Texas Instruments TPS 61058 INSTALLATION INSTRUCTIONS

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(3,25 mm x 3,25 mm)

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22 µF

4.7 µH

2.7 V . . 5.5 V

GND

TPS61058

GND

PVIN

VIN

SW VOUT

PGND

C1, C2, C3

IOK

FLASH ON (0/1.8 V)

22 µF

39 kΩ

22 kΩ

56 kΩ

1.5 Ω

62 kΩ

1 nF (COG)

5.6 kΩ

100

2.70 3.10 3.50 3.90 4.30 4.70 5.10 5.50

V - Input Voltage - V

LED Power Efficiency (P /P ) - %

LED IN

I = 500 mA @ V = 3.7 V

LED F

SYNCHRONOUS BOOST CONVERTER WITH DOWN MODE

HIGH POWER WHITE LED DRIVER

FEATURES DESCRIPTION

• 80% Efficient Synchronous Boost Converter

– 500-mA LED Current From 3.3-V Input

(TPS61058)

– 800-mA LED Current From 3.3-V Input

(TPS61059)

• Input Voltage Range: 2.7 V to 5.5 V

• Fixed Frequency 650 kHz (Typ) Operation

• LED Disconnect During Shutdown

• Open/Shorted LED Protection

• Over-Temperature Protection

• Low Shutdown Current: 100 nA (Typ)

• Total Solution Of Less Than 80 mm

• Small 3mm x 3mm QFN-10 Package

APPLICATIONS

• Torch/Camera White LED Supply for Cell

Phones, Smart-Phones and PDAs

TPS61058 TPS61059

SLVS572B – APRIL 2005 – REVISED DECEMBER 2005

The TPS61058/9 devices are fixed frequency, synchronous boost dc-dc converters with an integrated down conversion mode. The devices are optimized for driving high power single cell white LEDs up to 800 mA from a 2.7-V to 5.5-V input. The LED current can be programmed to different levels (e.g. torch, flashlight) by a set of external resistors.

The boost converter is based on a 650 kHz fixed frequency, pulse-width-modulation (PWM) controller using a synchronous rectifier to obtain maximum efficiency. The maximum peak current in the boost switch is limited to 1000 mA (TPS61058) and 1500

mA (TPS61059). The converter can be disabled to maximize battery

life. In the shutdown mode, the load is completely disconnected and the current consumption is reduced to less than 1 µA. Built-in precharge and soft-start circuitry prevents excessive inrush current during start-up.

The device is packaged in a 10-pin QFN PowerPAD™ package measuring 3 mm x 3 mm (DRC).

Figure 1. 500 mA Flashlight Application

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.

PowerPAD is a trademark of Texas Instruments.

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.

Figure 2. Flashlight Efficiency vs V

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TPS61058 TPS61059

SLVS572B – APRIL 2005 – REVISED DECEMBER 2005

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.

AVAILABLE OPTIONS

-40 ° C to 85 ° C 10-Pin QFN

(1) The DRC package is available taped and reeled. Add R suffix to device type (e.g. TPS61058DRCR, TPS61059DRCR) to order

quantities of 3000 devices per reel.

(2) For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI

website at www.ti.com.

CURRENT LIMIT PACKAGE MARKING PACKAGE PART NUMBER

1000 mA BNF TPS61058DRC 1500 mA BNG TPS61059DRC

ABSOLUTE MAXIMUM RATINGS

over operating free-air temperature range (unless otherwise noted)

Input voltage range on PVIN, VIN, EN, FB, IOK, SW, VOUT -0.3 V to 7 V Power dissipation Internally limited Operation temperature range, T Maximum operating junction temperature, TJ(max) 150 ° C Storage temperature range, T

(1) Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device. These are stress ratings

only, and functional operation of the device at these or any other conditions beyond those indicated under "recommended operating conditions" is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

stg

(1)

TPS61058/9

-40 ° C to 85 ° C

-65 ° C to 150 ° C

(1) (2)

DISSIPATION RATINGS TABLE

PACKAGE

DRC 48.7 ° C/W 2040 mW 21 mW/ ° C

THERMAL RESISTANCE POWER RATING DERATING FACTOR ABOVE

TA≤ 25 ° C TA= 25 ° C

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SLVS572B – APRIL 2005 – REVISED DECEMBER 2005

ELECTRICAL CHARACTERISTICS

= 3.6 V, I

otherwise noted)

DC/DC STAGE

OUT

OVP

f Oscillator frequency 550 650 750 kHz I

DS(on)

(SD)

CONTROL STAGE

(IL)

(IH)

(I)

= 500 mA, EN = VIN, L = 4.7 µH, C

LED

= 3x 22 µF, TA= –40 ° C to 85 ° C, typical values are at TA= 25 ° C (unless

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

Input voltage range VO> 2.0 V @ I

= 50 mA 2.7 5.5 V

LED

TPS61058/9 output voltage range 2.5 5.5 V Output overvoltage protection 5.9 6.1 6.3 V TPS61058/9 feedback voltage 490 500 510 mV

