Texas Instruments TPS61041 User manual

3
2
4
5
DDC, DBV PACKAGE
(Top View)
1
SW
GND
FB
VIN
EN
GND SW
VIN NC
EN FB
3
2
1
4
5
6
DRV PACKAGE
(Top View)
70
72
74
76
78
80
82
84
86
88
90
0.1 1 10 100
VI= 5 V
VI= 3.6 V
VI= 2.4 V
EFFICIENCY
vs
OUTPUT CURRENT
IO− Output Current − mA
Efficiency − %
VIN SW
FB
EN GND
L1
10 µHD1
R1
R2
CFF
CO
1µF
VOUT
VIN to 28 V
VIN
1.8 V to 6 V
CIN
4.7 µF
5
42
3
1
VO= 18 V
TPS61040
TPS61041
www.ti.com SLVS413F –OCTOBER 2002–REVISED DECEMBER 2010
LOW-POWER DC/DC BOOST CONVERTER IN SOT-23 AND SON PACKAGES
Check for Samples: TPS61040,TPS61041
1FEATURES DESCRIPTION
• 1.8-V to 6-V Input Voltage Range The TPS61040/41 is a high-frequency boost
converter dedicated for small to medium LCD bias
• Adjustable Output Voltage Range up to 28 V supply and white LED backlight supplies. The device
• 400-mA (TPS61040) and 250-mA (TPS61041) is ideal to generate output voltages up to 28 V from a
Internal Switch Current dual cell NiMH/NiCd or a single cell Li-Ion battery.
• Up to 1-MHz Switching Frequency The part can also be used to generate standard
3.3-V/5-V to 12-V power conversions.
• 28-mA Typical No-Load Quiescent Current
• 1-mA Typical Shutdown Current The TPS61040/41 operates with a switching
frequency up to 1 MHz. This allows the use of small
• Internal Soft Start external components using ceramic as well as
• Available in SOT23-5, TSOT23-5, tantalum output capacitors. Together with the thin
and 2 × 2 × 0.8-mm SON Packages SON package, the TPS61040/41 gives a very small
overall solution size. The TPS61040 has an internal
APPLICATIONS 400 mA switch current limit, while the TPS61041 has
• LCD Bias Supply a 250-mA switch current limit, offering lower output
voltage ripple and allows the use of a smaller form
• White-LED Supply for LCD Backlights factor inductor for lower power applications. The low
• Digital Still Camera quiescent current (typically 28 mA) together with an
• PDAs, Organizers, and Handheld PCs optimized control scheme, allows device operation at
• Cellular Phones very high efficiencies over the entire load current
range.
• Internet Audio Player
• Standard 3.3-V/5-V to 12-V Conversion
TYPICAL APPLICATION
1Please 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. Copyright © 2002–2010, Texas Instruments Incorporated
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.

+
+
-
RS Latch
Logic
S
R
Gate
Driver
_
Current Limit
Power MOSFET
N-Channel
RSENSE
Soft
Start
6 µs Max
On Time
VREF = 1.233 V
Error Comparator
400 ns Min
Off Time
Under Voltage
Lockout
Bias Supply
VIN
FB
EN
GND
SW
TPS61040
TPS61041
SLVS413F –OCTOBER 2002–REVISED DECEMBER 2010 www.ti.com
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.
Table 1. ORDERING INFORMATION (1)
SWITCH CURRENT PACKAGE
TAPART NUMBER(2) PACKAGE
LIMIT, mA MARKING
TPS61040DBV 400 SOT23-5 PHOI
TPS61040DDC 400 TSOT23-5 QXK
–40°C to TPS61041DBV 250 SOT23-5 PHPI
85°C TPS61040DRV 400 SON-6 2×2 CCL
TPS61041DRV 250 SON-6 2×2 CAW
(1) 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.
