Texas Instruments TPS53126EVM-600 User manual

User’s Guide
TPS53126 Buck Controller Evaluation Module User's
Guide
ABSTRACT
The TPS53126EVM-600 Evaluation Module presents an easy-to-use reference design for a common, dual-
output power supply using the TPS53126 controller in cost-sensitive applications.
Table of Contents
1 Introduction.............................................................................................................................................................................3
1.1 Description......................................................................................................................................................................... 3
1.2 Applications........................................................................................................................................................................3
1.3 Features............................................................................................................................................................................. 3
2 Electrical Performance Specifications................................................................................................................................. 4
3 Schematic................................................................................................................................................................................5
4 Connector and Test Point Descriptions................................................................................................................................6
4.1 Enable Switches – SW1 and SW2..................................................................................................................................... 6
4.2 Switching Frequency Select Switch – SW3....................................................................................................................... 6
4.3 Test Point Descriptions.......................................................................................................................................................6
5 Test Setup................................................................................................................................................................................8
5.1 Equipment.......................................................................................................................................................................... 8
5.2 Recommended Setup........................................................................................................................................................ 8
6 Test Procedure...................................................................................................................................................................... 10
6.1 Start-up Procedure...........................................................................................................................................................10
6.2 Line/Load Regulation and Efficiency Measurement Procedure....................................................................................... 10
6.3 Output Ripple Voltage Measurement Procedure..............................................................................................................10
6.4 Shutdown Procedure........................................................................................................................................................10
7 Performance Data and Typical Characteristic Curves.......................................................................................................11
7.1 Efficiency.......................................................................................................................................................................... 11
7.2 Line and Load Regulation................................................................................................................................................ 12
7.3 Output Voltage Ripple...................................................................................................................................................... 13
7.4 Switch Node Waveforms..................................................................................................................................................14
8 EVM Assembly Drawings and Layout.................................................................................................................................15
9 Bill of Materials..................................................................................................................................................................... 18
10 Revision History................................................................................................................................................................. 19
List of Figures
Figure 3-1. TPS53126EVM-600 Schematic.................................................................................................................................5
Figure 4-1. Tip and Barrel Measurement for Output Voltage Ripple............................................................................................7
Figure 5-1. TPS53126EVM-600 Recommended Test Setup....................................................................................................... 9
Figure 7-1. Efficiency vs Load (VIN = 8 V–22 V, VOUT1 = 1.05 V, IOUT1 = 0 A–4 A)....................................................................11
Figure 7-2. Efficiency vs Load (VIN = 8 V–22 V, VOUT2 = 1.8 V, IOUT2 = 0 A–4 A)......................................................................11
Figure 7-3. Output Voltage vs Load (VIN = 8 V–22 V, VOUT1 = 1.05 V, IOUT1 = 0 A–4 A)........................................................... 12
Figure 7-4. Output Voltage vs Load (VIN = 8 V–22 V, VOUT2 = 1.8 V, IOUT2 = 0 A–4 A)............................................................. 12
Figure 7-5. Output Voltage Ripple (VIN = 12 V, VOUT1 = 1.05 V, IOUT1 = 4 A, FSW = 350 kHz).................................................. 13
Figure 7-6. Output Voltage Ripple (VIN = 12 V, VOUT2 = 1.8 V, IOUT2 = 4 A, FSW = 350 kHz).................................................... 13
Figure 7-7. Switching Waveform (VIN = 12 V, VOUT1 = 1.05 V, IOUT1 = 4 A, FSW = 350 kHz).....................................................14
Figure 7-8. Switching Waveform (VIN = 12 V, VOUT2 = 1.08 V, IOUT2 = 4 A, FSW = 350 kHz).....................................................14
Figure 8-1. Top Assembly.......................................................................................................................................................... 15
Figure 8-2. Bottom Assembly.................................................................................................................................................... 15
Figure 8-3. Top Layer.................................................................................................................................................................16
Figure 8-4. Bottom Layer........................................................................................................................................................... 16
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Figure 8-5. Internal Layer 1....................................................................................................................................................... 17
Figure 8-6. Internal Layer 2....................................................................................................................................................... 17
List of Tables
Table 2-1. TPS53126EVM-600 Electrical and Performance Specifications.................................................................................4
Table 4-1. TPS53126EVM-600 Test Points Description.............................................................................................................. 6
Table 9-1. TPS53126EVM-600 Bill of Materials.........................................................................................................................18
Trademarks
D-CAP2™ is a trademark of Texas Instruments.
