Texas Instruments TPS61040EVM User manual


 
February 2002 PMP Portable Power
User’s Guide
SLVU065

IMPORTANT NOTICE
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enhancements, improvements, and other changes to its products and services at any time and to discontinue
any product or service without notice. Customers should obtain the latest relevant information before placing
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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.
TI assumes no liability for applications assistance or customer product design. Customers are responsible for
their products and applications using TI components. To minimize the risks associated with customer products
and applications, customers should provide adequate design and operating safeguards.
TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right,
copyright, mask work right, or other TI intellectual property right relating to any combination, machine, or process
in which TI products or services are used. Information published by TI regarding third−party products or services
does not constitute a license from TI to use such products or services or a warranty or endorsement thereof.
Use of such information may require a license from a third party under the patents or other intellectual property
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Reproduction of information in TI data books or data sheets is permissible only if reproduction is without
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Mailing Address:
Texas Instruments
Post Office Box 655303
Dallas, Texas 75265
Copyright 2002, Texas Instruments Incorporated

EVM IMPORTANT NOTICE
Texas Instruments (TI) provides the enclosed product(s) under the following conditions:
This evaluation kit being sold by TI is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION
PURPOSES ONLY and is not considered by TI to be fit for commercial use. As such, the goods being provided
may not be complete in terms of required design-, marketing-, and/or manufacturing-related protective
considerations, including product safety measures typically found in the end product incorporating the goods.
As a prototype, this product does not fall within the scope of the European Union directive on electromagnetic
compatibility and therefore may not meet the technical requirements of the directive.
Should this evaluation kit not meet the specifications indicated in the EVM User’s Guide, the kit may be returned
within 30 days from the date of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE
WARRANTY MADE BY SELLER TO BUYER AND IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED,
IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY
PARTICULAR PURPOSE.
The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user
indemnifies TI from all claims arising from the handling or use of the goods. Please be aware that the products
received may not be regulatory compliant or agency certified (FCC, UL, CE, etc.). Due to the open construction
of the product, it is the user’s responsibility to take any and all appropriate precautions with regard to electrostatic
discharge.
EXCEPT TO THE EXTENT OF THE INDEMNITY SET FORTH ABOVE, NEITHER PARTY SHALL BE LIABLE
TO THE OTHER FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES.
TI currently deals with a variety of customers for products, and therefore our arrangement with the user is not
exclusive.
TI assumes no liability for applications assistance, customer product design, software performance, or
infringement of patents or services described herein.
Please read the EVM User’s Guide and, specifically, the EVM Warnings and Restrictions notice in the EVM
User’s Guide prior to handling the product. This notice contains important safety information about temperatures
and voltages. For further safety concerns, please contact the TI application engineer.
Persons handling the product must have electronics training and observe good laboratory practice standards.
No license is granted under any patent right or other intellectual property right of TI covering or relating to any
machine, process, or combination in which such TI products or services might be or are used.
Mailing Address:
Texas Instruments
Post Office Box 655303
Dallas, Texas 75265
Copyright 2002, Texas Instruments Incorporated

EVM WARNINGS AND RESTRICTIONS
It is important to operate this EVM within the supply voltage range of 1.8 V to 6 V.
Exceeding the specified supply range may cause unexpected operation and/or irreversible
damage to the EVM. If there are questions concerning the supply range, please contact a TI
field representative prior to connecting the input power.
Applying loads outside of the specified output range may result in unintended operation and/or
possible permanent damage to the EVM. Please consult the EVM User’s Guide prior to
connecting any load to the EVM output. If there is uncertainty as to the load specification,
please contact a TI field representative.
During normal operation, some circuit components may have case temperatures greater than
125°C. The EVM is designed to operate properly with certain components above 125°C as
long as the input and output ranges are maintained. These components include but are not
limited to linear regulators, switching transistors, pass transistors, and current sense
resistors. These types of devices can be identified using the EVM schematic located in the
EVM User’s Guide. When placing measurement probes near these devices during operation,
please be aware that these devices may be very warm to the touch.
Mailing Address:
Texas Instruments
Post Office Box 655303
Dallas, Texas 75265
Copyright 2002, Texas Instruments Incorporated

