Texas Instruments TPS61054EVM-273 User manual

User's GuideSLVU214 – June 2008
TPS61054EVM-273
This user’s guide describes the characteristics, operation, and use of the TPS61054EVM-273 evaluationmodule (EVM). This EVM demonstrates the Texas Instruments TPS61054 synchronousboost-converter-based high-power WLED driver. This document includes setup instructions, a schematicdiagram, a bill of materials, and PCB layout drawings for the evaluation module.
Contents1 Introduction ................................................................................................................... 22 Input/Output Connector Descriptions...................................................................................... 23 Test Results .................................................................................................................. 44 Board Layout ................................................................................................................. 75 Schematic and Bill of Materials ........................................................................................... 106 Related Documentation From Texas Instruments ..................................................................... 12
List of Figures
1 LED Efficiency vs Input Voltage – Torch Mode with ILED=75mA ..................................................... 42 LED Efficiency vs Input Voltage – Single-Pulse Flash Mode with ILED=700mA .................................... 53 Torch Flash Sequence ...................................................................................................... 54 Start-Up in Torch ............................................................................................................. 65 Voltage-Mode Efficiency .................................................................................................... 66 Voltage-Mode Load Transient .............................................................................................. 77 Assembly Layer .............................................................................................................. 88 Top Layer ..................................................................................................................... 89 Layer 2 ........................................................................................................................ 910 Layer 3 ....................................................................................................................... 911 Bottom Layer ................................................................................................................ 1012 TPS61054/5EVM-273 Schematic ........................................................................................ 11
List of Tables
1 Typical Performance Specification Summary ............................................................................ 22 Jumper Settings .............................................................................................................. 43 HPA273E-1 Bill of Materials .............................................................................................. 12
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1 Introduction
1.1 Performance Specification Summary
1.2 Modifications
2 Input/Output Connector Descriptions
2.1 J1 – VIN
2.2 J2 – GND
2.3 J3 – FLASH / GND
Introduction www.ti.com
The Texas Instruments TPS61054EVM-273 evaluation module uses the TPS61054 synchronous boostconverter-based high-power WLED driver. This WLED driver requires an input voltage between 2.5 V and6 V. The driver is configurable by on-board jumpers to either regulate output voltage or the output current.The goal of the EVM is to facilitate evaluation of the TPS61054 IC.
Table 1 provides a summary of the TPS61054EVM-273 performance specifications. All specifications aregiven for an ambient temperature of 25 °C.
Table 1. Typical Performance Specification Summary
VOLTAGE RANGE CURRENT RANGE(V) (mA)CONDITION
MIN TYP MAX MIN TYP MAX
V
IN
2.5 6 2000supply
V
OUT
MODE0 = MODE1 = 1 4.85 5 5.15Torch current (MODE0 = 1 and MODE1 = 0 OR
75
(1)MODE0 = 0 and MODE1 = 1)I
LED
Flash current (MODE0 = 0 and MODE1 = 1 and
700
(2)FLASH_SYNC = 1)
(1)
±15% tolerance(2)
±12% tolerance
To aid user customization of the EVM, the board was designed with devices having 0603 or largerfootprints. A real implementation likely occupies less total board space.
Changing components can improve or degrade EVM performance. For example, adding a physicallylarger inductor with lower DCR improves efficiency.
This section describes the jumpers and connectors on the EVM as well as how properly to connect, setup, and use the TPS61054EVM-273.
This header is for the positive input supply voltage to the converter. The leads to the input supply shouldbe twisted and kept as short as possible to minimize EMI transmission and reduce inductive voltage droopat a load transient event.
This is the return connection for the input power supply of the converter.
This header connects to the FLASH_SYNC pin of the IC and to GND. It can be used to measure thevoltage on the FLASH_SYNC pin and/or apply an external signal to the FLASH_SYNC pin.
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2.4 J4 – PULSE GEN / GND
2.5 J5 – TRANS RES
2.6 J6 – VOUT
2.7 J7 – LED
2.8 J8 – GND
2.9 JP1 – TX-TOFF
2.10 JP2 – MODE0
2.11 JP3 – MODE1
2.12 JP5 – OPEN LED
2.13 S1 – FLASH
www.ti.com Input/Output Connector Descriptions
This header can be used to connect an external pulse generator to drive the gate of transistor Q1.Transistor Q1, along with components R2–R4, can be used to perform load transient testing and confirmstability.
