Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsPMICsPMIC - battery management Charge management LiFePO4 VQFN 16 Exposed Pad (3.5x3.5) Surface-

16 15 14 13

5 6 7 8

VCC

STAT

ISET

VREF

VFB

SRN

SRP

GND

LODRV

REGN

HIDRV

BTST

OAR

(bq24620)

QFN-16

TOP VIEW

bq24620

www.ti.com

SLUS893A –MARCH 2010– REVISED OCTOBER 2011

Stand-Alone Synchronous Switch-Mode Lithium Phosphate Battery Charger With Low I

Check for Samples: bq24620

FEATURES

APPLICATIONS

• 300-kHz NMOS-NMOS Synchronous Buck • Power Tool and Portable Equipment

Converter

• Personal Digital Assistants

• Stand-Alone Charger Designed Specifically for

• Handheld Terminals

Lithium Phosphate

• Industrial and Medical Equipment

• 5-V–28-V VCC Operating Range, Supports 1–7

• Netbook, Mobile Internet Device, and

Battery Cells

Ultramobile PC

• High-Accuracy Voltage and Current Regulation

– ±0.5% Charge Voltage Accuracy DESCRIPTION

The bq24620 is a highly integrated switch-mode

– ±3% Charge Current Accuracy

battery charge controller designed specifically for

• Integration

lithium phosphate batteries. It offers a

– Internal Loop Compensation

constant-frequency synchronous PWM controller with

high-accuracy current and voltage regulation, charge

– Internal Soft Start

preconditioning, termination, and charge status

• Safety

monitoring.

– Input Overvoltage Protection

The bq24620 charges the battery in three phases:

– Battery Thermistor Sense Suspend Charge

preconditioning, constant-current, and

at Hot/Cold Charge Suspend and

constant-voltage. Charge is terminated when the

Automatically I

CHARGE

/8 at WARM/COOL

current reaches a minimum level. An internal charge

– Battery Detection

timer provides a safety backup. The bq24620

automatically restarts the charge cycle if the battery

– Built-In Safety Timer

voltage falls below an internal threshold, and enters a

– Charge Overcurrent Protection

low-quiescent-current sleep mode when the input

– Battery Short Protection

voltage falls below the battery voltage.

– Battery Overvoltage Protection

– Thermal Shutdown

PACKAGE

• Status Outputs

– Adapter Present

– Charger Operation Status

• Charge Enable Pin

• 6-V Gate Drive for Synchronous Buck

Converter

• 30-ns Driver Dead Time and 99.95% Max.

Effective Duty Cycle

• 16-Pin 3.5-mm × 3.5-mm QFN Package

• Energy Star Low Iq

– < 15-μA Off-State Battery Discharge Current

– < 1.5-mA Off-State Input Quiescent Current

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 (35 pages)

