Texas Instruments TPS68401EVM User manual

User's Guide
SLVU812–November 2012
TPS68401EVM User’s Guide
The TPS68401EVM is an evaluation board to assist in evaluating the TPS68401 IC as a multifunction LED
driver.
The TPS68401 device is an advanced lighting management unit for handheld devices. It has three
independent channels optimized for driving RGB LEDs. The built-in fractional charge pump boosts the
input voltage to power the LEDs at low input voltage. Channel one can optionally be supplied directly from
the battery voltage to reduce power consumption and improve efficiency.
At the heart of the device is a programmable state machine which executes a lighting program consisting
of up to 16 instructions per channel. Once the program is loaded through the I2C™ interface the device is
fully independent from the main processor resulting in significant system-level power savings. The device
can issue an interrupt to the main processor via the INT pin. The TRIG I/O allows synchronization
between multiple devices. A general-purpose output pin is provided which is addressable through the
serial interface. In addition, the INT pin can also be configured as general-purpose output.
Figure 1. TPS68401EVM
The following related documents are available for download through the Texas Instruments web site
(http://www.ti.com) or via the links below.
Table 1. EVM Related Data Sheets
DEVICE LITERATURE NUMBER
TPS68401 SLVSA68
USB-TO-GPIO SLLU093
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Contents
1 INTRODUCTION ............................................................................................................ 3
1.1 Description .......................................................................................................... 3
1.2 Applications ......................................................................................................... 3
1.3 Features ............................................................................................................. 3
2 SYSTEM OVERVIEW ...................................................................................................... 4
3 BOARD LAYOUT ........................................................................................................... 5
4 HARDWARE OVERVIEW ................................................................................................. 9
4.1 Connectors .......................................................................................................... 9
4.2 Jumpers ............................................................................................................ 10
4.3 Test points ......................................................................................................... 10
4.4 EVM Operation ................................................................................................... 10
5 SOFTWARE ................................................................................................................ 11
5.1 Software Installation Instructions ............................................................................... 11
6 SCHEMATIC AND BILL OF MATERIALS .............................................................................. 13
List of Figures
1 TPS68401EVM.............................................................................................................. 1
2 System Block Diagram..................................................................................................... 4
3 USB-to-GPIO Adapter...................................................................................................... 4
4 TPS68401EVM Board Layer 1 (SIGNAL) ............................................................................... 5
5 TPS68401EVM Board Layer 2 (GND) ................................................................................... 6
6 TPS68401EVM Board Layer 3 (POWER) ............................................................................... 7
7 TPS68401EVM Board Layer 4 (SIGNAL) ............................................................................... 8
8 Ribbon Cable Connection................................................................................................ 10
9 setup.exe. File Location .................................................................................................. 11
10 TPS68401EVM GUI Main ................................................................................................ 12
11 TPS68401EVM GUI Basic ............................................................................................... 13
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www.ti.com INTRODUCTION
1 INTRODUCTION
1.1 Description
The Texas Instruments TPS68401 evaluation module (EVM) helps designers to evaluate TPS68401
advanced lighting management unit for handheld devices. These devices have three independent
channels optimized for driving RGB LEDs. The built-in fractional charge pump boosts the input voltage to
power the LEDs at low input voltage. Channel one can optionally be supplied directly from the battery
voltage to reduce power consumption and improve efficiency.
At the heart of the device is a programmable state machine which executes a lighting program consisting
of up to 16 instructions per channel. Once the program is loaded through the I2C interface the device is
fully independent from the main processor resulting in significant system-level power savings. The device
can issue an interrupt to the main processor via the INT pin.
The TRIG I/O allows synchronization between multiple devices. A general-purpose output pin is provided
which is addressable through the serial interface. In addition, the INT pin can also be configured as
general-purpose output.
The EVM contains four independent TPS68401 devices that can be programmed and controlled trough a
GUI.
1.2 Applications
• LED control for portable applications
• Accent lighting (mood, personalization, etc.)
• Function indication (charge, messages, etc.)
• Keypad illumination/backlight (white or RGB)
• Display backlight
1.3 Features
• Multifunction LED driver with three independent channels
• Integrated high efficiency 1x/1.5x charge pump with automatic or manual gain change
• 3 x 25.5-mA total output current
• Three independent program execution engines (3 x 16 instructions)
• 8-bit PWM with exponential control option
• 8-bit current DAC control
• 200-nA typical shutdown current
• Automatic power-save mode
• Autonomous operation without external control
• Trigger I/O for synchronizing multiple devices
• One or two general purpose output controlled via serial interface
• I2C interface
• Operating Temperature Range: -30ºC to 85ºC
• 20-ball WLCSP package with 0.4-mm pitch
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Host (PC)
USB-to-I C
2
Adapter
TPS68401
EVM
SYSTEM OVERVIEW www.ti.com
2 SYSTEM OVERVIEW
The system block diagram is shown below.
Figure 2. System Block Diagram
The system consists of the following components:
Host (PC)—A Windows®personal computer (PC) – used to configure and monitor the TPS68401EVM.
