Texas Instruments TPS61050EVM-215 User manual

User's GuideSLVU202B – May 2007 – Revised November 2007
TPS61050EVM-215 and TPS61052EVM-215
This user’s guide describes the characteristics, operation, and use of the TPS61050EVM-215 andTPS61052EVM-215 evaluation modules (EVMs). This EVM demonstrates either the Texas InstrumentsTPS61050 or TPS61052 synchronous boost converter based high power WLED driver with I
2
C interface.This document includes setup instructions, a schematic diagram, a bill of materials, and PCB layoutdrawings for the evaluation module.
Contents1 Introduction ................................................................................................................... 22 Setup .......................................................................................................................... 23 Software Setup and Operation ............................................................................................. 64 Test Results .................................................................................................................. 75 Board Layout ................................................................................................................ 116 Schematics and Bill of Materials ......................................................................................... 14
List of Figures
1 TPS6105x Software Main Panel ........................................................................................... 62 LED Efficiency vs. Input Voltage - Torch Mode .......................................................................... 73 LED Efficiency vs. Input voltage - Single Pulse Flash Mode ........................................................... 84 Torch Flash Sequence ...................................................................................................... 85 Start Up in Torch ............................................................................................................. 96 Inrush Current at Flash .................................................................................................... 107 Voltage Mode Efficiency ................................................................................................... 108 Voltage Mode Load Transient ............................................................................................ 119 Assembly Layer............................................................................................................. 1210 Top Layer .................................................................................................................... 1211 Layer 2 ....................................................................................................................... 1312 Layer 3 ...................................................................................................................... 1313 Bottom Layer ................................................................................................................ 1414 TPS61050/2EVM-215 Schematic ........................................................................................ 15
List of Tables
1 Jumper Settings .............................................................................................................. 52 HPA215 Bill of Materials................................................................................................... 16
Windows is a trademark of Microsoft Corporation.I
2
C is a trademark of Philips Corporation.VeriSign is a trademark of VeriSign, Inc..
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1 Introduction
1.1 Requirements
2 Setup
2.1 Input/Output Connector Descriptions
2.1.1 J1 – VIN
2.1.2 J2 – GND
Introduction
To operate this EVM, connect and properly configure the following components:A personal computer (PC) with a USB port is required to operate this EVM. The TPS61050/2 interfacesoftware runs on the PC and communicates with the EVM via the PC’s USB port. Commands can besent to the internal registers of the TPS61050/2 through the USB port.
Personal Computer Requirements•Windows™ 2000 or Windows™ XP operating system•USB port•Minimum of 30 MB of free hard disk space (100 MB recommended)•Minimum of 256 MB of RAM
Printed-Circuit Board AssemblyThe board contains the either the TPS61050 or TPS61052 IC in QFN package, its required externalcomponents and a high power WLED.
USB-TO-GPIO AdapterThe USB-TO-GPIO adapter is the link that allows the PC and the EVM to communicate. One end ofthe USB interface adapter connects to the PC with the supplied USB cable; the other side of the USBinterface adapter connects to the EVM with the supplied ribbon cable.When a command is written to the EVM, the interface program running on the PC sends thecommands to the PC USB port. The USB interface adapter receives the USB command, converts thesignal to an I
2
C protocol, and sends the I
2
C signal to the TPS61050/2 EVM board
Software
Texas Instruments provides software to assist in evaluating this EVM. The software can be installedfrom the supplied CD or downloaded from the Texas Instruments Web site at www.ti.com .
WARNINGThis EVM has a white LED that flashes very bright. Protective eyewear and/or a diffuser to cover the white LED is recommended.
This section describes the jumpers and connectors on the EVM as well as how to properly connect, setup, and use the TPS61050EVM-215 and TPS61052EVM-215.
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.
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2.1.3 J3 – I
2
C Input
2.1.4 J4 – PULSE GEN / GND
2.1.5 J5 – TRANS RES
2.1.6 J6 – VOUT
2.1.7 J7 – LED
2.1.8 J8 –GND
2.1.9 J9 –FLASH / GND
2.1.10 J10–SCL/SDA
2.1.11 JP1 –I
2
C PULLUP
2.1.12 JP2 –GPIO INPUT or OUTPUT
Setup
This header provides a connection for the included USBTOGPIO interface adapter. The included softwareuses the adapter to communicate with the EVM using the I
2
C protocol.
This header can be used to connect an external pulse generator to drive the gate of transistor Q1.Transistor Q1, along with components R5 - R7, can be used to perform load transient testing and confirmstability.
This header connects to transistor Q1's drain.
This header connects to the IC's VOUT pin. 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's cathode and can be used to measure the high-side WLED voltage.
This header connects to the IC's LED pin. In current regulation mode, it connects to the WLED's 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's ground plane and is the return for the VOUT header.
