Texas Instruments LP8580EVM User manual

Windows is a registered trademark of Microsoft.
SPI is a trademark of Motorola.
All other trademarks are the property of their respective owners.
Using the LP8580EVM Evaluation Module
User's Guide
Literature Number: SNVU495
March 2016

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Table of Contents
Contents
Preface ........................................................................................................................................ 3
1 Introduction......................................................................................................................... 4
2 Description of the LP8580 Device........................................................................................... 4
2.1 Features................................................................................................................... 4
2.2 Applications ............................................................................................................... 4
3 Hardware Setup ................................................................................................................... 6
3.1 LED Connectors.......................................................................................................... 6
3.2 VCC and VDD Jumpers................................................................................................. 6
3.3 Buttons..................................................................................................................... 7
3.4 Indicator LED ............................................................................................................. 7
3.5 Interface Setup ........................................................................................................... 7
4 LP8580EVM Evaluation Software ........................................................................................... 8
4.1 LP8580EVM Evaluation Software Installation........................................................................ 8
4.2 Driver Installation......................................................................................................... 8
4.3 Evaluation Software Removal ......................................................................................... 8
5 Using the LP8580EVM Evaluation Software............................................................................. 8
5.1 Digital Input Control...................................................................................................... 9
5.2 Interface Selection ....................................................................................................... 9
5.3 Register View ........................................................................................................... 10
5.4 Register Control Area .................................................................................................. 10
5.5 Direct Register Control................................................................................................. 10
5.6 EEPROM Control Area ................................................................................................ 10
5.7 Direct EEPROM Access ............................................................................................... 11
5.8 Status Bar................................................................................................................ 11
5.9 History Tab .............................................................................................................. 11
5.10 Menu Bar ................................................................................................................ 13
6 Examples .......................................................................................................................... 17
6.1 Starting up the LP8580EVM........................................................................................... 17
6.2 Turn Backlight ON and Control the Brightness..................................................................... 17
6.3 Using PWM Brightness Control....................................................................................... 17
6.4 Turning ON the VCOMTRIM Output ................................................................................. 18
6.5 Saving the EEPROM Content to a Text File........................................................................ 18
6.6 EEPROM Reprogramming ............................................................................................ 18
6.7 Saving Register Settings to a File.................................................................................... 19
6.8 Reading Control Register Values from a Text File................................................................. 19
6.9 Using Macros............................................................................................................ 19
7 Evaluation Board Schematic................................................................................................ 21
7.1 Bill of Materials for LP8580EVM...................................................................................... 23
8 LP8580EVM PCB Layout and Layers..................................................................................... 24

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Preface
Preface
SNVU495–March 2016
Read This First
Windows is a registered trademark of Microsoft.
SPI is a trademark of Motorola.
All other trademarks are the property of their respective owners.
About this Manual
This user’s guide describes the characteristics, operation, and use of the LP8580EVM evaluation module.
This user’s guide includes a schematic diagram and a bill of materials (BOM).
Related Documentation from Texas Instruments
LP8580 data sheet SNVSA65
FCC Warning
This equipment is intended for use in a laboratory test environment only. It generates, uses, and can
radiate radio frequency energy and has not been tested for compliance with the limits of computing
devices pursuant to subpart J of part 15 of FCC rules, which are designed to provide reasonable
protection against radio frequency interference. Operation of this equipment in other environments may
cause interference with radio communications, in which case the user, at their own expense, is required to
take whatever measures may be required to correct this interference.
If You Need Assistance
Contact your local TI sales representative.

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LP8580 Evaluation Board
User's Guide
SNVU495–March 2016
LP8580 Evaluation Board
1 Introduction
The Texas Instruments LP8580EVM evaluation module helps designers evaluate the operation and
performance of LP8580 integrated circuit (IC). The LP8580EVM uses the LP8580 high-efficiency boost
converter and six LED outputs to drive display backlight with local dimming capability. More information
about the LP8580 capabilities can be found in the device data sheet (SNVSA65).
In order to facilitate ease of testing and evaluation of this circuit, the EVM contains power supply
connection for the VIN and VDD voltages. Test points are provided for the key signals. The onboard
microcontroller can be used to control the digital input signals of the LP8580. A graphical user interface
(GUI) is provided for fast and easy evaluation of the device.
For evaluation purposes, the EVM has been tested over a 2.7-V to 27-V input voltage (VIN) range. VDD
voltage needs to be within 2.9 V to 5 V. This voltage range is within the absolute maximum input range of
the LP8580. Users are cautioned to evaluate their specific operating conditions and choose components
with the appropriate voltage ratings before designing this support circuitry into a final product.
Table 1.
PART NUMBER PACKAGE BODY SIZE (NOM)
LP8580 QFN (24) 4.00 mm × 4.00 mm
2 Description of the LP8580 Device
The LP8580 IC is a high-efficiency LED driver with an integrated boost converter. It has 6 high–precision
current sinks that can be controlled individually through an SPI™ and I2C interface. The LP8580 device
includes support for regional backlight control (1D local dimming) with up to 6 independently controlled
backlight regions. The LP8580 IC also supports whole screen (0D dimming) content adaptive backlight
control such as CABC.
2.1 Features
• High-efficiency asynchronous DC-DC boost converter with integrated power FET
• Six high-precision current sinks with up to 50-mA output current/channel
• Individual LED string brightness control
• Supports both SPI and I2C interfaces for brightness control
• Extensive protection features including open and shorted LED fault detections
• 2.7-V – 27-V VIN input voltage range
2.2 Applications
• Mobile Phones
• Tablet PCs
• Notebooks