The GUI operates on the host. For the GUI to execute properly, the host needs to have the correct
LabViewTM RunTimeTM version. If the host doesn’t have the correct RunTimeTM version it will be
prompted during GUI installation. More information in GUI installation section.
USB-to-I2C Adapter—TPS68401EVM uses the I2C interface for communication with the host. The TI-
supplied USB-to-I2C adapter does the appropriate conversion so the host can use the USB
interface for communication. USB-to-I2C adapter has a 3.3-V supply rail which is used to supply the
EVM so no external power supply is needed.
TPS68401EVM— EVM board that houses the TPS68401 and peripheral components.
The evaluation module is designed to provide access to the features of the TPS65281. Some
modifications can be made to this module to test performance at different input and output voltages,
current and switching frequency. Please contact TI Field Applications Group for advice on these matters.
Figure 3. USB-to-GPIO Adapter
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www.ti.com BOARD LAYOUT
3 BOARD LAYOUT
Figure 4. TPS68401EVM Board Layer 1 (SIGNAL)
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Figure 5. TPS68401EVM Board Layer 2 (GND)
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www.ti.com BOARD LAYOUT
Figure 6. TPS68401EVM Board Layer 3 (POWER)
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BOARD LAYOUT www.ti.com
Figure 7. TPS68401EVM Board Layer 4 (SIGNAL)
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www.ti.com HARDWARE OVERVIEW
4 HARDWARE OVERVIEW
The TPS68401EVM allows evaluation of the TPS68401 Advanced Lighting Management Unit for handheld
devices. TPS68401 has three independent channels optimized for driving RGB LEDs. The built-in
fractional charge pump boosts the input voltage to power the LEDs at low input voltage. At the heart of the
device is a programmable state machine which executes a lighting program consisting of up to 16
instructions per channel. Once the program is loaded through the I2C interface the device is fully
independent from the main processor resulting in significant system-level power savings. The TRIG I/O
allows synchronization between multiple devices.
The TPS68401EVM can be configured and monitored through a Windows GUI application running on a
PC. The GUI communicates with the TPS68401EVM through the USB Interface Adapter (included with
EVM kit), which acts as an I2C master for the board. TPS68401EVM has four TPS68401 devices and
those can be separately programmed through the GUI.
The TPS68401EVM provides the following functionality:
• Programming of the four different TPS68401 devices (all four devices have different I2C addresses
which can be selected from the GUI).
• Driving either RGB or white LED’s (see jumper setting).
• 32-kHz oscillator on board is used as an external clock the TPS68401 devices on board.
• Trigger button to enable synchronous program execution between several devices.
• Indicator LEDs for all four general purpose outputs (GPOs).
• Standard 400-kHz I2C communication via I2C connector to USB adapter for connection to a PC.
• Board can be supplied through the 3.3 V from the USB adapter or from an external power source (see
jumper setting).
4.1 Connectors
The TPS68401EVM has connectors for power and I2C communications. J1 provides a possibility to power
EVM from an external power supply (between 2.7 V and 5.5 V). USB adapter Interface Adapter has 3.3-V
power output that can be used to power the board so there is no need for external power source.
P1 header provides the I2C communication interface to the TPS68401EVM. The USB Interface Adapter
includes a ribbon cable that can be connected to P1. The adapter is connected to a Windows-based PC.
CAUTION
When using an external power supply for the TPS68401EVM, the
recommended supply range for TPS68401 is from 2.7 V to 5.5 V.
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HARDWARE OVERVIEW www.ti.com
Connecting the ribbon cable to TPS68401EVM pin one is marked on the EVM and with the red stripe in the ribbon
cable.
Figure 8. Ribbon Cable Connection
4.2 Jumpers
The TPS68401EVM operation can be configured using jumpers:
• Board power from external supply or USB Interface Adapter
• Driving RGB or white LEDs
Table 2. TPS68401EVM Jumpers
NO. FUNCTION DEFAULT SETTING
Board power supply selection. Connect to pins 1-2 when using 3.3 V from the USB Interface Pins 1-2 (Power from USB Interface
P2 Adapter and pins 2-3 if external power supply is used. Adapter)
RGB or white LEDs are connected. Connect to pins 1-2 if RGB LEDs are used and 2-3 when
P3 using white LEDs. If using U4 to generate PWM signals for other devices through P5 Pins 1-2 (RGB LEDs connected)
connector pin 2-3 need to be connected.
4.3 Test points
The TPS68401EVM provides test points that can be used for evaluation. Important voltages can be
monitored with a meter through the use of the test points.
4.4 EVM Operation
The TPS68401EVM operates from either USB Interface Adapter (through P1) or External Power Supply
(through J1). Jumper P2 can be used to select the power source.
1. Connect the USB Interface Adapter to the TPS68401EVM P1 connector using the ribbon cable
provided.
2. Plug the appropriate end of the USB cable into the adapter and the other end into your PC.
NOTE: If using an external power supply connect jumper’s pins 2-3 and use J1 to connect the power
supply.
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