This header connects to the IC's FLASH pin and GND. It can be used to measure the voltage on theFLASH pin and/or apply an external signal to the FLASH pin.
This header connects to the IC's 1
2
C SCL and SDA control and data lines. It can be used to monitor thedata traffic between the USBTOGPIO adapter and EVM.
This jumper is used to connect the SCL and SDA 15-kohm pull-up resistors to the board's input voltage.This jumper should remain in its default installed position if the USB-TO-GPIO adapter is used to providethe I
2
C interface. If jumper JP1 is uninstalled, then the low side of the jumper must be tied to the externalsource that is powering an alternate I
2
C interface OR R2 and/or R3 must be removed and the SCL andSDA data lines must be pulled up through resistors to that same external source using header J4.
The middle pin of this jumper connects to the GPIO pin on the TPS61050 and the ENVM pin on theTPS61052. If the TPS61050's GPIO pin is configured for input and this jumper is set to INPUT, then theGPIO pin is connected to JP4, which can be jumper connected to either VIN or GND. If the TPS61050'sGPIO pin is configured for output and this jumper is set to OUTPUT, then the GPIO pin is connected toJP3. When shorted, JP3 connects a diode in series with the GPIO output pin. Since the TPS61052'sENVM pin is an input pin, JP2 should be left open to allow for connection to external signal generator orshorted to INPUT. This jumper's default position is uninstalled.
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2.1.13 JP3 –OUTPUT LED
2.1.14 JP4 –INPUT: VIN or GND
2.1.15 JP5 –OPEN LED
2.1.16 S1 –FLASH
2.2 Software Setup
Setup
When shorted, this jumper connects diode D1 in series with the OUTPUT side of JP2. With theTPS61050's GPIO configured for output, the diode turns on when the GPIO output is low. JP2 must beconnected to OUTPUT for this jumper to be effective. This jumper's default position is uninstalled.
The middle pin of this jumper connects the INPUT side of JP2. This jumper is intended to facilitateconnection of either the TPS61050's GPIO, when configured as INPUT, or the TPS61052's ENVM pin toVIN, for a logic high, or GND, for a logic low. JP2 must be connected to INPUT for this jumper to beeffective. This jumper's default position is uninstalled.
This jumper is in series with power WLED, D2. For the WLED to turn on, this jumper must be shorted.Placing an ammeter in series allows the user to measure current. This jumper's default position isinstalled.
This push-button switch connects to the IC's FLASH pin and allows the user to initiate a WLED flashevent.
If installing from a CD, insert the CD and run Setup.exe; follow all the prompts to install the software.
If installing from the TI Web site, go to theURL,http://focus.ti.com/en/download/aap/DesignEnv/TPS6105xEVM-SW/publish.htm
Note: This installation page is best viewed with Microsoft Internet Explorer browser (It may notwork correctly with other browsers)
Click on the install button; your PC should give you a security warning and ask if you want to install thisapplication. Select Install to proceed. If version 22 or older is currently installed on your PC, you mustuninstall this version of the software before installing version 23 or later from either the CD or website.
With both types of installation, the software attempts to install the Microsoft Dot Net Framework 2.0 (if it isnot already installed) This framework is required for the software to run.
After installation, the software should automatically run. To run the software later, go to
Start->all programs-> Texas Instruments, Inc. -> TPS6105x EVM Software.
During future use of the software, it may prompt you to install a new version if one becomes available onthe Web.
Note: VeriSign™ Code Signing is used to prevent any malicious code from changing thisapplication. If at any time in the future the binaries are modified, the code will no longerattempt to run.
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2.3 Hardware Setup
Host
Computer
USB Cable
USB
Interface
Adapter
Green LED
Indicates
Power
10-Pin
Ribbon
Cable
EVM Board
USB Interface Adaptor Quick Connection Diagram
Setup
Table 1 below shows the board's DEFAULT jumper settings.
Table 1. Jumper Settings
JUMPER DEFAULT
JP1 Installed
JP2 Uninstalled
JP3 Uninstalled
JP4 Uninstalled
JP5 Installed
Connect the USB-TO-GPIO adapter to your PC using the supplied USB cable. Connect theTPS61050/2EVM's connector J3 to the USB-TO_GPIO adapter using the supplied 10-pin ribbon cable.The connectors on the ribbon cable are keyed to prevent incorrect installation.
Connect at least a 2-A rated input power supply set to provide between 2.5 V and 6.0 V output to J1 andJ2. The leads should be very short. Additional input capacitance may be required in order to mitigate theinductive voltage droop that occurs at torch current start up and especially when the flash pulse occurs(see figures 5 and 6). Turn on the power supply.
WARNINGThis EVM has a white LED that flashes very brightly. Protective eyewear and/or a diffuser to cover the white LED during operation isrecommended.
