Not Recommended for New Designs
TPS61058
TPS61059
(3,25 mm x 3,25 mm)
www.ti.com
SLVS572B – APRIL 2005 – REVISED DECEMBER 2005
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 mm2
Small 3mm x 3mm QFN-10 Package
APPLICATIONS
•
Torch/Camera White LED Supply for Cell
Phones, Smart-Phones and PDAs
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
frequency, pulse-width-modulation (PWM)
using a synchronous rectifier to obtain
efficiency. The maximum peak current in
switch is limited to 1000 mA (TPS61058)
mA (TPS61059).
kHz fixed
controller
maximum
the boost
and 1500
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).
VIN
4.7 µH
C IN
TPS61058
SW
VOUT
PVIN
22 µF
x3
VIN
22 µF
D1
R2
FB
C3
1 nF
(COG)
R1
22 kΩ
FLASH ON (0/1.8 V)
100
C1, C2, C3
EN
GND
GND
39 kΩ
R3
56 kΩ
Rs
1.5 Ω
R5
IOK
PGND
5.6 kΩ
R4
62 kΩ
Figure 1. 500 mA Flashlight Application
LED Power Efficiency (PLED/PIN) - %
L1
2.7 V . . 5.5 V
ILED = 500 mA @ VF = 3.7 V
90
80
70
60
50
40
30
20
10
0
2.70 3.10
3.50 3.90 4.30 4.70
VI - Input Voltage - V
5.10
5.50
Figure 2. Flashlight Efficiency vs VIN
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.
Copyright © 2005, Texas Instruments Incorporated
Not Recommended for New Designs
TPS61058
TPS61059
www.ti.com
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
TA
-40°C to 85°C
(1)
(2)
CURRENT LIMIT
PACKAGE MARKING
1000 mA
BNF
1500 mA
BNG
PACKAGE
10-Pin QFN
PART NUMBER (1) (2)
TPS61058DRC
TPS61059DRC
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.
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.
ABSOLUTE MAXIMUM RATINGS
over operating free-air temperature range (unless otherwise noted) (1)
TPS61058/9
Input voltage range on PVIN, VIN, EN, FB, IOK, SW, VOUT
-0.3 V to 7 V
Power dissipation
Internally limited
Operation temperature range, TA
-40°C to 85°C
Maximum operating junction temperature, TJ(max)
150°C
Storage temperature range, Tstg
(1)
-65°C to 150°C
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.
DISSIPATION RATINGS TABLE
2
PACKAGE
THERMAL RESISTANCE
ΘJA
POWER RATING
TA≤ 25°C
DERATING FACTOR ABOVE
TA = 25°C
DRC
48.7 °C/W
2040 mW
21 mW/°C
Not Recommended for New Designs
TPS61058
TPS61059
www.ti.com
SLVS572B – APRIL 2005 – REVISED DECEMBER 2005
ELECTRICAL CHARACTERISTICS
VIN = 3.6 V, ILED = 500 mA, EN = VIN, L = 4.7 µH, C O = 3x 22 µF, T A = –40°C to 85°C, typical values are at TA = 25°C (unless
otherwise noted)
DC/DC STAGE
PARAMETER
TEST CONDITIONS
TYP
MAX
UNIT
Input voltage range
VOUT
TPS61058/9 output voltage range
VOVP
Output overvoltage protection
5.9
6.1
6.3
V
VFB
TPS61058/9 feedback voltage
490
500
510
mV
f
Oscillator frequency
550
650
750
kHz
ISW
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
SWN switch on resistance
VO = 3.3V
260
SWP switch on resistance
VO = 3.3 V
290
rDS(on)
VO > 2.0 V @ ILED = 50 mA
MIN
VIN
Total accuracy (including line and load regulation)
2.7
5.5
V
2.5
5.5
V
84
mA
-3%
mΩ
mΩ
3%
IQ
Quiescent current
ILED = 0 mA, VO = 5.0 V,
Device switching at 650 kHz
5.5
I(SD)
Shutdown current
EN = GND, TA = 25°C
0.1
mA
1
µA
CONTROL STAGE
IOK switch on-resistance
VO = 5.0 V, IIOK = 100 µA
0.6
IOK output low current
IOK output leakage current
V(IL)
VIOK = 7 V
0.8
1
kΩ
100
300
µA
0.01
0.1
µA
0.4
V
0.1
µA
EN low-level input voltage
V(IH)
EN high-level input voltage
I(I)
EN input leakage current
1.4
Input tied to GND
V
0.01
EN pull-down resistance
400
kΩ
Overtemperature protection
140
°C
Overtemperature hysteresis
20
°C
3
Not Recommended for New Designs
TPS61058
TPS61059
www.ti.com
SLVS572B – APRIL 2005 – REVISED DECEMBER 2005
PIN ASSIGNMENTS
DRC Package
(TOP VIEW)
EN
VOUT
FB
IOK
GND
PGND
SW
VIN
GND
PVIN
Terminal Functions
TERMINAL
NAME
NO.
