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.