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bq24620 SLUS893A – MARCH 2010 – REVISED OCTOBER 2011 www.ti.com Stand-Alone Synchronous Switch-Mode Lithium Phosphate Battery Charger With Low Iq Check for Samples: bq24620 FEATURES APPLICATIONS • • • • • • • • • • • LODRV PACKAGE 16 15 14 13 12 REGN VCC 1 CE OAR (bq24620) 2 11 GND QFN-16 TOP VIEW STAT 3 10 SRP TS 4 9 5 6 7 8 VFB • The bq24620 charges the battery in three phases: preconditioning, constant-current, and constant-voltage.
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bq24620 SLUS893A – MARCH 2010 – REVISED OCTOBER 2011 www.ti.com This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure.
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bq24620 SLUS893A – MARCH 2010 – REVISED OCTOBER 2011 www.ti.com THERMAL INFORMATION bq24620 THERMAL METRIC (1) VAR UNIT 16 PINS Junction-to-ambient thermal resistance (2) θJA (3) 43.8 °C/W θJCtop Junction-to-case (top) thermal resistance 81 °C/W θJB Junction-to-board thermal resistance (4) 16 °C/W ψJT Junction-to-top characterization parameter (5) 0.6 °C/W 15.
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bq24620 SLUS893A – MARCH 2010 – REVISED OCTOBER 2011 www.ti.com RECOMMENDED OPERATING CONDITIONS VALUE UNIT –0.3 to 28 V PH –2 to 30 V VFB –0.3 to 14 V REGN, LODRV, TS –0.3 to 6.5 V BTST, HIDRV with respect to GND –0.3 to 34 V ISET –0.3 to 3.3 V 3.3 V VCC, SRP, SRN, CE, STAT, PG Voltage range VREF Maximum difference voltage SRP–SRN –0.2 to 0.
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bq24620 SLUS893A – MARCH 2010 – REVISED OCTOBER 2011 www.ti.com ELECTRICAL CHARACTERISTICS 5 V ≤ VVCC ≤ 28 V, 0°C < TJ< 125°C, typical values are at TA= 25°C, with respect to GND unless otherwise noted PARAMETER TEST CONDITIONS MIN TYP MAX UNIT OPERATING CONDITIONS VVCC_OP VCC input voltage operating range 5 28 V 15 μA QUIESCENT CURRENTS Total battery discharge current (sum of currents into VCC, BTST, PH, SRP, SRN, VFB), VFB ≤ 2.
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bq24620 SLUS893A – MARCH 2010 – REVISED OCTOBER 2011 www.ti.com ELECTRICAL CHARACTERISTICS (continued) 5 V ≤ VVCC ≤ 28 V, 0°C < TJ< 125°C, typical values are at TA= 25°C, with respect to GND unless otherwise noted PARAMETER SLEEP falling powerup deglitch TEST CONDITIONS MIN VCC rising above SRN, Delay to come out of SLEEP mode TYP MAX 30 UNIT ms BAT LOWV COMPARATOR VLOWV LOWV rising threshold (precharge to fast charge) VLOWV_HYS LOWV hysteresis Measured on VFB pin 0.333 0.35 0.
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bq24620 SLUS893A – MARCH 2010 – REVISED OCTOBER 2011 www.ti.com ELECTRICAL CHARACTERISTICS (continued) 5 V ≤ VVCC ≤ 28 V, 0°C < TJ< 125°C, typical values are at TA= 25°C, with respect to GND unless otherwise noted PARAMETER TEST CONDITIONS MIN TYP MAX UNIT CHARGE OVERCURRENT COMPARATOR (CYCLE-BY-CYCLE) Current rising, in non-synchronous mode, measure on V(SRP-SRN), VSRP < 2 V 45.5 Current rising, as percentage of V(IREG_CHG), in synchronous mode, VSRP > 2.
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bq24620 SLUS893A – MARCH 2010 – REVISED OCTOBER 2011 www.ti.com ELECTRICAL CHARACTERISTICS (continued) 5 V ≤ VVCC ≤ 28 V, 0°C < TJ< 125°C, typical values are at TA= 25°C, with respect to GND unless otherwise noted PARAMETER TEST CONDITIONS MIN TYP 255 300 MAX UNIT 345 kHz PWM OSCILLATOR VRAMP_HEIGHT PWM ramp height As percentage of VCC 7% PWM switching frequency (2) INTERNAL SOFT START (Eight Steps to Regulation Current ICHARGE) Soft-start steps Soft-start step time 8 step 1.6 ms 1.
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bq24620 SLUS893A – MARCH 2010 – REVISED OCTOBER 2011 www.ti.com TYPICAL CHARACTERISTICS Table 1.
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bq24620 SLUS893A – MARCH 2010 – REVISED OCTOBER 2011 20 V/div www.ti.com LODRV PH 2 A/div 2 A/div 5 V/div 20 V/div HIDRV 5 V/div 5 V/div PH IL LODRV IL t − Time = 200 ns/div t – Time = 200 ns/div Figure 7. Cycle-by-Cycle Synchronous to Nonsynchronous 5 V/div 10 V/div 20 V/div Figure 6. Continuous-Conduction-Mode Switching Waveform 2 A/div 2 A/div PH 10 V/div 10 V/div IL VBAT PH LDRV IL VBAT t – Time = 4 ms/div t – Time = 200 ms/div Figure 8. Battery Insertion Figure 9.
