Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsPMICsPMIC - battery management Charge management, Power management Li-Ion, Li-Po VQFN 24 (4x4)

SYS

BAT

DRV

PGND

BYP

/CE

BOOT

HOST

PMID

System

Load

TEMP

PACK+

PACK–

VBUS

D+

D–

GND

/PG/CHG

ILIM

ISET

VDPM

–

DRV_SDRV_S

bq24278

www.ti.com

SLUSB04 –JUNE 2012

2.5A, Single Input, Single Cell Switchmode Li-Ion BATTERY CHARGER with Power Path

Management

Check for Samples: bq24278

FEATURES

• Thermal Regulation Protection for Output

Current Control

• High-Efficiency Switch Mode Charger with

• Low Battery Leakage Current, BAT Short-

Separate Power Path Control

Circuit Protection

– Instantly Startup System from a Deeply

• Soft-Start feature to reduce inrush current

Discharged Battery or No Battery

• Thermal Shutdown and Protection

• 20V input rating, with 10.5V Over-Voltage

Protection (OVP)

• Available in small 49-ball WCSP or QFN-24

packages

• Integrated FETs for Up to 2.5A Charge Rate

• Highly Integrated Battery N-Channel MOSFET

APPLICATIONS

Controller for Power Path Management

• Handheld Products

• Safe and accurate Battery Management

Functions • Portable Media Players

– 0.5% Battery Regulation Accuracy • Portable Equipment

– 10% Charge Current Accuracy • Netbook and Portable Internet Devices

• Voltage-based, NTC Monitoring Input (TS)

– Standard Temp Range

APPLICATION SCHEMATIC

DESCRIPTION

The bq24278 highly integrated single cell Li-Ion battery charger and system power path management device

targeted for space-limited, portable applications with high capacity batteries. The single cell charger operates

from a dedicated charging source such as an AC adapter or Wireless Power.

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

Summary of content (30 pages)