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3 Software Setup and Operation
Software Setup and Operation
This section provides descriptions of the EVM software.
The supplied software is used to communicate with the TPS61050/2EVM. Click on the icon on the hostPC to start the software. The host PC software first checks the firmware version of the USB-TO-GPIOadapter box. If an incorrect firmware version is installed, the software automatically searches on theInternet (if connected) for updates. If a new update is available, the software notifies the user of theupdate, downloads and installs the software. Note that after the firmware is updated, the user mustdisconnect and then reconnect the USB cable between the adapter and PC, as instructed during theinstall process. The host PC software automatically searches on the Internet (if connected) for updates. Ifa new update is available, the software notifies the user of the update, downloads and installs the update.
The software then asks which version of the IC is on the board and the desired current limit. Check theapproriate box for the IC, then select the desired current limit, and finally click the continue button.Although the PCB can be powered up after the software is initiated, in order for the user to be able to setthe current limit to a value other than the default, the PCB must be powered on before the software isinitiated.
The software displays the main control panel for the user interface. Figure 1 shows the user interface maincontrol panel.
Figure 1. TPS6105x Software Main Panel
It is recommended that the user press the READ ALL REGISTERS button immediately after loading thesoftware to confirm that the software and cable connections are working properly. The message box at thetop right of the control panel displays whether or not the TPS61050/2 is operational and the middlemessage box at the bottom displays whether or not the USB-TO-GPIO connection s functional.
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4 Test Results
0
10
20
30
40
50
60
70
80
90
2.5 3 3.5 4 4.5 5 5.5
V - Input Voltage - V
I
LED Efficiency (PLED/PIN) - %
ILED = 50 mA
ILED = 200 mA
Test Results
The software itself performs no calculations or computations and simply reads and writes to and from theIC's four registers through the I
2
C interface. Each register's bits can either be changed manually bychanging the buttons corresponding to each bit in the panel's bottom half or they can be changed throughthe drop-down boxes and buttons in the panel's top half. Bits or drop-down boxes that are greyed-out areeither read (display) only or not operational. For example, since the TPS61052 does not have a GPIO pin,the main panel that appears when the user selects the TPS61052 IC has the GPIO related box, buttonand bits greyed-out. Following any change to an individual bit, drop-down box or button, the user mustwrite the new values to the registers by either clicking the red W button to the left of each affected registeror by clicking the WRITE ALL REGISTERS button in the middle of the screen. It is recommended but notrequired that the user click the red R to the left of register or click READ ALL REGISTERS following eachsoftware write to the register or board level change (e.g., pressing S1/S2 to initiate a FLASH event).
Although the data sheet explains each register, the explanation of the functionality of register 2 isreiterated in this user's guide. Writing to the ILIM and STIM bits of register 2 is allowed prior to the firstflash event following the IC's power on. Writing to bits 5 and 6 of register 2 sets the ILIM bits which is theIC's current limit. This current limit value cannot be read back because performing a read of bits 3, 4 and 5of register 2 results in the last valid ADC measurement. For these reasons, even though the IC allowswriting to both ILIM and STIM bits prior to the first flash event, following the IC's the power on, the EVMsoftware only allows the user to set the current limit when the software is initializing, following IC poweron. The current limit drop-down box is greyed-out and only displays the selection previously made andwritten to the IC. In order to change current limit, the IC must be power cycled and the software must beshut down and re-started. Otherwise, on a READ, the current limit drop down box displays the wrongcurrent limit value as bit 5 of register 2, the most significant bit of the ADC value, changes. The inductorinstalled on the EVM has a saturation current of 1.5-A; therefore, the current limit for the EVM as builtshould not be set higher than 1.5 A. Also, a valid ADC measurement is only taken after a FLASH event,either through the board's push-button switch, by clicking the SFT button, followed by a WRITE or byclicking the main panel's START MEASUREMENT button, followed by a WRITE. However, after eachREAD, the software displays the current bits in the ADC register, which is the last valid ADC measurementtaken.
This section provides typical performance waveforms for the TPS61050/2EVM-215 board.
Figure 2. LED Efficiency vs. Input Voltage - Torch Mode
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0
10
20
30
40
50
60
70
80
90
100
2.5 3 3.5 4 4.5 5 5.5
V - Input Voltage - V
I
LED Efficiency (PLED/PIN) - %
ILED = 300 mA
ILED = 700 mA
Test Results
Figure 3. LED Efficiency vs. Input voltage - Single Pulse Flash Mode
Figure 4. Torch Flash Sequence
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Test Results
Figure 5. Start Up in Torch
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0
10
20
30
40
50
60
70
80
90
100
1 10 100 1000
I - Output Current - mA
O
Efficiency - %
V = 3.6 V,
V = 5 V
I
O
Test Results
Figure 6. Inrush Current at Flash
Figure 7. Voltage Mode Efficiency
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