I/O
DESCRIPTION
EN
1
I
This is the enable pin of the device. Connect this pin to ground forces the device into shutdown mode. Pulling
this pin above 1.4V enables the device. This pin has an internal pull-down resistor.
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
resistor. The feedback voltage is set internally to 500mV.
IOK
4
O
This pin indicates that the dc-dc converter is ready for high current operation (open drain output).
GND
5, 7
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
PGND
10
PowerPAD™
4
Control / logic ground.
This is the switching pin of the converter.
Power ground.
Must be soldered to achieve appropriate power dissipation. Should be connected to PGND.
Not Recommended for New Designs
TPS61058
TPS61059
www.ti.com
SLVS572B – APRIL 2005 – REVISED DECEMBER 2005
FUNCTIONAL BLOCK DIAGRAM (TPS61058/9)
SW
VIN
PVIN
VOUT
20 pF
EN
10 kW
Vmax
control
Gate
Control
PGND
PGND
PGND
Regulator
ErrorAmplifier
FB
Vref
OVP
Vref
Control Logic
Oscillator
Temperature
Control
EN
400 kW
IOK
GND
GND
5
Not Recommended for New Designs
TPS61058
TPS61059
www.ti.com
SLVS572B – APRIL 2005 – REVISED DECEMBER 2005
PARAMETER MEASUREMENT INFORMATION
L1
2.7 V . . 5.5 V
VIN
TPS61058/9
SW
4.7 mF
CIN
VOUT
PVIN
C1, C2, C3
22 mF
VIN
x3
D1
R2
FB
22 mF
C3
1 nF (COG)
Rs
R1
22 kW
TORCH ON (0/1.8 V)
EN
R3
R6
GND
IOK
GND
PGND
R5
C4
(Optional)
R4
FLASH (0 . .2 V)
List of Components:
L1 = TDK VLF5014AT-4R7
T
C1,C2,C3 = TDK C2012X5R0J226MTJ
500 mA Flashlight Application
Rs = 1.3 W
R2 = 56 kW
R3 = 100 kW
R4 = 2.4 kW
R5 = 6.2 kW
R6 = 91 kW
700 mA Flashlight Application
Rs = 1.2 W
R2 = 47 kW
R3 = 51 kW
R4 = 3.3 kW
R5 = 4.3 kW
R6 = 120 kW
C4 = 100 nF
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
6
Not Recommended for New Designs
TPS61058
TPS61059
www.ti.com
SLVS572B – APRIL 2005 – REVISED DECEMBER 2005
TPS61058
LED POWER EFFICIENCY
vs
INPUT VOLTAGE
TPS61059
LED POWER EFFICIENCY
vs
INPUT VOLTAGE
100
100
LED Power Efficiency (PLED/PIN) − %
90
LEDPowerEfficiency(PLED/PIN)-%
ILED = 150 mA @ VF = 3.0 V
ILED = 150 mA @ VF = 3.4 V
80
70
60
50
ILED = 500 mA @ VF = 3.7 V
40
30
20
10
0
2.70
90
80
70
60
50
ILED = 700 mA @ VF = 3.4 V
40
30
20
10
3.10
3.50
3.90
4.30
4.70
5.10
5.50
0
2.70
VI - Input Voltage - V
100
3.10
3.50
3.90
4.30
4.70
5.10
5.50
VI − Input Voltage − V
Figure 3.
