Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsPMICsPMIC - battery management Charge management VRLA, LiFePO4, Li-Ion, Li-Po VQFN 16 Exposed P

VCC

MPPSET

STAT1

BTST

HIDRV

LODRV

REGN

GND

SRP

SRN

VFB

VREF

STAT2

bq24650

5 6 7 8

1314

1516

TERM_EN

PAS

bq24650

www.ti.com

SLUSA75 –JULY 2010

Synchronous Switch-Mode Battery Charge Controller for Solar Power

With Maximum Power Point Tracking

Check for Samples: bq24650

FEATURES

DESCRIPTION

• Maximum Power Point Tracking (MPPT)

Capability by Input Voltage Regulation

The bq24650 is a highly integrated switch-mode

battery charge controller. It provides input voltage

• Programmable MPPT Setting

regulation, which reduces charge current when input

• 5V-28V Input Solar Panel

voltage falls below a programmed level. When the

• 600kHz NMOS-NMOS Synchronous Buck

input is powered by a solar panel, the input regulation

Controller

loop lowers the charge current so that the solar panel

can provide maximum power output.

• Resistor Programmable Float Voltage

• Accommodates Li-Ion/Polymer, LiFePO4, Lead

The bq24650 offers a constant-frequency

Acid Chemistries

synchronous PWM controller with high accuracy

current and voltage regulation, charge

• Accuracy

preconditioning, charge termination, and charge

– ±0.5% Charge Voltage Regulation

status monitoring.

– ±3% Charge Current Regulation

The bq24650 charges the battery in three phases:

– ±0.6% Input Voltage Regulation

pre-conditioning, constant current, and constant

• High Integration

voltage. Charge is terminated when the current

reaches 1/10 of the fast charge rate. The pre-charge

– Internal Loop Compensation

timer is fixed at 30 minutes. The bq24650

– Internal Digital Soft Start

automatically restarts the charge cycle if the battery

• Safety

voltage falls below an internal threshold and enters a

low quiescent current sleep mode when the input

– Input Over-Voltage Protection

voltage falls below the battery voltage.

– Battery Temperature Sensing

The bq24650 supports a battery from 2.1V to 26V

– Battery Absent Detection

with VFB set to a 2.1V feedback reference. The

– Thermal Shutdown

charge current is programmed by selecting an

• Charge Status Outputs for LED or Host

appropriate sense resistor. The bq24650 is available

Processor

in a 16 pin, 3.5×3.5 mm

thin QFN package.

• Charge Enable on MPPSET Pin

• Automatic Sleep Mode for Low Power

Consumption

– <15mA Off-State Battery Discharge Current

• Small 3.5 × 3.5 mm

QFN-16 Package

APPLICATIONS

• Solar Powered Applications

• Remote Monitoring Stations

• Portable Handheld Instruments

• 12V to 24V Automotive Systems

• Current-Limited Power Source

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 (33 pages)