v
Read This First

About This Manual
This users guide describes the characteristics, operation, and use of the
TPS61040EVM LCD bias supply evaluation module (EVM). This EVM is a
Texas Instruments high-efficiency boost converter that is configured to
generate 18 V at 20 mA, for LCD bias supply, from a single cell Li−Ion battery.
The users guide includes a schematic diagram, bill of materials (BOM), and
test data.
How to Use This Manual
This document contains the following chapters:
-Chapter 1—Introduction
-Chapter 2—Setup and Test Results
-Chapter 3—Board Layout
-Chapter 4—Schematic and Bill of Materials
Related Documentation From Texas Instruments
-TPS601040/41 data sheet (literature number SLVS413).
FCC Warning
This equipment is intended for use in a laboratory test environment only. It
generates, uses, and can radiate radio frequency energy and has not been
tested for compliance with the limits of computing devices pursuant to subpart
J of part 15 of FCC rules, which are designed to provide reasonable protection
against radio frequency interference. Operation of this equipment in other
environments may cause interference with radio communications, in which
case the user at his own expense will be required to take whatever measures
may be required to correct this interference.

vi

Running Title—Attribute Reference
vii
Contents

1 Introduction 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.1 Background 1-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2 Performance Specification Summary 1-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 Setup and Test Results 2-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1 Input/Output Connections 2-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2 EVM Operation 2-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3 Start-Up 2-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.4 Output Voltage Ripple 2-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.5 Switching Waveforms 2-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.6 Input Voltage Ripple 2-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.7 Efficiency 2-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.8 Output Adjust 2-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.8.1 Variable Resistor Output Voltage Adjust 2-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.8.2 Variable Control Voltage Output Voltage Adjust 2-6. . . . . . . . . . . . . . . . . . . . . . . . . .
3 Board Layout 3-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.1 Layout 3-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4 Schematic and Bill of Materials 4-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.1 Schematic 4-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2 Bill of Materials 4-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2−1 Start-Up Waveforms 2-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2−2 Output Ripple 2-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2−3 SW Waveform 2-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2−4 Input Ripple Voltage 2-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2−5 Typical Efficiency 2-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3−1 Assembly Layer 3-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3−2 Top Layer Routing 3-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3−3 Bottom Layer Routing 3-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4−1 TPS61040EVM−001 Schematic 4-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Running Title—Attribute Reference
viii

1−1 TPS61040 Performance Specification Summary 1-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2−1 Input/Output Connections 2-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4−1 TPS61040EVM−001 Bill of Materials 4-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-1
Introduction

This chapter contains background information for the TPS61040 and support
documentation for the TPS61040EVM−001 evaluation module.
Topic Page
1.1 Background 1-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2 Performance Specification Summary 1-2. . . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter 1

Background
1-2 Introduction
1.1 Background
This TPS61040EVM uses the TPS61040 boost converter to generate an 18-V
output from a single cell Li-Ion battery (3 V to 4.2 V). This EVM operates over
an input voltage range of 1.8 V to 6 V, but has been optimized over the 3-V to
5-V input range. Operation with an input voltage down to 1.8 V is possible,
depending on the output current and voltage settings. The EVM includes an
adjust pin that allows the user to adjust the LCD bias with either a variable
resistance or an analog voltage.
The output voltage of the TPS61040EVM can be adjusted up to 28 V by
modifying the resistor values used in resistor divider R1 & R2. The EVM can
also be configured for higher or lower output currents. For lower currents, the
TPS61040 may be replaced by the pin for pin compatible TPS61041. More
information about output voltage adjustment and current ratings of
TPS61040/41 devices can be found in the data sheet Literature Number
SLVS413.
1.2 Performance Specification Summary
Table 1−1 provides a summary of the TPS61040EVM−001 performance
specifications. All specifications are given for an ambient temperature of 25°C.
The EVM may be modified to operate over different input and output currents
and voltages, per the TPS61040 data sheet specifications.
Table 1−1.TPS61040 Performance Specification Summary
Specification Test Conditions Min Typ Max Unit
Input voltage range IO= 20 mA 3 5 V
Output voltage 18 V
Output current 5 20 mA
Output voltage ripple 100 mV
Efficiency 88.5%

2-1
Setup and Test Results
   
This chapter describes how to properly connect, setup, and use the
TPS61040EVM−001. This chapter also presents the test results for this EVM.
Topic Page
2.1 Input/Output Connections 2-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2 EVM Operation 2-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3 Start-Up 2-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.4 Output Voltage Ripple 2-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.5 Switching Waveforms 2-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.6 Input Voltage Ripple 2-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.7 Efficiency 2-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.8 Output Adjust 2-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter 2

