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7

SNVU382A – April 2014 – Revised June 2014

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Copyright © 2014, Texas Instruments Incorporated

Description of the LP8860-Q1

Chapter 2

SNVU382A – April 2014 – Revised June 2014

Description of the LP8860-Q1

The LP8860-Q1 is an automotive high-efficiency LED driver with integrated boost controller. It has 4 high-
precision current sinks that can be controlled by a PWM input signal, an SPI/I

2

C master, or both.

The boost converter has adaptive output voltage control based on the LED current sink headroom
voltages. This feature minimizes the power consumption by adjusting the voltage to the lowest sufficient
level in all conditions. A boost controller supports spread spectrum for switching frequency and an external
synchronization with a dedicated pin. The high switching frequency allows the LP8860-Q1 to avoid
disturbance for AM radio band.

The LP8860-Q1 supports built-in Hybrid PWM and Current Dimming which reduces EMI, extends the LED
lifetime, and increases the total optical efficiency. Phase-shift PWM allows reduced audible noise and
smaller boost output capacitors.

The LP8860-Q1 can drive an external p-FET to disconnect the input supply from the system in the event
of a fault and reduce inrush current and standby power consumption.

The input voltage range for LP8860-Q1 is 3 V to 48 V to support car stop/start conditions. The device
integrates extensive safety and protection features.

2.1

Features

•

Four High-Precision Current Sinks

–

Current Matching 0.5% typ

–

Output Current up to 150 mA/Channel

–

Individual LED String Current Adjustment

–

Dimming Ratio >13000:1 with External PWM Brightness Control

–

16-bit dimming control with SPI or I

2

C Control

–

Two Modes: Display Mode and Cluster Mode with Individual Control

•

Hybrid PWM and Current Dimming for Higher LED Drive Optical Efficiency

•

Synchronization for LED PWM

•

Boost Controller With Programmable Switching Frequency 100 kHz to 2.2 MHz and Spread Spectrum
Option

•

Boost Synchronization Input

•

Input Voltage Operating Range 3 V to 48 V

•

Power Line FET Control for Inrush Current Protection and Standby Energy Saving

•

Automatic LED Current Reduction with External Temperature Sensor

•

Extensive Safety and Fault Tolerance Features

•

SPI or I

2

C Interface

2.2

Applications

•

Automotive Infotainment, Instrument Cluster and Backlighting Systems

Summary of Contents for LP8860-Q1

Page 1: ...Using the LP8860 Q1EVM Evaluation Module User s Guide Literature Number SNVU382A April 2014 Revised June 2014 ...

Page 2: ...us Tab 25 9 2 4 Boost Tab 26 9 2 5 Fault and Adaptive Voltage Control Tab 27 9 2 6 LED Drivers Tab 28 9 2 7 Temperature Tab 31 9 2 8 EEPROM Map Tab 32 9 2 9 History Tab 33 A Virtual COM Port Configuration 34 B Virtual COM Port Communication 37 C LED Load Board 38 D Quick Start Guide 41 D 1 EVM Board Default Jumper and Cable Positions 41 D 2 First Step Light up LEDs 46 D 3 Changing EEPROM Parameter...

Page 3: ...tness Control Tab 24 9 4 Fault and Status Tab 25 9 5 Boost Controls Tab 26 9 6 Interactive Boost Diagram Window 26 9 7 Fault and Adaptive Voltage Control Tab 27 9 8 LED Fault And Adaptive Voltage Control Functionality Diagram 27 9 9 LED Driver Controls 28 9 10 LED Driver Diagram Window 28 9 11 PLL Diagram Window 29 9 12 PLL Calculator for External VSYNC Steps Show Order for Applying Commands 29 9 ...

Page 4: ...www ti com 4 SNVU382A April 2014 Revised June 2014 Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated List of Figures ...

Page 5: ...hapter 7 Evaluation Board Schematic Chapter 8 Bill of Materials Chapter 9 Evaluation Software Appendix A Virtual COM Port Configuration Appendix B Virtual COM Port Communication Appendix C LED Load Board Appendix D Quick Start Guide Related Documentation from Texas Instruments LP8860 Q1 data sheet FCC Warning This equipment is intended for use in a laboratory test environment only It generates use...