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bq24650 www.ti.
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bq24650 SLUSA75 – JULY 2010 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. TYPICAL APPLICATION Solar Cell Half Panel VIN D1 R6: 10Ω R5 2Ω C1 2.2µF VCC bq24650 VREF C3 R3 1µF 499kΩ R9 5.23kΩ C2 1uF C4:1µF REGN D2 MPPSET Pack Thermistor TS R10 30.
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bq24650 www.ti.com SLUSA75 – JULY 2010 ABSOLUTE MAXIMUM RATINGS over operating free-air temperature range (unless otherwise noted) (1) (2) (3) VALUE VCC, STAT1, STAT2, SRP, SRN Voltage range (with respect to GND) UNIT –0.3 to 33 PH –2 to 36 VFB –0.3 to 16 REGN, LODRV, TS, MPPSET, TERM_EN –0.3 to 7 V BTST, HIDRV with respect to GND –0.3 to 39 VREF –0.3 to 3.6 SRP–SRN –0.5 to 0.
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bq24650 SLUSA75 – JULY 2010 www.ti.com ELECTRICAL CHARACTERISTICS 5.0V ≤ VVCC ≤ 28V, –40°C < TJ + 125°C, typical values are at TA = 25°C, with respect to GND (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNITS OPERATING CONDITIONS VVCC_OP VCC input voltage operating range 5 28 V 15 µA VCC > VBAT, VCC > VUVLO, CE = LOW 5 µA VCC > VBAT, VCC > VVCCLOWV, CE = HIGH, Charge done 5 µA 0.
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bq24650 www.ti.com SLUSA75 – JULY 2010 ELECTRICAL CHARACTERISTICS (continued) 5.0V ≤ VVCC ≤ 28V, –40°C < TJ + 125°C, typical values are at TA = 25°C, with respect to GND (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNITS 1.54 1.55 1.
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bq24650 SLUSA75 – JULY 2010 www.ti.com ELECTRICAL CHARACTERISTICS (continued) 5.0V ≤ VVCC ≤ 28V, –40°C < TJ + 125°C, typical values are at TA = 25°C, with respect to GND (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX 6.0 6.3 UNITS REGN REGULATOR VREGN_REG REGN regulator voltage VVCC > 10 V, MPPSET > 175 mV 5.
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bq24650 www.ti.com SLUSA75 – JULY 2010 TYPICAL CHARACTERISTICS VCC = 25V, bq24650 Application Circuit, TA = 25°C unless otherwise noted MPPSET 1V/div VCC 10V/div LODRV 5V/div VREF 2V/div PH 20V/div REGN 5V/div STAT1 20V/div IBAT 1A/div 400 ms/div 800 ms/div Figure 2. Power Up on VCC Figure 3. Charge Start on MPPSET MPPSET 1V/div MPPSET 1V/div LODRV 5V/div LODRV 5V/div PH 20V/div PH 20V/div IBAT 1A/div IBAT 1A/div 10 ms/div 4 ms/div Figure 4. Charge Soft Start on MPPSET Figure 5.
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bq24650 SLUSA75 – JULY 2010 www.ti.com TYPICAL CHARACTERISTICS (continued) VCC = 25V, bq24650 Application Circuit, TA = 25°C unless otherwise noted HIDRV 20V/div HIDRV 20V/div PH 20V/div PH 20V/div LODRV 5V/div LODRV 5V/div IL 1A/div IL 1A/div 400 ms/div 100 ns/div Figure 8. Switching at 100% Duty Cycle VIN 5V/div MPPT Regulation Point Figure 9. Recharge the BTST-PH Capacitor VIN 20V/div VBAT 5V/div PH 20V/div IBAT 0.5A/div IL 1A/div 10 ms/div 1 s/div Figure 11.
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bq24650 www.ti.com SLUSA75 – JULY 2010 TYPICAL CHARACTERISTICS (continued) VCC = 25V, bq24650 Application Circuit, TA = 25°C unless otherwise noted 100 95 Efficiency - % ICHG 2A ICHG 1A 90 85 80 0 5 10 VO - Output Voltage - V 15 20 Figure 14.
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bq24650 SLUSA75 – JULY 2010 www.ti.com PIN FUNCTIONS PIN NO. NAME DESCRIPTION 1 VCC P IC power positive supply. Place a 1-mF ceramic capacitor from VCC to GND and place it as close as possible to IC. Place a 10-Ω resistor from input side to VCC pin to filter the noise. 2 MPPSET I Input voltage set point. Use a voltage divider from input source to GND to set voltage on MPPSET to 1.2V. To disable charge, pull MPPSET below 75mV.
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bq24650 www.ti.com SLUSA75 – JULY 2010 BLOCK DIAGRAM bq24650 VREF VOLTAGE REFERENCE VCC - SRN+100 mV + SLEEP VREF 3.3V LDO UVLO VCC VCC - VUVLO + SLEEP UVLO VCC 175 mV + FBO MPPSET 1.2 V COMP ERROR AMPLIFIER + - EAI 2.1 V CE + + 1V + VFB BTST EAO PWM - LEVEL SHIFTER - BAT_OVP 20uA SRP SRP-SRN + SYNCH PH + 20X - V(SRP-SRN) 0.
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bq24650 SLUSA75 – JULY 2010 www.ti.com DETAILED DESCRIPTION Regulation Voltage VRECH Regulation Current Precharge Current Regulation Phase Fastcharge Current Regulation Phase Fastcharge Voltage Regulation Phase Termination Charge Current Charge Voltage VLOWV IPRECH & ITERM Figure 16. Typical Charging Profile BATTERY VOLTAGE REGULATION The bq24650 uses a high accuracy voltage regulator for the charging voltage.
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bq24650 www.ti.com SLUSA75 – JULY 2010 If the solar panel or other input source cannot provide the total power of the system and bq24650 charger, the input voltage drops. Once the voltage sensed on the MPPSET pin drops below 1.2V, the charger maintains the input voltage by reducing the charge current. If the MPPSET pin voltage is forced below 1.2V, the bq24650 stays in the input voltage regulation loop while the output current is zero. The STAT1 pin is LOW and STAT2 pin is HIGH.
