Texas Instruments TL5001EVM-097 User manual

TL5001EVM-097
3.3ĆV/5ĆV Selectable Output, 2.5ĆA Buck
Conve te Module
2001 Mixed-Signal Linear Products
User’s Guide
SLVU002B

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Related Documentation From Texas Instruments
iii
Read This First
Preface
Read This First
About This Manual
This user’s guide is a reference manual for the TL5001EVM–097. This docu-
ment provides information to assist managers and hardware engineers in ap-
plication development.
How to Use This Manual
This manual provides the information and instructions necessary to design,
construct, operate, and understand the SLVP097. Chapter 1 describes and
lists the hardware requirements; Chapter 2 describes design considerations
and procedures.
Related Documentation From Texas Instruments
The following books describe the TL5001 and related support tools. To obtain
a copy of any of these TI documents, call the Texas Instruments Literature
ResponseCenterat(800)477–8924.Whenordering,pleaseidentifythebook
by its title and literature number.
TL5001 Pulse-Width-Modulation Control Circuits Data Sheet (Literature
number SLVS084C).
Designing with the TL5001C PWM Controller Application Report
(Literature number SLVA034).
TPS2816, TPS2817, TPS2818, and TPS2819 Single-Channel High-Speed
MOSFET Driver Data Sheet (Literature number SLVS160)

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iv
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Running Title—Attribute Reference
v
Chapter Title—Attribute Reference
Contents
1 Hardware 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.1 Introduction 1-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2 Schematic 1-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3 Input/Output Connections 1-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.4 Board Layout 1-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.5 Bill of Material 1-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.6 Test Results 1-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 Design Procedure 2-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1 Introduction 2-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2 Operating Specifications 2-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3 Design Procedures 2-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3.1 Duty Cycle Estimate 2-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3.2 Output Filter 2-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3.3 Power Switch 2-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3.4 Rectifier 2-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3.5 Snubber Network 2-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3.6 Controller Functions 2-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3.7 Loop Compensation 2-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Running Title—Attribute Reference
vi
Figures
1–1 Typical Buck Converter Block Diagram 1-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–2 SLVP097 Schematic 1-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–3 I/O Connections 1-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–4 Board Layout 1-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–5 Top Layer 1-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–6 Bottom Layer 1-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–7 Output Voltage Vs Output Current (3.3-V Mode) 1-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–8 Output Voltage Vs Output Current (5-V Mode) 1-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–9 Output Voltage Vs Supply Voltage (3.3-V Mode) 1-9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–10 Output Voltage Vs Supply Voltage (5-V Mode) 1-9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–11 Efficiency Vs Output Current (5-V Mode) 1-10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2–1 Power Stage Response 2-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2–2 Required Compensation Response 2-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-1
Chapter Title—Attribute Reference
Hardware
TheTL5001EVM–097(SLVP097)providesamethodforevaluatingtheperfor-
mance of a buck converter using the TL5001 pulse-width-modulation (PWM)
controllercoupledwithaTPS2817MOSFETdriver.Thismanualexplainshow
toconstructbasic powerconversioncircuitsincludingthedesignofthecontrol
chip functions and the basic loop. This chapter includes the following topics:
Topic Page
1.1 Introduction 1–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2 Schematic 1–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3 Input/Output Connections 1–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.4 Board Layout 1–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.5 Bill of Materials 1–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.6 Test Results 1–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter 1

Introduction
1-2
1.1 Introduction
Low cost and design simplicity make buck converters popular solutions in dc/
dc step-down applications where lack of isolation from the input source is not
aconcern.Loopcompensationforthebuckconvertercanbesetforhighband-
widths. This mode is desirable for the low peak-to-average current ratio, eas-
ing the component worst-case design parameters.
Figure 1–1 shows a block diagram of a typical buck converter. The converter
passes a duty-cycle modulated waveform through a low-pass output filter. To
maintain the desired output voltage, a controller senses the output voltage,
comparesittoaninternalreferencevoltageandadjuststhewidthofthepower
switch (Q1) on time, . A commutating diode (CR1) maintains continuous
current through the inductor when the power switch is turned off.
Figure 1–1.Typical Buck Converter Block Diagram
Controller
FB
R1
R2
Q1
R3 CR1 +
C2
+
C1
VO
VI
L1
The SLVP097 buck converter uses the TI TL5001 PWM controller and the
TPS2817 MOSFET driver to give a 0- to 2.5-A output with a selectable output
voltage of either 3.3 V or 5 V. The converter operates over an input voltage
rangeof5.5Vto12Vwithatypicalefficiencyof90percent.Chapter2listsfull
design specifications.
Note: Peak currents in excess of 2.5 A may be obtained from this EVM,
butduetothermal restraints, should notbesubtained.This EVM shuts
down when a short circuit is encountered. Input power must be re-
cycled to restart the module.