Switch current limit (TPS61058) VO= 3.3 V 900 1100 1300 mA Switch current limit (TPS61059) VO= 3.3 V 1200 1500 1800 mA Pre-charge current VO= 2.5 V, TA= -10 ° C to 85 ° C 84 mA SWN switch on resistance VO= 3.3V 260 m Ω SWP switch on resistance VO= 3.3 V 290 m Ω Total accuracy (including line and load regulation) -3% 3%

= 0 mA, VO= 5.0 V,

Quiescent current 5.5 mA

LED

Device switching at 650 kHz

Shutdown current EN = GND, TA= 25 ° C 0.1 1 µA

IOK switch on-resistance VO= 5.0 V, I

= 100 µA 0.6 0.8 1 k Ω

IOK

IOK output low current 100 300 µA IOK output leakage current V

= 7 V 0.01 0.1 µA

IOK

EN low-level input voltage 0.4 V EN high-level input voltage 1.4 V EN input leakage current Input tied to GND 0.01 0.1 µA EN pull-down resistance 400 k Ω Overtemperature protection 140 ° C Overtemperature hysteresis 20 ° C

TPS61058 TPS61059

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IOK

GND

PVIN

VOUT

GND

VIN

PGND

DRC Package

(TOP VIEW)

TPS61058 TPS61059

SLVS572B – APRIL 2005 – REVISED DECEMBER 2005

PIN ASSIGNMENTS

Terminal Functions

TERMINAL

NAME NO.

EN 1 I This is the enable pin of the device. Connect this pin to ground forces the device into shutdown mode. Pulling

VOUT 2 O This is the output of the dc-dc converter. FB 3 I This is the feedback pin of the device. The feedback pin measures the LED current through the sense

IOK 4 O This pin indicates that the dc-dc converter is ready for high current operation (open drain output). GND 5, 7 Control / logic ground. PVIN 6 I This is the input voltage pin of the device. Connect directly to the input bypass capacitor. VIN 8 I This pin needs to be tied to the input voltage pin of the device. SW 9 I This is the switching pin of the converter. PGND 10 Power ground. PowerPAD™ Must be soldered to achieve appropriate power dissipation. Should be connected to PGND.

I/O DESCRIPTION

this pin above 1.4V enables the device. This pin has an internal pull-down resistor.

resistor. The feedback voltage is set internally to 500mV.

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Vmax

control

Gate

Control

Regulator Error-

Amplifier

Vref

Oscillator

PGND

PVIN

VOUT

GND

PGND

GND

VIN

OVP

Vref

Control Logic

PGND

20 pF

Temperature

Control

10 kW

IOK

400 kW

FUNCTIONAL BLOCK DIAGRAM (TPS61058/9)

TPS61058 TPS61059

SLVS572B – APRIL 2005 – REVISED DECEMBER 2005

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22 Fm

4.7 Fm

2.7 V . . 5.5 V

GND

TPS61058/9

GND

PVIN

VIN

SW VOUT

PGND

C1, C2, C3

IOK

TORCH ON (0/1.8 V)

22 Fm

22 kW

1 nF (COG)

FLASH (0 . .2 V)

500 mA Flashlight Application

Rs = 1.3

R2 = 56 k R3 = 100 k R4 = 2.4 k R5 = 6.2 k R6 = 91 k

W W W

700 mA Flashlight Application

Rs = 1.2

R2 = 47 k R3 = 51 k R4 = 3.3 k R5 = 4.3 k R6 = 120 k

W W

List of Components:

L1 = TDK VLF5014AT-4R7T

C1,C2,C3 = TDK C2012X5R0J226MTJ

(Optional)

C4 = 100 nF

TPS61058 TPS61059

SLVS572B – APRIL 2005 – REVISED DECEMBER 2005

PARAMETER MEASUREMENT INFORMATION

TYPICAL CHARACTERISTICS

Table of Graphs

FIGURE

(TPS61058) LED Power Efficiency vs. Input Voltage 3 (TPS61059) LED Power Efficiency vs. Input Voltage 4 (TPS61058) LED Power Efficiency vs LED Current 5 (TPS61058) DC Input Current vs. Input Voltage 6 (TPS61058) LED Current vs. Input Voltage 7 Oscillator Frequency 8 (TPS61059) Current Limit vs. Temperature 9 Waveforms Switching Waveforms in Boost Mode (TPS61058) 10

Switching Waveforms in Down-Mode (TPS61058) 11 High Current Flashlight Pulse Waveform (TPS61058) 12 Torch to Flashlight Transistion (TPS61058) 13 Start-Up After Enable (TPS61058) 14 Overvoltage Protection (TPS61058) 15 Duty Cycle Jitter (TPS61058) 16

