TI’s intelligent LED drivers in automotive cluster

systems
Shirley He
LED Drivers
Outline
• Automotive instrument cluster system trends
• Automotive LED indicator
• Global dimming backlight LED driver
• Local dimming backlight architecture and LED driver
• Aid functional safety cluster system design
• Q&A

2
Automotive instrument cluster system demand volume

• Hybrid cluster: consists of both analog

gauges and a display panel

• Solid state cluster: consists of a single

display panel, containing no analog
gauges

Source: Strategy Analytics, Automotive Instrument Clusters: Moving Towards Cockpit Integration and 3D Displays, May 2020 3
LED drivers in instrument clusters

Source: Ford Source: Audi

• Hybrid cluster: • Solid state cluster:

- backlight LED driver (low/mid power) - backlight LED driver (mid/high power)
- LED indicator - LED indicator for tell-tales (optional)

4
 Multi-channel automotive LED indicator family
TLC6C598/12-Q1 TLC6C5816-Q1 TLC6C5712-Q1 TLC6C5716/24-Q1
(> 100m Ω) Generation

 Shift Register Power Logic  Shift Register Power Logic  Const. Current Sink  Const. Current Sink
New

 40V Breakdown Voltage  40V Breakdown Voltage  7V Breakdown Voltage  7V Breakdown Voltage
 Vcc = 3 ~ 5.5V  Vcc = 3 ~ 5.5V  Vcc = 3 ~ 5.5V, SPI  Vcc = 3 ~ 5.5V, Serial I/F
 Cont. <50mA per channel (8/12  Cont. <50mA per channel (16 ch)  Cont. <75mA/ch (12 ch)  Cont. <50mA/ch (24/16 ch)
ch)  2 PWM Input  8 bit Dot Correction  7 bit Dot Correction, 8 bit BC
 Thermal Shutdown Protection  LED Open & Short Diagnostic  6 Ext. PWM arbitrary mapping  12/10/8 bit Int. Ind. PWM
 Full Diagnostic & Protection  Full Diagnostic & Protection
Old High Side

 Deactivated LED Fault Detection  Deactivated LED Fault Detection

TLC5916/17-Q1
TPIC6C596 TPIC2810 TLC5941-Q1 TLC59116-Q1
TLC5926/27-Q1
Generation

 Shift Register Power Logic  I2C Power Logic  Const. Current Sink  Const. Current Sink  Const. Current Sink
 33V Breakdown Voltage  40V Breakdown Voltage  17V Breakdown Voltage  17V Breakdown Voltage  17V Breakdown Voltage
 Vcc = 4.5 ~ 5.5V  Vcc = 3 ~ 5.5V  Vcc = 3 ~ 5.5V, Serial I/F  Vcc = 3 ~ 5.5V, Serial I/F  Vcc = 3 ~ 5.5V, FM+ I2C
 Cont. <100mA per channel (8 ch)  Cont. <100mA per channel (8 ch)  Cont. <120mA/ch (8/16 ch)  Cont. <90mA/ch (16 ch)  Cont. <120mA/ch (16 ch)
 8 bit Global Dot Correction  6 bit Ind. Dot Correction  8 bit Global Dot Correction
 OT, LED Open  12 bit Int. Ind. PWM  8 bit Int. Ind. PWM
 LED Short (7 only)  OT, LED Open  OT, LED Open