Schematic
1-3
Hardware
1.2 Schematic
Figure 1–2 shows the SLVP097 schematic.
Figure 1–2.SLVP097 Schematic
R2
R5
SCP
COMP
GND
VCC
5 1
2
FB
RT
8
U2
TL5001
Optional
µF
C1
100
µF
+
2
3
4
1
J1
+2
3
4
1J2
4.5 V to 12.6 V Q1
IRF7406
CR1
30WQ04FN
C4
1000 pF
L1
33µH
C5
220µF
Input
+
GND
GND 20 V
C2
0.1
µF
C3
0.1
OUT IN
GND
VDD
VCC
U1
TPS2817
4 5
3 2 1
R1
+
10 V
C6
220µF
10 V
+
(Optional)
C7
0.1µF
3.3/5 V, 2.5 A
Output
+
+
GND
GND
7 4
OUT
DTC
3 6
R3
1%
C12
C11
1000 pF
.047µF
C9
0.1µF
C8
0.1µF
R4 C13
0.018µF
R6
1%
R7
1%
2 3 1
R8
1%
JP1
1–2 = 5 V
2–3 = 3.3 V
R8A
CW CCW
W
Adjustable Output
(Replace JP1 and R8)
VO= 1.36–5 V
1.0 kΩ
47 kΩ
1.8 kΩ
1.00 kΩ
330 Ω
4.02 kΩ
30.1 kΩ
732 Ω
22 Ω
µF1
C10
+
†
Notes: 1) Frequency set to 275 kHz by R3.
2) This unit and the components are thermally rated to 2.5 A. The output current should not exceed 2.5 A unless
proper thermal management is put in place.
3) DO NOT change the set output voltage jumper (JP1) while power is applied to the unit.
†Input voltage range for 3.3 V output. When using 5-V output, minimum input voltage must be greater than 5.5 V.

Input/Output Connections
1-4
1.3 Input/Output Connections
Figure 1–3 shows the SLVP097 input and output connections.
Figure 1–3.I/O Connections
Q1
SLVP097
3.3/5 V, 2.5 AMP
Rev. A.1 1997
R4
L1
J1
IN
J2
C9
U2
–+
LOAD –
+
Power Supply
.330
C5
+
+
C7
C6
C4R1
CR1
R3
R2
1.0 C10
R8
1
C2
JP1
C1
+
C8
C3
U1
R6
R7
R5
C11
C12
1OUT
C13
1–2 = 5 V
2–3 = 3.3 V
Notes: 1) The input power supply should be rated at least 3 A with current limit set high enough for proper operation.
2) The load should be rated at least 2.5 A with proper power dissipation. Fixed or variable resistors may be used.

Board Layout
1-5
Hardware
1.4 Board Layout
Figures 1–4 through 1–6 show the SLVP097 board layout.
Figure 1–4.Board Layout
Q1
SLVP097
3.3/5V, 2.5 AMP
Rev. A.1 1997
R4
L1
J1
IN
J2
C9
U2
.330
C5
+
+
C7
C6
C4R1
CR1
R3
R2
1.0 C10
R8
1
C2
JP1
C1
+
C8
C3
U1
R6
R7
R5
C11
C12
1OUT
C13
1–2 = 5V
2–3 = 3.3V
1
1.6”
2.4”
Figure 1–5.Top Layer
1.6”
2.4”

Board Layout
1-6
Figure 1–6.Bottom Layer
1.6”
2.4”