(2) The devices are available in tape and reel and in tubes. Add R suffix to the part number (e.g.,
TPS61040DRVR) to order quantities of 3000 parts in tape and reel or add suffix T (e.g.,
TPS61040DRVT) to order a tube with 250 pieces..
FUNCTIONAL BLOCK DIAGRAM
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Ipeak(typ) +ILIM )VIN
L 100 ns
Ipeak(typ) +400 mA )VIN
L 100 ns for the TPS61040
Ipeak(typ) +250 mA )VIN
L 100 ns for the TPS61041
TPS61040
TPS61041
www.ti.com SLVS413F –OCTOBER 2002–REVISED DECEMBER 2010
Table 2. Terminal Functions
TERMINAL I/O DESCRIPTION
DDC,
NAME DRV NO.
DBV NO.
This is the enable pin of the device. Pulling this pin to ground forces the device into shutdown
EN 4 3 I mode reducing the supply current to less than 1 mA. This pin should not be left floating and needs
to be terminated.
This is the feedback pin of the device. Connect this pin to the external voltage divider to program
FB 3 4 I the desired output voltage.
GND 2 1 – Ground
NC – 5 – No connection
Connect the inductor and the Schottky diode to this pin. This is the switch pin and is connected to
SW 1 6 I the drain of the internal power MOSFET.
VIN 5 2 I Supply voltage pin
DETAILED DESCRIPTION
OPERATION
The TPS61040/41 operates with an input voltage range of 1.8 V to 6 V and can generate output voltages up to
28 V. The device operates in a pulse-frequency-modulation (PFM) scheme with constant peak current control.
This control scheme maintains high efficiency over the entire load current range, and with a switching frequency
up to 1 MHz, the device enables the use of very small external components.
The converter monitors the output voltage, and as soon as the feedback voltage falls below the reference voltage
of typically 1.233 V, the internal switch turns on and the current ramps up. The switch turns off as soon as the
inductor current reaches the internally set peak current of typically 400 mA (TPS61040) or 250 mA (TPS61041).
See the Peak Current Control section for more information. The second criteria that turns off the switch is the
maximum on-time of 6 ms (typical). This is just to limit the maximum on-time of the converter to cover for extreme
conditions. As the switch is turned off the external Schottky diode is forward biased delivering the current to the
output. The switch remains off for a minimum of 400 ns (typical), or until the feedback voltage drops below the
reference voltage again. Using this PFM peak current control scheme the converter operates in discontinuous
conduction mode (DCM) where the switching frequency depends on the output current, which results in very high
efficiency over the entire load current range. This regulation scheme is inherently stable, allowing a wider
selection range for the inductor and output capacitor.
PEAK CURRENT CONTROL
The internal switch turns on until the inductor current reaches the typical dc current limit (ILIM) of 400 mA
(TPS61040) or 250 mA (TPS61041). Due to the internal propagation delay of typical 100 ns, the actual current
exceeds the dc current limit threshold by a small amount. The typical peak current limit can be calculated:
(1)
The higher the input voltage and the lower the inductor value, the greater the peak.
By selecting the TPS61040 or TPS61041, it is possible to tailor the design to the specific application current limit
requirements. A lower current limit supports applications requiring lower output power and allows the use of an
inductor with a lower current rating and a smaller form factor. A lower current limit usually has a lower output
voltage ripple as well.
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Product Folder Link(s): TPS61040 TPS61041

ILIM
4
ILIM
2
TPS61040
TPS61041
SLVS413F –OCTOBER 2002–REVISED DECEMBER 2010 www.ti.com
SOFT START
All inductive step-up converters exhibit high inrush current during start-up if no special precaution is made. This
can cause voltage drops at the input rail during start up and may result in an unwanted or early system shut
down.
The TPS61040/41 limits this inrush current by increasing the current limit in two steps starting from for 256
cycles to for the next 256 cycles, and then full current limit (see Figure 14).
ENABLE
Pulling the enable (EN) to ground shuts down the device reducing the shutdown current to 1 mA (typical).