VBAT: 9-18V
Topology

VBAT: 9-18V
VCC

MCU MCU
MCU
- No Diagnostic - No Diagnostic or Simple Diagnostic - Diagnostic
- Simple ON/OFF - Simple ON/OFF - Constant Current w/ Rsense
- Requires Parallel wires from MCU - MCU Serial I/F & Daisy Chain Option - MCU Serial I/F & Daisy Chain Option 5
 TLC6C5816-Q1
Features Benefits
• AEC-Q100 Qualified for Automotive Applications • 16 channels in one chip for more cost efficient to power each LED
• 16 Channel Power DMOS Transistor Outputs • On-demand LED Short & Open Detection to easy fulfill diagnostics and save system cost
• Open drain output up to 50mA/channel
• Optimized Slew Rate helps reduce EMI
• Rdson 6.2 Ohm (25C Junction, typ)
• Rdson 13.5 Ohm (150C Junction, worst case) • Dual PWM input to support two different dimming scenarios
• 40V Output for load dump, support load directly connect to battery • SPI Checksum readback to enhance SPI communication reliability
• Optimized slow slew rate helps reduce EMI
• Serial Interface & PWM inputs Battery 5 V - 40 V
• Shift register compatible with 596/598/5912
• Fault register readback with RCK high 3 V – 5.5 V
• 2 PWM inputs, each control 8 outputs.
• Diagnostic & Protection VCC

• Over Temperature Protection EN

DRAIN0
• 8 Channel On-demand LED Open / Short Diagnostics RCK
• Serial Interface Communication Error Detection DRAIN1 /
SER IN
• Open-drain error output for MCU interruption DIAG0

• Package SRCK

• HTSSOP-28 MCU CLR TLC6C5816-Q1

SER OUT

ERR
DRAIN14
G1

G2 DRAIN15 /
GND DIAG14

Applications Key Parameter Overview

• Instrumentation Cluster Vcc operating voltage 3 ~ 5.5 V
• HVAC / Head-unit Faceplate Output voltage maximum rating 40 V
• Center Stack HMI Channel output maximum current 50 mA
• Electronic Gear Shifter Rds(on) typical 6.2 Ω
6
 TLC6C5712-Q1
Features Benefits
• AEC-Q100 Qualified for Automotive Applications • Output current high accuracy ensure whole system close to zero deviation in LED Display
• 12 Channel Power DMOS Transistor Outputs • Full Programmable via SPI to offer the flexibility for various applications
• Constant current up to 75mA, set via external resistor
• Complete Diagnostic and Protection to meet high functional safety requirements
• Breakdown voltage up to 7V
• Max drop-out voltage: 0.75V @ 50mA/ch, 1.2V @ 75mA/ch
• Configurable slew rate for optimized EMI performance
• Precision Constant Current
• Channel-Channel difference < ±3%
• Device-Device difference < ±3%
• 8-bit, 256-step linear dot correction for each channel
• Serial Interface & PWM inputs
• 6 PWM Inputs with frequency supervision
• Programmable PWM mapping capability via SPI interface
• Diagnostic & Protection
• Open-load, Short-to-GND, Shorted-LED detection for both activated and deactivated states
• LED Weak Supply Detection
• Adjacent Pin Short Detection
• Reference Resistor Open/Short Detection & Protection
• Thermal Prewarning and Shutdown
• Input PWM Timeout Monitoring
• Open-drain Error reporting
• Force Error for SPI Integrity Diagnostics
• SPI register lock for content protection
• Small & thermal effective package
• 28 HTSSOP (PowerPAD)

Applications Key Parameter Overview

• Instrumentation Cluster Vcc operating voltage 3 ~ 5.5 V
• HVAC / Head-unit Faceplate, Center Stack HMI, Electronic Gear Shifter Output voltage maximum rating 7 V
• Local Dimming Display Full range output current 75 mA
• RGB Ambient Lighting Output current accuracy ±3 %
7
 TLC6C5716/24-Q1
Features Benefits
• AEC-Q100 Qualified for Automotive Applications • High system reliability by fault detection and readback, including PWM error,
• 24/16 Channel Outputs GCLK missing, etc
• Constant current up to 50mA, set via external resistor
• Suitable to drive eight RGB color mixing LED lamps
• Breakdown voltage up to 7V
• Precision Constant Current • Mixed LED Binning with DC/BC compensation and high accuracy of constant
• Channel to Channel: ±8% current
• Device to Device: ±2% • EMI friendly with low inrush current and group delay
• 7-bit, 128-step Dot correction for each channel
• 8-bit, 256-step Brightness Control for each color group
• Serial Interface & PWM Dimming
• up to 4MHz SCK and 8MHz GCLK frequency, optimized for Automotive application
• 12/10/8 Bits internal PWM dimming configurable by each channel
• EMI friendly with programmable Output Channel Turn On/Off Slew Rate
• Grouped Delay to Prevent Inrush Current
• Diagnostic & Protection
• LED open error (LOD), LED short error (LSD), Output pin short to GND error (OSD)
• LOD/LSD detection circuit failure, LOD/LSD register failure
• PWM operation error, GCLK signal missing error
• Adjacent pin short error (APS)
• Thermal Prewarning (TPW), Thermal error and Shutdown (TEF)
• IREF resistor open failure (IOF), IREF resistor short failure (ISF)
• Small & thermal effective package
• 38 HTSSOP (PowerPAD)

