +

    Battery Pack

    CT0.1F

    Chip Enable

    1, 5, 7, 25 (Exposed Pad)GND

    14EN

    AC_ON

    CHG_S

    BAT_ON

    1F

    1F

    System

    12 ISETU

    21

    10F

    LX1

    FB1

    2.2HVOUT1

    L1

    24

    4

    COUT1R1

    R2

    C1

    IR210F

    LX2

    FB2

    2.2HVOUT2

    L2

    6

    10

    COUT2R3

    R4

    C2

    IR4

    VDD1

    EN12.5V to 5.5V

    VIN 3

    24.7F

    CIN1

    VDD2

    EN2

    2.5V to 5.5VVIN9

    84.7FCIN2

    VACIN

    VUSBRSETA

    RT9511Package TypeQW : WQFN-24L 4x4 (W-Type)Lead Plating SystemG : Green (Halogen Free and Pb Free)

  • RT9511

    3DS9511-01 April 2011 www.richtek.com

    Functional Pin DescriptionPin No. Pin Name Pin Function 1, 5, 7,

    17 (Exposed Pad) GND

    The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation.

    2 EN1 Chip Enable Input Pin of Buck Converter 1. (Active High)

    3 VDD1 Power Input Pin of Buck Converter 1.

    4 LX1 Switching Output Pin of Buck Converter 1.

    6 FB2 Feedback Voltage Input Pin of Buck Converter 2.

    8 EN2 Chip Enable Input Pin of Buck Converter 2. (Active High)

    9 VDD2 Power Input Pin of Buck Converter 2.

    10 LX2 Switching Output Pin of Buck Converter 2.

    11 ISETA Adaptor Supply Charge Current Set Point.

    12 ISETU USB Supply Charge Current Set Input.

    13 NC No Internal Connection.

    14 EN Charge Enable Input Pin of Charger. (Active Low)

    15 TIMER Safe Charge Timer Setting.

    16 TS Temperature Sense Input.

    17 BATT Battery Charge Current Output.

    18 BAT_ON Power path controller output. This pin is used to turn on an external P-MOSFET.

    19 SYS System Voltage Detector Input Pin.

    20 USB USB Supply Voltage Input Pin.

    21 AC_ON P-MOSFET Switch Control Output (open drain).

    22 ACIN Adaptor Supply Voltage Input Pin.

    23 CHG_S Charge Status Indicator Output. (Open Drain)

    24 FB1 Feedback Voltage Input Pin of Buck Converter 1.

  • RT9511

    4DS9511-01 April 2011www.richtek.com

    Function Block Diagram

    Pre-Charge Phase Fast Charge Phase

    Constant Voltage Phase &

    Standby PhaseRe-Charge Phase

    Programmed Charge Current

    4.1V Recharge Threshold

    2.8V Precharge Threshold

    1/10 Programmed Charge Current

    Charge Complete

    Battery Voltage

    Charging Current

    Figure 1 . Charging I-V Curve

    Charge Input Selection

    ACIN/USB

    ACIN

    ISETABATT

    ACINP-MOSFETSENSEMOSFET

    Loop Controller

    TemperatureSense

    Temperature Fault

    TS

    VREF Thermal Sense

    VFB

    DRV

    OVP+-

    2.5V

    OVPComparator

    SYS

    Timer TIMER

    USB Current Setting

    USB

    USBP-MOSFET

    SENSEMOSFET

    GND

    ISETU

    CHG_S

    ENBAT_ON

    AC_ON

    Logic

    EN1FB1

    VDD1

    LX1

    +- Control Logic &

    VREF

    EN2FB2

    VDD2

    LX2

    +- Control Logic &

    VREF

  • RT9511

    5DS9511-01 April 2011 www.richtek.com

    Start-Up Precharge Phase Fast Charge Phase Standby/Fault Recharge Phase

    RT9511 Flow Chart

    DIS

    AB

    LEU

    VP

    SLE

    EP

    Sta

    rt-U

    p

    ACIN/USB Power Up

    V/CE > 1.4V ?

    NO

    NO

    VACIN < 4.3Vand

    VUSB < 3.9V?

    DISABLE MODE

    PFET OFFIBATT = 0

    YES

    UVP MODEPFET OFFIBATT = 0

    YES

    VACIN < VBATTand

    VUSB < VBATT?

    SLEEP MODEPFET OFFIBATT = 0

    YES

    VBATT > 2.8V?

    NO

    IBATT = 0.1 Charge Current

    /CHG_S Strong Pull Down

    NO

    ? TCHARGE UP?

    1ms Delay &

    Start Timer

    VBATT > 2.8V?

    NO

    IBATT = Charge Current

    /CHG_S Strong Pull Down

    YES

    YES

    YES

    NO

    VTS > 2.5Vor

    VTS < 0.5V?

    TIME FAULT

    IBATT < 0.1 ICHG?

    YES

    TCHARGE UP?

    NO

    NO

    YES

    STANDBYPFET OFFIBATT = 0

    YES

    TEMP FAULT

    YES

    /CHG_S HIGH IMPEDANCE

    VBATT > 4.1 V?

    YES

    VBATT > 4.1 V?

    NO

    RECHARGE

    YES

    NO

    OVP MODENO

    RT9511 Flow Chart

  • RT9511

    6DS9511-01 April 2011www.richtek.com

    Absolute Maximum Ratings (Note 1)l Supply Input Voltage, ACIN -------------------------------------------------------------------------------------------- 0.3V to 18Vl Supply Input Voltage, USB -------------------------------------------------------------------------------------------- 0.3V to 7Vl Supply Input Voltage, EN1, EN2, FB1, FB2 ----------------------------------------------------------------------- 0.3V to 6Vl VDD1, VDD2 -------------------------------------------------------------------------------------------------------------- 6.5Vl Power Dissipation, PD @ TA = 25C

    WQFN-24L 4x4 ----------------------------------------------------------------------------------------------------------- 1.923Wl Package Thermal Resistance (Note 2)

    WQFN-24L 4x4, JA ----------------------------------------------------------------------------------------------------- 52C/WWQFN-24L 4x4, JC ----------------------------------------------------------------------------------------------------- 7C/W

    l Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------ 260Cl Junction Temperature --------------------------------------------------------------------------------------------------- 150Cl Storage Temperature Range ------------------------------------------------------------------------------------------- 65C to 150Cl ESD Susceptibility (Note 3)

    HBM (Human Body Mode) --------------------------------------------------------------------------------------------- 2kVMM (Machine Mode) --------------

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