Texas Instruments TPS544 20 Series User manual

User’s Guide
TPS544x20 Step-Down Converter Evaluation Module
User's Guide
ABSTRACT
The PWR-634EVM evaluation module uses either the TPS544C20 or TPS544B20 devices. The TPS544C20
and TPS544B20 are highly integrated synchronous buck converters that are designed for up to 30-A or 20-A
current output, respectively.
Table of Contents
1 Description.............................................................................................................................................................................. 2
1.1 Typical Applications............................................................................................................................................................2
1.2 Features............................................................................................................................................................................. 2
2 Electrical Performance Specifications................................................................................................................................. 3
3 Schematic................................................................................................................................................................................4
4 Test Setup................................................................................................................................................................................5
4.1 Test and Configuration Software........................................................................................................................................ 5
4.2 Test Equipment.................................................................................................................................................................. 6
4.3 The PWR-634EVM.............................................................................................................................................................7
4.4 Test Set up and USB Interface Adapter............................................................................................................................. 8
4.5 List of Test Points............................................................................................................................................................... 9
5 EVM Configuration Using the Fusion GUI..........................................................................................................................10
5.1 Configuration Procedure.................................................................................................................................................. 10
6 Test Procedure...................................................................................................................................................................... 11
6.1 Line/Load Regulation and Efficiency Measurement Procedure........................................................................................11
6.2 Efficiency.......................................................................................................................................................................... 11
6.3 Equipment Shutdown....................................................................................................................................................... 11
7 Performance Data and Typical Characteristic Curves...................................................................................................... 12
7.1 Efficiency..........................................................................................................................................................................12
7.2 Load Regulation............................................................................................................................................................... 12
7.3 Transient Response......................................................................................................................................................... 13
7.4 Output Ripple................................................................................................................................................................... 14
8 Screen Shots.........................................................................................................................................................................17
8.1 Fusion GUI Screen Shots................................................................................................................................................ 17
9 EVM Assembly Drawing and PCB Layout.......................................................................................................................... 31