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bq24620 SLUS893A – MARCH 2010 – REVISED OCTOBER 2011 www.ti.com PIN FUNCTIONS PIN NO. FUNCTION DESCRIPTION NAME 1 VCC IC power positive supply. Connect through a 10-Ω resistor to the common-source (diode-OR) point: source of high-side P-channel MOSFET and source of reverse-blocking power P-channel MOSFET. Or connect through a 10-Ω resistor to the cathode of the input diode. Place a 1-μF ceramic capacitor from VCC to GND pin close to the IC. 2 CE Charge-enable active-HIGH logic input.
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bq24620 SLUS893A – MARCH 2010 – REVISED OCTOBER 2011 www.ti.com BLOCK DIAGRAM bq24620 VREF VOLTAGE REFERENCE VREF 3.3 V LDO VCC - SRN +100 mV + SLEEP UVLO VCC VCC - V UVLO + SLEEP UVLO VCC CE 1M COMP ERROR AMPLIFIER BTST CE + + 1V + LEVEL SHIFTER - 1.8 V PWM - VFB 20 mA SRP + SRP-SRN SYNCH PH - IBAT_ REG SRN 5 mV VCC - 20XV(SRP-SRN) PWM CONTROL LOGIC + - + + 20 X - BTST _ 20 mA PH 6V LDO REFRESH + ENA _BIAS 4.
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bq24620 SLUS893A – MARCH 2010 – REVISED OCTOBER 2011 www.ti.
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bq24620 SLUS893A – MARCH 2010 – REVISED OCTOBER 2011 www.ti.com DETAILED DESCRIPTION Regulation Voltage V RECH Regulation Current Precharge Current Regulation Phase Fastcharge Current Regulation Phase Fastcharge Voltage Regulation Phase Termination Charge Current Charge Voltage V LOWV I PRECH & I TERM Precharge Time Fastcharge Safety Time Figure 11. Typical Charging Profile BATTERY VOLTAGE REGULATION The bq24620 uses a high-accuracy voltage band gap and regulator for the charging voltage.
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bq24620 SLUS893A – MARCH 2010 – REVISED OCTOBER 2011 www.ti.com PRECHARGE On power up, if the battery voltage is below the VLOWV threshold, the bq24620 applies 125 mA to the battery. (1) The precharge feature is intended to revive deeply discharged cells. If the VLOWV threshold is not reached within 30 minutes of initiating precharge, the charger turns off and a FAULT is indicated on the status pins.
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bq24620 SLUS893A – MARCH 2010 – REVISED OCTOBER 2011 www.ti.com AUTOMATIC INTERNAL SOFT-START CHARGER CURRENT The charger automatically soft-starts the charger regulation current every time the charger goes into fast-charge to ensure there is no overshoot or stress on the output capacitors or the power converter. The soft-start consists of stepping up the charge regulation current into eight evenly divided steps up to the programmed charge current. Each step lasts around 1.
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bq24620 SLUS893A – MARCH 2010 – REVISED OCTOBER 2011 www.ti.com At very low currents during non-synchronous operation, there may be a small amount of negative inductor current during the 80-ns recharge pulse. The charge should be low enough to be absorbed by the input capacitance. Whenever the converter goes into zero-percent duty cycle, the high-side MOSFET does not turn on, and the low-side MOSFET does not turn on (only 80-ns recharge pulse) either, and there is almost no discharge from the battery.
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bq24620 SLUS893A – MARCH 2010 – REVISED OCTOBER 2011 www.ti.com charge and the safety timer and waits until the battery temperature is within the VLTF to VHTF range. If the battery temperature is between the VLTF and VCOOL thresholds or between the VHTF and VWARM thresholds, charge is automatically reduced to ICHARGE/8. To avoid early termination during COOL/WARM condition, set ITERM ≤ ICHARGE/10. The controller suspends charge by turning off the PWM charge FETs.
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bq24620 SLUS893A – MARCH 2010 – REVISED OCTOBER 2011 www.ti.com æ 1 ö 1 VVREF ´ RTHCOOL ´ RTHWARM ´ ç ÷ V V WARM ø è COOL RT2 = æV ö æ V ö RTHWARM ´ ç VREF - 1÷ - RTHCOOL ´ ç VREF - 1÷ è VWARM ø è VCOOL ø (5) VVREF -1 VCOOL RT1 = 1 1 + RT2 RTHCOOL (6) VREF bq24620 RT1 TS RT2 RTH 103AT Figure 14. TS Resistor Network For example, a 103AT NTC thermistor is used to monitor the battery pack temperature. Select TCOOL = 0ºC, TWARM = 60ºC.
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bq24620 SLUS893A – MARCH 2010 – REVISED OCTOBER 2011 www.ti.com CE (Charge Enable) The CE digital input is used to disable or enable the charge process. A high-level signal on this pin enables charge, provided all the other conditions for charge are met (see Enable and Disable Charging, ENABLE AND DISABLE CHARGING). A high-to-low transition on this pin also resets all timers and fault conditions. There is an internal 1-MΩ pulldown resistor on the CE pin, so if CE is floatedthe charge does not turn on.