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100

2.70 3.10 3.50 3.90 4.30 4.70 5.10 5.50

LEDPowerEfficiency(P /P )-%

LED IN

I = 500 mA @ V = 3.7 V

LED F

I = 150 mA @ V = 3.4 V

LED F

V - Input Voltage - V

100

2.70 3.10 3.50 3.90 4.30 4.70 5.50 VI − Input Voltage − V

LED Power Efficiency (P

LED

) − %

LED

= 700 mA @ VF = 3.4 V

LED

= 150 mA @ VF = 3.0 V

5.10

200

400

600

800

1000

1200

1400

2.70 3.10 3.50 3.90 4.30 4.70 5.10 5.50

Input DC Current - mA

V - Input Voltage - V

I = 500 mA

LED

100

100 150 200 250 300 350 400 450 500

LED Current - mA

LED Power Efficiency (P /P ) - %

LED IN

V = 3.3 V

V = 4.2 V

V = 3.6 V

TPS61058 TPS61059

SLVS572B – APRIL 2005 – REVISED DECEMBER 2005

LED POWER EFFICIENCY LED POWER EFFICIENCY

TPS61058 TPS61059

vs vs

INPUT VOLTAGE INPUT VOLTAGE

Figure 3. Figure 4.

TPS61058 TPS61058

EFFICIENCY DC INPUT CURRENT

vs vs

LED CURRENT INPUT VOLTAGE

Figure 5. Figure 6.

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100

200

300

400

500

600

2.70 3.10 3.50 3.90 4.30 4.70 5.10 5.50

LED Current - mA

I = 500 mA

LED

I = 150 mA

LED

V - Input Voltage - V

606

615

622

629

636

643

650

657

664

672

f − Oscillator Frequency − kHz

Percent of Units − %

TA = 25C

Switch Current Limit − Am

Ambient Temperature − C

1250

1350

1450

1550

1650

1750

-40 -30 -20 -10 0 10 20 30 40 50 60 70 80

SW (2 V/div)

V = 3.6 V, I = 500 mA

I LED

I (200 mA/div)

V (10 mV/div - 3.8 V OFFSET)

OUT

I (200 mA/div)

LED

t - Time - 500 ns/div

TPS61058 TPS61059

SLVS572B – APRIL 2005 – REVISED DECEMBER 2005

TPS61058 OSCILLATOR FREQUENCY

LED CURRENT

INPUT VOLTAGE

Figure 7. Figure 8.

TPS61059 TPS61058

CURRENT LIMIT SWITCHING WAVEFORMS IN BOOST MODE

TEMPERATURE

Figure 9. Figure 10.

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(2 V/div)

I (200 mA/div)

I (200mA/div)

LED

(10 mV/div - 3.8 V OFFSET)

OUT

V = 4.5 V, I = 500 mA

I LED

t - Time - 500 ns/div

EN (1 V/div)

t - Time - 5 ms/div

I (200 mA/div)

V (1 V/div)

OUT

I (200 mA/div)

LED

V = 3.6 V

V (1 V/div)

OUT

I (200 mA/div)

LED

I (500 mA/div)

t - Time - 50 s/divm

EN (1 V/div)

V (1 V/div)

OUT

I (50 mA/div)

LED

I (100 mA/div)

t - Time - 200 s/divm

TPS61058 TPS61059

SLVS572B – APRIL 2005 – REVISED DECEMBER 2005

SWITCHING WAVEFORMS IN DOWN MODE HIGH CURRENT FLASHLIGHT PULSE WAVEFORM

TPS61058 TPS61058

Figure 11. Figure 12.

TPS61058 TPS61058

TORCH TO FLASHLIGHT TRANSISTION START-UP AFTER ENABLE

Figure 13. Figure 14.

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SW (2 V/div)

V = 3.6 V

I = 500 mA

LED

Triggered On Falling Edge

t - Time - 50 ns/div

V (200 mV/div - 5 V OFFSET)

OUT

t - Time - 50 ms/div

TPS61058 TPS61059

SLVS572B – APRIL 2005 – REVISED DECEMBER 2005

OVERVOLTAGE PROTECTION DUTY CYCLE JITTER

TPS61058 TPS61058

Figure 15. Figure 16.

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TPS61058 TPS61059

SLVS572B – APRIL 2005 – REVISED DECEMBER 2005

DETAILED DESCRIPTION

OPERATION

The TPS61058/9 familly is based on a fixed frequency multiple feedforward controller topology. Input voltage, output voltage, and voltage drop on the NMOS switch are monitored and forwarded to the regulator. So changes in the operating conditions of the converter directly affect the duty cycle and must not take the indirect and slow way through the control loop and the error amplifier.

The control loop, determined by the error amplifier, only has to handle small signal errors. The input for it is the feedback voltage on the FB pin. It is compared with the internal reference voltage to generate an accurate and stable LED current.