Bill of Material
1-7
Hardware
1.5 Bill of Material
Table 1–1 lists materials required for the SLVP097.
Table 1–1.Bill of Materials
Reference Part Number Mfr Description
C1 20SA100M Sanyo Capacitor, Os-Con, 100 m F, 20 V, F-case
C2 Capacitor, Ceramic, 0.1 m F, 50 V, 1206
C3 Capacitor, Ceramic, 0.1 m F, 50 V, 1206
C4 Capacitor, Ceramic, 1000 pF, 50 V, 1206
C5 10SA220M Sanyo Capacitor, Os-Con, 220 m F, 10 V, F-case
C6*10SA220M Sanyo Capacitor, Os-Con, 220
m F, 10 V, F-case
C7 Capacitor, Ceramic, 0.1 m F, 50 V, 1206
C8 Capacitor, Ceramic, 0.1 m F, 50 V, 1206
C9 Capacitor, Ceramic, 0.1 m F, 50 V, 1206
C10 ECS-T1EY105R Digikey Capacitor, Tantalum, 1.0 m F, 25 V, 1206
C11 Capacitor, Ceramic, 1000 pF, 50 V, 1206
C12 Capacitor, Ceramic, 0.047 m F, 50 V, 1206
C13 Capacitor, Ceramic, 0.018 m F, 50 V, 1206
CR1 30WQ04FN IR Diode, Schottky, 3.3 A, 40 V, D-Pak
J1 Header, 4-pin, 0.025”sq  0.100”centers
J2 Header, 4-pin, 0.025”sq  0.100”centers
JP1 Header, 3-pin, 0.025”sq  0.100”centers
L1 SLF12565-330M2R8 TDK Inductor, 33 m H, 2.8 A, 0.041 W , 0.50”square
Q1 IRF7406 MOSFET, P-Ch, 30 V, 0.045 W , 4.7 A, SO-8
R1 Resistor, CF, 22 W , 1/10 W, 5%, 1206
R2 Resistor, CF, 47 k W , 1/10 W, 5%, 0805
R3 Resistor, MF, 30.1 k W , 1/10 W, 1%, 0805
R4 Resistor, CF, 1.8 k W , 1/10 W, 5%, 0805
R5 Resistor, CF, 330 W , 1/10 W, 5%, 0805
R6 Resistor, MF, 4.02 k W , 1/10 W, 1%, 0805
R7 Resistor, MF, 1.00 k W , 1/10 W, 1%, 0805
R8 Resistor, MF, 732 W , 1/10 W, 1%, 0805
R8A*CT9W102-ND Digikey Potentiometer, 1 k
W , 10%, 18-turn, 9mm-
square
U1 TPS2817DBV TI MOSFET driver, noninverting, single channel,
SOT-25
U2 TL5001CD TI PWM controller, SO-8
–– Shunt, standard profile
–– SLVP097 TI PCB, TPS2817 EVM, 2.40”
 1.60”
* Optional parts not on present board.

Test Results
1-8
1.6 Test Results
Figures 1–7 through 1–11 show test results for the the SLVP097.
Figure 1–7.Output Voltage Vs Output Current (3.3-V Mode)
3.3
3.25
3.2
3.15 0 0.5 1 1.5
–Output Voltage –V
3.35
3.4
OUTPUT VOLTAGE
vs
OUTPUT CURRENT (3.3-V MODE)
3.45
2 2.5 3
IO–Output Current –A
VO
VCC = 9 V
Figure 1–8.Output Voltage Vs Output Current (5-V Mode)
5
4.95
4.9
4.85 01
5.05
5.1
OUTPUT VOLTAGE
vs
OUTPUT CURRENT (5-V MODE)
5.15
23
IO–Output Current –A
–Output Voltage –VVO
0.5 1.5 2.5
VCC = 9 V

Test Results
1-9
Hardware
Figure 1–9.Output Voltage Vs Supply Voltage (3.3-V Mode)
3.245
3.24
3.235
3.23 5678910
3.25
3.255
OUTPUT VOLTAGE
vs
SUPPLY VOLTAGE (3.3-V MODE)
3.26
11 12 13
–Output Voltage –VVO
VCC –Supply Voltage –V
IO= 0.25 A
IO= 2.5 A
Figure 1–10. Output Voltage Vs Supply Voltage (5-V Mode)
4.905
4.9
4.895
4.89 5678910
4.91
4.915
OUTPUT VOLTAGE
vs
SUPPLY VOLTAGE (5-V MODE)
4.92
11 12 13
–Output Voltage –VVO
VCC –Supply Voltage –V
IO= 0.25 A
IO= 2.5 A

