Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsPMICsPMIC - power management - special purpose WSON 8 (2x2)

1 MΩ

10 µF

22 µF

OUT

VIN

ILIM

GND

VOUT

20 k

ILIM

100 pF

243 kΩ

1 μH

768 kΩ

OUT

TPS61252

Power Good

Output

2.3 V to

6.0 V

5.0 V

TPS61252

www.ti.com

SLVSAG3 –SEPTEMBER 2010

TINY 1.5-A BOOST CONVERTER WITH ADJUSTABLE INPUT CURRENT LIMIT

Check for Samples: TPS61252

FEATURES

• Short Circuit Protection

• Resistor Programmable Input Current Limit • Typical Operating Frequency 3.25 MHz

– ±20% Current Accuracy at 500 mA over Full • Available in a 2×2-mm QFN-8 Package

Temperature Range

APPLICATIONS

– Programmable from 100 mA up to 1500 mA

• USB Host Supplies from a Single Li-Ion

• Up to 92% Efficiency

Battery

• V

Range from 2.3 V to 6.0 V

• Current Limited Applications

• Power Good Indicates Appropriate Output

• Li-Ion Applications

Voltage Level

• Audio Applications

• Adjustable Output Voltage up to 6.5 V

• RF-PA Buffer

• 100% Duty-Cycle Mode When V

> V

OUT

• Load Disconnect and Reverse Current

Protection

DESCRIPTION

The TPS61252 device provides a power supply solution for products powered by either a three-cell alkaline,

NiCd or NiMH battery, or an one-cell Li-Ion or Li-polymer battery. The wide input voltage range is ideal to power

portable applications like mobile phones or for computer peripherals. The device has a resistor programmable

ILIM

) input current limit and is suitable for a wide variety of applications.

During light loads the device will automatically enter skip mode (PFM), which allows the converter to maintain the

required output voltage, while only drawing 30 mA from the battery. This will allow maximum efficiency at lowest

quiescent currents.

TPS61252 allows the use of small inductors and input capacitors to achieve a small solution size. The possibility

to reduce the current limit by a external resistor offers the potential use of physically even smaller inductors with

lower rated current to further reduce total solution sizes of the power supply. During shutdown, the load is

completely disconnected from the battery. The TPS61252 is available in a 8-pin QFN package measuring 2×2

mm (DSG).

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 (23 pages)