Input/Output Connections
2-2 Setup and Test Results
2.1 Input/Output Connections
The TPS61040EVM−001 PWB has several connections, which are described
in Table 2−1.
Table 2−1.Input/Output Connections
Reference
Designator Name Description
J1 Vin This is the positive connection to the input power supply. The leads to the input
supply should be twisted and kept as short as possible.
J2 GND This is the return connection to the input power supply.
J3 Adjust
A variable resistor may be connected between J3−1 and J3−2 to vary the output
voltage of the EVM. J3−1 has a square pad and is connected directly to the FB pin
of the TPS61040. J3−2 has a round pad and is connected directly to ground. The
output voltage may also be adjusted by connecting an analog voltage through a
resistor to J3−1.
J4 GND This is the return pin for the load.
J5 Vout This is the positive connection for the load.
JP1 Enable
Use this connector to enable and disable the power supply. Connect a jumper
between the ON pin and the center pin to enable the supply, and connect a jumper
between the Off pin and the center pin to disable the supply. When the EN pin of the
TPS61040 is left open, its state is undetermined. The jumper must either be
connected to On (Vin) or to Off (GND) for the EVM to operate correctly.
2.2 EVM Operation
Connect an input supply and a load to the appropriate connectors provided on
the EVM. The absolute maximum input voltage is 7 V. The TPS61040 is
designed to operate with a maximum 6-V input voltage. Move the adjust
jumper from the Off position to the On position to enable the supply.
Placing a variable resistor across the adjust pins of the EVM allows the user
to vary the output voltage. Specific design equations may be found in the
TPS61040 data sheet.
2.3 Start-Up
Figure 2−1 shows the startup voltage and current waveforms of the EVM.
When the EVM is enabled, the TPS61040 goes through its programmed
three-stage soft-start sequence to reduce inrush current at turn on.

Output Voltage Ripple
2-3
Setup and Test Results
Figure 2−1.Start-Up Waveforms
2.4 Output Voltage Ripple
Figure 2−2 shows the output voltage ripple with IO= 20 mA. The top trace
shows the ripple with 3.6-V input, and the bottom trace shows the ripple with
a 4.2-V input. The difference in switching frequency between the two traces
is expected and is explained in the data sheet.
Figure 2−2.Output Ripple

Switching Waveforms
2-4 Setup and Test Results
2.5 Switching Waveforms
Figure 2−3 shows the switching waveform at the SW pin of the TPS61040.
When the internal FET turns on, the voltage at the SW pin is pulled to ground
until the inductor current reaches 450 mA. When the inductor current reaches
450 mA, the FET turns off and the voltage at the SW pin rises to the output
voltage plus the forward voltage drop of the diode. During this time, the
inductor transfers its stored energy to the load and the output capacitor. When
the inductor current decays to zero, the SW node rings at a frequency
determined by the output inductor and the drain capacitance of the internal
FET. This ringing is indicative of a discontinuous boost power supply topology.
Figure 2−3.SW Waveform
2.6 Input Voltage Ripple
Figure 2−4 shows the input voltage and current ripple of the supply with
Vin = 3.6 V and IO= 20 mA. The input capacitance of the TPS61040 and the
impedance of the input voltage supply largely determine the input voltage and
current ripple. Increasing the input capacitance or lowering the source
impedance reduces the input voltage and current ripple.

Efficiency
2-5
Setup and Test Results
Figure 2−4.Input Ripple Voltage
Input Ripple Voltage
Input Ripple Current
2.7 Efficiency
Figure 2−5 shows the measured efficiency of the TPS61040.
Figure 2−5.Typical Efficiency
80
81
82
83
84
85
86
87
88
89
90
2.5 5 7.5 10 12.5 15 17.5 20
VI= 6 V
VI= 4.2 V
VI= 3.6 V
VI= 2.5 V
Efficiency − %
IO− Output Current − mA