The peak current of the NMOS switch is also sensed to limit the maximum current flowing through the switch and the inductor. The typical peak current limit is set to 1000mA (TPS61058) and 1500 mA (TPS61059). An internal temperature sensor prevents the device from getting overheated in case of excessive power dissipation.

Synchronous Rectifier

The device integrates an N-channel and a P-channel MOSFET transistor to realize a synchronous rectifier. Because the commonly used discrete Schottky rectifier is replaced with a low RDS(ON) PMOS switch, the power conversion stage itself can reach 96% efficiency.

In order to avoid ground shift due to the high currents in the NMOS switch, two separate ground pins are used. The reference for all control functions is the GND pin. The source of the NMOS switch is connected to PGND. Both grounds must be connected on the PCB at only one point close to the GND pin.

A special circuit is applied to disconnect the load from the input during shutdown of the converter. In conventional synchronous rectifier circuits, the backgate diode of the high-side PMOS is forward biased in shutdown and allows current flow from the battery to the output. This device however uses a special circuit which takes the cathode of the backgate diode of the high-side PMOS and disconnects it from the source when the regulator is not enabled (EN = Low).

The benefit of this feature for the system design engineer is that the battery is not depleted during shutdown of the converter. No additional components have to be added to the design to make sure that the battery is disconnected from the output of the converter.

Down Regulation

In general, a boost converter only regulates output voltages which are higher than the input voltage. This device operates differently and is capable of driving high power single die white LEDs from a fully charged Li-Ion cell. To control this applications properly, a down conversion mode is implemented.

If the input voltage reaches or exceeds the output voltage necessary to maintain the LED current within regulation, the converter changes to a down conversion mode. In this mode, the control circuit changes the behavior of the rectifying PMOS transitor. It sets the voltage drop across the PMOS as high as needed to regulate the output voltage. This means the power losses in the converter increase. This has to be taken into account for thermal consideration especially when operating with low V

LEDs, high battery voltages and high

LED currents.

Enable

The device is put into operation when EN is set high. It is put into a shutdown mode when EN is set to GND. The EN input pin has an internal 400-k Ω pull-down resistor to disable the device when this pin is floating.

In shutdown mode, the regulator stops switching, the internal control circuitry is switched off, and the load is isolated from the input (as described in the Synchronous Rectifier Section). This also means that the output voltage can drop below the input voltage during shutdown.

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TPS61058 TPS61059

SLVS572B – APRIL 2005 – REVISED DECEMBER 2005

DETAILED DESCRIPTION (continued)

Softstart

To avoid high inrush current during start-up, special care is taken to control the inrush current. When the device is first enabled, the output capacitor is charged with a constant pre-charge current of 115mA (typ) until either the output voltage is typically 0.1V below the input voltage or the feedback voltage is 500mV (typ). The rectifying switch is current limited during the pre-charge phase. This also limits the output current under short circuit conditions at the output.

The fixed pre-charge current during start-up allows the device to start up without problems when driving single die white LEDs as long as the LED start-up current is set to a value lower than the pre-charge current (84 mA min.). Refer to the application section for more details.

When the device has finished start-up and is ready for high current operation, the device forces IOK output to ground, starts switching and regulates the LED current to the desired value (e.g. torch or flashlight current level).

Overvoltage Protection (OVP)

As with any current source, the output voltage rises when the load becomes high impedance or gets disconnected. To prevent the output voltage exceeding the maximum switch voltage rating (7 V) of the main switch, an overvoltage protection circuit is integrated. As soon as the output voltage exceeds the OVP threshold, the converter stops switching and the output voltage decreases. When the output voltage falls below the OVP threshold, the converter continues operation until the output voltage exceeds the OVP threshold again.

Efficiency and Sense Voltage

The voltage across the sense resistor (R voltage does not contribute to the output power (P

) has a direct effect of the converter efficiency. Because the sense

), the lower this voltage the higher the efficiency. It is

LED

therefore recommended to operate with a sense voltage of approximately 0.75V at maximum LED current.

Thermal Shutdown

An internal thermal shutdown is implemented and turns off the internal MOSFETs when the typical junction temperature of 140 ° C is exceeded. The thermal shutdown has a hysteresis of typically 20 ° C. Refer to the Thermal Information section.

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nFLASH

IOK

ILED

Flashlight

MOVIE-LIGHT

Hi-Z Hi-Z

Pre-Charge

Movie-Light

GND

PVIN

VIN

VOUT

PGND

IN D1

nFLASH

IOK Vx

2.7 V . . 5.5 V

4.7 µH

22 µF

MOVIE-LIGHT

C1, C2, C3

22 µF

1 nF (COG)

R1 22 kΩ

SENSE

TPS61058/9

100nF



SENSE

LED

SLVS572B – APRIL 2005 – REVISED DECEMBER 2005

APPLICATION INFORMATION

DESIGN PROCEDURE

The standard application circuit (Figure 17 ) of the TPS61058/9 is a complete solution to drive high-power white LEDs with two discrete current steps.