Applications Key Parameter Overview

• Instrumentation Cluster Vcc operating voltage 3 ~ 5.5 V
• HVAC / Head-unit Faceplate, Center Stack HMI, Electronic Gear Shifter Output voltage maximum rating 7 V
• Local Dimming Display Full range output current 50 mA
• RGB Ambient Lighting Output current accuracy ±8 %
8
TFT LCD architecture

Mostly used in
Local Dimming

Mostly used in
Global Dimming

9
 Global dimming LED backlight driver roadmap
LP8864S-Q1 LP8864-Q1 LP8866S-Q1 LP8866-Q1
 3V to 48V VIN  3V to 48V VIN  3V to 48V VIN  3V to 48V VIN
 4 x 150mA LED Current  4 x 200mA LED Current  6 x 150mA LED Current  6 x 200mA LED Current
 Dimming Ratio > 32,000:1  Dimming Ratio > 32,000:1  Dimming Ratio > 32,000:1  Dimming Ratio > 32,000:1
 Power Line FET Driver  Power Line FET Driver  Power Line FET Driver  Power Line FET Driver
 Phase Shift, Hybrid Dimming  Phase Shift, Hybrid Dimming  Phase Shift, Hybrid Dimming  Phase Shift, Hybrid Dimming
 Full Diagnostics w/ I2C  Full Diagnostics w/ I2C  Full Diagnostics w/ I2C  Full Diagnostics w/ I2C
Diagnostic Level

LP8863-Q1
 3V to 48V VIN
 6 x 150mA LED Current
 Dimming Ratio > 32,000:1
 Ch. Current Ind. Control
 Power Line FET Driver
 Phase Shift, Hybrid Dimming
 Advanced Diagnostics w/ I2C

LP8869-Q1 LP8867-Q1
3A 3A
 4.5V to 40V VIN  4.5V to 40V VIN
 3 x 120mA LED Current  4 x 120mA LED Current
 Dimming Ratio 10,000:1  Dimming Ratio 10,000:1
 Power Line FET Driver  Power Line FET Driver
 Current De-rating w/ Ext NTC  Current De-rating w/ Ext NTC

LP8869C-Q1 LP8867C-Q1
3A 3A
 4.5V to 40V VIN  4.5V to 40V VIN
 3 x 120mA LED Current  4 x 120mA LED Current xxA Power FET Current
 Dimming Ratio 10,000:1  Dimming Ratio 10,000:1