VIN
GPU/AP
FB
SW
L1 D1
VDD
CIN COUT
LED0
LED1
LED2
LED3
LED4
LED5
GNDs
EN
VOUT
CVDD
VSYNC
SDO/ PWM
SDI/ SDA
SS/ ADDRSEL
SCLK/ SCL
1V8
TCON
EN
SPI
eDP
EN
Panel
LP8580
(battery)
3.3V
CLDO
HSYNC
IFSEL
DAC
AVDD
VCOM
VDDIO
CVDDIO
1.8/3.3V
NAVDD
VCOMTRIM
INT
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LP8580 Evaluation Board
Figure 1. Typical Application

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3 Hardware Setup
Figure 2 shows how to set up LP8580EVM. An external 2.9-V to 5-V power source must be connected to
VDD input connector, and boost input voltage between 2.7 V to 27 V must be connected to the VIN
connector. If an onboard microcontroller is used, the LP8580EVM must be connected to a Windows®PC
with a USB cable.
Figure 2. LP8580EVM Hardware Setup
3.1 LED Connectors
An external LED load board must be connected to LED connectors. Use of six strings of white LEDs with
3 to 13 LEDs in each string is recommended. The sum of LED forward voltages of the LED strings must
be between 10 V to 40 V. Either connector (J121 or J111) can be used to connect the LEDs. Connector
J111 has series resistors on the LED outputs and boost output, while the connector J121 connects
straight to LED output pins (see Section 7 for connection details). LED anodes must be connected to
BOOST pin and the cathodes to LEDx pins. The GND pin is provided for measurement purposes only and
does not need to be connected to the LEDs.
If LEDs are connected to connector J111, connector J122 can be used to measure the individual LED
currents and boost converter output current. LEDx– and LEDx OUT pins connect to the different sides of
the current sense resistors and LED current can be measured by connecting a voltage meter on these
pins. BOOST and BOOST OUT pins connect to the different sides of the boost output current sense
resistor. Boost output has a 1-Ωcurrent sense resistor while LED outputs have 10-Ωcurrent sense
resistors.
3.2 VCC and VDD Jumpers
The VDD jumper selects the VDD input voltage source for the LP8580 IC. If the VDD jumper is set to the
EXT side the LP8580 is powered from a external voltage source that is connected to the external VDD
supply connector (J101). If the VDD jumper is set to the VUSB side, the LP8580 IC is powered from a
USB ports 5-V input voltage. Note that boost converter input voltage always comes from the VIN input
connectors.

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LP8580 Evaluation Board
The VCC jumper can be used to select the input voltage for the onboard microcontroller. If the VCC
jumper is set to the 3.3-V side, the microcontroller is powered from the USB bus. A 3.3-V voltage regulator
is used to lower the 5-V input voltage from the USB port to 3.3 V. If the VCC jumper is set to RAIL side,
the microcontroller is powered from the same source as the LP8580 IC. This jumper also selects the
VDDIO voltage for the LP8580 IC.
3.3 Buttons
There are two push buttons on the EVM. Button S200 (FW LOAD) is used for microcontroller firmware
programming during LP8580EVM manufacturing and does require input from the user. Button S201
(RESET) can be used to reset the onboard microcontroller if firmware gets stuck for any reason.
3.4 Indicator LED
When LP8580EVM is connected to the USB port LED D201 should be blinking indicating that the firmware
of the onboard microcontroller is running. If LED D201 is not blinking, check that the VCC jumper is set to
the 3.3-V position or that the external power supply is connected.
3.5 Interface Setup
The LP8580 supports SPI and I2C interfaces. Interface selection of LP8580EVM shunts must be set
correctly for each interface. Figure 3 and Figure 4 show how to set up the shunts for each interface.
Figure 3. SPI Settings Figure 4. I2C Settings