Page 6: ...ssor to provide easy communication via USB Power supply connection for the VIN VDD and test points for each signal can be found on the evaluation board Windows SW is used to control I2 C SPI registers of the device A separate LED board can be used as a load it is also possible to connect LCD panel to the output connectors For evaluation purposes the EVM has been tested over a 3 V to 48 V input ran...

Page 7: ...ise and smaller boost output capacitors The LP8860 Q1 can drive an external p FET to disconnect the input supply from the system in the event of a fault and reduce inrush current and standby power consumption The input voltage range for LP8860 Q1 is 3 V to 48 V to support car stop start conditions The device integrates extensive safety and protection features 2 1 Features Four High Precision Curre...

Page 8: ... MOSI SDA MISO NSS VDDIO EN IF FAULT LP8860 Q1 Q2 D L VIN 3 40 V VDD 3 3 V BOOST SYNC V H SYNC BRIGHTNESS FAULT RESET ENABLE FAULT VDDIO Typical Applications www ti com 8 SNVU382A April 2014 Revised June 2014 Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated Description of the LP8860 Q1 2 3 Typical Applications Figure 2 1 Typical Application Simple PWM Control VDD 3 3 V C...

Page 9: ... SCLK SCL MOSI SDA MISO NSS VDDIO EN IF FAULT LP8860 Q1 Q2 D L VIN 3 40 V VDD 5 V BOOST SYNC V H SYNC BRIGHTNESS NSS ENABLE FAULT VDDIO SCLK MOSI MISO www ti com Typical Applications 9 SNVU382A April 2014 Revised June 2014 Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated Description of the LP8860 Q1 Figure 2 2 Typical Application SPI Control VDD 5 V Charge Pump Off 2 Str...

Page 10: ...WM SCLK SCL MOSI SDA MISO NSS VDDIO EN IF FAULT LP8860 Q1 Q2 D L VIN 3 40 V VDD 3 3 V BOOST SYNC V H SYNC BRIGHTNESS FAULT RESET ENABLE FAULT VDDIO SCL SDA Typical Applications www ti com 10 SNVU382A April 2014 Revised June 2014 Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated Description of the LP8860 Q1 Figure 2 3 Typical Application I2 C Control VDD 3 3 V Charge Pump ...

Page 11: ...C VSYNC PWM SCLK SCL MOSI SDA MISO NSS VDDIO EN IF FAULT LP8860 Q1 D L VIN 3 40 V VDD 5 V BRIGHTNESS ENABLE www ti com Typical Applications 11 SNVU382A April 2014 Revised June 2014 Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated Description of the LP8860 Q1 Figure 2 4 Typical Application without Serial Interface VDD 5 V Charge Pump Off 3 Strings ...

Page 12: ...nterface selection Jumpers for connecting C digital signals to LP8860 Q1 LP8860 Q1 needed external components FAULT red LED USB ok blinking green LED 12 SNVU382A April 2014 Revised June 2014 Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated Hardware Setup Chapter 3 SNVU382A April 2014 Revised June 2014 Hardware Setup Figure 3 1 shows connectors and main components on the ...

Page 13: ...014 Revised June 2014 Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated Board Layout Chapter 4 SNVU382A April 2014 Revised June 2014 Board Layout Figure 4 1 Top Layer Figure 4 2 Bottom Layer GND ...

Page 14: ...tors Feedback line Connection between PGND and GND LP8860 Q1 ISENSE FB SGND PWM OUT1 OUT2 OUT3 OUT4 L1 D1 VBATT FILTER VSYNC SD GD VSENSE_N Q2 ISENSE_GND CPUMP C1P C1N VDD SYNC VDDIO EN SCLK SCL MOSI SDA MISO NSS PGND LGND PAD IF VSENSE_P R1 TSENSE ISET FAULT SQW VDD 3 3V Q1 R2 C1 C2 C3 C4 C5 R3 R4 R5 C6 C7 C8 C9 2 32 31 5 6 3 1 12 9 13 18 16 15 14 17 19 20 11 10 29 23 7 8 21 22 24 25 4 26 27 28 3...

Page 15: ...opyright 2014 Texas Instruments Incorporated Board Stackup Chapter 5 SNVU382A April 2014 Revised June 2014 Board Stackup Figure 5 1 Evaluation Board Stackup Details 2 layer board FR4 Top layer copper 35 µm Core 1 6 mm Bottom Layer copper 35 µm Surface finish immersion gold ...