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bq24620 SLUS893A – MARCH 2010 – REVISED OCTOBER 2011 www.ti.com BATTERY DETECTION For applications with removable battery packs, the bq24620 provides a battery-absent detection scheme to reliably detect insertion or removal of battery packs. CE must be HIGH to enable battery detection function.
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bq24620 SLUS893A – MARCH 2010 – REVISED OCTOBER 2011 www.ti.com Battery not Detected V REG V RECH Battery Inserted V LOWV Battery Detected t LOWV_ DEG tWAKE t RECH _ DEG Figure 16. Battery-Detect Timing Diagram Care must be taken that the total output capacitance at the battery node is not so large that the discharge current source cannot pull the voltage below the LOWV threshold during the 1-second discharge time.
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bq24620 SLUS893A – MARCH 2010 – REVISED OCTOBER 2011 www.ti.com Component List for Typical System Circuit of Figure 1 PART DESIGNATOR QTY DESCRIPTION Q4, Q5 2 N-channel MOSFET, 40 V, 30 A, PowerPAK SO-8, Vishay-Siliconix, SiR426DN D1 1 Diode, dual Schottky, 30 V, 200 mA, SOT23, Fairchild, BAT54C D2 1 Schottky diode, 40 V, 5 A, SMC, ON Semiconductor, MBRS540T3 RSR 2 Sense resistor, 10 mΩ, 1%, 1 W, 2010, Vishay-Dale, WSL2010R0100F L1 1 Inductor, 6.8 μH, 5.
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bq24620 SLUS893A – MARCH 2010 – REVISED OCTOBER 2011 www.ti.com APPLICATION INFORMATION Inductor Selection The bq24620 has a 300-kHz switching frequency to allow the use of small inductor and capacitor values.
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bq24620 SLUS893A – MARCH 2010 – REVISED OCTOBER 2011 www.ti.com Power MOSFET Selection Two external N-channel MOSFETs are used for a synchronous switching battery charger. The gate drivers are internally integrated into the IC with 6 V of gate drive voltage. 30-V or higher voltage rating MOSFETs are preferred for 20-V input voltage, and 40-V MOSFETs are preferred for 20-V to 28-V input voltage.
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bq24620 SLUS893A – MARCH 2010 – REVISED OCTOBER 2011 www.ti.com PVREF = (VIN - VVREF ) × IVREF PICLOSS = PICLOSS _ driver + PVREF + PQuiescent (22) Input Filter Design During adapter hot plug-in, the parasitic inductance and input capacitor from the adapter cable form a second-order system. The voltage spike at the VCC pin may be beyond the IC maximum voltage rating and damage the IC. The input filter must be carefully designed and tested to prevent an overvoltage event on VCC pin.
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bq24620 SLUS893A – MARCH 2010 – REVISED OCTOBER 2011 www.ti.com charger power ground to the charger analog ground. Just beneath the IC, use the copper pour for analog ground, but avoid power pins to reduce inductive and capacitive noise coupling. Connect analog ground to GND. Connect the analog ground and power ground together using the thermal pad as the single ground connection point. Or using a 0-Ω resistor to tie analog ground to power ground (the thermal pad should tie to analog ground in this case).
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bq24620 SLUS893A – MARCH 2010 – REVISED OCTOBER 2011 www.ti.com REVISION HISTORY Changes from Revision Original (March 2010) to Revision A Page • Replaced Thermal Information table ..................................................................................................................................... 3 • Changed description for PH and BTST pins .......................................................................................................................
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE MATERIALS INFORMATION www.ti.com 26-Jan-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant BQ24620RVAR VQFN RVA 16 3000 330.0 12.4 3.75 3.75 1.15 8.0 12.0 Q1 BQ24620RVAT VQFN RVA 16 250 180.0 12.4 3.75 3.75 1.15 8.0 12.
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PACKAGE MATERIALS INFORMATION www.ti.com 26-Jan-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) BQ24620RVAR VQFN RVA 16 3000 367.0 367.0 35.0 BQ24620RVAT VQFN RVA 16 250 210.0 185.0 35.
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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.