All trademarks are the property of their respective owners.
Trademarks www.ti.com
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1 Introduction
1.1 Description
The TPS53126EVM-600 evaluation board provides the user with a convenient way to evaluate the TPS53126
Dual D-CAP2™ Mode Control Step-Down Controller in a realistic, cost-sensitive application. Providing both a low
core-type 1.05-V and I/O type 1.8-V output at up to 4 A from a loosely regulated 12-V (8-V to 22-V) source,
the TPS53126EVM-600 includes switches and test points to assist users in evaluating the performance of the
TPS53126 controller in their applications.
1.2 Applications
• Digital television
• Set-top box
• DSL and cable modems
• Cost-sensitive digital consumer products
1.3 Features
• 8-V to 22-V input
• 1.05-V and 1.8-V output
• Up to 4 A per channel output
• Switch selectable 350-kHz or 700-kHz pseudo-fixed frequency D-CAP2™ mode control
• Independent enable switches for power-on/power-off testing
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2 Electrical Performance Specifications
Table 2-1. TPS53126EVM-600 Electrical and Performance Specifications
Parameter Notes and Conditions Min Typ Max Unit
INPUT CHARACTERISTICS
VIN Input voltage 8 12 22 V
IIN Input Current VIN = 12 V, IOUT1 = 4 A, IOUT2 = 4 A – 1.2 1.5 A
No-Load Input Current VIN = 12 V, IOUT = 0 A, SW3 = 350 kHz – 20 – mA
VIN_UVLO Input UVLO IOUT = 4 A 4.0 4.2 4.5 V
OUTPUT CHARACTERISTICS
VOUT1 Output Voltage 1 VIN = 12 V, IOUT1 = 2 A – 1.05 – V
Line Regulation VIN = 8 V to 22 V – – 1%
Load Regulation IOUT1 = 0 A to 4 A – – 1%
VOUT1_rip Output Voltage Ripple VIN = 12 V, IOUT2 = 4 A – – 30 mVpp
IOUT1 Output Current 1 VIN = 8 V to 22 V 0 4 A
VOUT2 Output Voltage 2 VIN = 12 V, IOUT2 = 2 A – 1.80 – V
Line Regulation VIN = 8 V to 22 V – – 1%
Load Regulation IOUT2 = 0 A to 4 A – – 1%
VOUT2_rip Output Voltage Ripple VIN = 12 V, IOUT2 = 4 A – – 30 mVpp
IOUT2 Output Current 2 VIN = 8 V to 22 V 0 4 A
SYSTEMS CHARACTERISTICS
FSW Switching Frequency SW3 = 350 kHz 200 350 400 kHz
ηpk1 Peak Efficiency of Output 1 VIN = 12 V, SW3 = 350 kHz – 88%
η1Full Load Efficiency of Output 1 VIN = 12 V, IOUT1 = 4 A, SW3 = 350 kHz – 85%
ηpk2 Peak Efficiency of Output 2 VIN = 12 V, SW3 = 350 kHz – 9%1
η2Full Load efficiency of Output 2 VIN = 12 V, IOUT2 = 4 A, SW3 = 350 kHz – 91%
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3 Schematic
+
+
+
For Reference Only, See Table 9-1 for Specific Values
Figure 3-1. TPS53126EVM-600 Schematic
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4 Connector and Test Point Descriptions
4.1 Enable Switches – SW1 and SW2
TPS53126EVM-600 includes independent enable switches for each of the two outputs. When the switch is in the
DIS position, the channel is disabled and discharged per the TPS53126’s internal discharge characteristics.
To enable VOUT1, place SW1 in the EN position. To enable VOUT2, place SW2 in the EN position.