Page 16: ... the VDD_UVLO voltage level and the VDDIO EN voltage is set above threshold voltage 1 2 V 6 1 Start up Sequence The backlight is started either by setting PWM input high or by writing not zero brightness value to registers depending on the brightness control mode and phase shift configuration See the LP8860 Q1 datasheet for details 6 2 Shutdown Sequence The backlight is shut down either with setti...

Page 17: ... VSSU 49 PU 0 DP 50 PUR 51 PU 1 DM 52 VBUS 53 VUSB 54 V18 55 AVSS2 56 P5 2 XT2IN 57 P5 3 XT2OUT 58 TEST SBWTCK 59 PJ 0 TDO 60 PJ 1 TDI TCLK 61 PJ 2 TMS 62 PJ 3 TCK 63 RST NMI SBWTDIO 64 QFN PAD 65 U2 MSP430F5510IRGC Green 1 2 D2 Orange 1 2 D3 GND LED2 LED2 LED1 LED1 NSS UC MISO UC SDA MOSI UC SCL SCLK UC FAULT UC SYNC UC VSYNC UC PWM UC EN UC IF UC 1 50k R17 10k R18 VCC SDA MOSI UC SCL SCLK UC FAU...

Page 18: ...0 175u 677k HSYNC 50kHz BW3db 330Hz VCO Mhz C33 C32 R21 5 22n 322n 5 6k 10 12n 161n 11 2k 20 6 2n 80n 22 3k 40 3 1n 40n 44 7k HSYNC 20kHz BW3db 330Hz VCO Mhz C33 C32 R21 5 10n 129n 14k 10 5n 65n 28k 20 2 5n 32n 56k 40 1 2n 16n 112k C33 C32 84 5k R21 GND GND C1P 1 C1N 2 VDD 3 SQW 4 VSENSE_N 5 VSENSE_P 6 ISET 7 TSENSE 8 FILTER 9 SGND 10 FAULT 11 SYNC 12 VSYNC 13 MISO 14 MOSI SDA 15 SCLK SCL 16 NSS 1...

Page 19: ...31C102KAT2A 1 C17 CAP CERM 10uF 16V 20 X5R 0603 Taiyo Yuden EMK107BBJ106MA T 1 C18 CAP CERM 47pF 50V 5 C0G NP0 0603 Kemet C0603C470J5GACTU 1 C20 C24 C27 C28 C29 CAP CERM 0 1uF 16V 20 X7R 0603 Kemet C0603C104M4RACTU 5 C21 C22 C23 C26 CAP CERM 1uF 10V 10 X5R 0603 Kemet C0603C105K8PACTU 4 C25 CAP CERM 0 22uF 16V 10 X7R 0603 Kemet C0603C224K4RACTU 1 C30 C31 CAP CERM 22pF 50V 5 C0G NP0 0603 Kemet C0603...

Page 20: ...2512 Bourns CRA2512 FZ R020ELF 1 R4 RES 20k ohm 5 0 1W 0603 Vishay Dale CRCW060320K0JNEA 1 R5 RES 0 025 ohm 1 3W 2512 Bourns CRA2512 FZ R025ELF 1 R6 R7 RES 27 ohm 5 0 1W 0603 Vishay Dale CRCW060327R0JNEA 2 R8 R12 RES 10 ohm 5 0 1W 0603 Vishay Dale CRCW060310R0JNEA 2 R9 R16 R17 RES 1 50k ohm 1 0 1W 0603 Yageo America RC0603FR 071K5L 3 R10 RES 1 0Meg ohm 5 0 1W 0603 Vishay Dale CRCW06031M00JNEA 1 R1...

Page 21: ...I PWM SYNC VSYNC VDDIO EN IF and FAULT communication can be controlled from an external source using pin headers if needed Test point for all of the signals is provided but jumpers to the on board microcontroller must be removed if an external source is used for control 9 2 Usage The LP8860 Q1 evaluation software helps the user to control the evaluation hardware connected to the computer The evalu...

Page 22: ... Graphical control tab Small picture frame blue registers red EEPROM none pin control or protocol Firmware compilation date Usage www ti com 22 SNVU382A April 2014 Revised June 2014 Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated Evaluation Software Figure 9 1 Main Window Structure ...

