Texas Instruments LM5122EVM-2PH User manual

LM5122EVM-2PH Evaluation Module
User's Guide
Literature Number: SNVU205
APRIL 2013

Contents
1 Introduction ........................................................................................................................ 4
2 Features and Electrical Performance ..................................................................................... 4
3 Test Points ......................................................................................................................... 4
3.1 Test Points ............................................................................................................... 4
4 Test Equipment ................................................................................................................... 5
4.1 Power Supply ............................................................................................................ 5
4.2 Electronic Load .......................................................................................................... 5
4.3 Meters ..................................................................................................................... 5
4.4 Oscilloscope .............................................................................................................. 5
5 Test Setup and Procedure .................................................................................................... 5
5.1 Precaution & Wire Gauge .............................................................................................. 5
5.2 Test Setup ................................................................................................................ 6
5.3 Quick Test Procedure ................................................................................................... 6
6 Performance Curves ............................................................................................................ 6
6.1 Efficiency ................................................................................................................. 6
6.2 Load Transient ........................................................................................................... 7
6.3 Interleaving ............................................................................................................... 7
6.4 Light Load Operations .................................................................................................. 8
6.5 Startup .................................................................................................................... 9
6.6 Loop Response .......................................................................................................... 9
7 Schematic ......................................................................................................................... 10
8 Layout .............................................................................................................................. 12
9 Bill of Materials ................................................................................................................. 15
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List of Figures
1 Connection Diagram........................................................................................................ 5
2 Efficiency..................................................................................................................... 6
3 Load Transient .............................................................................................................. 7
4 Interleaving................................................................................................................... 7
5 Pulse Skip.................................................................................................................... 8
6 Skip Cycle.................................................................................................................... 8
7 Forced PWM................................................................................................................. 8
8 Startup........................................................................................................................ 9
9 Loop Response.............................................................................................................. 9
10 Schematic (Power Block)................................................................................................. 10
11 Schematic (Control Block)................................................................................................ 11
12 Top Silk (Top View) ....................................................................................................... 12
13 Bottom Silk (X-Ray View) ................................................................................................ 12
14 Top Copper (Top View)................................................................................................... 13
15 Mid1 Copper (X-Ray View)............................................................................................... 13
16 Mid2 Copper (X-Ray View)............................................................................................... 14
17 Bottom Copper (X-Ray View)............................................................................................ 14
List of Tables
1 Electrical Performance Specifications.................................................................................... 4
2 Pin Descriptions............................................................................................................. 4
3 Bill of Materials............................................................................................................. 15
3
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User's Guide
SNVU205–APRIL 2013
LM5122EVM-2PH Evaluation Module
1 Introduction
The LM5122EVM-2PH evaluation module (EVM) provides the design engineer with a fully functional dual
phase synchronous boost converter to evaluate the Texas Instruments LM5122 synchronous boost
controller device. The EVM provides 28 V output at up to 7 A current from a 9 V to 20 V input. The EVM is
designed to start up from a single power supply without any additional bias voltage.
2 Features and Electrical Performance
• 9 V to 20 V input voltage range
• 28 V target output voltage
• Up to 7 A output current
• 250 kHz typical switching frequency
• Dual phase interleaved operation
Table 1. Electrical Performance Specifications
PARAMETER TEST CONDITIONS MIN TYP MAX UNITS
Input Characteristics
Input Voltage 9 12 20 V
Input Current VSUPPLY = 12 V, ILOAD = 7A 17 A
Output Characteristics
Output Voltage ILOAD = 7A 27.02 28 28.98 V
Output Current 7 A
System Characteristics
Switching Frequency 250 kHz
Full Load Efficiency VSUPPLY = 12 V 96%
VSUPPLY = 20 V 98%
3 Test Points
3.1 Test Points
Table 2. Pin Descriptions
PIN NAME DESCRIPTIONS
TP7, TP8 Power Ground
TP5, TP9, TP10 Analog Ground
TP6 UVLO
J1#1 External Synchronization Pulse Positive Input
J1#2 External Synchronization Pulse Negative Input
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Oscilloscope
ACOM
Ampere Meter
+-
Power Supply
Electronic Load
+- V
Voltage Meter
COM
-s +s
www.ti.com Test Equipment
4 Test Equipment
4.1 Power Supply
Power Supply should be capable of 20 V / 25 A, current monitoring and remote sensing.
