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Table Of Contents

User's Guide

SLVU251A–June 2008– Revised May 2011

High-Performance Synchronous Buck EVM Using the

TPS51220

Contents

1 Description ................................................................................................................... 2

2 Electrical Performance ..................................................................................................... 2

3 Schematic .................................................................................................................... 3

4 Test Setup and Procedure ................................................................................................. 4

5 Configuration ................................................................................................................ 4

6 Bill of Materials .............................................................................................................. 7

7 EVM Assembly Drawing and PCB Layout ............................................................................... 9

8 Reference ................................................................................................................... 11

List of Figures

1 HPA302 EVM Schematic Diagram (DCR-Sensing) ................................................................... 3

2 Equipment Setup for TPS51220EVM Board ............................................................................ 4

3 (CH1) Cut Trace Underneath R6 ......................................................................................... 6

4 (CH2) Cut Trace Underneath R20........................................................................................ 6

5 Top Layer/ Assembly ....................................................................................................... 9

6 Inner Layer 1 ................................................................................................................ 9

7 Inner Layer 2............................................................................................................... 10

8 Bottom Layer/ Assembly.................................................................................................. 10

List of Tables

1 Switching Frequency Selection ........................................................................................... 5

2 Skip Mode Selection........................................................................................................ 5

3 Current-Sensing Scheme Selection (CH1) .............................................................................. 5

4 Current Sensing Scheme Selection (CH2) .............................................................................. 5

5 TRIP/ Discharge Mode Selection ......................................................................................... 6

6 Control Mode/OVP Selection.............................................................................................. 6

7 Soft-Start Setting Selection ............................................................................................... 6

8 Bill of Materials .............................................................................................................. 7

SLVU251A–June 2008–Revised May 2011 High-Performance Synchronous Buck EVM Using the TPS51220

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Summary of content (13 pages)

PAGE 1
User's Guide SLVU251A – June 2008 – Revised May 2011 High-Performance Synchronous Buck EVM Using the TPS51220 1 2 3 4 5 6 7 8 Contents Description ................................................................................................................... 2 Electrical Performance ..................................................................................................... 2 Schematic ...........................................................................................................
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Description 1 www.ti.com Description The TPS51220 is a dual, peak-current mode, synchronous step-down controller with three low-dropout (LDO) regulators. It is optimized for 5-V /3.3-V notebook system power supplies. A 99% duty cycle operation enables designers to complete Li-ion battery applications from 2-cells to 4-cells cost effectively. The TPS51220 supports high-efficiency, fast transient response and 99% duty cycle operation.
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Schematic www.ti.com Schematic + + + + + + 3 Figure 1.
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Test Setup and Procedure www.ti.com 4 Test Setup and Procedure 4.1 Test Setup Connect test equipment and HPA302-EVM board as shown in Figure 2. CH1 Oscilloscope TP7 (VREG5) SYNC TP9 (VREG3) GNDS VOUT1 TP1 - TP2 + - Electronic Load-1 DMM1 DMM4 DMM5 + + + TP8 (VREF2) - GND1 + + TP15 TP14 DMM3 - VIN - 12 V/10 A Power Supply GNDI GND2 + TP13 DMM6 - - Electronic Load-1 DMM2 HPA302 TPS5122xEVM + + TP12 VOUT2 CH2 Oscilloscope Figure 2.
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Configuration www.ti.com Table 1. Switching Frequency Selection Connection Add RF-resistor from RF to GND and be R31 open Internal f sw = Apply external clock signal to SYNC (5 Vpp and 50% duty) , remove R15 in addition, and add 0-Ω to R31. External 5.2 1 ´ 108 [kHz] RF [W] Skip Mode and Control Scheme Selection The skip mode can be set by the SKIPSEL1,2 pins using JP3 and JP4 on the EVM. Default setting is Auto-skip. Table 2. Skip Mode Selection 5.
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Configuration www.ti.com For external resistor sensing, cut the trace as follows. Figure 3. (CH1) Cut Trace Underneath R6 5.4 Figure 4. (CH2) Cut Trace Underneath R20 Overcurrent Limit and Discharge Selection The overcurrent limit threshold and discharge function can be set by the TRIP pin using JP1 on the EVM. Default setting is 60 mV and discharge enabled. Table 5. TRIP/ Discharge Mode Selection Jumper (JP2) set to 5.
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Bill of Materials www.ti.com 5.7 Output Voltage Adjustment Output voltage is programmable by changing R2, R3, and R5 for CH1 and R21, R23, and R24 for CH2. Default setting is 5 V for CH1 and 3.3 V for CH2. Vout(CH1) = (R5 + R2 + R3) x Vref (= 1 V) R3 (1) When Vout(CH1) is set above 5 V, V5SW input resistor (R22) must be open. Vout(CH2) = 6 (R21 + R23 + R24) x Vref (= 1 V) R24 (2) Bill of Materials Table 8.
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Bill of Materials www.ti.com Table 8. Bill of Materials (continued) Reference Description Size Mfr Part Number R16 0 Resistor, Chip 0603 Std Std R18, R28 2 Resistor, Chip, 5.
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EVM Assembly Drawing and PCB Layout www.ti.com 7 EVM Assembly Drawing and PCB Layout Figure 5. Top Layer/ Assembly Figure 6.
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EVM Assembly Drawing and PCB Layout www.ti.com Figure 7. Inner Layer 2 Figure 8.
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Reference www.ti.com 8 Reference 1. TPS51220; Fixed Frequency, 99% Duty Cycle Peak Current Mode Notebook System Power Controller data sheet (SLVS785) 2.
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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.