Figure 4.
TPS61058
EFFICIENCY
vs
LED CURRENT
TPS61058
DC INPUT CURRENT
vs
INPUT VOLTAGE
1400
VIN = 3.3 V
90
Input DC Current - mA
LED Power Efficiency (PLED/PIN) - %
1200
80
VIN = 4.2 V
70
60
VIN = 3.6 V
50
40
30
1000
800
600
400
ILED = 500 mA
20
200
10
0
100
0
150
200
250
300
350
LED Current - mA
Figure 5.
400
450
500
2.70
3.10
3.50 3.90 4.30 4.70
VI - Input Voltage - V
5.10
5.50
Figure 6.
7
Not Recommended for New Designs
TPS61058
TPS61059
www.ti.com
SLVS572B – APRIL 2005 – REVISED DECEMBER 2005
TPS61058
LED CURRENT
vs
INPUT VOLTAGE
OSCILLATOR FREQUENCY
16
600
TA = 25C
ILED = 500 mA
14
Percent of Units − %
LED Current - mA
500
400
300
200
ILED = 150 mA
12
10
8
6
4
100
2
f − Oscillator Frequency − kHz
Figure 7.
Figure 8.
TPS61059
CURRENT LIMIT
vs
TEMPERATURE
TPS61058
SWITCHING WAVEFORMS IN BOOST MODE
Switch Current Limit − mA
1750
VI = 3.6 V, ILED = 500 mA
1650
SW (2 V/div)
1550
IL (200 mA/div)
1450
ILED (200 mA/div)
1350
1250
-40 -30 -20 -10
0 10 20 30 40 50 60 70 80
Ambient Temperature − C
Figure 9.
8
VOUT (10 mV/div - 3.8 V OFFSET)
t - Time - 500 ns/div
Figure 10.
672
664
657
650
643
0
636
5.50
629
5.10
622
3.50 3.90 4.30 4.70
VI - Input Voltage - V
615
3.10
606
0
2.70
Not Recommended for New Designs
TPS61058
TPS61059
www.ti.com
SLVS572B – APRIL 2005 – REVISED DECEMBER 2005
TPS61058
SWITCHING WAVEFORMS IN DOWN MODE
TPS61058
HIGH CURRENT FLASHLIGHT PULSE WAVEFORM
EN (1 V/div)
SW
(2 V/div)
VOUT(1 V/div)
IL(200 mA/div)
IL(200 mA/div)
ILED (200mA/div)
ILED(200 mA/div)
VOUT
(10 mV/div - 3.8 V OFFSET)
VI = 4.5 V, ILED = 500 mA
t - Time - 500 ns/div
VI = 3.6 V
t - Time - 5 ms/div
Figure 11.
Figure 12.
TPS61058
TORCH TO FLASHLIGHT TRANSISTION
TPS61058
START-UP AFTER ENABLE
VOUT (1 V/div)
EN (1 V/div)
V OUT (1 V/div)
IL (500 mA/div)
I LED (50 mA/div)
I L (100 mA/div)
ILED (200 mA/div)
t - Time - 50 ms/div
Figure 13.
t - Time - 200 ms/div
Figure 14.
