Texas Instruments TPS51120 User manual

User’s Guide
TPS51120 Buck Controller Evaluation Module User's
Guide
Table of Contents
1 Description.............................................................................................................................................................................. 2
2 Electrical Performance...........................................................................................................................................................2
3 Schematic................................................................................................................................................................................3
4 Test Setup and Results.......................................................................................................................................................... 4
4.1 Test Setup.......................................................................................................................................................................... 4
4.2 Test Procedure................................................................................................................................................................... 4
4.3 Start-Up Performance........................................................................................................................................................ 5
4.4 Transient Performance.......................................................................................................................................................5
5 Configuration.......................................................................................................................................................................... 6
5.1 Switching Frequency Selection.......................................................................................................................................... 6
5.2 Skip Mode and Faults Disable Selection............................................................................................................................6
5.3 Output Voltage Setting Selection....................................................................................................................................... 6
5.4 Control Scheme Selection..................................................................................................................................................6
6 EVM Assembly Drawing and PCB Layout............................................................................................................................ 8
7 List of Materials.....................................................................................................................................................................11
8 References.............................................................................................................................................................................11
9 Revision History....................................................................................................................................................................11
Trademarks
D-CAP™ is a trademark of Texas Instruments.
All trademarks are the property of their respective owners.
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TPS51120 Buck Controller Evaluation Module User's Guide 1
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1 Description
The TPS51120 is a highly sophisticated dual current mode synchronous step-down controller. It is a full-featured
controller designed to run directly off three to four-cell Li-ion battery and provide high power and 5-V, 3.3-V, or
both, standby regulation for all the downstream circuitry in a notebook computer system. High current, 100-mA,
5-V, or 3.3-V on-board linear regulators have glitch-free switch over function to SMPS and can be kept alive
independently during standby state. The pseudo-constant frequency adaptive on-time control scheme supports
full range of current mode operation including simplified loop compensation, ceramic output capacitors, and
seamless transition to reduced frequency operation at light-load condition. Optional D-CAP™ mode operation
optimized for SP-CAP or POSCAP output capacitors allows further reduction of external compensation parts.
The TPS51120EVM-001 evaluation module is a high efficiency, dual synchronous buck converter providing 5 V
at 6 A and 3.3 V at 6 A from 8-V to 25-V input. This user’s guide describes the TPS51120EVM-001 performance
in D-CAP mode and RDS(on) current sensing.
2 Electrical Performance
Table 2-1. Electrical Performance
Specifications Test Conditions MIN TYP MAX Unit
Input voltage range (VBAT) 8 12 25 V
CH1
Output voltage 5 V
Operating frequency TONSEL: VREF2, VBAT = 12 V, IOUT1 = 6 A 280 kHz
Output current VBAT = 8 V to 25 V 6 A
Overcurrent limit VBAT = 12 V 10 A
Output ripple voltage VBAT = 12 V, IOUT1 = 6 A 40 mVp-p
CH2
Output voltage 3.3 V
Operating frequency TONSEL: VREF2, VBAT = 12 V, IOUT2 = 6 A 430 kHz
Output current VBAT = 8 V to 25 V 6 A
Overcurrent limit VBAT = 12 V 10 A
Output ripple voltage VBAT = 12 V, IOUT2 = 6 A 45 mVp-p
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3 Schematic
Figure 3-1. TPS51120 EVM Schematic Diagram
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4 Test Setup and Results
4.1 Test Setup
Connect the test equipment and TPS51120EVM-001 board as shown in Figure 4-1.
4. Test Setup and Results
4.1. Test setup
Connect test equipment and TPS51120EVM-001 board as shown in Figure 2.
HPA153
TPS51120EVM
+
-Electronic
Load2
Oscilloscope
CH2
Electronic
Load1
+
-
Oscilloscope
CH1
V O 1
V O 1_G N D
V O 2
V O 2_G N D
12V/10A
Power supply
V B AT_G N D
V B A T
DMM4
+
-
+
-
DMM3
+
-
DMM2
+
-
DMM1
+
-
V R EG 5
V R EG 3
DMM6
+
-
DMM5
+
-
V R EF2
C N 1
C N 2
Figure 4-1. Equipment Setup for TPS51120EVM-001 Board
4.2 Test Procedure
1. Make sure the switches SW1 (EN1), SW2 (EN2), SW3 (EN5), and SW4 (EN3) are in the “OFF” position.
2. Make sure the shunt jumper for JP1 is set 5-pin to 6-pin (Med2), and shunt jumper for JP2 is set 1-pin to 2-
pin (auto-skip).