Output Adjust
2-6 Setup and Test Results
2.8 Output Adjust
The TPS61040EMV−001 provides two methods of output voltage adjustment
for LCD contrast control. The first method of output voltage adjustment is
accomplished with a variable resistor, while the second method is
accomplished using a variable control voltage.
2.8.1 Variable Resistor Output Voltage Adjust
This method is accomplished by removing R2 on the EVM and then placing
a variable resistor between J3−1 and ground. The equations provided below
calculate the range of the variable resistor where:
-R(adjust),min = minimum value for R2
-R(adjust),max = maximum value for R2
-R1 = value for R1
-VO,max = maximum desired output voltage
-VO,min = minimum desired output voltage
Radjust,min +1.233 V R1
ǒVO,max *1.233 VǓ(1)
Radjust,max +1.233 V R1
ǒVO,min *1.233 VǓ(2)
For example, if VO,max = 19 V, VO,min = 17 V, and R1 = 2.21 MΩ, then
R(adjust),min = 153.4 kΩ, and R(adjust),max = 172.8 kΩ. This scenario is best
implemented using a 154-kΩresistor in series with a 20-kΩpotentiometer.
2.8.2 Variable Control Voltage Output Voltage Adjust
This method is accomplished by connecting a variable control voltage through
a resistor, R(adjust), to J3−1. The equations provided below calculate R2 and
R(adjust) where:
ǒVadjust,max *Vadjust,minǓ
ƪ1.233 VǒVO,min *VO,max )Vadjust,min *Vadjust,maxǓ*Vadjust,min xV
O,min )Vadjust,max xV O,maxƫ
(
3)
R2
+
1.233 V
R1
Radjust +R2 R1 ǒVadjust,max *1.233 VǓ
ƪ1.233 V(R2 )R1)*VO,min R2ƫ(4)
For example, if VO,max= 19 V, VO,min = 17 V, V(adjust),min = 0 V, V(adjust),max =
3.3 V, and R1 = 1 MΩ, then R2 = 72.4 kΩ, and R(adjust) = 1.65 MΩ. When
V(adjust) = 0 V then VO= 19 V. When V(adjust) = 3.3 V then VO= 17 V.

3-1
Board Layout
 
This chapter provides the TPS61040EVM−001 board layout and illustrations.
Topic Page
3.1 Layout 3-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.1 Layout Board layout is critical for all switch mode power supplies. Figures 3−1, 3−2
and 3−3 show the board layout for the TPS61040EVM−001 PWB. The nodes
with high-switching frequency are short and isolated from the noise-sensitive
feedback circuitry. Careful attention has been given to the routing of
high-frequency current loops. Refer to the data sheet for specific layout
guidelines.
Figure 3−1.Assembly Layer
Chapter 3

Layout
3-2 Board Layout
Figure 3−2.Top Layer Routing
Figure 3−3.Bottom Layer Routing

4-1
Schematic and Bill of Materials
    
This chapter provides the TPS61040EVM−001 schematic and bill of materials.
Topic Page
4.1 Schematic 4-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2 Bill of Material 4-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter 4

Schematic
4-2 Schematic and Bill of Materials
4.1 Schematic
Figure 4−1.TPS61040EVM−001 Schematic
L1
10 µHD1
MBR0530
U1
TPS61040DBV
VIN
EN
SW
GND
FB
5
4
1
2
3
1
JP1
C1
4.7 µF
1
2
1
2
J1
J2
VI
GND
J3
Adjust 1
2
R1
2.21 MΩ
R2
162 kΩ
C3
1 µF
C2
22 pF
1
2
1
2
J5
J4
VO
GND
4.2 Bill of Materials
Table 4−1.TPS61040EVM−001 Bill of Materials
Reference Description Size Qty. MFG Part #
C1 Capacitor, ceramic, 4.7 µF, 6.3 V, X5R, 15% 0805 1 Murata GRM21B60J475KA11
C2 Capacitor, ceramic, 22 pF, 50 V, C0G, 5% 0603 1 Murata GRM1885C1H220JZ01
C3 Capacitor, ceramic, 1 µF, 25 V, X7R, 10% 1206 1 Murata GRM31MR7E105KC01
D1 Diode, Schottky 0.5 A 30 V SOD−123 1 On Semi MBR0530T1
J1 − J5 Header, 2-pin, 100-mil spacing (36-pin strip) 0.1 x 2” 5 Sullins PTC36SAAN
JP1 Header, 3-pin, 100-mil spacing (36-pin strip) 0.1 x 3” 1 Sullins PTC36SAAN
L1 Inductor, SMT, 10 µH, 0.76 A, 0.23 Ω0.15 x
0.162 1 Sumida CR32−100
R1 Resistor, chip, 2.21 MΩ, 1/16 W, 1% 0603 1 Standard Standard
R2 Resistor, chip, 162 kΩ, 1/16 W, 1% 0603 1 Standard Standard
U1 IC, high efficiency boost converter SOT23−5
(DBV) 1 TI TPS61040DBV
PCB, 1.5’ x 1” x 0.062” 1 Any SLVP209
Shunts, 100-mil, black 0.1 mm 1 3M 929950-00