3 CH 4 CH 6 CH 10
LP8866-Q1 / LP8866S-Q1
Features Benefits
• AEC-Q100 Qualified for Automotive Applications (Grade 1: TA -40C to +125C) • High brightness and big size LCD panel support with
• Six High-Precision Current Sinks • 6 * 200/150 mA LED output
• Output Current up to 200/150 mA/Channel • Good Cold cranking behavior with
• Current Matching 1% (typical) • Input Voltage Operating Range 3 V to 48 V
• Up to 16-bit LED Dimming Resolution • Good EMI Performance with
• Individual LED String Brightness Control • Phase shifted LED outputs
• Dimming Ratio 32,000:1 @ 152Hz PWM • Boost converter Spread Spectrum
• I2C, PWM Brightness Control Modes • Hybrid Dimming (Linear + PWM)
• 8 configurable LED strings configuration • Boost synchronization input
• Automatically adjusts phase shift for number of LED strings • Ease Customer design with
• Boost Controller for LED String Power • Resistor configuration for PWM /Boost frequency/LED configuration/Dimming mode
• Input Voltage Operating Range 3 V to 48 V • Integrated Discharge function
• Switching Frequency 100 kHz to 2.2 MHz
• Boost SYNC input to set boost switching frequency from an external clock
• Spread Spectrum for lower EMI
• Adaptive Voltage Control for Power Optimization
• Output voltage automatically discharged when boost is disabled
• Full Protection and Diagnostic Features
• Open, Shorted, Short-to-GND LED Fault Detection
• Boost Output OVP and OCP
• Boost Input UVLO, OVP and OCP
• External Resistor Fault/Charge Pump Fault/CRC Errors
• VDD UVLO and Thermal Shutdown
• HTSSOP-38 Package (DCP)
Applications
• Backlight for:
• Automotive Infotainment
• Automotive Instrument Clusters
• Smart Mirrors
• Heads-Up Displays (HUD)
• Central Information Displays (CID)
11
• Audio-Video Navigation (AVN)
Full diagnostics

The LP8866-Q1 contains several diagnostic registers that can be read

with the I2C interface for debugging or additional device information.
LED SHORT_TO_GND

• Support the industry’s

quickest detection of LED
short to GND fault

• Avoid the glare when LED

is short to GND
• Risk of blinding driver
at night

13
Full fault detection and handling

Supply Fault Boost Fault • The Interrupt Fault Status registers can
VIN undervoltage Boost OVP low
VIN overvoltage Boost OVP high be read back in three fault registers
VIN overcurrent Boost overcurrent
VDD undervoltage LEDSET detection fault
Charge pump fault MODE detection fault • Fault in red means critical fault which
Charge pump
components missing
FSET detection fault will make the chip enter into fault
ISET resistor fault
Boost sync clock recovery state. It will shutdown all the
invalid fault Thermal shutdown
Internal Register modules and retry periodically
CRC Fault
LED Fault
Open LED string
Shorted LED
LED short to GND fault
Invalid LED string detected

14
High reliability & diagnostic coverage
Damage?
Adjacent pin
Name Open Short to GND
Short
VDD No No No
EN No No No
C1N No No No
C1P No No No
CPUMP No No No
CPUMP No No No
GD No No No
PGND No No No
LP8866-Q1 could survive (no PGND
ISNS
No
No
No
No
No
No
ISNSGND No No No
damage) when any pin is OPEN/ ISET
FB
No
No
No
No
No
No

Short to GND or short with NC

DISCHARGE
No
No
No
No
No
No
NC No No No
adjacent pin OUT6
OUT5
No
No
No
No
No
No
OUT4 No No No
OUT3 No No No
OUT2 No No No
OUT1 No No No
NC No No No
INT No No No
SDA No No No
SCL No No No
BST_SYNC No No No
PWM No No No
SGND No No No
LED_SET No No No
PWM_FSET No No No
BST_FSET No No No
MODE No No No
DGND No No No
UVLO No No No
VSENSE_P No No No
VSENSE_N No No No
SD No No No 15
Local dimming architecture
Global Dimming Local Dimming

TCON Process Video stream only Process both Video stream and backlight control signal

LED Backlight Unit Mostly edge-lit Direct lit only. Each zone contains at least one LED

LED Driver Channel current output Channel current output individually controlled
global controlled Digital interface cascaded

Video
LCD Panel
Stream

1
2
Timing
LED
Controller
System Board Backlight
(TCON)
Unit
HX8880

SPI 3 LED Driver

SPI
LED Driver
Backlight
Control Signal
16
Channel individual control LED driver (direct)
• All the LEDs are driven at the same time in parallel
• One backlight zone needs one LED driver’s channel