Page 23: ...ntrol Tab From the Pin Control tab see Figure 9 2 the user can control all the basic functions of the device Figure 9 2 Main Window and Pin Control Tab In this tab Interface mode I2 C SPI can be set VDDIO EN control enables disables the device Frequency generators PWM for brightness control SYNC for boost and VSYNC for LED output PWM synchronization are in this tab ...

Page 24: ...l brightness control functions of the device Here are provided additional register based controls like slope control current control current scale and EEPROM control If all outputs are configured as display mode outputs only Display Cluster_1 brightness and current controls can be used Additional controls are functional when one or more outputs are in cluster mode Please refer to the LP8860 Q1 dat...

Page 25: ... Status tab see Figure 9 4 the user has access to LP8860 Q1 faults and status bits Faults can be reset by software fault reset register write or hardware NSS pin in I2 C interface mode Temperature and output current PWM reading are available from this tab as well Output PWM and current reading can help to understand better Hybrid PWM and Current dimming functionality Figure 9 4 Fault and Status Ta...

Page 26: ...rom the Boost Control tab see Figure 9 5 the user controls all boost functions of the device Figure 9 5 Boost Controls Tab This tab controls all boost functionality bits charge pump and gate driver controls By clicking Diagram button the user can open interactive boost diagram window which shows all parameters in block diagram Figure 9 6 Interactive Boost Diagram Window ...

Page 27: ...trol tab see Figure 9 7 the user controls fault and adaptive boost settings Figure 9 7 Fault and Adaptive Voltage Control Tab Fault comparators are used for LED fault detection and adaptive boost control Clicking Diagram button opens LED fault and adaptive voltage control diagram see Figure 9 8 This window explains LED fault and adaptive boost control functionality Figure 9 8 LED Fault And Adaptiv...

Page 28: ...rols LED driver settings maximum current scale for all modes initial current for display mode and current correction for every outputs LED output PWM controls input brightness PWM controls and PLL controls are available from this tab as well By clicking the Diagram button opens window with LED driver diagram Figure 9 10 and PLL Diagram Figure 9 11 PLL calculator for defining settings for external ...

Page 29: ...VU382A April 2014 Revised June 2014 Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated Evaluation Software Figure 9 11 PLL Diagram Window Figure 9 12 PLL Calculator for External VSYNC Steps Show Order for Applying Commands ...

Page 30: ...sage www ti com 30 SNVU382A April 2014 Revised June 2014 Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated Evaluation Software Figure 9 13 PLL Calculator for Internal Oscillator ...

Page 31: ...rporated Evaluation Software 9 2 7 Temperature Tab From the Temperature tab see Figure 9 14 the user controls internal and external sensors functionality current de rating with internal temperature sensor LED temperature control mode and current dimming with external temperature sensor Figure 9 14 Temperature Sensors Control ...

Page 32: ...opyright 2014 Texas Instruments Incorporated Evaluation Software 9 2 8 EEPROM Map Tab From the EEPROM Map tab see Figure 9 15 the user can see actual value of EEPROM registers bit and control bits directly by writing or reading bytes buttons W and R on the right side Figure 9 15 EEPROM Map ...

Page 33: ... 2014 Texas Instruments Incorporated Evaluation Software 9 2 9 History Tab The History tab see Figure 9 16 provides information on the I2 C SPI writes used to configure control the LP8860 Q1 device This can be used as a reference for developing software for real application Figure 9 16 History Tab ...

Page 34: ...iguration When the USB COM port number is bigger than 9 the evaluation program is not able to recognize the board COM port number can be manually changed from Windows Device Manager The below figures describe this sequence in Windows7 The Device Manager can be found from the Control Panel Note that one may need to have Administrator rights to make the changes Figure A 1 Device Manager View Select ...

Page 35: ... 2014 Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated Virtual COM Port Configuration Figure A 2 Open Properties by Clicking Right Mouse Button on Virtual COM Port Figure A 3 Select Port Settings from the Virtual COM Port Properties ...

Page 36: ...April 2014 Revised June 2014 Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated Virtual COM Port Configuration Figure A 4 Select Advanced from Virtual COM Port Properties and Select COM Port Number 9 or smaller ...

Page 37: ...nfigured as outputs I1234 Serial interface read 12 interface and address for I2C 0x80 SPI otherwise I2C 34 register Returns error code and data I8010 00_28_OK 0x0A SPI Read register 0x10 Return error 00 no errors and date 0x28 LED_FAULTS for LP8860 Q1 O123456 Serial interface write 12 interface and address for I2 C 0x80 SPI otherwise I2 C 34 register 56 data Returns error code O2D1101 00_OK 0x0A I...