Because there is a conductive path from the input to the output through the inductor and Schottky diode, the
output voltage is equal to the input voltage during shutdown. The enable pin needs to be terminated and should
not be left floating. Using a small external transistor disconnects the input from the output during shutdown as
shown in Figure 18.
UNDERVOLTAGE LOCKOUT
An undervoltage lockout prevents misoperation of the device at input voltages below typical 1.5 V. When the
input voltage is below the undervoltage threshold, the main switch is turned off.
THERMAL SHUTDOWN
An internal thermal shutdown is implemented and turns off the internal MOSFETs when the typical junction
temperature of 168°C is exceeded. The thermal shutdown has a hysteresis of typically 25°C. This data is based
on statistical means and is not tested during the regular mass production of the IC.
ABSOLUTE MAXIMUM RATINGS
over operating free-air temperature (unless otherwise noted) (1)
UNIT
Supply voltages on pin VIN (2) –0.3 V to 7 V
Voltages on pins EN, FB (2) –0.3 V to VIN + 0.3 V
Switch voltage on pin SW (2) 30 V
Continuous power dissipation See Dissipation Rating Table
TJOperating junction temperature –40°C to 150°C
Tstg Storage temperature –65°C to 150°C
(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.
(2) All voltage values are with respect to network ground terminal.
DISSIPATION RATING TABLE
DERATING
TA≤25°C FACTOR TA= 70°C TA= 85°C
PACKAGE RqJA POWER RATING ABOVE POWER RATING POWER RATING
TA= 25°C
DBV 250°C/W 357 mW 3.5 mW/°C 192 mW 140 mW
DDC, DRV 76°C/W 1300 mW 13 mW/°C 688 mW 500 mW
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Product Folder Link(s): TPS61040 TPS61041

TPS61040
TPS61041
www.ti.com SLVS413F –OCTOBER 2002–REVISED DECEMBER 2010
RECOMMENDED OPERATING CONDITIONS MIN TYP MAX UNIT
VIN Input voltage range 1.8 6 V
VOUT Output voltage range 28 V
L Inductor(1) 2.2 10 mH
f Switching frequency(1) 1 MHz
CIN Input capacitor (1) 4.7 mF
COUT Output capacitor (1) 1mF
TAOperating ambient temperature –40 85 °C
TJOperating junction temperature –40 125 °C
(1) See application section for further information.
ELECTRICAL CHARACTERISTICS
VIN = 2.4 V, EN = VIN, TA= –40°C to 85°C, typical values are at TA= 25°C (unless otherwise noted)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
SUPPLY CURRENT
VIN Input voltage range 1.8 6 V
IQOperating quiescent current IOUT = 0 mA, not switching, VFB = 1.3 V 28 50 mA
ISD Shutdown current EN = GND 0.1 1 mA
VUVLO Under-voltage lockout threshold 1.5 1.7 V
ENABLE
VIH EN high level input voltage 1.3 V
VIL EN low level input voltage 0.4 V
IIEN input leakage current EN = GND or VIN 0.1 1 mA
POWER SWITCH AND CURRENT LIMIT
Vsw Maximum switch voltage 30 V
toff Minimum off time 250 400 550 ns
ton Maximum on time 4 6 7.5 ms
RDS(on) MOSFET on-resistance VIN = 2.4 V; ISW = 200 mA; TPS61040 600 1000 mΩ
RDS(on) MOSFET on-resistance VIN = 2.4 V; ISW = 200 mA; TPS61041 750 1250 mΩ
MOSFET leakage current VSW = 28 V 1 10 mA
ILIM MOSFET current limit TPS61040 350 400 450 mA
ILIM MOSFET current limit TPS61041 215 250 285 mA
OUTPUT
VOUT Adjustable output voltage range VIN 28 V
Vref Internal voltage reference 1.233 V
IFB Feedback input bias current VFB = 1.3 V 1 mA
VFB Feedback trip point voltage 1.8 V ≤VIN ≤6 V 1.208 1.233 1.258 V
1.8 V ≤VIN ≤6 V; VOUT = 18 V; Iload = 10 mA;
Line regulation (1) 0.05 %/V
CFF = not connected
Load regulation(1) VIN = 2.4 V; VOUT = 18 V; 0 mA ≤IOUT ≤30 mA 0.15 %/mA
(1) The line and load regulation depend on the external component selection. See the application section for further information.