TPS61058 TPS61059

Figure 17. Typical Application

The LED current is programmed using external resistors (R the LED is to enable the device (EN = High). After charging the output capacitor, the device forces IOK to ground, starts switching, and regulates the LED current to the desired value. The control signal, nFLASH, injects current into the feedback network through R4, thereby, changing the LED current. For this reason, the nFLASH control signal needs at least to be biased up until IOK goes low. In case this is not done properly the converter stays stuck in the pre-chage phase.

To faciliate the sizing of the external resistor network, it is recommended to use the calculation sheet available in the device product folder.

1. Sense resistor, R

The voltage across the sense resistor should be set to approximately 0.75 V at maximum LED current.

Check the power rating of the sense resistor (P

2. LED current setting

Figure 19 shows an equivalent circuit for the feedback network. The regulation loop is using an external

control voltage (nFLASH) to set the LED current. With the help of this voltage the feedback bias current (I

) can be adjusted which, in effect, controls the LED current without changing any externals.

BIAS

In most applications a variable control voltage is not available to set the LED current. In practical applications, nFLASH can either be:

A constant bias voltage (2.8 V for example) which in combination with IOK can be used to switch between two LED currents (Off, Flashlight).

A logic signal generated by the imaging processor. This configuration permits three different LED currents: Off, Movie-light (nFLASH = High), Flashlight (nFLASH = Low).

Figure 18. Waveform Profiles

, R2, R3, R4, R5, and R6). The first step to turn on

(1)

= RS× I

LED

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LED



0.5 R2 I

BIAS



BIAS



R3 (R4  R5)

nFLASH 

0.5 R3

, assuming R4R5 is small compared R3.

LED



0.5 R2 I

BIAS2





2  R



2  R3  R



R3 R

BIAS2



R5

R3 (R4  R5)

nFLASH 

0.5 R3

, with R5 

R5 R6 R5 R6

LED(FLASH)



R2 R3

2  R3  R

, assumingR4R5R6 is small compared R3.

Vx 

1 2



2  R2

 I

LED(MOVIELIGHT,PRECHARGE)

R3 R

Vx 

R5

R4 R5

nFLASH, with R5 

R5  R6 R5  R6

TPS61058 TPS61059

SLVS572B – APRIL 2005 – REVISED DECEMBER 2005

The circuit operation can be split into different phases:

1. Pre-Charge Phase (IOK = Hi-Z) During this phase IOK is kept high-impedance. For proper startup the external loop components need to be

chosen so that the regulation loop can settle for a maximum LED current of less than 84 mA. This can be achieved by increasing the bias voltage (V

2. High-Current Operation (IOK = GND) After the pre-charge phase, IOK is automatically pulled to ground. This modifies the feedback divider network

changing the potential of the V

node. As a consequence the LED current is adjusted accordingly.

) of the feedback network.

(2)

(3)

(4)

For operation at maximum LED current (flashlight mode), nFLASH needs to be set to ground level.

For operation at other LED currents (movie-light or pre-charge), nFLASH applies a positive bias voltage (1.8 V for example) to the feedback divider network. The following equations show the relationship between LED current and bias voltage Vx.

For stable operation, it is recommended that R3 be set in the range of 50 k Ω to 150 k Ω and R5 in the range of

3.3 k Ω to 10 k Ω . Best performance is obtained with a pre-charge current of 45 mA typ. For single current level applications (e.g. torch or flashlight only) it is recommended to operate with R4 in the

range of 50k Ω to 200 k Ω . In that case R5 is not need anymore.

(5)

(6)

(7)

(8)

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

SENSE

LED



0.75

0.5

 1.5 

OUT(MAX)

 4.4  0.75  5.15 V

LED(FLASH)



R2 R3

2  R3  R

R3  100 k (recommended value) R2  47 k (calculated)

Vx 

1 2



2  R2

 I

LED

R3 R

VX 1.1 V @ I

LED

 150 mA (movie−light)

VX 1.4 V @ I

LED

 45 mA (pre−load)

Vx 

R4 R5

nFLASH

R4 R5

 0.78

R5  10 k (recommended value) R4  2.7 k (calculated)

Vx 

R5

R4 R5

nFLASH

R5

R4 R5

 0.61, R5  1.57  R4, R5 

R5 R6 R5 R6

R6  7.5 k (calculated)

IOK

nFLASH

LED

SENSE

BIAS

FB = 500 mV

TPS61058 TPS61059

SLVS572B – APRIL 2005 – REVISED DECEMBER 2005

The following example is used to explain the procedure to size the external components for a given set of requirements:

• Movie-light mode: I

• Flashlight mode: I

• LED forward voltage: V

• nFLASH signal is 1.8 V logic compliant (0 V and 1.8 V ± 4%)

Step 1 – Current Sense Resistor Calculation – R

Step 2 – Feedback Divider Resistor Calculation – R2, R3

Step 3 – Bias Resistor Network Calculation – R4, R5, R6

= 150 mA

LED

= 500 mA

LED

F (MAX)

= 4.4 V at 500 mA

(9)

(10)

During the pre-charge phase, IOK is high impedance.