LED su pply

SENSE OUTG0 OUTB7 SENSE OUTG0 OUTB7 GND

SDI SDO SDI SDO

SCK ERR SCK ERR

LATCH LATCH
µC
TLC6C572 4-Q1 TLC6C572 4-Q1
GCLK VCC GCLK VCC

BLA NK BLA NK

IRE F IRE F

GND GND
GND GND

17
Channel individual control LED driver (scan)
• The backlight LEDs are driven sequentially in groups.
• One LED driver’s channel could cover multiple zones (depending on multiplexing config)
• High peak current for each LED and LED driver’s channel since each LED could be only
on in a duty cycle (25% in the 4:1 multiplexing example below).
VLE D

COM 0

VLE D

COM N-2

VLE D

COM N-1

× 48 × 48 × 48

0 N-2 N-1 OUTR0 OUTB15 OUTR0 OUTB15 OUTR0 OUTB15

DATA
SIN SOUT SIN SOUT SIN SOUT
SCLK VCC VCC VCC
SCLK TLC6C572 4-Q1 SCLK TLC6C572 4-Q1 SCLK TLC6C572 4-Q1
LAT VCC VCC VCC
LAT LAT LAT
IC0 ICn-2 ICn-1
GSCLK
GSCLK GSCLK GSCLK

IRE F Thermal IRE F Thermal IRE F Thermal

IRE FGND Pad IRE FGND Pad IRE FGND Pad
Controller RIREF RIREF RIREF

3
DATA B ACK

18
Thermal dissipation

Direct Drive Scan

• Feasible to put chip on LED board • Higher LED power consumption and
higher LED driver power consumption
• Higher PCB thermal peak
• Unfeasible to put chip on LED board
19
Direct vs. scanning LED driver placement
Direct Drive Integrated Scanning
(Drivers on board) (Drivers on external board)

• LED drivers & LEDs • LEDs only

VLED/VDD/SPI(4)/CLK/GND HSx (4) + LEDx (all channel)

• LED Drivers
• TCON/MCU • TCON/MCU
Control Board
• Power • Power
Bigger connectors & more PCB space
20
Local dimming roadmap

TLC5941-Q1 TLC6C5716/24-Q1 TLC6C5748-Q1

 16 CH Const. Current Sink  16/24 CH Const. Current Sink  48 CH Const. Current Sink
 17V breakdown Voltage  8V breakdown Voltage  11V breakdown Voltage
 Vcc = 3 ~ 5.5V, 30MHz Serial I/F  Vcc = 3 ~ 5.5V, 4MHz Serial I/F  Vcc = 3 ~ 5.5V, 25MHz Serial I/F
 60mA/ch  50mA/ch  32mA/ch
 6 bit Dot Correction  7 bit Dot Correction, 8 bit BC  7 bit Dot Correction, 7 bit BC
 12 bit Int. Ind. PWM  12/10/8 bit Int. Ind. PWM  3 bit MC, Integrated IREF
 OT, LED Open  OT, LED Open/Short/Short-to-GND  16 bit Int. Ind. PWM, ES-PWM
 HTTSOP-28, 4.4 mm* 9.7 mm  HTTSOP-38, 6.2 mm* 12.5 mm  OT, LED Open/Short
 HTTSOP-56, 6.1 mm * 14 mm