Test Results
1-10
Figure 1–11. Efficiency Vs Output Current (5-V Mode)
5 V
87
85
82
80 0 0.5 1 1.5
Efficiency –%
89
92
EFFICIENCY
vs
OUTPUT CURRENT
93
2 2.5
91
90
88
86
84
83
81
IO–Output Current –A
3.3 V
VCC = 9 V

2-1
Chapter Title—Attribute Reference
Design
Procedure
TheSLVP097evaluationmoduleprovidesamethodfor evaluating the perfor-
mance of the TPS2817 MOSFET driver and the TL5001 PWM controller. The
TPS2817 contains all of the circuitry necessary to drive large MOSFETs, in-
cluding a voltage regulator for higher voltage applications. This section ex-
plains how to construct basic power conversion circuits including the design
of the control chip functions and the basic loop. This chapter includes the fol-
lowing topics:
Topic Page
2.1 Introduction 2–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2 Operating Specifications 2–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3 Design Procedure 2–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter 2

Introduction
2-2
2.1 Introduction
The SLVP097 is a dc-dc buck converter module that provides a 5-V or 3.3-V
outputatupto 2.5Awithaninputvoltage rangeof5.5Vto12 V.Thecontroller
is a TL5001 PWM operating at a nominal frequency of 275 kHz. The TL5001
is configured for a maximum duty cycle of 100 percent and has short-circuit
protection built in. Output voltage selection is implemented with jumper JP1.

Operating Specifications
2-3
Design Procedure
2.2 Operating Specifications
Table 2–1 lists the operating specifications for the SLVP097.
Table 2–1.Operating Specifications
Specification Min Typ Max Units
Input Voltage Range 4.5†12.6 V
Output Voltage Range
5-V Mode 4.7 5.0 5.3 V
3.3-V Mode 3.1 3.3 3.5 V
Output Current Range 0 2.6 A
Operating Frequency 275 kHz
Output Ripple 50 mV
Efficiency 85% 90%
†For 3.3 V only, minimum input voltage for 5 V output is 5.5 V.

Design Procedures
2-4
2.3 Design Procedures
Detailed steps in the design of a buck-mode converter may be found in
Designing With the TL5001C PWM Controller (literature number SLVA034)
from Texas Instruments. This section shows the basic steps involved in this
design, using the 3.3-V output mode.
2.3.1 Duty Cycle Estimate
The duty cycle for a continuous-mode step-down converter is approximately:
D +
VO ) Vd
VI * VSAT
Assuming the commutating diode forward voltage Vd= 0.5 V and the power
switch on voltage VSAT = 0.1 V, the duty cycle for Vi= 5.5, 9, and 12 V is 0.70,
0.42, and 0.32, respectively.
2.3.2 Output Filter
Abuckconverterusesasingle-stage LC filter. Choose aninductortomaintain
continuous-mode operation down to 6 percent of the rated output load:
D IO + 2 0.06 IO + 2 0.06 2.5 + 0.30 A
The inductor value is:
L +
(VI * VSAT
* VO) D t
D IO
+
(12 * 0.1 * 3.3) 0.32 ǒ
3.63 10–6
Ǔ
0.30
+ 33.3 m H
Assumingthatall oftheinductorripplecurrent flowsthroughthecapacitorand
the effective series resistance (ESR) is zero, the capacitance needed is:
C +
D IO
8 f ǒ
D VO
Ǔ+
0.3
8 ǒ
275 103
Ǔ
0.05
+ 2.73 m F
Assuming the capacitance is very large, the ESR needed to limit the ripple to
50 mV is:
ESR +
D VO
D IO
+
0.05
0.3
+ 0.167 W
The output filter capacitor should be rated at least ten times the calculated
capacitance and 30–50 percent lower than the calculated ESR. This design
used a 220- m F OS-Con capacitor in parallel with a ceramic to reduce ESR.
2.3.3 Power Switch
Basedonthepreliminaryestimate,rDS(ON)shouldbelessthan0.10V  2.5 A
= 40 m W . The IRF7406 is a 30-V p-channel MOSFET with rDS(ON) = 40 m W.
Power dissipation (conduction + switching losses) can be estimated as:
PD +ǒ
I2
O
rDS(ON) D
Ǔ)ǒ
0.5 Vi IO tr
) f
f
Ǔ