4.2 Switching Frequency Select Switch – SW3
TPS53126EVM-600 includes a frequency select switch (SW3) to select the frequency programmed by the
TEST2 IC pin of the TPS53126. When in the 350-kHz position, the D-CAP2™ mode control selects the Ton
for 350-kHz operation. When in the 700-kHz position, the D-CAP2™ mode control selects the Ton for 700-kHz
operation. For more details of switching frequency verse VIN and IOUT, see the TPS53126 data sheet .
Do not switch the position of SW3 while the TPS53126EVM-600 module is running. To change frequency
selection, disable both Channel 1 and Channel 2 before changing the switching frequency.
4.3 Test Point Descriptions
Table 4-1 lists the test points, their labels, uses, and where additional information is located.
Table 4-1. TPS53126EVM-600 Test Points Description
Test Point Label Use Section
TP1 TEST1 Not Used
TP2 TEST2 Monitor Frequency Select Voltage (5 V or GND)
TP3 GND Ground for Input Voltage Section 4.3.1
TP4 GND Ground for Channel-1 Output Voltage Section 4.3.2
TP5 SW1 Monitor Switching Node for Channel 1 Section 4.3.4
TP6 GND Ground for Channel-2 Output Voltage Section 4.3.3
TP7 VOUT2 Monitor Output Voltage for Channel 2 Section 4.3.3
TP8 VOUT1 Monitor Output Voltage for Channel 1 Section 4.3.2
TP9 VIN Monitor Input Voltage Section 4.3.1
TP10 VREG5 Monitor Output of VREG5 Regulator Section 4.3.5
TP11 SW2 Monitor Switching Node for Channel 2 Section 4.3.4
4.3.1 Input Voltage Monitoring –TP3 and TP9
TPS53126EVM-600 provides two test points for measuring the voltage applied to the module. This allows the
user to measure the actual module voltage without losses from input cables and connectors. Measure all input
voltage between TP9 and TP3. To use TP9 and TP3, connect a voltmeter positive terminal to TP9 and negative
terminal to TP3.
4.3.2 Channel-1 Output Voltage Monitoring – TP4 and TP8
TPS53126EVM-600 provides two test points for measuring the voltage generated at the VOUT1 output by the
module. This allows the user to measure the actual output voltage without losses from output cables and
connectors. Measure all dc output voltage measurements between TP8 and TP4. To use TP8 and TP4, connect
a voltmeter positive terminal to TP8 and negative terminal to TP4.
For output ripple measurements, TP8 and TP4 allow a user to limit the ground loop area by using the tip and
barrel measurement technique shown in Figure 4-1.
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TP4TP8
Metal Ground Barrel
Probe Tip
Figure 4-1. Tip and Barrel Measurement for Output Voltage Ripple
4.3.3 Channel-2 Output Voltage Monitoring – TP6 and TP7
TPS53126EVM-600 provides two test points for measuring the voltage generated at the VOUT2 output by the
module. This allows the user to measure the actual output voltage without losses from output cables and
connectors. Measure all dc output voltage between TP7 and TP6. To use TP7 and TP6, connect a voltmeter
positive terminal to TP7 and negative terminal to TP6.
For output ripple measurements, TP7 and TP6 allow a user to limit the ground loop area by using the tip and
barrel measurement technique shown in Figure 4-1.
4.3.4 Switching Node Monitoring – TP3, TP5, and TP11
TPS53126EVM-600 provides two test points for measuring the switching node waveform voltages. TP5 monitors
the switching node of Channel 1. TP2 monitors the switching node of Channel 2. To use TP5 or TP11, connect
an oscilloscope probe between TP5 or TP11 and TP3.
4.3.5 5-V Regulator Output Monitoring – TP3 and TP10
TPS53126EVM-600 provides a test point for measuring the output of the internal 5-V regulator. TP10 monitors
the output voltage of the internal 5-V regulator. To use TP10, connect a voltmeter positive terminal to TP10 and
negative terminal to TP3.
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5 Test Setup
5.1 Equipment
5.1.1 Voltage Source
The input voltage source (VIN) shall be a 0-V to 25-V variable dc source capable of supplying 3 Adc minimum.
