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User's Guide

SLVU470–June 11

TPS54478EVM-037 4-A, SWIFT™ Regulator Evaluation

Module

Contents

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

2 Test Setup and Results .................................................................................................... 4

3 Board Layout ............................................................................................................... 13

4 Schematic and Bill of Materials .......................................................................................... 16

List of Figures

1 TPS54478EVM-037 Efficiency ............................................................................................ 5

2 TPS54478EVM-037 Low Current Efficiency............................................................................. 5

3 TPS54478EVM-037 Load Regulation .................................................................................... 6

4 TPS54478EVM-037 Line Regulation..................................................................................... 6

5 TPS54478EVM-037 Transient Response ............................................................................... 7

6 TPS54478EVM-037 Loop Response .................................................................................... 7

7 TPS54478EVM-037 Output Ripple ...................................................................................... 8

8 TPS54478EVM-037 Input Ripple ........................................................................................ 8

9 TPS54478EVM-037 Start-Up Relative to V

........................................................................... 9

10 TPS54478EVM-037 Start-up Relative to Enable ...................................................................... 9

11 TPS54478EVM-037 Start-up into Pre-bias............................................................................. 10

12 TPS54478EVM-037 Shut-down Relative to V

........................................................................ 10

13 TPS54478EVM-037 Shut-down Relative to EN ....................................................................... 11

14 TPS54478EVM-037 Hiccup Mode Current Limit Shut-down ........................................................ 11

15 TPS54478EVM-037 Hiccup Mode Current Limit Re-start into Short Circuit....................................... 12

16 TPS54478EVM-037 Top-Side Layout .................................................................................. 13

17 TPS54478EVM-037 Bottom-Side Layout .............................................................................. 14

18 TPS54478EVM-037 Layout 2............................................................................................ 14

19 TPS54478EVM-037 Layout 3............................................................................................ 15

20 TPS54478EVM-037 Top-Side Assembly............................................................................... 15

21 TPS54478EVM-037 Schematic.......................................................................................... 16

List of Tables

1 Input Voltage and Output Current Summary ............................................................................ 2

2 TPS54478EVM-037 Performance Specification Summary............................................................ 2

3 Output Voltages Available ................................................................................................. 3

4 EVM Connectors and Test Points ........................................................................................ 4

5 TPS54478EVM-037 Bill of Materials.................................................................................... 17

6 Label Marking .............................................................................................................. 19

SWIFT is a trademark of Texas Instruments.

SLVU470–June 11 TPS54478EVM-037 4-A, SWIFT™ Regulator Evaluation Module

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Summary of content (21 pages)