PAGE 1
bq24278 www.ti.com SLUSB04 – JUNE 2012 2.5A, Single Input, Single Cell Switchmode Li-Ion BATTERY CHARGER with Power Path Management Check for Samples: bq24278 FEATURES • 1 • • • • • • High-Efficiency Switch Mode Charger with Separate Power Path Control – Instantly Startup System from a Deeply Discharged Battery or No Battery 20V input rating, with 10.5V Over-Voltage Protection (OVP) Integrated FETs for Up to 2.
PAGE 2
bq24278 SLUSB04 – JUNE 2012 www.ti.com These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. DESCRIPTION (CONTINUED) The power path management feature allows the bq24278 to power the system from a high efficiency DC to DC converter while simultaneously and independently charging the battery.
PAGE 3
bq24278 www.ti.com SLUSB04 – JUNE 2012 THERMAL INFORMATION bq24278 THERMAL METRIC (1) YFF (48 PINS) QFN (24 PINS) θJA Junction-to-ambient thermal resistance 49.8 32.6 θJCtop Junction-to-case (top) thermal resistance 0.2 30.5 θJB Junction-to-board thermal resistance 1.1 3.3 ψJT Junction-to-top characterization parameter 1.1 0.4 ψJB Junction-to-board characterization parameter 6.6 9.3 θJCbot Junction-to-case (bottom) thermal resistance N/A 2.
PAGE 4
bq24278 SLUSB04 – JUNE 2012 www.ti.com ELECTRICAL CHARACTERISTICS (continued) Circuit of Figure 2, VUVLO < VIN < VOVP AND VIN>VBAT+VSLP, TJ = 0°C–125°C and TJ = 25°C for typical values (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX YFF pkg 37 57 RGE pkg 50 70 UNIT BATTERY CHARGER RON(BAT-SYS) VBATREG Measured from BAT to SYS, VBAT = 4.2 V Internal battery charger MOSFET on-resistance Battery regulation voltage mΩ TA = 25°C 4.179 4.2 4.221 VWARM < VTS < VCOOL 4.
PAGE 5
bq24278 www.ti.
PAGE 6
bq24278 SLUSB04 – JUNE 2012 www.ti.com BLOCK DIAGRAM PMID BYP 5.2V Reference DRV IN 5A + BOOT CbC Current Limit IN IINLIM ILIM Q1 IN VINDPM DC-DC CONVERTER PWM LOGIC, COMPENSATION AND BATTERY FET CONTROL VSYS(REG) IBAT (REG) VBAT (REG) SW DIE Temp Regulation Q2 PGND SYS VSUPPLY DRV_S References ISET V INOVP 10% of ICHARGE + OVP Comparator + V IN Termination Comparator Q3 IBAT BAT Recharge Comparator V IN V BAT +V SLP Start Recharge Cycle + + V BATREG – 0.
PAGE 7
bq24278 www.ti.
PAGE 8
bq24278 SLUSB04 – JUNE 2012 www.ti.com PIN FUNCTIONS PIN NAME NUMBER I/O DESCRIPTION YFF RGE IN A1-A4 21 I Input power supply. IN is connected to the external DC supply (AC adapter or alternate power source). Bypass IN to PGND with at least a 1μF ceramic capacitor. AGND A5-A7 22 I Ground terminal. Connect to the thermal pad (for QFN only) and the ground plane of the circuit. PMID B1-B4 20 O Reverse Blocking MOSFET and High Side MOSFET Connection Point for High Power Input.
PAGE 9
bq24278 www.ti.com SLUSB04 – JUNE 2012 TYPICAL APPLICATION CIRCUIT SW VBUS IN PMID D– System Load 0.01 μF D+ BOOT GND 1 μF 4.7 μF SYS PGND VDPM 10 μF ILIM BGATE BAT BYP V DRV 0.1 μF 1 μF GND TS DRV PACK+ TEMP HOST DRV_S 1 μF + – DRV_S ISET PACK– /PG /CHG bq24278 CD GPIO CE GPIO Figure 1.
PAGE 10
bq24278 SLUSB04 – JUNE 2012 www.ti.com DETAILED DESCRIPTION The bq24278 is a highly integrated single cell Li-Ion battery charger and system power path management devices targeted for space-limited, portable applications with high capacity batteries. The power path management feature allows the bq24278 to power the system from a high efficiency DC to DC converter while simultaneously and independently charging the battery.
PAGE 11
bq24278 www.ti.com SLUSB04 – JUNE 2012 PWM Controller in Charge Mode The bq24278 provides an integrated, fixed 1.5 MHz frequency voltage-mode controller with to power the system and supply the charge current. The converter is internally compensated and provides enough phase margin for stable operation, allowing the use of small ceramic capacitors with very low ESR. The bq24278 input scheme prevents battery discharge when the supply voltage is lower than VBAT.
PAGE 12
bq24278 SLUSB04 – JUNE 2012 www.ti.com Battery Detection When termination conditions are met, a battery detection cycle is started. During battery detection, IDETECT is pulled from VBAT for tDETECT to verify there is a battery. If the battery voltage remains above VDETECT for the full duration of tDETECT, a battery is determined to be present and the IC enters “Charge Done”. If VBAT falls below VDETECT, a “Battery Not Present” fault is signaled and battery detection continues.
PAGE 13