10 List of Materials.................................................................................................................................................................. 35
11 Revision History..................................................................................................................................................................37
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1 Description
The PWR-634EVM is designed as a single output DC-DC converter that demonstrates either the TPS544C20
or the TPS544B20 in a typical low-voltage application while providing a number of test points to evaluate the
performance. It uses a nominal 12-V input bus to produce a regulated 1.0-V output at up to either 30-A or 20-A
of load current, depending on the device installed.
1.1 Typical Applications
• High-Density Power Solutions
• Communications equipment
• Servers and Computing equipment
• Smart Power Systems
1.2 Features
• Regulated 1.0-V output up to 30-ADC, steady-state output current
• Output is marginable and trimmable via the PMBus interface.
– Programmable: UVLO, Soft Start, and Enable via the PMBus interface
– Programmable overcurrent warning and fault limits and programmable response to faults via the PMBus
interface
– Programmable overvoltage warning and fault limit and programmable response to faults via the PMBus
interface
– Programmable high- and low-output margin voltages with a maximum range of 10%, –20% of nominal
output voltage
• Convenient test points for probing critical waveforms
Description www.ti.com
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2 Electrical Performance Specifications
Table 2-1. PWR-634EVM Electrical Performance Specifications
PARAMETER TEST CONDITIONS MIN TYP MAX UNITS
Input Characteristics
Voltage range VIN 8 12 14 V
Maximum input current VIN = 8 V, IO = 30 A, 5 A
No load input current VIN = 14 V, IO = 0 A 100 mA
Output Characteristics
VOUT Output voltage Output current = 10 A 1.0 V
IOUT Output load current IOUT_min to IOUT_max 0 30 A
Output voltage regulation Line regulation: Input voltage = 8 V to 14 V 0.5%
Load regulation: Output current = 0 A to IOUT_max 0.5%
VOUT Output voltage ripple VIN = 12 V, IOUT = 20 A 30 mVpp
VOUT Output overcurrent 20 A
Systems Characteristics
Switching frequency FSW 500 kHz
VOUT Peak efficiency VIN = 8 V, IO = 10 A, FSW = 300 kHz 92%
VOUT Full-load efficiency VIN = 8 V, IO = 10 A, FSW = 300 kHz 90%
Operating temperature Toper 105 °C
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3 Schematic
CNTL 1
ADDR1 2 ADDR0 3
DATA 4
CLK 5
SMBALERT 6
BOOT 7
SW 8 SW 9 SW 10 SW 11 SW 12
AGNDSNS
13
GND
14
GND
15
GND
16
GND
17
GND
18
GND
19
GND
20
VIN
21
VIN
22
VIN
23
VIN
24
VIN
25
PGND
26
BP3
27
BP6
28
VDD
29
BPEXT
30
VOUTS+
31
VOUTS-
32
DIFFO 33
FB 34
COMP 35
PGOOD 36
TSNS 37
AGND 38
MODE 39
RT 40
PAD
U1
TPS544C20RVF
10μF
C15
1000pF
C17
0.1μF
C16
10μF
C14
10μF
C13
10μF
C12
GND
VIN
0.1μF
C8
0
R14
SMBALERT
CLK
DATA
47μF C18
47μF
C19
Open
C11
DNP
Open
R16
DNP
GND
38.3k
R11
38.3k
R12
Open
R5 DNP
0
R3 BP3
CNTL
0.1μF C7
4.7μF
C6
BP3
BP6
4.7μF C5
VIN
VOUTS+
VOUTS-
VOUT
49.9 R15 49.9 R13
VOUTS+
VOUTS-
20.0k
R6
30.1k
R9
Open R4
DNP
ADJ
Output Voltage Adjust
May be used with LM10011
0.01μF
C4
100k
R1
BP3
Q1
MMBT3904
1000pF
C2
PGOOD
VIN = 10V - 14V
VOUT = 1.0V @ 30A MAX
FSW = 500KHz
400nH
L1
1 2
J2
TP8 TP7
TP5 TP6
TP1
TP2
TP9
TP11
TP10
12 34 56 78 910
J1
DATA
CLK
SMBALERT
CNTL
0
R10
GND
Open C3
DNP
Open C1
DNP
Open R2
DNP
560μF
C9
560μF
C10
Open
C20
DNP
1000pF
C21
AGND
TP12
TP3
1 2
J3
1 2
J4
100k R17
BP6
1 Fμ C22
TP4
AGND
AGND
GND
GND
VOUT
GND
VIN
47μF C24
47μF
C25
470μF
C23
1 Fμ C26
Open
C27
DNP
Open
R7DNP 38.3k
R8
33pF
C28
AGND
Figure 3-1. PWR-634EVM Schematic
Schematic www.ti.com
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4 Test Setup
4.1 Test and Configuration Software
To change any of the default configuration parameters on the EVM, it is necessary to obtain the TI Fusion Digital
Power Designer software. This can be downloaded from the TI website.
4.1.1 Description
The Fusion Digital Power Designer is the graphical user interface (GUI) used to configure and monitor the Texas
Instruments TPS544B20 or TPS544C20 power converter installed on this evaluation module. The application
uses the PMBus protocol to communicate with the controller over serial bus by way of a TI USB adapter (see
Figure 4-2).
4.1.2 Features
Some of the tasks you can perform with the GUI include:
• Turn on or off the power supply output, either through the hardware control line or the PMBus operation
command.
• Monitor real-time data. Items such as input voltage, output voltage, output current, temperature, and warnings
and faults are continuously monitored and displayed by the GUI.
• Configure common operating characteristics such as VOUT trim and margin, UVLO, soft-start time, warning
and fault thresholds, fault response, and ON/OFF.