In movie-light mode, IOK is grounded.

(11)

(12)

(13)

Figure 19. Feedback Network Equivalent Circuit

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IL I

OUT



OUT

VIN 0.8

OUT

 V

F(LED)

 RS I

LED

L 





OUT

 V



IL ƒ  V

OUT

TPS61058 TPS61059

SLVS572B – APRIL 2005 – REVISED DECEMBER 2005

INDUCTOR SELECTION

A boost converter normally requires two main passive components for storing energy during the conversion. A boost inductor and a storage capacitor at the output are required. To select the boost inductor, it is recommended to keep the possible peak inductor current below the current limit threshold of the power switch in the chosen configuration. For example, the current limit threshold of the TPS61059 switch is 1700 mA at an output voltage of 5 V. The highest peak current through the inductor and the switch depends on the output load, the input voltage and the output voltage. Estimation of the maximum average inductor current can be done using

Equation 14 :

For example, for an output current of 500 mA at 4.5 V, at least 800 mA of average current flows through the inductor at a minimum input voltage of 3.3 V.

The second parameter for choosing the inductor is the desired current ripple in the inductor. In order to optimized the solution size, inductor ripple currents as high as 40% of the average inductor current can be tolerated. A smaller ripple reduces the magnetic hysteresis losses in the inductor, as well as output voltage ripple and EMI. With those parameters, it is possible to calculate the value for the inductor by using Equation 16 :

(14) (15)

Parameter f is the switching frequency and ∆ ILis the ripple current in the inductor, i.e., 40% × IL. In this example, the desired inductor has the value of 4.5 µH. With this calculated value and the calculated currents, it is possible to choose a suitable inductor. In typical high current white LED applications a 4.7 µH inductance is recommended. Care has to be taken that load transients and losses in the circuit can lead to higher currents as estimated in Equation 16 . Also, the losses in the inductor caused by magnetic hysteresis losses and copper losses are a major parameter for total circuit efficiency.

The following inductor series from different suppliers have been used with the TPS61058/9 converters:

Table 1. List of Inductors

MANUFACTURER SERIES DIMENSIONS REMARKS

COILCRAFT LPS3015 3 mm x 3 mm x 1.5 mm max. height TPS61058

TDK

TAIYO YUDEN NP04SZB 5 mm x 5 mm x 2.0 mm max. height TPS61059

VLF3014AT 2.6 mm x 2.8 mm x 1.4 mm max. height TPS61058 VLF5014AT 4.5 mm x 4.7 mm x 1.4 mm max. height TPS61059

(16)

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min



OUT





OUT

 V



ƒ  V  V

OUT

V

ESR

 I

OUT

 R

ESR

TPS61058 TPS61059

SLVS572B – APRIL 2005 – REVISED DECEMBER 2005

CAPACITOR SELECTION

Input Capacitor

For good input voltage filtering low ESR ceramic capacitors are recommended. At least a 10-µF input capacitor is recommended to improve transient behavior of the regulator and EMI behavior of the total power supply circuit. The input capacitor should be placed as close as possible to the input pin of the converter.

Output Capacitor

The major parameter necessary to define the output capacitor is the maximum allowed output voltage ripple of the converter. This ripple is determined by two parameters of the capacitor, the capacitance and the ESR. It is possible to calculate the minimum capacitance needed for the defined ripple, supposing that the ESR is zero, by using Equation 17 :

Parameter f is the switching frequency and ∆ V is the maximum allowed ripple. With a chosen ripple voltage of 10 mV, a minimum capacitance of 22 µF is needed. The total ripple is larger due

to the ESR of the output capacitor. This additional component of the ripple can be calculated using Equation 18 :

The total ripple is the sum of the ripple caused by the capacitance and the ripple caused by the ESR of the capacitor. Additional ripple is caused by load transients. This means that the output capacitor has to completely supply the load during the charging phase of the inductor. A reasonable value of the output capacitance depends on the speed of the load transients and the load current during the load change.

For the high current white LED application, a minimum of 20 µF effective output capacitance is usually required when operating with 4.7 µH (typ) inductors. For solution size reasons, this is usually one or more X5R/X7R ceramic capacitors. In order to maintain the control loop stable, the addition of a compensation network formed by R1 (22 k Ω ) and C3 (1 nF COG) is necessary.

(17)

(18)

CHECKING LOOP STABILITY

The first step of circuit and stability evaluation is to look from a steady-state perspective at the following signals:

• Switching node, SW

• Inductor current, I

• Output ripple voltage, V

These are the basic signals that need to be measured when evaluating a switching converter. When the switching waveform shows large duty cycle jitter or the output voltage or inductor current shows oscillations, the regulation loop may be unstable. This is often a result of board layout and/or L-C combination.