9
TPS61058
TPS61059
Not Recommended for New Designs
www.ti.com
SLVS572B – APRIL 2005 – REVISED DECEMBER 2005
TPS61058
OVERVOLTAGE PROTECTION
TPS61058
DUTY CYCLE JITTER
VOUT (200 mV/div - 5 V OFFSET)
SW (2 V/div)
VI = 3.6 V
Triggered On Falling Edge
t - Time - 50 ms/div
Figure 15.
10
ILED= 500 mA
t - Time - 50 ns/div
Figure 16.
Not Recommended for New Designs
www.ti.com
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 VF 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-kΩ 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.
11
TPS61058
TPS61059
Not Recommended for New Designs
www.ti.com
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 (RS) has a direct effect of the converter efficiency. Because the sense
voltage does not contribute to the output power (PLED), the lower this voltage the higher the efficiency. It is
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.
12
Not Recommended for New Designs
TPS61058
TPS61059
www.ti.com
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.
VIN
TPS61058/9
4.7 µH
CIN
SW
PVIN
VIN
VOUT
MOVIE-LIGHT
C1, C2, C3
22 µF
x3
22 µF
D1
R2
FB
1 nF (COG)
R3
R1
22 kΩ
MOVIE-LIGHT
EN
IOK
nFLASH
C4
R6
C5
R5
V SENSE
L1
2.7 V . . 5.5 V
Rs
IOK
Hi-Z
Hi-Z
Movie-Light
Vx
Flashlight
100nF
R4
GND
GND
PGND
ILED
Pre-Charge
nFLASH
Figure 18. Waveform Profiles
Figure 17. Typical Application
The LED current is programmed using external resistors (RS, R2, R3, R4, R5, and R6). The first step to turn on
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, RS
The voltage across the sense resistor should be set to approximately 0.75 V at maximum LED current.
V
R SENSE
S
I
LED
Check the power rating of the sense resistor (PD = RS× ILED
(1)
2).
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
(IBIAS) can be adjusted which, in effect, controls the LED current without changing any externals.
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).
13
Not Recommended for New Designs
TPS61058
TPS61059
www.ti.com
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 (VX) of the feedback network.
0.5 R2 I
I
LED
BIAS
R
S
R5
I
nFLASH 0.5 , assuming R4R5 is small compared R3.
BIAS
R3 (R4 R5)
R3
(2)
(3)
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 VX node. As a consequence the LED current is adjusted accordingly.
0.5 R2 I
BIAS2
1
R2
R2
Vx
2R
2 R3 R
R3 R
S
S
S
S
R5
I
nFLASH 0.5 , with R5 R5 R6
BIAS2
R3 (R4 R5)
R3
R5 R6
I
LED
R
For operation at maximum LED current (flashlight mode), nFLASH needs to be set to ground level.
I
R2 R3 , assumingR4R5R6 is small compared R3.
LED(FLASH)
2 R3 R
S
(4)
(5)
(6)
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.
R3 R
S
Vx 1 R3 I
LED(MOVIELIGHT,PRECHARGE)
2 2 R2
R2
(7)
Vx
R5
nFLASH, with R5 R5 R6
R4 R5
R5 R6
(8)
For stable operation, it is recommended that R3 be set in the range of 50 kΩ to 150 kΩ and R5 in the range of
3.3 kΩ to 10 kΩ. 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 50kΩ to 200 kΩ. In that case R5 is not need anymore.
14
Not Recommended for New Designs
TPS61058
TPS61059
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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: ILED = 150 mA
• Flashlight mode: ILED = 500 mA
• LED forward voltage: VF (MAX) = 4.4 V at 500 mA
• nFLASH signal is 1.8 V logic compliant (0 V and 1.8 V ±4%)
Step 1 – Current Sense Resistor Calculation – RS
V
R SENSE 0.75 1.5
V
4.4 0.75 5.15 V
S
OUT(MAX)
0.5
I
LED
(9)
Step 2 – Feedback Divider Resistor Calculation – R2, R3
I
LED(FLASH)
R2 R3
2 R3 R
R3 100 k (recommended value)
R2 47 k (calculated)
S
(10)
Step 3 – Bias Resistor Network Calculation – R4, R5, R6
Vx 1 R3 I
LED
2 2 R2
R3 R
S
R2
150 mA (movie−light)
V 1.1 V @ I
LED
X
V 1.4 V @ I
45 mA (pre−load)
X
LED
During the pre-charge phase, IOK is high impedance.