4.2 Electronic Load
Electronic load should be capable of 32 V / 7 A. Use Constant Current (CC) mode.
4.3 Meters
One current meter is required to measure input current accurately. Maximum current rating of the meter
should be carefully considered. Input current can be as high as 25 A at full load current and minimum
input voltage. Output voltage is monitored by a voltage meter which should be capable of monitoring up to
32 V.
4.4 Oscilloscope
Oscilloscope and 10x probe with at least 20 MHz bandwidth are required.
5 Test Setup and Procedure
Figure 1. Connection Diagram
5.1 Precaution & Wire Gauge
Prolonged operation with low input voltage at full power will cause heating of the MOSFETs. A fan with a
minimum of 200LFM should be always provided.
Wire gauge for the input power supply should be 6-8 AWG minimum and no longer than 1 foot each for
VIN and GND. Wire gauge for the output electronic load should be 12 AWG minimum and no longer than
1 foot each for VOUT and GND.
5
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80
85
90
95
100
0 2 4 6 8
EFFICIENCY [%]
LOAD CURRENT [A]
C001
FSW = 250 kHz
VOUT = 28V
VSUPPPLY = 20V
VSUPPLY = 9V
VSUPPLY = 12V
Performance Curves www.ti.com
5.2 Test Setup
5.2.1 Power Supply
Connect the power supply’s positive terminal (+) to ‘A’ terminal of ampere meter and negative terminal (-)
to TP4 GND. Connect the power supply’s positive remote sense terminal to TP2 VIN and negative remote
sense terminal to TP4 GND.
5.2.2 Meter
Connect ‘COM’ terminal of ampere meter to TP2 VIN. Double check ‘A’ terminal is connected to the power
supply’s positive terminal.
Voltage meter is used to measure output voltage. Connect positive terminal (V) of the voltage meter to
TP1 VOUT and negative terminal (COM) of the voltage meter to TP3 GND.
5.2.3 Load
Connect electronic load’s positive terminal (+) to TP1 VOUT and negative terminal (-) to TP3 GND.
5.3 Quick Test Procedure
5.3.1 Startup
• Set load current to 0 A and turn the load on
• Set power supply current limit to 25 A
• Turn on the power supply and increase voltage slowly up to 20 V
• Increase load current slowly up to 7 A
5.3.2 Shutdown
• Turn off the load
• Decrease the input voltage down to 0 V
• Turn on the load and discharge output capacitor
6 Performance Curves
The following curves are presented for reference, the actual field data may differ from these curves. Actual
performance data can be affected by measurement techniques, equipment setting and environmental
variables.
6.1 Efficiency
Figure 2. Efficiency
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6.2 Load Transient
VSUPPLY = 12 V, 3.5 A to 7 A and 7 A to 3.5 A load transient
C1: VOUT
Figure 3. Load Transient
6.3 Interleaving
VSUPPLY = 12 V
C1: SW1, C2: SW2
Figure 4. Interleaving
7
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Performance Curves www.ti.com
6.4 Light Load Operations
Forced PWM (FPWM) and Skip Cycle mode can be configured by controlling MODE pin voltage.
VSUPPLY = 12 V, ILOAD =0A
C1:SW1
Figure 5. Pulse Skip
C1: SW1
Figure 6. Skip Cycle
C1: SW1
Figure 7. Forced PWM
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-180
-135
-90
-45
0
45
90
135
180
-40
-30
-20
-10
0
10
20
30
40
100 1000 10000 100000
GAIN [dB]
FREQUENCY [Hz]
C002
PHASE
GAIN
VSUPPLY = 12V
I
LOAD
= 7.0A
PHASE [°]
www.ti.com Performance Curves
6.5 Startup
VSUPPLY = 12 V, ILOAD =0A
C1: VOUT, C2: SS, C4: VSUPPLY
Figure 8. Startup
6.6 Loop Response
Figure 9. Loop Response
9
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Schematic www.ti.com
7 Schematic
Figure 10. Schematic (Power Block)
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