This software is available for download at http://www.ti.com/tool/fusion_digital_power_designer
www.ti.com Test Setup
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4.2 Test Equipment
Voltage Source: The input voltage source VIN must be a 0-V to 14-V variable dc source capable of supplying at
least 5 Adc. Connect VIN to J2 Figure 4-1.
Multimeters: It is recommended to use two separate multimeters Figure 4-1. One meter is used to measure Vin
and one to measure Vout.
Output Load: A variable electronic load is recommended for testing Figure 4-1. It must be capable of 30 A at
voltages as low as 0.9 V.
Oscilloscope: An oscilloscope is recommended for measuring output noise and ripple. Output ripple must be
measured using a Tip-and-Barrel method or better as shown in Figure 4-3.The scope must be adjusted to
20-MHz bandwidth, ac coupling at 50 mV/division, and must be set to 1-µs/division.
Fan: During prolonged operation at high loads, it may be necessary to provide forced air cooling with a small fan
aimed at the EVM. Temperature of the devices on the EVM must be maintained below 105°C.
USB-to-GPIO Interface Adapter: A communications adapter is required between the EVM and the host
computer. This EVM was designed to use the Texas Instruments USB-to-GPIO Adapter (see Figure 4-2). This
adapter can be purchased at http://www.ti.com/tool/usb-to-gpio.
Recommended Wire Gauge: The voltage drop in the load wires must be kept as low as possible in order to
keep the working voltage at the load within its operating range. See the following table for recommended wire
gauge and length to achieve a voltage drop of no more than 0.2 V at the maximum 30-A load.
AWG GAUGE Ω PER FOOT
(Ω)
LOAD WIRES COMBINED
LENGTH
(Ft)
EACH WIRE LENGTH
(Ft)
12 1.59E-3 6.30 3.15
14 2.53E-3 3.96 1.98
16 4.02E-3 2.49 1.25
18 6.39E-3 1.57 0.78
As an example, if AWG 12 wire is used, no more than 3.15 feet of wire must be used between the EVM and the
load.
Test Setup www.ti.com
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4.3 The PWR-634EVM
Figure 4-1. PWR-634EVM Overview
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4.4 Test Set up and USB Interface Adapter
Figure 4-2. Complete Test Setup Including Texas Instruments USB-to-GPIO Adapter
Metal Ground
Barrel
Probe
Tip
Tip and Barrel VOUT Ripple
Measurement
Figure 4-3. Tip and Barrel Measurement
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4.5 List of Test Points
Table 4-1. The Function of Each Test Point
TEST POINT TYPE NAME DESCRIPTION
TP1 T-H loop PGOOD Power good signal for VOUT.
TP2 T-H loop ADJ Output voltage adjust
TP3 T-H loop SMBALERT SMB alert signal
TP4 T-H loop BPEXT Bypass connect
TP5 T-H loop VOUT + Sense
TP6 T-H loop VOUT – Sense
TP7 T-H loop VOUT+
TP8 T-H loop VIN+
TP9 T-H loop VIN–
TP10 T-H loop GND
TP11 T-H loop VOUT–
TP12 T-H loop CNTL Control signal
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5 EVM Configuration Using the Fusion GUI
The TPS544B20 or TPS544C20 installed on this EVM leave the factory pre-configured. See Table 5-1 for a short
list of key factory configuration parameters as obtained from the configuration file.