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Product Folder Link(s): TPS61040 TPS61041

Efficiency − %
70
72
74
76
78
80
82
84
86
88
90
0.1 1 10 100
VI= 5 V
VI= 3.6 V
VI= 2.4 V
IO− Output Current − mA
VO= 18 V
70
72
74
76
78
80
82
84
86
88
90
0.1 1 10 100
TPS61040
TPS61041
IL− Load Current − mA
L = 10 µH
VO= 18 V
Efficiency − %
TPS61040
TPS61041
SLVS413F –OCTOBER 2002–REVISED DECEMBER 2010 www.ti.com
TYPICAL CHARACTERISTICS
Table 3. Table of Graphs
FIGURE
vs Load current 1, 2, 3
hEfficiency vs Input voltage 4
IQQuiescent current vs Input voltage and temperature 5
VFB Feedback voltage vs Temperature 6
ISW Switch current limit vs Temperature 7
vs Supply voltage, TPS61041 8
ICL Switch current limit vs Supply voltage, TPS61040 9
vs Temperature 10
RDS(on) RDS(on) vs Supply voltage 11
Line transient response 12
Load transient response 13
Start-up behavior 14
EFFICIENCY EFFICIENCY
vs vs
OUTPUT CURRENT LOAD CURRENT
Figure 1. Figure 2.
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70
72
74
76
78
80
82
84
86
88
90
0.1 1 10 100
L = 10 µH
L = 3.3 µH
IL− Load Current − mA
VO= 18 V
Efficiency − %
70
72
74
76
78
80
82
84
86
88
90
1 2 3 4 5 6
IO= 10 mA
IO= 5 mA
VI− Input Voltage − V
L = 10 µH
VO= 18 V
Efficiency − %
1.23
1.232
1.234
1.236
1.238
1.24
−40 −20 0 20 40 60 80 100 120
VCC = 2.4 V
TA− Temperature − °C
VFB − Feedback Voltage − V
0
5
10
15
20
25
30
35
40
1.8 2.4 3 3.6 4.2 4.8 5.4 6
VI− Input Voltage − V
TA= 85°C
TA= 27°C
TA= −40°C
Quiescent Current − µA
TPS61040
TPS61041
www.ti.com SLVS413F –OCTOBER 2002–REVISED DECEMBER 2010
EFFICIENCY EFFICIENCY
vs vs
LOAD CURRENT INPUT VOLTAGE
Figure 3. Figure 4.
TPS61040
QUIESCENT CURRENT FEEDBACK VOLTAGE
vs vs
INPUT VOLTAGE FREE-AIR TEMPERATURE
Figure 5. Figure 6.
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230
250
270
290
310
330
350
370
390
410
430
−40−30−20−10 0 10 20 30 40 50 60 70 80 90
TPS61040
TPS61041
TA− Temperature − °C
I(SW) − Switch Current Limit − mA
240
242
244
246
248
250
252
254
256
258
260
1.8 2.4 3 3.6 4.2 4.8 5.4 6
VCC − Supply Voltage − V
TA= 27°C
I(CL) − Current Limit − mA
0
200
400
600
800
1000
1200
−40−30 −20 −10 0 10 20 30 40 50 60 70 80 90
TA− Temperature − °C
TPS61041
TPS61040
rDS(on) − Static Drain-Source On-State Resistance − mΩ
380
385
390
395
400
405
410
415
420
1.8 2.4 3 3.6 4.2 4.8 5.4 6
VCC − Supply Voltage − V
TA= 27°C
I(CL) − Current Limit − mA
TPS61040
TPS61041
SLVS413F –OCTOBER 2002–REVISED DECEMBER 2010 www.ti.com
TPS61040/41 TPS61041
SWITCH CURRENT LIMIT CURRENT LIMIT
vs vs
FREE-AIR TEMPERATURE SUPPLY VOLTAGE
Figure 7. Figure 8.