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bq24650 SLUSA75 – JULY 2010 www.ti.com ENABLE AND DISABLE CHARGING The following conditions have to be valid before charging is enabled: • Charge is allowed (MPPSET > 175mV) • Device is not in Under-Voltage-Lock-Out (UVLO) mode and VCC is above the VCCLOWV threshold • Device is not in SLEEP mode (i.e.
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bq24650 www.ti.com SLUSA75 – JULY 2010 SYNCHRONOUS AND NON-SYNCHRONOUS OPERATION The charger operates in synchronous mode when the SRP-SRN voltage is above 5mV (0.5-A inductor current for a 10-mΩ sense resistor). During synchronous mode, the internal gate drive logic ensures there is break-before-make complimentary switching to prevent shoot-through currents. During the 30ns dead time where both FETs are off, the body-diode of the low-side power MOSFET conducts the inductor current.
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bq24650 SLUSA75 – JULY 2010 www.ti.com BATTERY OVER-VOLTAGE PROTECTION The converter does not allow the high-side FET to turn on until the BAT voltage goes below 102% of the regulation voltage. This allows one-cycle response to an over-voltage condition – such as occurs when the load is removed or the battery is disconnected. A current sink from SRP to GND is on to discharge the stored energy on the output capacitors.
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bq24650 www.ti.com SLUSA75 – JULY 2010 VVREF -1 VLTF RT1 = 1 1 + RT2 RTHCO LD (8) VREF RT1 bq24650 TS RTH 103AT RT2 Figure 18. TS Resistor Network CHARGE ENABLE MPPSET is used to disable or enable the charge process. A voltage above 175mV on this pin enables charge, provided all other conditions for charge are met (see the Enabling and Disabling Charge section). A voltage below 75mV on this pin also resets all timers and fault conditions.
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bq24650 SLUSA75 – JULY 2010 www.ti.com BATTERY DETECTION For applications with removable battery packs, the bq24650 provides a battery absent detection scheme to reliably detect insertion or removal of battery packs.
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bq24650 www.ti.com SLUSA75 – JULY 2010 Battery not detected VREG VRECH (VWAKE) Battery inserted VLOWV (VDISCH) Battery detected tLOWV_DEG tWAKE tRECH_DEG Figure 20. 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 VFB voltage below the LOWV threshold during the 1 second discharge time.
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bq24650 SLUSA75 – JULY 2010 www.ti.com Component List for the Typical System Circuit in Figure 1 PART DESIGNATOR QTY DESCRIPTION Q1, Q2 2 N-channel MOSFET, 40 V, 10 A, PowerPAK SO-8, Vishay-Siliconix, Si7288 D2 1 Diode, Dual Schottky, 30 V, 200 mA, SOT23, Fairchild, BAT54C D3, D4 2 LED Diode, Green, 2.
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bq24650 www.ti.com SLUSA75 – JULY 2010 APPLICATION INFORMATION INDUCTOR SELECTION The bq24650 has a 600-kHz switching frequency to allow the use of small inductor and capacitor values.
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bq24650 SLUSA75 – JULY 2010 www.ti.com Figure-of-merit (FOM) is usually used for selecting a proper MOSFET based on a tradeoff between conduction loss and switching loss. For a top-side MOSFET, FOM is defined as the product of the MOSFET's on-resistance, RDS(on), and the gate-to-drain charge, QGD. For a bottom-side MOSFET, FOM is defined as the product of the MOSFET's on-resistance, RDS(on), and the total gate charge, QG.
PAGE 23
bq24650 www.ti.com SLUSA75 – JULY 2010 There are several methods to damping or limiting the over-voltage spike during adapter hot plug-in. An electrolytic capacitor with high ESR as an input capacitor can damp the over-voltage spike well below the IC maximum pin voltage rating. A high current capability TVS Zener diode can also limit the over-voltage level to an IC safe level. However, these two solutions may not be lowest cost or smallest size.
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bq24650 SLUSA75 – JULY 2010 www.ti.com R21: 20Ω VIN Solar Panel R20 2Ω C21 2.2mF C21 0.47mF LM234 VCC R3 I1 RSET ISET VREG R4 I2 MPPSET bq24650 Figure 23. Feedback Network In the circuit shown in Figure 23, for the LM234 temperature sensor, 227 μV/ °K ISET = ´ Temp RSET (23) Thus, 0.
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bq24650 www.ti.com SLUSA75 – JULY 2010 PCB LAYOUT The switching node rise and fall times should be minimized for minimum switching loss. Proper layout of the components to minimize the high frequency current path loop (see Figure 24) is important to prevent electrical and magnetic field radiation and high frequency resonant problems. The following is a PCB layout priority list for proper layout. Layout of the PCB according to this specific order is essential. 1.
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bq24650 SLUSA75 – JULY 2010 www.ti.com Charge Current Direction R SNS To Inductor To Battery Current Sensing Direction To SRP and SRN pin Figure 25.
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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 BQ24650RVAR VQFN RVA 16 3000 330.0 12.4 3.75 3.75 1.15 8.0 12.0 Q1 BQ24650RVAT 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) BQ24650RVAR VQFN RVA 16 3000 367.0 367.0 35.0 BQ24650RVAT VQFN RVA 16 250 210.0 185.0 35.
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