Table 5-1. Key Factory Configuration Parameters
ADDRESS HEX ADDRESS DEC PART ID
0x1B 27 TPS544x20
GENERAL
CMD ID WITH PHASE CMD CODE HEX ENCODED HEX DECODED NUMERIC COMMENTS
VIN_OFF 0x36 0xF014 5.00 V 5 Turn OFF voltage
VIN_ON 0x35 0xF01C 7.00 V 7 Turn ON voltage
TPS544B20 COMMENTS
IOUT_CAL_GAIN 0x38 0x8821 1.0071 mΩ 1.0071 DCR of output inductor
IOUT_CAL_OFFSET 0x39 0xE000 0.0000 A 0 Current offset for GUI readout
IOUT_OC_FAULT_LIMIT 0x46 0xF83C 30.0 A 30 OC fault level
IOUT_OC_FAULT_RESPONSE 0x47 0x3C Restart continuously Response to OC fault
IOUT_OC_WARN_LIMIT 0x4A 0xF832 25.0 A 25 OC warning level
MFR_04 (VREF_TRIM) 0xD4 0x0000 0.000 V 0 Trim voltage
ON_OFF_CONFIG 0x02 0x02 Mode: always converting Control signal and operation command not
required
OPERATION 0x01 0x00 Unit: immediate off; margin: none Response to turn OFF trigger
OT_FAULT_LIMIT 0x4F 0x007D 125°C 125 OT fault level
OT_WARN_LIMIT 0x51 0x0064 100°C 100 OT warn level
TON_RISE 0x61 0xE02B 2.6875 ms 2.6875 Soft-start time
TPS544C20 COMMENTS
IOUT_CAL_GAIN 0x38 0x8821 1.0071 mΩ 1.0071 DCR of output inductor
IOUT_CAL_OFFSET 0x39 0xE000 0.0000 A 0 Current offset for GUI readout
IOUT_OC_FAULT_LIMIT 0x46 0xF832 25.0 A 25 OC fault level
IOUT_OC_FAULT_RESPONSE 0x47 0x3C Restart continuously Response to OC fault
IOUT_OC_WARN_LIMIT 0x4A 0xF828 20.0 A 20 OC warning level
MFR_04 (VREF_TRIM) 0xD4 0x0000 0.000 V 0 Trim voltage
ON_OFF_CONFIG 0x02 0x02 Mode: always converting Control signal and operation command not
required
OPERATION 0x01 0x00 Unit: immediate off; margin: none Response to turn off trigger
OT_FAULT_LIMIT 0x4F 0x007D 125°C 125 OT fault level
OT_WARN_LIMIT 0x51 0x0064 100°C 100 OT warn level
TON_RISE 0x61 0xE02B 2.6875 ms 2.6875 Soft-start time
If it is desired to configure the EVM to settings other than the factory settings shown in Table 5-1, the TI Fusion
Digital Power Designer software can be used for reconfiguration. It is necessary to have input voltage applied
to the EVM prior to launching the software so that the TPS544B20 or TPS544C20 installed is active and able
to respond to the GUI and the GUI can recognize the device. The default configuration for the EVM is to start
converting at an input voltage of 4.5 V; therefore, to avoid any converter activity during configuration, an input
voltage less than 4.5 V must be applied. An input voltage of 4 V is recommended.
5.1 Configuration Procedure
1. Adjust the input supply to provide 4 VDC, current limited to 1 A.
2. Apply the input voltage to the EVM. See Figure 4-1 and Figure 4-2 for connections and test setup.
3. Launch the Fusion GUI software. See the screen shots in Section 8 for more information.
4. Configure the EVM operating parameters as desired.
EVM Configuration Using the Fusion GUI www.ti.com
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6 Test Procedure
6.1 Line/Load Regulation and Efficiency Measurement Procedure
1. Set up the EVM as described in Section 4.3 and Figure 4-1.
2. Ensure that the electronic load is set to draw 0 ADC.
3. Increase VIN from 0 V to 12 V using the DMM to measure input voltage.
4. Use the other DMM to measure output voltage VOUT.
5. Vary the load from 0 ADC to maximum rated output ADC (TPS544B20 = 20 A, TPS544C20 = 30 A). VOUT
must remain in regulation as defined in Table 2-1.
6. Vary VIN from 8 V to 14 V. VOUT must remain in regulation as defined in Table 2-1.
7. Decrease the load to 0 A.
8. Decrease VIN to 0 V.
6.2 Efficiency
To measure the efficiency of the power train on the EVM, it is important to measure the voltages at the correct
location. This is necessary because otherwise the measurements will include losses in efficiency that are not
related to the power train itself. Losses incurred by the voltage drop in the copper traces and in the input and
output connectors are not related to the efficiency of the power train, and they must not be included in efficiency
measurements.