Page 38: ...drivers and can use up to 6 strings and up to 20 LEDs in the string number of LEDs in use are defined by jumpers Cree Xlamp ML B LEDs with maximum current 175 mA and maximum forward voltage 3 5 mA 80 mA 3 3 V typ are used on the board For LP8860 Q1 4 strings are assembled NOTE The LED board is not included with the EVM contact your local TI sales representative if board is needed Figure C 1 LED Lo...

Page 39: ...1 2 3 J58 1 2 3 J59 1 2 3 J60 1 2 3 J61 1 2 3 J62 1 2 3 J63 GND 1 2 3 4 J64 D80 D79 D78 D77 D76 D75 D74 D73 1 2 3 J77 1 2 3 J78 1 2 3 J79 1 2 3 J80 1 2 3 J81 1 2 3 J82 1 2 3 J83 1 2 3 J84 GND 1 2 3 4 J85 D100 D99 D98 D97 D96 D95 D94 D93 1 2 3 J98 1 2 3 J99 1 2 3 J100 1 2 3 J101 1 2 3 J102 1 2 3 J103 1 2 3 J104 1 2 3 J105 GND 1 2 3 4 J106 D120 D119 D118 D117 D116 D115 D114 D113 1 2 3 J119 1 2 3 J12...

Page 40: ...mber Qty R1 R2 R3 R4 R5 R6 Resistor 10 0 ohm 1 0 1W 0603 not assembled Vishay Dale CRCW060310R0FKEA 6 J1 J22 J43 J64 J85 J106 J127 Header 100mi 2x2 Samtec TSW 102 07 G D 7 J2 J21 J23 J42 J44 J63 J65 J84 J86 J105 J107 J126 J129 Header 100mi 3x1 Samtec TSW 103 07 G S 121 J130 Header 100mi 7x1 Samtec TSW 107 07 G S 1 D1 D120 Cool White SMD LED XLamp mL B Cree MLBAWT A1 0000 000W51 120 Figure C 4 Forw...

Page 41: ...D contains step by step explanations about how to start using the LP8860 Q1 EVM The assumption is that an optional LED load board with EVM is used Some examples refer to eep files example default EEPROM 300kHz eep These files are provided as part of the LP8860 Q1EVM software which can be downloaded from the LP8860 Q1 tools folder on the Texas Instruments website D 1 EVM Board Default Jumper and Ca...

Page 42: ...ntation Feedback Copyright 2014 Texas Instruments Incorporated Quick Start Guide Figure D 1 and Figure D 2 show the jumper and cable positions when the EVM is delivered NOTE Keep jumper J1 at a 3 3 V setting to ensure safe operation regardless of RAIL value MSP430 doesn t tolerate a 5 V input or output voltage ...

Page 43: ...om EVM Board Default Jumper and Cable Positions 43 SNVU382A April 2014 Revised June 2014 Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated Quick Start Guide Figure D 1 Jumper Positions ...

Page 44: ... CPUMP should be shorted EVM Board Default Jumper and Cable Positions www ti com 44 SNVU382A April 2014 Revised June 2014 Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated Quick Start Guide Figure D 2 CPUMP Jumper ...

Page 45: ...www ti com EVM Board Default Jumper and Cable Positions 45 SNVU382A April 2014 Revised June 2014 Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated Quick Start Guide ...

Page 46: ...t 5V supply to J6 Check jumper J8 it should be at EXT EXT RAIL position For basic functionality testing demo purposes you can also use USB cable connected to J4 to provide 5V In this case J8 should be at 5V position 3 Connect VBATT 12V supply to J2 4 Run software a Press Init USB the user should see line stating firmware version This step is not mandatory if software is opened after USB was connec...

Page 47: ... SNVU382A April 2014 Revised June 2014 Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated Quick Start Guide d Set LED brightness using the Display Cluster 1 control Default mode default EEPROM is set to Display mode ...

Page 48: ...OM Parameters The procedure is similar for any EEPROM parameter change Section D 3 describes general procedure In following chapters some specific examples are given 1 Make sure LED brightness is 0 Also check that PLL is disabled in LED drivers tab 2 Read EEPROM 3 Unlock EEPROM 4 Change parameter 5 If user wants to save new setting in EEPROM Burn EEPROM After EEPROM burning toggle VDDIO EN ...