3. Apply appropriate VBAT voltage to VBAT1 and VBAT_GND1 terminals.
4. Turn on SW3 (EN5) and VREG5 (5V-LDO) starts up.
5. Turn on SW4 (EN3) and VREG3 (3.3V-LDO) starts up.
6. When SW3 and SW4 stay on, VREF2 (2V-REF) enables.
7. When SW3 and SW4 stay on and turn on SW1 (EN1), CH1-output will start up.
8. When SW3 and SW4 stay on and turn on SW2 (EN2), CH2-output will start up.
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4.3 Start-Up Performance
Figure 4-2. 5-V Start-Up Waveforms Figure 4-3. 3.3-V Start-Up Waveforms
4.4 Transient Performance
Figure 4-4. 5-V Load Transient Response Figure 4-5. 3.3-V Load Transient Response
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TPS51120 Buck Controller Evaluation Module User's Guide 5
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5 Configuration
This EVM could be set to the user’s desirable configurations. Please refer to the following specific configuration
setting sections.
5.1 Switching Frequency Selection
The switching frequency can be set by the TONSEL pin using JP1 on the EVM. The default setting is Medium2.
Table 5-1. Switching Frequency Selection
Jumper (JP1) Set to Frequency(1)
TYP CH1 CH2
Top (1-2 pin shorted) Slow 180 kHz 270 kHz
2nd (3-4 pin shorted) Medium1 220 kHz 330 kHz
3rd (5-6 pin shorted) Medium2 280 kHz 430 kHz
Bottom (7-8 pin shorted) Fast 380 kHz 580 kHz
(1) Frequencies are approximate.
5.2 Skip Mode and Faults Disable Selection
Skip mode can be set by the SKIPSEL pin using JP2 on the EVM. In addition, faults disable mode can be
selected for debugging purpose. The default setting is auto-skip and fault enable.
Table 5-2. Skip Mode Selection
Jumper (JP2) set to Skip Faults
Top (1-2 pin shorted) Auto-skip Enable
2nd (3-4 pin shorted) Auto-skip Disable
Bottom (5-6 pin shorted) PWM Enable
5.3 Output Voltage Setting Selection
Output voltage can be set by the VFBx pin using some resistors on the EVM. The default setting is adjustable
output.
Table 5-3. Output Voltage Setting Selection (CH1)
R3 R4 R9
Adjustable output 7.5 kW 30 kW Open
Fixed output; 5 V Open Open 0 W
Table 5-4. Output Voltage Setting Selection (CH2)
R28 R29 R25
Adjustable output 7.5 kW 17.2 kW Open
Fixed output; 3.3 V Open Open 0 W
5.4 Control Scheme Selection
The control scheme can be set by the COMPx pin using some resistors and capacitors on the EVM. The default
setting is D-CAP mode.
Table 5-5. Control Scheme Selection (CH1)
R12 C9 C11 R14
D-CAP mode Shorted Open Open Open
Current mode(1) Open Put on Put on Put on
(1) When current mode is selected, please add appropriate parts on C9, C11, and R14 and cut the trace between the pads of R12.
Table 5-6. Control Scheme Selection (CH2)
R24 C15 C14 R20
D-CAP mode Shorted Open Open Open
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Table 5-6. Control Scheme Selection (CH2) (continued)
R24 C15 C14 R20
Current mode(1) Open Put on Put on Put on
(1) When current mode is selected, please add appropriate parts on C15, C14, and R20 and cut the trace between the pads of R24.
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6 EVM Assembly Drawing and PCB Layout
Figure 6-1. Top Assembly
Figure 6-2. Bottom Assembly
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Figure 6-3. Top Layer
Figure 6-4. Inner Layer 1
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Figure 6-5. Inner Layer 2
Figure 6-6. Bottom Layer
EVM Assembly Drawing and PCB Layout www.ti.com
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