Lower cost per channel

21
TLC6C5748-Q1
48ch, 16bit PWM LED Driver with low headroom voltage and high output voltage

Features Benefits
• 48 Outputs with 7bit DC for each output • Best to drive 48 LED zones with uniformity
• 16bit PWM Constant-Current with 7bit Brightness Control and 3bit Max • Perfect solution for chip-on-LED-board architecture
Current Control for 31.9mA, no external RIREF resister • Direct daisy chain interface with TCON controller
• IC Supply Voltage Range: 3.0 – 5.5V • Max 3 single-junction LEDs/ 1 dual-junction LED in series
• LED Breakdown Voltage: 11V • Reduces system power consumption
• Precise Constant Current Regulation: • Reduces system cost
Channel-to-Channel: ± 2% (typ) • Unlimited device cascading
Device-to-Device: ± 2% (typ)
• Low Headroom Voltage: 0.25V@19mA
• LED Open/Short Detection
• Over Temperature Detection
• Power Save Mode: 7uA consumption
• HTTSOP-56 Package (DCA) 6.1 mm * 14 mm
• Operating Junction Temperature Range: -40 C to +125C

Applications
• Automotive Local Dimming Backlight
• Automotive Pixel Lamp
• Automotive RGB display

22
XTIDA-020036 384-Zone 12” Local Dimming Backlight Reference Design
Features
• 384 zones & LEDs
• 12x32 matrix; 1S1P
• 0.9 cm pitch
• PCB Specifications
• Direct driver on back of PCB
• 2 layer PCB
• SPI control for 8x daisy-chain
• 8x 48-ch low-side LED drivers
• Compatible with local dimming TCONs
• LED Specifications ~500mV headroom
• OSRAM Mini TOPLED White 120° SMD 30C temperature
increase
• Size : 2.3mm x 1.9mm (91mil x 75mil) TOP
• Single junction @ 3.05V forward voltage
• 20mA per LED
Tools & Resources
• TIDA-020036 Folder • Device Datasheets:
• Design Guide ‒ TLC6C5748-Q1
• Design Files: Schematics, ‒ SN74LVC2G17 BOTTOM
BOM, Gerbers, Software, etc. ‒ LCW MVSG.EC-BXCX

23
Aiding Functional Safety cluster system designs
• TI offers Functional Safety-Capable LED drivers to aid system-level
functional-safety cluster system design

• Documentation we can provide:

• Functional safety FIT rate
- Based on IEC TR 62380 or SN 29500 standards
- Calculated at a 90% confidence interval for safety-related rate estimation in compliance with IEC 61508
and ISO 26262
• Failure mode distribution (FMD)
• Pin FMA *
• Diagnostic description and fault handling routine *

* Available for select products

24
Q&A

25
SLYP666
 IMPORTANT NOTICE AND DISCLAIMER

TI PROVIDES TECHNICAL AND RELIABILITY DATA (INCLUDING DATASHEETS), DESIGN RESOURCES (INCLUDING REFERENCE
DESIGNS), APPLICATION OR OTHER DESIGN ADVICE, WEB TOOLS, SAFETY INFORMATION, AND OTHER RESOURCES “AS IS”
AND WITH ALL FAULTS, AND DISCLAIMS ALL WARRANTIES, EXPRESS AND IMPLIED, INCLUDING WITHOUT LIMITATION ANY
IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT OF THIRD
PARTY INTELLECTUAL PROPERTY RIGHTS.
These resources are intended for skilled developers designing with TI products. You are solely responsible for (1) selecting the appropriate
TI products for your application, (2) designing, validating and testing your application, and (3) ensuring your application meets applicable
standards, and any other safety, security, or other requirements. These resources are subject to change without notice. TI grants you
permission to use these resources only for development of an application that uses the TI products described in the resource. Other
reproduction and display of these resources is prohibited. No license is granted to any other TI intellectual property right or to any third
party intellectual property right. TI disclaims responsibility for, and you will fully indemnify TI and its representatives against, any claims,
damages, costs, losses, and liabilities arising out of your use of these resources.
TI’s products are provided subject to TI’s Terms of Sale (www.ti.com/legal/termsofsale.html) or other applicable terms available either on
ti.com or provided in conjunction with such TI products. TI’s provision of these resources does not expand or otherwise alter TI’s applicable
warranties or warranty disclaimers for TI products.

Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265
Copyright © 2020, Texas Instruments Incorporated