Page 49: ...k Copyright 2014 Texas Instruments Incorporated Quick Start Guide D 4 Recovering Original EEPROM Parameters To recover original EEPROM settings 1 Make sure LED brightness is 0 Also check that PLL is disabled in LED drivers tab 2 Unlock EEPROM if it is not done already 3 Load EEPROM setup file default EEPROM 300kHz eep ...

Page 50: ... EEPROM Parameters www ti com 50 SNVU382A April 2014 Revised June 2014 Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated Quick Start Guide 4 Burn EEPROM 5 Toggle VDDIO EN to restart the LP8860 Q1 ...

Page 51: ... signal is generated by MSP430 so that the user does not need to bring external signal for the first testing To use PWM input pin for brightness control EEPROM setting needs to be modified using the following procedure 1 Make sure LED brightness is 0 Also check that PLL is disabled in LED drivers tab 2 In LED drivers tab for Display brightness mode select PWM input pin duty cycle control 3 If the ...

Page 52: ...and slope time can be adjusted In GUI slope is controlled on Brightness Controls tab Slope control is effective through brightness control registers brightness change can be controlled by sliding control However manually using the sliding control in the GUI may introduce some unintended delay Another option is to use external PWM pin for brightness control See Section D 5 for instructions how to s...

Page 53: ... Switching Frequency to 2 2 MHz By default the boost switching frequency is 300 kHz see Boost tab in GUI The procedure for testing boost operation at 2 2 MHz 1 Make sure LED brightness is 0 Also check that PLL is disabled in LED drivers tab 2 Unlock EEPROM if it is not done already 3 Load EEPROM setup file for 2 2 MHz default EEPROM 2200kHz eep This file contains optimized parameter set for 2 2 MH...

Page 54: ...to 2 2 MHz www ti com 54 SNVU382A April 2014 Revised June 2014 Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated Quick Start Guide 4 Burn EEPROM if necessary 5 LEDs can be turned on from Brightness controls tab ...

Page 55: ...sabling boost adaptive mode Because of this the LED current is also limited to avoid overheating In normal operation an LED string in cluster mode must be connected to a separate supply instead of the LP8860 Q1 boost if string s in display mode use s boost for powering The procedure for testing cluster mode 1 Make sure LED brightness is 0 Also check that PLL is disabled in LED drivers tab if you h...

Page 56: ...rightness Control www ti com 56 SNVU382A April 2014 Revised June 2014 Submit Documentation Feedback Copyright 2014 Texas Instruments Incorporated Quick Start Guide 4 Brightness of each LED string can be controlled individually through Cluster 1 4 ...

Page 57: ...operation without MCU the most straightforward way to control brightness is to use an external PWM input signal To use PWM input pin for brightness control the EEPROM setting needs to be modified using the following procedure 1 Make sure LED brightness is 0 Also check that PLL is disabled in LED drivers tab 2 Unlock EEPROM 3 In LED drivers tab for Display brightness mode select PWM input pin duty ...

Page 58: ... checked from the LP8860 Q1 register SYNC VSYNC connect to ground not used in this example MISO leave floating SPI interface output not used in this example SDA SCL connect to ground I2 C is not used NSS input for clearing faults PWM connect external PWM signal 100 500 Hz for brightness control EN enable for the LP8860 Q1 IF connect to ground by connecting J20 to Manual and J18 to I2C position Sig...

Page 59: ... Incorporated Revision History Revision History NOTE Page numbers for previous revisions may differ from page numbers in the current version Changes from Original April 2014 to A Revision Page Changed terminal to pin preview to production data 5 Deleted values 7 Changed Applications list 7 Changed wording in first para Chapter 6 16 ...

Page 60: ... TI Resource NO OTHER LICENSE EXPRESS OR IMPLIED BY ESTOPPEL OR OTHERWISE TO ANY OTHER TI INTELLECTUAL PROPERTY RIGHT AND NO LICENSE TO ANY TECHNOLOGY OR INTELLECTUAL PROPERTY RIGHT OF TI OR ANY THIRD PARTY IS GRANTED HEREIN including but not limited to any patent right copyright mask work right or other intellectual property right relating to any combination machine or process in which TI product...

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