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User's Guide

SLVU198A – February 2007 – Revised May 2007

Using the TPS40131EVM, A 40A Single Output

Two-Phase Synchronous Buck Converter

Contents

1 Introduction .......................................................................................... 2

2 Description ........................................................................................... 2

3 TPS40131EVM Electrical Performance Specifications ........................................ 3

4 Schematic ........................................................................................... 4

5 Test Set Up .......................................................................................... 5

6 TPS40131EVM Typical Performance Data and Characteristic Curves .................... 10

7 EVM Assembly Drawings and Layout .......................................................... 13

8 List of Materials .................................................................................... 19

List of Figures

1 TPS40131EVM Power Stage/Control Schematic For Reference Only, See Table 3:

Bill of Materials for Specific Values .............................................................. 4

2 TPS40131EVM Recommended Test Set-Up ................................................... 7

3 Output Ripple Measurement ...................................................................... 8

4 Default EN Configuration .......................................................................... 9

5 EN/SYNC Configuration ........................................................................... 9

6 Connect External Clock to J2 ..................................................................... 9

7 TPS40131EVM Efficiency V

= 10.8–13.2V, V

OUT

= 1.5V, I

OUT

= 0–40A ................. 11

8 TPS40131EVM V

OUT

= 1.5V Load Regulation ................................................ 11

9 TPS40131EVM V V

OUT

= 1.5V Line Regulation ............................................... 12

10 Loop Gain When V

= 13.2V and I

OUT

= 40A ................................................. 12

11 0–15A load step, Ch1: I

OUT

; Ch4: V

OUT

........................................................ 13

12 TPS40131EVM Component Placement (Viewed from Top) ................................ 14

13 TPS40131EVM Top Copper (Viewed from Top) .............................................. 15

14 TPS40131EVM Layer 2 Copper (X-Ray View from Top) .................................... 16

15 TPS40131EVM Layer 3 Copper (X-Ray View from Top) .................................... 17

16 TPS40131EVM Bottom Copper (X-Ray View from Top) ..................................... 18

List of Tables

1 TPS40131EVM Electrical and Performance Specifications ................................... 3

2 List of Test Points ................................................................................. 10

3 TPS40131EVM Bill of Materials ................................................................. 19

SLVU198A – February 2007 – Revised May 2007 Using the TPS40131EVM, A 40A Single Output 1

Two-Phase Synchronous Buck Converter

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Summary of content (21 pages)