TPS61040 TPS61040/41
CURRENT LIMIT STATIC DRAIN-SOURCE ON-STATE RESISTANCE
vs vs
SUPPLY VOLTAGE FREE-AIR TEMPERATURE
Figure 9. Figure 10.
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VI
2.4 V to 3.4 V
VO
100 mV/div
200 µS/div
VO= 18 V
0
100
200
300
400
500
600
700
800
900
1000
1.8 2.4 3 3.6 4.2 4.8 5.4 6
VCC − Supply Voltage − V
TPS61041
TPS61040
rDS(on) − Static Drain-Source On-State Resistance − mΩ
VO
5 V/div
EN
1 V/div
II
50 mA/div
VO= 18 V
VO
1 mA to 10 mA
200 µS/div
VO
100 mA/div
VO= 18 V
TPS61040
TPS61041
www.ti.com SLVS413F –OCTOBER 2002–REVISED DECEMBER 2010
TPS61040/41
STATIC DRAIN-SOURCE ON-STATE RESISTANCE
vs
SUPPLY VOLTAGE
Figure 11. Figure 12. Line Transient Response
Figure 13. Load Transient Response Figure 14. Start-Up Behavior
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fSmax +
VIN(min) (VOUT *VIN)
IP L VOUT
fSǒIloadǓ+2 Iload (VOUT *VIN )Vd)
I2
P L
Iload max +h
I2
P L fSmax
2 (VOUT *VIN)
TPS61040
TPS61041
SLVS413F –OCTOBER 2002–REVISED DECEMBER 2010 www.ti.com
APPLICATION INFORMATION
INDUCTOR SELECTION, MAXIMUM LOAD CURRENT
Because the PFM peak current control scheme is inherently stable, the inductor value does not affect the stability
of the regulator. The selection of the inductor together with the nominal load current, input and output voltage of
the application determines the switching frequency of the converter. Depending on the application, inductor
values between 2.2 mH and 47 mH are recommended. The maximum inductor value is determined by the
maximum on time of the switch, typically 6 ms. The peak current limit of 400 mA/250 mA (typically) should be
reached within this 6-ms period for proper operation.
The inductor value determines the maximum switching frequency of the converter. Therefore, select the inductor
value that ensures the maximum switching frequency at the converter maximum load current is not exceeded.
The maximum switching frequency is calculated by the following formula:
Where:
IP= Peak current as described in the Peak Current Control section
L = Selected inductor value
VIN(min) = The highest switching frequency occurs at the minimum input voltage (2)
If the selected inductor value does not exceed the maximum switching frequency of the converter, the next step
is to calculate the switching frequency at the nominal load current using the following formula:
Where:
IP= Peak current as described in the Peak Current Control section
L = Selected inductor value
Iload = Nominal load current
Vd = Rectifier diode forward voltage (typically 0.3V) (3)
A smaller inductor value gives a higher converter switching frequency, but lowers the efficiency.
The inductor value has less effect on the maximum available load current and is only of secondary order. The
best way to calculate the maximum available load current under certain operating conditions is to estimate the
expected converter efficiency at the maximum load current. This number can be taken out of the efficiency
graphs shown in Figure 1 through Figure 4. The maximum load current can then be estimated as follows:
Where:
IP= Peak current as described in the Peak Current Control section
L = Selected inductor value
fSmax = Maximum switching frequency as calculated previously
h= Expected converter efficiency. Typically 70% to 85% (4)
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Product Folder Link(s): TPS61040 TPS61041