R5
0.78
R4 R5
R5
Vx
nFLASH
R4 R5
R5 10 k (recommended value)
R4 2.7 k (calculated)
(11)
(12)
In movie-light mode, IOK is grounded.
Vx
R5
0.61, R5 1.57 R4, R5 R5 R6
R5 R6
R4 R5
R5
nFLASH
R4 R5
R6 7.5 k (calculated)
(13)
I LED
FB = 500 mV
R2
R3
IOK
VSENSE
RS
I BIAS
R6
VX
M1
R5
R4
nFLASH
Figure 19. Feedback Network Equivalent Circuit
15
Not Recommended for New Designs
TPS61058
TPS61059
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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:
V
OUT
I I
L
OUT V 0.8
IN
(14)
V
V
R I
OUT
F(LED)
S
LED
(15)
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:
V
V
V
IN
OUT
IN
L
I ƒ V
L
OUT
(16)
Parameter f is the switching frequency and∆ IL is 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
COILCRAFT
TDK
TAIYO YUDEN
16
SERIES
LPS3015
DIMENSIONS
REMARKS
3 mm x 3 mm x 1.5 mm max. height
TPS61058
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
5 mm x 5 mm x 2.0 mm max. height
TPS61059
NP04SZB
Not Recommended for New Designs
www.ti.com
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:
I
C
min
V
V
OUT
OUT
IN
ƒ V V
OUT
(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:
V
I
R
ESR
OUT
ESR
(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 kΩ) and C3 (1 nF COG) is necessary.
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, IL
• Output ripple voltage, VOUT(AC)
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. VOUT can be
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
rDS(on)) that are temperature dependant, the loop stability analysis has to be done over the input voltage range,
LED current range, and temperature range.
17
Not Recommended for New Designs
TPS61058
TPS61059
www.ti.com
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
18
Not Recommended for New Designs
TPS61058
TPS61059
www.ti.com
SLVS572B – APRIL 2005 – REVISED DECEMBER 2005
APPLICATION EXAMPLES
TPS61058
L1
VOUT
SW
4.7 H
C1, C2, C3
22 F
x3
PVIN
2.7 V . . 5.5 V
CIN
VIN
VIN
D1
R2
39 k
FB
22 F
C3
1 nF
(COG)
Rs
1.5
R3
56 k
R1
22 k
FLASH ON (0/1.8 V)
R6
EN
IOK
GND
5.6 k
PGND
GND
R4
68 k
List of Components:
L1 = COILCRAFT LPS3015−4R7
C1,C2, C3 = TDK C2012X5R0J226MTJ
Figure 22. 500 mA Flashlight Application - 1.8 V Logic
TPS61059
L1
2.7 V . . 5.5 V
4.7 H
CIN
V
IN
SW
PVIN
VOUT
C1, C2, C3
22 F
x3
VIN
22 F
D1
R2
FB
C4
1nF (COG)
33 k
R1
22 k
R3
75 k
Rs
1.2
EN
MOVIE−LIGHT (0/2.8V)
R6
IOK
10 k
GND
GND
R5
4.7 k
PGND
C5
100 nF
R4
3.9 k
nFLASH (0/2.8V)
List of Components:
L1 = TDK VLF5014AT−4R7
C1,C2, C3 = TDK C2012X5R0J226MTJ
MOVIE− LIGHT
0
0
1
1
nFLASH
0
1
0
1
Note: Before turning into the flashlight mode, the
device to be driven into movie−light mode. See the
Design Procedure section for more details.