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4 LP8580EVM Evaluation Software
The LP8580EVM is connected to the computer via USB. The EVM is controlled with special evaluation
software. The onboard MSP430 microcontroller is used to provide easy I2C/SPI communication, as well
as to control the digital inputs of the LP8580 IC. The microcontroller is powered by default from USB. The
LP8580 IC is powered from external power supply.
4.1 LP8580EVM Evaluation Software Installation
Before LP8580 evaluation software can be used it must be installed. Open the folder containing the
installation package and double click the “LP8580_setup.exe”. If Windows prompts you to verify the
installation click “Yes”. The license agreement window opens. Click “I Agree” for the license agreement.
Next choose to include the start-up menu and desktop shortcuts. Select the ones you like and click “Next”.
The installer then prompts for installation folder. Installing the program to its default location is
recommended. Click “Install”. Once installation is complete, close the installer by clicking “Close” button.
4.2 Driver Installation
When the LP8580EVM is connected to a computer for the first time, Windows should recognize it
automatically and start to install the driver. A “Found New Hardware” dialog box prompts user to locate the
missing driver. Select “No, not this time” and continue with “Next”. Select “Install from a list or specific
location (Advanced)” to install the driver. Select the directory where the TI_CDC_Virtual_Port driver is
located. If LP8580 evaluation software was installed to its default location, the driver can be found at
C:\Program Files (x86)\Texas Instruments\LP8580\Driver. Windows should now install the driver. The
driver generates a virtual COM port which is used to communicate with the evaluation board.
4.3 Evaluation Software Removal
The LP8580 evaluation software can be uninstalled through Windows Control Panel. Open Control Panel
→Programs and Features. Find LP8580 from the list, right click it, then select "Uninstall".
5 Using the LP8580EVM Evaluation Software
When LP8580 evaluation software is run it looks like Figure 5. This is the main view where all the controls
are located. A short description of the main GUI areas follows, explaining how they can be used to control
the LP8580EVM.

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LP8580 Evaluation Board
Figure 5. Evaluation Software
5.1 Digital Input Control
Controls in the digital input control area are used to control the digital input pins of the LP8580 IC. The
Enable button controls the state of the EN pin. The Interface button controls the state of the IFSEL pin.
The Addr1 button controls the state of the SS/ADDRSEL pin when LP8580EVM is set up for I2C mode.
Dimming control can be used to control the SDO/PWM pin when LP8580EVM is set up for I2C mode. This
can be used for PWM brightness control. The PWM frequency and duty cycle can be set, and the PWM
generator can be turned on and off. The Update button needs to be pressed to update new frequency or
duty cycle to the PWM generator.
VSYNC control can be used to control the VSYNC pin. The VSYNC frequency and duty cycle can be set and
the VSYNC generator can be turned on and off. The Update button needs to be pressed to update new
frequency or duty cycle to the VSYNC generator.
HSYNC control can be used to control the HSYNC pin. The HSYNC frequency can be set, and HSYNC generator
can be turned on and off. Update button needs to be pressed to update new frequency to the VSYNC
generator.
5.2 Interface Selection
The LP8580 supports both SPI and I2C interfaces. The interface is selected with the IFSEL pin of the
LP8580. In I2C mode the LP8580 supports two I2C slave addresses (0x2C and 0x3C). The LP8580 I2C
address is selected with the SS/ADDRSEL pin. Before LP8580 registers can be read or written, hardware
settings and evaluation software interface selection must be set correctly. The Interface and the Addr1
buttons control the digital input pins of the LP8580, and Interface selection controls how the onboard
microcontroller communicates with the LP8580 IC.
To use the SPI interface, shunts of the IC must be set as shown in Figure 6. The Interface button in the
digital control area of the evaluation software must be in OFF state, and SPI must be selected in the
interface selection area.

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Figure 6. SW SPI Settings
To use the I2C interface shunts of the LP8580 must be set as shown in Figure 6 and the Interface button
in the Digital control area of the evaluation software must be in an ON state. To use I2C interface with
0x2C address Addr1 button must be in OFF state.
Figure 7. I2C Settings With 0x2C Address
To use the I2C interface with 0x3C address the Interface and Addr1 buttons must be in an ON state.
Interface selection must be made with I2C (0x3C).
Figure 8. I2C Settings With 0x3C Address
5.3 Register View
The register view shows the content of all the registers in the LP8580 IC. Registers are grouped into
logical register blocks. Each block can be opened or closed by clicking the arrow on the left side of the
block name. Register view is not automatically updated. When evaluation software is started up all register
values are shown as zeros. To read the content of the LP8580 registers into register view, click Operation
→Read All Registers.
5.4 Register Control Area
When any of the registers is selected it appears in the register control area. All registers of the LP8580 are
16 bits long, but the unused bits are hidden in the register control. Changing the register bit settings does
not automatically update the register value. Once all the register bits are set the WR button must be
pressed to write the new value into the register. Register values can be read by clicking the RD button on
the right side of the register control area.
5.5 Direct Register Control
Single register values can be written or read with the direct register control area. To read a register value,
set the register address in an address field in a 16-bit hexadecimal value, and click the Read button. The
register value appears in the Data field. To write a new value to a register, write the new data into the data
field and click the Write button.
5.6 EEPROM Control Area
The EEPROM control area can be used to read and write the whole content or a specific area of the
EEPROM. Clicking the Read button reads the content of the LP8580 EEPROM to the EEPROM content
window where start and end addresses can be defined. This is useful if only part of the EEPROM must be
updated.