As a next step in the evaluation of the regulation loop, the load transient response is tested. V monitored for settling time, overshoot or ringing that helps judge the converter's stability. Without any ringing, the loop has usually more than 45 ° of phase margin.

Because the damping factor of the circuitry is directly related to several resistive parameters (e.g., MOSFET r

) that are temperature dependant, the loop stability analysis has to be done over the input voltage range,

DS(on)

LED current range, and temperature range.

OUT(AC)

OUT

can be

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TPS61058 TPS61059

SLVS572B – APRIL 2005 – REVISED DECEMBER 2005

LAYOUT CONSIDERATIONS

As for all switching power supplies, the layout is an important step in the design, especially at high peak currents and high switching frequencies. If the layout is not carefully done, the regulator could show stability problems as well as EMI problems. Therefore, use wide and short traces for the main current path and for the power ground tracks.

The input capacitor, output capacitor, and the inductor should be placed as close as possible to the IC. Use a common ground node for power ground and a different one for control ground to minimize the effects of ground noise. Connect these ground nodes at any place close to one of the ground pins of the IC.

The compensation network as well as the current setting resistors should be placed as close as possible to the control ground pin of the IC. To lay out the control ground, it is recommended to use short traces as well, separated from the power ground traces. This avoids ground shift problems, which can occur due to superimposition of power ground current and control ground current.

Figure 20. Suggested Layout – Top Side

Figure 21. Suggested Layout – Bottom Side

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APPLICATION EXAMPLES

22 F

4.7 H

2.7 V . . 5.5 V

GND

TPS61058

GND

PVIN

VIN

SW VOUT

PGND

C1, C2, C3

IOK

FLASH ON (0/1.8 V)

22 F

39 k

22 k

56 k

1.5 

68 k

1 nF (COG)

5.6 k

List of Components: L1 = COILCRAFT LPS3015−4R7

C1,C2, C3 = TDK C2012X5R0J226MTJ

GND

TPS61059

GND

PVIN

VIN

SW VOUT

PGND

C1, C2, C3

1nF (COG)

List of Components: L1 = TDK VLF5014AT−4R7

C1,C2, C3 = TDK C2012X5R0J226MTJ

MOVIE−LIGHT nFLASH ILED

0 0 OFF 0 1 OFF 1 0 FLASHLIGHT 1 1 MOVIE− LIGHT

IOK

22 F

33 k

1.2 

3.9 k

10 k

R1 22 k

4.7 H

2.7 V . . 5.5 V

22 F

R3 75 k

MOVIE−LIGHT (0/2.8V)

nFLASH (0/2.8V)

4.7 k

100 nF

Note: Before turning into the flashlight mode, the device to be driven into movie−light mode. See the Design Procedure section for more details.

TPS61058 TPS61059

SLVS572B – APRIL 2005 – REVISED DECEMBER 2005

Figure 23. 150 mA Movie-Light/600 mA Flashlight Application - 2.8 V Logic

Figure 22. 500 mA Flashlight Application - 1.8 V Logic

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GND

TPS61058

GND

PVIN

VIN

VOUT

PGND

C1, C2, C3

1nF (COG)

IOK

List of Components: L1 = COILCRAFT LPS3015−4R7

C1,C2, C3 = TDK C2012X5R0J226MTJ

1.5 

R4 150 k

4.7 H

R3 51 k

FLASH ON (0/2.8V)

22 F

39 k

10 k

22 k

2.7 V . . 5.5 V

22 F

4.7 H

GND

TPS61059

GND

PVIN

VIN

VOUT

PGND

C1, C2, C3

1nF (COG)

MOVIE−LIGHT (0/1.8 V)

List of Components: L1 = TDK VLF5014AT−4R7

C1,C2, C3 = TDK C2012X5R0J226MTJ

TX−TOFF (0/1.8 V)

IOK

n FLASH (0/1.8 V)

LVC1G32

1V8

68 k

100 k

3.6 k

22 k

22 F

2.7 V . . 5.5 V

1.2 

12 k

6.8 k

100nF

TPS61058 TPS61059

SLVS572B – APRIL 2005 – REVISED DECEMBER 2005

Figure 24. 500 mA Flashlight Application - 2.8 V Logic

Figure 25. 150 mA Movie-Light/700 mA Flashlight with No-Latency Current Reduction

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GND

TPS61059

GND

PVIN

VIN

VOUT

PGND

C1, C2, C3

1nF (COG)

IOK

List of Components: L1 = TDK VLF5014AT−4R7

C1,C2, C3 = TDK C2012X5R0J226MTJ

2.0 

R6 110 k

4.7 H

R5 75 k

FLASH ON (0/2.8V)

22 F

75 k

5.1 k

22 k

2.7 V . . 5.5 V

2.0 

75 k

C5 100 nF

TPS61058 TPS61059

SLVS572B – APRIL 2005 – REVISED DECEMBER 2005

Figure 26. 2x 350 mA Flashlight Application - 2.8 V Logic

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D(MAX)



J(MAX)

 T

JA



125°C  85°C

48.7 °CW

 820 mW

TPS61058 TPS61059

SLVS572B – APRIL 2005 – REVISED DECEMBER 2005

THERMAL INFORMATION

Implementation of integrated circuits in low-profile and fine-pitch surface-mount packages typically requires special attention to power dissipation. Many system-dependent issues such as thermal coupling, airflow, added heat sinks and convection surfaces, and the presence of other heat-generating components affect the power-dissipation limits of a given component.