PAGE 1
User's Guide SLVU198A – February 2007 – Revised May 2007 Using the TPS40131EVM, A 40A Single Output Two-Phase Synchronous Buck Converter 1 2 3 4 5 6 7 8 Contents Introduction .......................................................................................... 2 Description ........................................................................................... 2 TPS40131EVM Electrical Performance Specifications ........................................ 3 Schematic ................................
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www.ti.com Introduction 1 Introduction The TPS40131EVM evaluation module (EVM) is a single output two-phase synchronous buck converter. The EVM delivers 1.5V at 40A. The module uses the TPS40131 Synchronous Buck Controller. 2 Description TPS40131EVM is designed to use a regulated 10.8V to 13.2V bus to produce a high current, regulated output. The output is capable of supplying up to 40A of load current.
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www.ti.com TPS40131EVM Electrical Performance Specifications 3 TPS40131EVM Electrical Performance Specifications Table 1. TPS40131EVM Electrical and Performance Specifications Parameter Notes and Conditions Min Typ Max Units 13.2 V INPUT CHARACTERISTICS Input voltage range (VIN1) 10.8 Max input current VIN1 = 10.8 V, IOUT = 40 A 6.5 A No-load input current VIN1 = 13.2 V, IOUT = 0A 35 mA Input voltage range(VIN2) 4.5 Max input current 5.
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www.ti.com Schematic 4 Schematic 1 + + + + + + + Figure 1.
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www.ti.com Test Set Up 5 Test Set Up 5.1 Recommended Test Equipment 5.1.1 Voltage Source The input voltage source VIN1 should be a 0–15 V variable DC source capable of 10 A. Connect VIN1 to J1 as shown in Figure 2. The input voltage source VIN2 should be a 0–6 V variable DC source capable of 2 A. Connect VIN2 to J2 as shown in Figure 2. 5.1.2 Meters V1: VIN 0–15 V voltmeter V2: VOUT 0–5 V voltmeter I1: IIN, 0–10 A current meter 5.1.
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www.ti.com Test Set Up 5.2 Equipment Setup Shown in Figure 2 is the basic test set up recommended to evaluate the TPS40131EVM. Working at an ESD workstation, make sure that any wrist straps, bootstraps or mats are connected referencing the user to earth ground before power is applied to the EVM. Electrostatic (ESD) smock and safety glasses should also be worn. 5.2.1 Input Connections 1. Prior to connecting the DC input source, VIN1, it is advisable to limit the source current from VIN1 to 10A maximum.
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www.ti.com Test Set Up 5.2.4 Set Up Diagram - + - + V IN1 VIN2 I1 + - + - - + + V1 V IN J1 - Loop injection point for stability analysis. F A N - + +V2 VOUT LOAD + - Figure 2.
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www.ti.com Test Set Up Figure 3. Output Ripple Measurement 5.3 Start Up and Test Procedure 1. 2. 3. 4. Ensure LOAD is set to constant current mode and to sink 0A DC. Set VIN2 to 5V. Increase VIN1 from 0V to 12V, VOUT should be in regulation per Table 1. Vary LOAD from 0–40Adc, VOUT should remain in regulation per Table 1 for all combinations of load on LOAD up to 40A. 5. Vary VIN1 from 10.8V to 13.2V, VOUT should remain in regulation per Table 1 for all combinations of load on LOAD up to 40A. 5.
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www.ti.com Test Set Up 5.5 5.5.1 EN/SYNC Configuration EN High (Default) Configure JP1 with a jumper as shown in Figure 4. The controller will generate its own clock and the operation is enabled. Figure 4. Default EN Configuration 5.5.2 External Synchronization Configure JP1 with a jumper as shown in the following figure and connect a clock source to SYNC and GND pins of J2 as shown in Figure 6. The controller will synchronize to the external clock. Figure 5. EN/SYNC Configuration Figure 6.
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www.ti.com TPS40131EVM Typical Performance Data and Characteristic Curves 5.6 Test Points Several test points are located around the board. These can be used to sense what is occurring at different points of the converter. Table 2 lists these test points and what they are used for. Table 2. List of Test Points 5.
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www.ti.com TPS40131EVM Typical Performance Data and Characteristic Curves 6.1 Efficiency EFFICIENCY vs LOAD CURRENT 100 VI = 10.8 V 90 80 70 h - Efficiency - % VI = 13.2 V VI = 12 V 60 50 40 30 VI = 10.8-13.2 V, VOUT = 1.5 V, IOUT = 0-40 A 20 10 0 0 5 10 15 20 25 30 35 40 45 IOUT- Load Current - A Figure 7. TPS40131EVM Efficiency VIN = 10.8–13.2V, VOUT = 1.5V, IOUT = 0–40A 6.2 Line and Load Regulation OUTPUT VOLTAGE vs LOAD CURRENT 1.510 VO - Output Voltage - V 1.505 VI = 10.
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www.ti.com TPS40131EVM Typical Performance Data and Characteristic Curves OUTPUT VOLTAGE vs INPUT VOLTAGE (Line Regulation) 1.51 IO = 20 A VO - Output Voltage - V 1.508 1.506 VO 1.504 1.502 1.5 10.8 11.3 11.8 12.3 VI - Input Voltage - V 12.8 Figure 9. TPS40131EVM V VOUT = 1.5V Line Regulation 6.3 Bode Plot Figure 10. Loop Gain When VIN = 13.
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www.ti.com EVM Assembly Drawings and Layout 6.4 Transient Response Ch4: VO Ch1: IO Figure 11. 0–15A load step, Ch1: IOUT ; Ch4: VOUT 7 EVM Assembly Drawings and Layout The following figures (Figure 12 through Figure 16) show the design of the TPS40131EVM printed circuit board. The EVM has been designed using a four layer, 2-ounce, copper-clad circuit board with all components on the top side, allowing the user to easily view, probe and evaluate the TPS40131 control IC in a practical application.
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www.ti.com EVM Assembly Drawings and Layout Figure 12.
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www.ti.com EVM Assembly Drawings and Layout Figure 13.
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www.ti.com EVM Assembly Drawings and Layout Figure 14.
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www.ti.com EVM Assembly Drawings and Layout Figure 15.
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www.ti.com EVM Assembly Drawings and Layout Figure 16.
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www.ti.com List of Materials 8 List of Materials Table 3 lists the EVM components as configured according to the schematic shown in Figure 1. Table 3. TPS40131EVM Bill of Materials Count RefDes Description Part Number MFR 6 C1, C2, C3, C18, C19, C34 Capacitor, Ceramic, 22-µF, 16-V, X5R, 20%, 1210 Std Std 11 C6, C10, C11, C20, C22, C24, C25, Capacitor, Ceramic, 0.1-µF, 16-V, X7R, 10%, 0603 C26, C27, C30, C31 Std Std 6 C12, C13, C14, C15, C16, C17 Capacitor, Aluminum-SE, 180-µF, 6.
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EVALUATION BOARD/KIT IMPORTANT NOTICE Texas Instruments (TI) provides the enclosed product(s) under the following conditions: This evaluation board/kit is intended for use for ENGINEERING DEVELOPMENT, DEMONSTRATION, OR EVALUATION PURPOSES ONLY and is not considered by TI to be a finished end-product fit for general consumer use. Persons handling the product(s) must have electronics training and observe good engineering practice standards.
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IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, 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 orders and should verify that such information is current and complete.