This header connects to the drain of transistor Q1.
This header connects to the VOUT pin IC. In voltage-regulation mode, it can be used to measure theregulated output voltage and connect an external load resistance. In current-regulation mode, it connectsto the WLED cathode and can be used to measure the high-side WLED voltage.
This header connects to the LED pin of the IC. In current-regulation mode, it connects to the WLED anodeand can be used to measure the low-side WLED voltage. It is not used in voltage-regulation mode.
This header connects to the board ground plane and is the return for the VOUT header.
This jumper can be used to connect the TX-TOFF pin high (to the input voltage) or low (to ground).
This jumper can be used to connect the MODE0 pin high (to the input voltage) or low (to ground). See thedevice data sheet (SLUS760 ) for an explanation of configuration settings.
This jumper can be used to connect the MODE1 pin high (to the input voltage) or low (to ground). See thedevice data sheet (SLUS760 ) for an explanation of configuration settings.
This jumper is in series with power WLED D1. For the WLED to turn on, this jumper must be shorted.Placing an ammeter in series allows the user to measure current. The jumper in its default position isinstalled.
This push-button switch connects to the IC FLASH_SYNC pin and allows the user to initiate a WLED flashevent.
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2.14 Hardware Setup
3 Test Results
VI− Input Voltage − V
40
50
60
70
80
90
100
2.5 3.0 3.5 4.0 4.5 5.0 5.5
LED Efficiency − %
G001
Test Results www.ti.com
Table 2 shows the DEFAULT board jumper settings.
Table 2. Jumper Settings
JUMPER DEFAULT
JP1 LOJP2 LOJP3 LOJP4 SHORTED
Connect to J1 and J2 an input power supply rated at least 2-A and set to provide between 2.5 V and 6 V.The leads should be very short. Additional input capacitance on the C4 pads may be required in order tomitigate the inductive voltage droop that occurs at torch-current start-up and especially when the flashpulse occurs. Turn on the power supply.
WARNINGWARNING: This EVM has a white LED that flashes very brightly.Protective eye wear and/or a diffuser to cover the white LED duringoperation is recommended.
This section provides typical performance waveforms for the TPS61054/5EVM-273 board.
Figure 1. LED Efficiency vs Input Voltage – Torch Mode with ILED=75mA
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VI− Input Voltage − V
0
10
20
30
40
50
60
70
80
90
2.5 3.0 3.5 4.0 4.5 5.0 5.5
LED Efficiency (PLED/PIN) − %
G002
ILED = 700 mA
www.ti.com Test Results
Figure 2. LED Efficiency vs Input Voltage – Single-Pulse Flash Mode with ILED=700mA
Figure 3. Torch Flash Sequence
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0
10
20
30
40
50
60
70
80
90
100
IO− Output Current − mA
VI= 3.6 V
VO= 5 V
Efficiency − %
10 100 1k 10k
G003
Test Results www.ti.com
Figure 4. Start-Up in Torch
Figure 5. Voltage-Mode Efficiency
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4 Board Layout
www.ti.com Board Layout
Figure 6. Voltage-Mode Load Transient
This section provides the TPS61054EVM-273 board layout and illustrations.
Board layout is critical for all high-frequency, switch-mode power supplies. Figure 7 through Figure 11show the board layout for the TPS61054EVM-273 PCB. The nodes with high switching frequencies andcurrents are kept as short as possible to minimize trace inductance. Careful attention has been given tothe routing of high-frequency current loops, and a single-point grounding scheme is used. See the devicedata sheet (SLUS760 ) for specific layout guidelines.
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K001
K002
Board Layout www.ti.com
Figure 7. Assembly Layer
Figure 8. Top Layer
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K003
K004
www.ti.com Board Layout
Figure 9. Layer 2
Figure 10. Layer 3
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K005
5 Schematic and Bill of Materials
Schematic and Bill of Materials www.ti.com
Figure 11. Bottom Layer
This section provides the TPS61054EVM-273 schematic and bill of materials.
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