ILED
OFF
OFF
FLASHLIGHT
MOVIE − LIGHT
Figure 23. 150 mA Movie-Light/600 mA Flashlight Application - 2.8 V Logic
19
Not Recommended for New Designs
TPS61058
TPS61059
www.ti.com
SLVS572B – APRIL 2005 – REVISED DECEMBER 2005
TPS61058
L1
2.7 V . . 5.5 V
V IN
4.7 H
CIN
SW
PVIN
VIN
VOUT
C1, C2, C3
22 F
x3
22 F
D1
R2
FB
C4
1nF (COG)
39 k
Rs
1.5
R3
51 k
R1
22 k
EN
FLASH ON (0/2.8V)
R6
IOK
10 k
GND
GND
R4
150 k
PGND
List of Components:
L1 = COILCRAFT LPS3015−4R7
C1,C2, C3 = TDK C2012X5R0J226MTJ
Figure 24. 500 mA Flashlight Application - 2.8 V Logic
TPS61059
L1
2.7 V . . 5.5 V
VIN
4.7 H
C IN
SW
PVIN
VIN
VOUT
C1, C2, C3
22 F
x3
22 F
D1
R2
FB
C4
1nF (COG)
R3
100 k
R1
22 k
MOVIE−LIGHT (0/1.8 V)
EN
IOK
TX−TOFF (0/1.8 V)
n FLASH (0/1.8 V)
Rs
1.2
R6
12 k
C5
R5
6.8 k
GND
GND
68 k
100nF
R4
3.6 k
PGND
1V8
LVC1G32
List of Components:
L1 = TDK VLF5014AT−4R7
C1,C2, C3 = TDK C2012X5R0J226MTJ
Figure 25. 150 mA Movie-Light/700 mA Flashlight with No-Latency Current Reduction
20
Not Recommended for New Designs
TPS61058
TPS61059
www.ti.com
SLVS572B – APRIL 2005 – REVISED DECEMBER 2005
TPS61059
L1
2.7 V . . 5.5 V
V IN
4.7 H
CIN
SW
PVIN
VIN
VOUT
C1, C2, C3
22 F
x3
22 F
D1
R3
R4
FB
C3
1nF (COG)
R1
22 k
D2
75 k
75 k
V1
R1
2.0
R5
75 k
V2
R2
2.0
EN
FLASH ON (0/2.8V)
R7
IOK
5.1 k
GND
GND
C5
100 nF
PGND
R6
110 k
List of Components:
L1 = TDK VLF5014AT−4R7
C1,C2, C3 = TDK C2012X5R0J226MTJ
Figure 26. 2x 350 mA Flashlight Application - 2.8 V Logic
21
TPS61058
TPS61059
Not Recommended for New Designs
www.ti.com
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 (TJ) of the TPS61058/9 devices is 125°C. The thermal
resistance of the 10-pin QFN 3 x 3 package (DRC) is RθJA = 48.7 °C/W, if the PowerPAD is soldered. Specified
regulator operation is assured to a maximum ambient temperature TA of 85°C. Therefore, the maximum power
dissipation is about 820 mW. More power can be dissipated if the maximum ambient temperature of the
application is lower.
T
T
J(MAX)
A
P
125°C 85°C 820 mW
D(MAX)
R
48.7 °CW
JA
(19)
22
PACKAGE OPTION ADDENDUM
www.ti.com
23-Aug-2017
PACKAGING INFORMATION
Orderable Device
Status
(1)
TPS61059DRCT
NRND
Package Type Package Pins Package
Drawing
Qty
VSON
DRC
10
250
Eco Plan
Lead/Ball Finish
MSL Peak Temp
(2)
(6)
(3)
Green (RoHS
& no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
Op Temp (°C)
Device Marking
(4/5)
-40 to 85
BNG
(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)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
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