Table 6-1. List of Test Points for Efficiency Measurements
TEST POINT NODE NAME DESCRIPTION
TP8 VIN Measurement point for VIN +VE
TP9 PGND Measurement point for VIN –VE
TP7 VOUT Measurement point for VOUT +VE
TP11 PGND Measurement point for VOUT –VE
Input current can be measured at any point in the input wires, and output current can be measured anywhere
in the output wires of the output being measured. Using these measurement points result in efficiency
measurements that do not include losses due to the connectors and PCB traces.
6.3 Equipment Shutdown
1. Reduce the load current on both outputs to 0 A.
2. Reduce input voltage to 0 V.
3. Shut down the external fan if in use.
4. Shut down equipment.
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7 Performance Data and Typical Characteristic Curves
Figure 7-1 through Figure 7-9 present typical performance curves for the PWR-634EVM.
7.1 Efficiency
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
1 2 3 4 5 6 7 8 9 101112 131415 161718 19202122 2324
8V
12V
14V
Figure 7-1. Efficiency of 1-V Output vs Line and Load
7.2 Load Regulation
1.000
1.002
1.004
1.006
1.008
1.010
1.012
1.014
1 2 3 4 5 6 7 8 9 101112 13141516 1718 1920 2122 2324
8V
12V
14V
Figure 7-2. Load Regulation of 1-V Output
Performance Data and Typical Characteristic Curves www.ti.com
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7.3 Transient Response
Ch1 = VOUT1 at 50-mV/division, Ch2 = IOUT1 at 5-A/division
Figure 7-3. Transient Response of 1-V Output at 12 VIN, Transient is 10 A to 20 A
Ch1 = VOUT1 at 50-mV/division, Ch2 = IOUT1 at 5-A/division
Figure 7-4. Transient Response of 1-V Output at 12 VIN, Transient is 20 A to 10 A
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7.4 Output Ripple
Ch1 = VOUT1 at 20-mV/division, Ch2 = SW Node at 10-V/division
Figure 7-5. Output Ripple and SW Node of 1-V Output at 12 VIN, 1-A Output
Ch1 = VOUT1 at 20-mV/division, Ch2 = SW Node at 10-V/division
Figure 7-6. Output Ripple and SW Node of 1-V Output at 12 VIN, 20-A Output
Performance Data and Typical Characteristic Curves www.ti.com
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Ch1 = VOUT2 at 20-mV/division, Ch2 = SW Node at 10-V/division
Figure 7-7. Start up from Control 1-V Output at 12 VIN, 20-A Output
Ch1 = VOUT2 at 20-mV/division, Ch2 = SW Node at 10-V/division
Figure 7-8. Shutdown from Control and SW Node of 1-V Output at 12 VIN, 20-A Output
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Figure 7-9. 50% PreBias Start (No Load)
Performance Data and Typical Characteristic Curves www.ti.com
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8 Screen Shots
8.1 Fusion GUI Screen Shots
Figure 8-1. First Window at Fusion Launch
Device Found
Figure 8-2. Scan Finds Device Successfully
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Figure 8-3. Software Launch Continued
Figure 8-4. Software Launch Continued
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Use this next screen to configure the following (Figure 8-5):
• OC fault and OC warn
• OT fault and OT warn
• Power good limits
• Fault response
• UVLO
• On/Off configuration
• Soft-start time
• Margin voltage
Figure 8-5. First Screen After Successful Launch: Configure- Limits & On/Off
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Use this screen to configure the following (Figure 8-6) :
• VREF trim
• IOUT cal gain (DCR of output choke)
Figure 8-6. Configure – Other
Use this screen to configure all of the configurable parameters (Figure 8-7). The screen also shows other details,
like hexadecimal (hex) encoding.
Figure 8-7. Configure – All
Screen Shots www.ti.com
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