PAGE 1
User's Guide SLVU470 – June 11 TPS54478EVM-037 4-A, SWIFT™ Regulator Evaluation Module 1 2 3 4 Contents Introduction .................................................................................................................. 2 Test Setup and Results .................................................................................................... 4 Board Layout ...............................................................................................................
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Introduction 1 www.ti.com Introduction This user's guide contains background information for the TPS54478 as well as support documentation for the TPS54478EVM-037 evaluation module (HPA375). Also included are the performance specifications, the schematic, and the bill of materials for the TPS54478EVM-037. 1.1 Background The TPS54478 dc/dc converter is designed to provide up to a 4 A output from an input voltage source of 2.95 V to 6 V.
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Introduction www.ti.com 1.3 Modifications These evaluation modules are designed to provide access to the features of the TPS54478. Some modifications can be made to this module. 1.3.1 Output Voltage Set Point The voltage divider R9 and R10 is used to set the output voltage. To change the output voltage of the EVM, it is necessary to change the value of resistor R9. Changing the value of R9 can change the output voltage above 0.6 V.
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Test Setup and Results 2 www.ti.com Test Setup and Results This section describes how to properly connect, set up, and use the TPS54478EVM-037 evaluation module. The section also includes test results typical for the evaluation module and covers efficiency, output voltage regulation, load transients, loop response, output ripple, input ripple, and start-up. 2.1 Input / Output Connections The TPS54478EVM-037 is provided with input/output connectors and test points as shown in Table 4.
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Test Setup and Results www.ti.com 2.2 Efficiency The efficiency of this EVM peaks at a load current of about 0.5 A – 1 A and then decreases as the load current increases towards full load. Figure 1 shows the efficiency for the TPS54478EVM-037 at an ambient temperature of 25°C. 100 90 VIN = 3.3 V 80 VIN = 5 V Efficiency - % 70 60 50 40 30 20 10 0 0 0.5 1 1.5 2 2.5 Output Current - A 3 3.5 4 Figure 1.
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Test Setup and Results 2.3 www.ti.com Output Voltage Load Regulation Figure 3 shows the load regulation for the TPS54478EVM-037. 0.2 0.15 Output Voltage Deviation - % VIN = 5 V 0.1 0.05 VIN = 3.3 V 0 -0.05 -0.1 -0.15 -0.2 0 0.5 1 3 1.5 2 2.5 Output Current - A 3.5 4 Figure 3. TPS54478EVM-037 Load Regulation Measurements are given for an ambient temperature of 25°C. 2.4 Output Voltage Line Regulation Figure 4 shows the line regulation for the TPS54478EVM-037. 0.
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Test Setup and Results www.ti.com 2.5 Load Transients Figure 5 shows the TPS54478EVM-037 response to load transients. The current step is from 25% to 75% of maximum rated load at 3.3 V input. Total peak-to-peak voltage variation is as shown, including ripple and noise on the output. VOUT = 50 mV / div (ac coupled) IOUT = 1 A / div Load step = 1 - 3 A, slew rate = 0.167 A / µsec Time = 100 µsec / div Figure 5. TPS54478EVM-037 Transient Response 2.
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Test Setup and Results 2.7 www.ti.com Output Voltage Ripple Figure 7 shows the TPS54478EVM-037 output voltage ripple. The output current is the rated full load of 4A and VIN = 3.3 V. The ripple voltage is measured directly across the output capacitors. VOUT = 20 mV / div (ac coupled) PH = 2 V / div Time = 500 nsec / div Figure 7. TPS54478EVM-037 Output Ripple 2.8 Input Voltage Ripple Figure 8 shows the TPS54478EVM-037 input voltage ripple.
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Test Setup and Results www.ti.com 2.9 Powering Up Figure 9 and Figure 10 show the start-up waveforms for the TPS54478EVM-037. In Figure 9, the output voltage ramps up as soon as the input voltage reaches the UVLO threshold as set by the R1 and R2 resistor divider network. In Figure 10, the input voltage is initially applied and the output is inhibited by using a jumper at JP1 to tie EN to GND. When the jumper is removed, EN is released.
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Test Setup and Results www.ti.com The TPS54478 is designed to start up into pre-biased outputs. Figure 11 shows the output voltage start up waveform when the output is pre-biased with 500 mV. EN = 5 V / div VOUT = 500 mV / div Pre-bias voltage = 500 mV Time = 2 msec / div Figure 11. TPS54478EVM-037 Start-up into Pre-bias 2.10 Powering Down Figure 12 and Figure 13 show the start-up waveforms for the TPS54478EVM-037.
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Test Setup and Results www.ti.com VIN = 5 V / div EN = 5 V / div VOUT = 2 V / div PWRGD = 5 V / div Time = 2 msec / div Figure 13. TPS54478EVM-037 Shut-down Relative to EN 2.11 Hiccup Mode Current Limit The TPS54478 has hiccup mode current limit. When the peak switch current exceeds the current limit threshold, the device shuts down and restarts. Hiccup mode current limit operation is shown in Figure 14 and Figure 15. Figure 14 shows the activation of hiccup mode current limit.
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Test Setup and Results www.ti.com VOUT = 1 V / div IOUT = 5 A / div Time = 5 msec / div Figure 15.
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Board Layout www.ti.com 3 Board Layout This section provides a description of the TPS54478EVM-037, board layout, and layer illustrations. 3.1 Layout Figure 16 through Figure 20 shows the board layout for the TPS54478EVM-037. The topside layer of the EVM is laid out in a manner typical of a user application. The top, bottom and internal layers are 2-oz. copper. The top layer contains the main power traces for VIN, VOUT, and VPHASE.
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Board Layout www.ti.com Figure 17. TPS54478EVM-037 Bottom-Side Layout Figure 18.
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Board Layout www.ti.com Figure 19. TPS54478EVM-037 Layout 3 Figure 20. TPS54478EVM-037 Top-Side Assembly 3.2 Estimated Circuit Area The estimated printed circuit board area for the components used in this design is 0.37 in2 (239 mm2). This area does not include test point or connectors.
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Schematic and Bill of Materials 4 www.ti.com Schematic and Bill of Materials This section presents the TPS54478EVM-037 schematic and bill of materials. 4.1 Schematic Figure 21 is the schematic for the TPS54478EVM-037. Spacer TP1 J1 VIN 1 GND 2 16 C1 C2 1 R1 C3 TP2 2 10uF 1 0.1uF 14.3k 15 6 VSNS 7 C4 JP1 EN 1 GND 2 220pF R2 8 9 11.5k VIN PH VIN PH VIN PH EN BOOT VSNS PWRGD COMP GND RT/CLK GND AGND SS/TR L1 1.
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Schematic and Bill of Materials www.ti.com 4.2 Bill of Materials Table 5 presents the bill of materials for the TPS54478EVM-037. Table 5. TPS54478EVM-037 Bill of Materials Count RefDes Value Description Size Part Number MFR 0 C1 Open Capacitor Multi sizes Engineering Only Std 1 C2 10μF Capacitor, Ceramic, 16V, X5R, 20% 1206 Std Std 2 C3, C8 0.1μF Capacitor, Ceramic, 25V, X5R, 10% 0603 Std Std 2 C4.
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Schematic and Bill of Materials www.ti.com Table 5. TPS54478EVM-037 Bill of Materials (continued) Count RefDes Value Description Size Part Number MFR 3. These assemblies must comply with workmanship standards IPC-A-610 Class 2. 4. Ref designators marked with an asterisk ('**') cannot be substituted. All other components can be substituted with equivalent MFG's components. 5. Install label in silkscreened box after final wash. Text shall be 8 pt font.
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Schematic and Bill of Materials www.ti.com Table 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.