5.1.2 Meters
A1: 0-Adc to 5-Adc, ammeter
V1: VIN, 0-V to 25-V voltmeter
V2: VOUT1, 0-V to 2-V voltmeter
V3: VOUT2, 0-V to 2-V voltmeter
5.1.3 Loads
LOAD1: One output load is an electronic load set for constant-current mode capable of 0 Adc to 4 Adc at 1.05
Vdc.
LOAD2: The other output load is an electronic load set for constant-current mode capable of 0 Adc to 4 Adc at
1.8 Vdc.
5.1.4 Oscilloscope and Probe
The oscilloscope, analog or digital, must be set for ac-coupled measurement with 20-MHz bandwidth limiting.
Use 20-mV/division vertical resolution, 1-µs/division horizontal resolution for output ripple voltage test.
Oscilloscope probes with exposed conductive ground barrels are recommended.
5.1.5 Recommended Wire Gauge
VIN to J3 – The connection between the source voltage VIN and J1 of TPS53126EVM-600 can carry as much
as 2 Adc. The minimum recommended wire size is AWG 16 with the total length of wire less than 2 feet (1-foot
input, 1-foot return).
J1 to LOAD1 and J2 to LOAD2 – The connection between J1 and LOAD1, and J2 and LOAD2 of
TPS53126EVM-600 can carry as much as 4 Adc each. The minimum recommended wire size is AWG 14
with the total length of wire less than 2 feet (1-foot input, 1-foot return).
5.1.6 Other Test Equipment
FAN – The TPS53126EVM-600 evaluation module includes components that can get hot to touch. Because this
EVM is not enclosed to allow probing of circuit nodes, a small fan capable of 200-400 lfm is recommended to
reduce component temperatures when operating.
5.2 Recommended Setup
Figure 5-1 shows the recommended test setup to evaluate the TPS53126EVM-600. Working at an ESD
workstation, ensure that any wrist straps, bootstraps, or mats are connected referencing the user to earth ground
before power is applied to the EVM. An electrostatic smock and safety glasses also are recommended.
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LOAD1
1.05V @
4A V2
+
-
LOAD2
1.8 V @
4A
V3
-
+
-
+
-
+
A1
-
+
V
VIN
V1
+-
FAN
Figure 5-1. TPS53126EVM-600 Recommended Test Setup
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6 Test Procedure
6.1 Start-up Procedure
1. Prior to connecting the dc input source VIN, it is advisable to limit the source current from VIN to 2 Adc
maximum. Ensure that VIN is initially set to 0 V.
2. Ensure LOAD1 and LOAD2 are set to constant-current mode to sink 0 A before VIN is applied.
3. Verify SW1, SW2, and SW3 are in the desired position.
4. Place a fan as shown in Figure 5-1 and turn on, making sure air is flowing across the EVM.
5. Increase VIN from 0 V to 12 Vdc.
6.2 Line/Load Regulation and Efficiency Measurement Procedure
1. Set up TPS53126EVM-600 per Section 5.2.
2. Start up the TPS53126EVM-600 per Section 6.1.
3. Adjust VIN to desired value between 8 Vdc and 22 Vdc.
4. Adjust LOAD1/LOAD2 to desired load between 0 Adc and 4 Adc.
5. Read input voltage, output voltage, and input current from V1, V2/V3, and A1, respectively.
6. Shut down the TPS53126EVM-600 per Section 6.4.
6.3 Output Ripple Voltage Measurement Procedure
1. Set up the TPS53126EVM-600 per Section 5.2.
2. Start up the TPS53126EVM-600 per Section 6.1.
3. Adjust VIN to desired value between 8 Vdc and 22 Vdc.
4. Adjust LOAD1/LOAD2 to desired load between 0 A and 4 Adc.
5. Connect the oscilloscope probe to TP8 and TP4 for VOUT1, or TP7 and TP6 for VOUT2 as shown in Figure
4-1.
6. Measure output ripple.
7. Shut down TPS53126EVM-600 per Section 6.4.
6.4 Shutdown Procedure
1. Set SW1 to DIS.
2. Set SW2 to DIS.
3. Decrease LOAD1 to 0 A, and shut down LOAD1.
4. Decrease LOAD2 to 0 A, and shut down LOAD2.
5. Decrease VIN to 0 V, and shut down VIN.
6. Shut down the fan.
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