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TPS61252 www.ti.com SLVSAG3 – SEPTEMBER 2010 TINY 1.5-A BOOST CONVERTER WITH ADJUSTABLE INPUT CURRENT LIMIT Check for Samples: TPS61252 FEATURES 1 • • • • • • • Resistor Programmable Input Current Limit – ±20% Current Accuracy at 500 mA over Full Temperature Range – Programmable from 100 mA up to 1500 mA Up to 92% Efficiency VIN Range from 2.3 V to 6.0 V Power Good Indicates Appropriate Output Voltage Level Adjustable Output Voltage up to 6.
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TPS61252 SLVSAG3 – SEPTEMBER 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.
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TPS61252 www.ti.com SLVSAG3 – SEPTEMBER 2010 RECOMMENDED OPERATING CONDITIONS MIN NOM MAX UNIT Supply voltage at VIN 2.3 6.0 Output voltage at VOUT 3.0 6.5 V Programmable valley switch current limit set by RILIM 100 1500 mA Operating free air temperature range, TA –40 85 °C Operating junction temperature range, TJ –40 125 °C V ELECTRICAL CHARACTERISTICS Over recommended free air temperature range, typical values are at TA = 25°C.
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TPS61252 SLVSAG3 – SEPTEMBER 2010 www.ti.com PIN ASSIGNMENTS 8 VIN GND 1 FB 3 ILIM 4 d ose d Exp al Pa rm The VOUT 2 7 SW 6 EN 5 PG Table 1. TERMINAL FUNCTIONS TERMINAL NAME NO. I/O DESCRIPTION EN 6 I Enable input. (1 enabled, 0 disabled) FB 3 I Voltage feedback pin GND 1 ILIM 4 I Adjustable input valley current limit. Can be connected to VIN for maximum current.
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TPS61252 www.ti.com SLVSAG3 – SEPTEMBER 2010 FUNCTIONAL BLOCK DIAGRAM SW VIN Gate Drive VOUT PMOS NMOS Valley Current Sense FB Error Amplifier Pulse Modulator PWM Softstart VREF EN Control Logic Input Current Sense Thermal Shutdown Undervoltage Lockout Averaging Circuit gm VREF2 1V VOUT IAVE Error Amp.
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TPS61252 SLVSAG3 – SEPTEMBER 2010 www.ti.com PARAMETER MEASUREMENT INFORMATION L1 VOUT VOUT L VIN R1 VIN C1 C2 C3 FB EN R4 R2 ILIM R3 PG GND Power Good Output U1 Table 2. List of Components REFERENCE DESCRIPTION MANUFACTURER U1 TPS61252 Texas Instruments L1 1.0 mH, 2.1 A, 27 mΩ, 2.8 mm x 2.8 mm x 1.5 mm DEM2815C, TOKO C1 1 x 4.
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TPS61252 www.ti.com SLVSAG3 – SEPTEMBER 2010 TYPICAL CHARACTERISTICS TABLE OF GRAPHS DESCRIPTION FIGURE Efficiency vs Output current (VOUT = 5.0 V, ILIM = 1.5 A) Figure 1 vs Output current in 100% Duty-Cycle Mode (VOUT = 5.0 V, ILIM = 1.5 A) Figure 2 vs Input voltage (VOUT = 5.0 V, ILoad = {10; 100; 1000 mA}) , ILIM = 1.5 A Figure 3 Maximum output current vs Input voltage (TPS61252, VOUT = 5.0 V) Figure 4 Output voltage vs Output current (VOUT = 5.0 V, ILIM = 1.
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TPS61252 SLVSAG3 – SEPTEMBER 2010 www.ti.com EFFICIENCY vs INPUT VOLTAGE 100 MAXIMUM OUTPUT CURRENT vs INPUT VOLTAGE IO = 1000 mA 90 IO = 100 mA Efficiency - % 70 IO = 10 mA IO - Output Current - A 80 60 50 40 30 20 VO = 5 V, Ilim = max 10 0 2.3 2.7 3.1 3.5 3.9 4.3 4.7 5.1 VI - Input Voltage - V 5.5 5.9 1.7 1.6 1.5 1.4 1.3 1.2 1.1 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 2.3 IO (I_Lim = 1.5 A) IO (I_Lim = 1 A) IO (I_Lim = 0.5 A) IO (I_Lim = 0.2 A) IO (I_Lim = 0.1 A) 2.8 3.3 3.8 4.3 4.
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TPS61252 www.ti.com SLVSAG3 – SEPTEMBER 2010 LOAD TRANSIENT RESPONSE ILIM = 1000 mA (50 to 550 mA) STARTUP AFTER ENABLE ILIM = 500mA, NO LOAD VIN = 3.6 V, ILIM = 0.5 A VIN = 3.6 V, ILIM = 1.0 A VOUT 2.0V/div; -2V offset VOUT 100mV/div; 4.77V offset Output Current @ 1Ω 500mV/div Inductor Current 0.5A/div; 0.5A offset Inductor Current 0.5A/div; 1.5A offset Voltage @ SW pin 2.0V/div; 8V offset Time = 500μs/div Time = 100μs/div Figure 7. Figure 8.
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TPS61252 SLVSAG3 – SEPTEMBER 2010 www.ti.com DETAILED DESCRIPTION OPERATION The TPS61252 Boost Converter operates as a quasi-constant frequency adaptive on-time controller. In a typical application the frequency will be 3.25 MHz and is defined by the input to output voltage ratio and does not vary from moderate to heavy load currents. At light load currents the converter will automatically enter Power Save Mode and operates then in PFM (Pulse Frequency Modulation) mode.
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TPS61252 www.ti.com SLVSAG3 – SEPTEMBER 2010 POWER-SAVE MODE The TPS61252 integrates a power save mode to improve efficiency at light load. In power save mode the converter only operates when the output voltage trips below a set threshold voltage. It ramps up the output voltage with several pulses and goes into power save mode once the output voltage exceeds the set threshold voltage.
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TPS61252 SLVSAG3 – SEPTEMBER 2010 www.ti.com POWER GOOD The device has a built in power good function to indicate whether the output voltage operates within appropriate levels. The power good output (PG) is set high after the feedback voltage reaches 95% of its nominal value and stays there until the feedback voltage falls below 90 % of the nominal value. The power good is operable as long as the converter is enabled and VIN is present.
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TPS61252 www.ti.com SLVSAG3 – SEPTEMBER 2010 APPLICATION INFORMATION EXAMPLE During the following Application Information section one specific example will be used to define and work with the different equations. Parameter Symbol Value Unit Input Voltage VIN 3.6 V Minimum Input Voltage VIN(min) 2.6 V Output Voltage VOUT 5.0 V Input Current Limit set by RILIM ILIM 1000 mA Feedback Voltage VFB 1.2 V Switching Frequency f 3.
PAGE 14
TPS61252 SLVSAG3 – SEPTEMBER 2010 www.ti.com IL(max) = ILIM + DIL = ILIM + VIN(min) g D Lg f with D = 1 - VIN(min) g h VOUT (8) Regarding the above example the current ripple (ΔIL) will be 426 mA and therefore an inductor with a rated current of about 1.5 A should be used. The TPS61252 is designed to work with inductor values between 1.0 µH and 2.2 µH. For typical applications a 1.5 µH inductor is recommended.
PAGE 15
TPS61252 www.ti.com SLVSAG3 – SEPTEMBER 2010 CHECKING LOOP STABILITY The first step of circuit and stability evaluation is to look from a steady-state perspective at the following signals: • Switch node, SW • Inductor current, IL • Output ripple voltage, VOUT(AC) These are the basic signals that need to be measured when evaluating a switching converter.
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TPS61252 SLVSAG3 – SEPTEMBER 2010 www.ti.com 10mm (0.39in) VOUT VIN COUT 7mm (0.27in) GND CIN L1 R1 R2 CFF RILIM GND Figure 11. Suggested Layout (Top) THERMAL INFORMATION The implementation of integrated circuits in low-profile and fine-pitch surface-mount packages typically requires special attention to power dissipation.
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE MATERIALS INFORMATION www.ti.com 15-Oct-2010 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 TPS61252DSGR WSON DSG 8 3000 179.0 8.4 2.2 2.2 1.2 4.0 8.0 Q2 TPS61252DSGT WSON DSG 8 250 179.0 8.4 2.2 2.2 1.2 4.0 8.
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PACKAGE MATERIALS INFORMATION www.ti.com 15-Oct-2010 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) TPS61252DSGR WSON DSG 8 3000 195.0 200.0 45.0 TPS61252DSGT WSON DSG 8 250 195.0 200.0 45.
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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.