bq24278 www.ti.com SLUSB04 – JUNE 2012 2000mA 1800mA IOUT 800mA 0mA 1500mA IIN ~850mA 0mA 1A IBAT 0mA -200mA 3.7V 3.5V DPPM loop active VOUT ~3.1V Supplement Mode Figure 3. Example DPPM Response (VSupply=5V, VBAT = 3.1V, 1.5A Input current limit) If the VBAT(REG) threshold is ever less than the battery voltage, the battery FET is turned off to allow the battery to relax down to VBAT(REG) and the SYS output is regulated to VSYSREG(FETOFF).
PAGE 14
bq24278 SLUSB04 – JUNE 2012 www.ti.com Battery Discharge FET (BGATE) The bq24278 contains a MOSFET driver to drive an external P-Channel MOSFET between the battery and the system output. This external FET provides a low impedance path for supply the system from the battery. Connect BGATE to the gate of the external discharge MOSFET. BGATE is on under the following conditions: 1. No valid input supply connected. 2.
PAGE 15
bq24278 www.ti.com SLUSB04 – JUNE 2012 VDRV DISABLE TS COLD + VDRV TS HOT RHI + TS PACK + TEMP bq24278 RLO PACK - Figure 4. TS Circuit 1.0 °C 0.5 °C Portion of spec not covered by TS Implementation on bq 24278 4.25 V 4.15 V 4.1 V T1 (0°C) T2 (10°C) T3 T4 (45°C) (50°C) T5 (60°C) Figure 5.
PAGE 16
bq24278 SLUSB04 – JUNE 2012 www.ti.com é 1 1 ù VDRV ´ RCOLD ´ RHOT ´ ê ú V V ë COLD HOT û RLO = éV ù é V ù RHOT ´ ê DRV - 1ú - RCOLD ´ ê DRV - 1ú ë VHOT û ë VCOLD û (3) VDRV -1 VCOLD RHI = 1 1 + RLO RCOLD (4) Where: VCOLD = 0.60 × VDRV VHOT = 0.30 × VDRV Where RHOT is the NTC resistance at the hot temperature and RCOLD is the NTC resistance at cold temperature. The WARM and COOL thresholds are not independently programmable.
PAGE 17
bq24278 www.ti.com SLUSB04 – JUNE 2012 Figure 6. bq24278 VIN-DPM The VINDPM threshold for the IN input is set using a resistor divider with VDPM connected to the center tap. Select 10kΩ for the bottom resistor. The top resistor is selected using Equation 7: RTOP = 10kW ´ ( VINDPM - VDPM ) VDPM (7) Where VINDPM is the desired VINDPM threshold and VDPM is the regulation threshold specified in the Electrical Characteristics table.
PAGE 18
bq24278 SLUSB04 – JUNE 2012 www.ti.com The CHG output indicates new charge cycles. When a new charge cycle is initiated by CE, toggling High Impedance mode or toggling the input power, CHG goes low and remains low until termination. After termination, CHG remains high impedance until a new charge cycle is initiated. CHG does not go low during recharge cycles. Table 2 illustrates the CHG behavior under different conditions.
PAGE 19
bq24278 www.ti.com SLUSB04 – JUNE 2012 APPLICATION INFORMATION Output Inductor and Capacitor Selection Guidelines When selecting an inductor, several attributes must be examined to find the right part for the application. First, the inductance value should be selected. The bq24278 is designed to work with 1.5µH to 2.2µH inductors. The chosen value will have an effect on efficiency and package size. Due to the smaller current ripple, some efficiency gain is reached using the 2.
PAGE 20
bq24278 SLUSB04 – JUNE 2012 www.ti.com PCB Layout Guidelines It is important to pay special attention to the PCB layout. Figure 7 provides a sample layout for the high current paths of the bq24278. GND PMID BYP BOOT SW PGND ILIM ISET SYS SYS BAT (RGE Package) Figure 7. Recommended bq24278 PCB Layout for RGE Device IN PMID GND SW SW PGND BOOT ILIM SYS BAT ISET PGND SW SYS (YFF Package) Figure 8.
PAGE 21
bq24278 www.ti.com • • SLUSB04 – JUNE 2012 also recommended to put vias inside the PGND pads for the IC, if possible. A star ground design approach is typically used to keep circuit block currents isolated (high-power/low-power small-signal) which reduces noisecoupling and ground-bounce issues. A single ground plane for this design gives good results.
PAGE 22
PACKAGE OPTION ADDENDUM www.ti.
PAGE 23
PACKAGE OPTION ADDENDUM www.ti.
PAGE 24
PACKAGE MATERIALS INFORMATION www.ti.com 24-Aug-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device BQ24278RGER Package Package Pins Type Drawing VQFN RGE 24 BQ24278RGET VQFN RGE BQ24278YFFR DSBGA YFF BQ24278YFFT DSBGA YFF SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant 3000 330.0 12.4 4.25 4.25 1.15 8.0 12.0 Q2 24 250 180.0 12.4 4.25 4.25 1.15 8.0 12.0 Q2 49 3000 180.0 8.4 2.93 2.93 0.81 4.0 8.
PAGE 25
PACKAGE MATERIALS INFORMATION www.ti.com 24-Aug-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) BQ24278RGER VQFN RGE 24 3000 367.0 367.0 35.0 BQ24278RGET VQFN RGE 24 250 210.0 185.0 35.0 BQ24278YFFR DSBGA YFF 49 3000 182.0 182.0 17.0 BQ24278YFFT DSBGA YFF 49 250 182.0 182.0 17.
PAGE 26
PAGE 27
PAGE 28
PAGE 29
PAGE 30
IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve 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. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.