Three basic approaches for enhancing thermal performance are listed below.

• Improving the power dissipation capability of the PCB design

• Improving the thermal coupling of the component to the PCB

• Introducing airflow in the system

The maximum recommended junction temperature (T resistance of the 10-pin QFN 3 x 3 package (DRC) is R regulator operation is assured to a maximum ambient temperature T dissipation is about 820 mW. More power can be dissipated if the maximum ambient temperature of the application is lower.

) of the TPS61058/9 devices is 125 ° C. The thermal

= 48.7 ° C/W, if the PowerPAD is soldered. Specified

θ JA

of 85 ° C. Therefore, the maximum power

(19)

PACKAGE OPTION ADDENDUM

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5-Feb-2007

PACKAGING INFORMATION

Orderable Device Status

(1)

Package

Type

Package Drawing

Pins Package

Qty

Eco Plan

TPS61058DRCR ACTIVE SON DRC 10 3000 Green (RoHS &

no Sb/Br)

TPS61058DRCRG4 ACTIVE SON DRC 10 3000 Green (RoHS &

no Sb/Br)

TPS61059DRCR ACTIVE SON DRC 10 3000 Green (RoHS &

no Sb/Br)

TPS61059DRCRG4 ACTIVE SON DRC 10 3000 Green (RoHS &

no Sb/Br)

TPS61059DRCT ACTIVE SON DRC 10 250 Green (RoHS &

no Sb/Br)

TPS61059DRCTG4 ACTIVE SON DRC 10 250 Green (RoHS &

no Sb/Br)

(1)

The marketing status values are defined as follows:

ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in

a new design.

PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device.

(2)

Lead/Ball Finish MSL Peak Temp

CU NIPDAU Level-2-260C-1 YEAR

(3)

(2)

Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check

http://www.ti.com/productcontent for the latest availability information and additional product content details.

TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements

for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material)

(3)

MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder

temperature.

Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.

In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.

Addendum-Page 1

PACKAGE MATERIALS INFORMATION

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17-May-2007

TAPE AND REEL INFORMATION

Pack Materials-Page 1

PACKAGE MATERIALS INFORMATION

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Device Package Pins Site Reel

Diameter

(mm)

TPS61058DRCR DRC 10 MLA 330 12 3.3 3.3 1.1 8 12 PKGORN

TPS61059DRCR DRC 10 MLA 330 12 3.3 3.3 1.1 8 12 PKGORN

TPS61059DRCT DRC 10 MLA 180 12 3.3 3.3 1.1 8 12 PKGORN

Reel

Width

(mm)

A0 (mm) B0 (mm) K0 (mm) P1

(mm)W(mm)

17-May-2007

Pin1

Quadrant

T2TR-MS

TAPE AND REEL BOX INFORMATION

Device Package Pins Site Length (mm) Width (mm) Height (mm)

TPS61058DRCR DRC 10 MLA 346.0 346.0 29.0 TPS61059DRCR DRC 10 MLA 346.0 346.0 29.0 TPS61059DRCT DRC 10 MLA 190.0 212.7 31.75

Pack Materials-Page 2

PACKAGE MATERIALS INFORMATION

www.ti.com

17-May-2007

Pack Materials-Page 3

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TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TI’s standard warranty. Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty. Except where mandated by government requirements, testing of all parameters of each product is not necessarily performed.

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Texas Instruments TPS 61058 INSTALLATION INSTRUCTIONS

Specifications and Main Features

Frequently Asked Questions

User Manual

FEATURES DESCRIPTION

APPLICATIONS

ABSOLUTE MAXIMUM RATINGS

DISSIPATION RATINGS TABLE

ELECTRICAL CHARACTERISTICS

PIN ASSIGNMENTS

PARAMETER MEASUREMENT INFORMATION

TYPICAL CHARACTERISTICS

DETAILED DESCRIPTION

OPERATION

Synchronous Rectifier

Down Regulation

Enable

Softstart

Overvoltage Protection (OVP)

Efficiency and Sense Voltage

Thermal Shutdown

APPLICATION INFORMATION

DESIGN PROCEDURE

INDUCTOR SELECTION

CAPACITOR SELECTION

Input Capacitor

Output Capacitor

CHECKING LOOP STABILITY

LAYOUT CONSIDERATIONS

APPLICATION EXAMPLES

THERMAL INFORMATION