DATASHEET ISL78171 FN8602 Rev.1.00 6-Channel, 50mA Automotive LED Driver with Ultra-High Dimming Ratio and Oct 20, 2017 Phase Shift Control The ISL78171 is a 6-channel, 50mA, LED driver capable of very Features high dynamic range dimming. It offers an integrated boost 6 channels at 50mA maximum per channel converter, six high precision, adjustable current sinks and a 2 SMBus/I C interface for digital programmability and extensive Input voltage: 4.5V to 26.5V, output voltage: 40V max diagnostics. These features provide the ISL78171 with the Bootstrap operation Input:3V to 21V output: 26.5V max capabilities to design a compact, highly versatile LED backlight PWM dimming with phase shift control for a wide variety of ambient lighting conditions. 2 SMBus/I C controlled PWM or DC dimming The integrated peak current mode PWM boost converter operates with a constant frequency and can boost an input Direct PWM dimming voltage range of 4.5V - 26.5V to an output up to 40V and supply Internal PWM dimming mode linearity: 0.4% to 100%, six strings of LEDs with up to 50mA each. A dynamic headroom dimming frequency <30kHz control circuit detects and regulates the highest voltage string to Direct PWM dimming duty cycle linearity: 0.007% to 100% improve efficiency in multistring configurations. at a dimming frequency of 200Hz The six high precision adjustable current sinks offer typical Current matching 0.7% typ current matching better than 1% and a dimming ratio capable of exceeding 60,000:1. The dimming ratio can be 600kHz/800kHz/1.2MHz selectable switching frequency 2 adjusted with either or both the I C/SMBus and an external Dynamic headroom control PWM signal. They also feature an optional channel phase shift Fault protection control which helps to reduce the input and output - String open/short-circuit, OVP, OTP and optional output capacitance and ripple, to improve efficiency and to prevent short-circuit fault protection audible noise. 2 AEC-Q100 qualified The SMBus/I C interface offers a wide range of programmability that includes the boost FET slew rate control, Applications individual string enabling, and converter switching frequency selections. It offers a wide range of protection features and Infotainment display LED backlighting diagnostics that cover all perceivable faults, enabling the LCD monitor LED backlighting system to self-diagnose the functioning of the backlight and react to such conditions as failed LEDs. The ISL78171 is offered Field sequential RGB LED backlighting in a compact and thermally efficient 20 Ld QFN package with an ambient temperature range of -40C to +105C. Related Literature For a full list of related documents, visit our website - ISL78171 product page 40V, 6 x 50mA* 40V, 6 x 50mA* VIN = 4.5~26.5V VIN = 4.5~26.5V 40V, 6 x 50mA* VIN = 4.5~26.5V Q1 (OPTIONAL) Q1 (OPTIONAL) Q1 (OPTIONAL) ISL78171 ISL78171 ISL78171 1 FAULT 1 FAULT 1 FAULT LX 20 LX 20 LX 20 2 VIN 2 VIN 2 VIN OVP OVP OVP 16 16 16 4 4 4 VDC VDC VDC 8 FPWM PGND PGND 19 PGND 19 19 7 7 7 SMBCLK/SCL SMBCLK/SCL SMBCLK/SCL CH0 10 CH0 10 CH0 10 6 SMBDAT/SDA SMBDAT/SDA 6 SMBDAT/SDA 6 CH1 11 CH1 11 CH1 11 5 PWM 5 5 PWM PWM CH2 12 CH2 12 CH2 12 3 EN EN 3 EN 3 CH3 13 CH3 CH3 13 13 17 RSET CH4 14 17 CH4 14 17 RSET CH4 14 RSET CH5 15 CH5 CH5 8 15 8 FPWM 15 FPWM *VIN > 12V COMP 18 *VIN > 12V 9 AGND COMP *VIN > 12V 9 COMP 18 9 AGND 18 AGND 2 FIGURE 1A. SMBus/I C CONTROLLED DIMMING FIGURE 1B. PWM DIMMING WITH PWM INPUT FIGURE 1C. DIRECT PWM DIMMING AND ADJUSTABLE DIMMING AND ADJUSTABLE DIMMING FREQUENCY FREQUENCY FIGURE 1. ISL78171 TYPICAL APPLICATION DIAGRAMS FN8602 Rev.1.00 Page 1 of 29 Oct 20, 2017ISL78171 Table of Contents Block Diagram 3 Ordering Information 3 Pin Configuration 4 Pin Descriptions . 4 Absolute Maximum Ratings . 5 Thermal Information . 5 Operating Conditions 5 Electrical Specifications . 5 Typical Performance Curves 8 Theory of Operation . 12 PWM Boost Converter 12 Enable . 12 Current Matching and Current Accuracy . 12 Dynamic Headroom Control . 12 PWM Dimming Frequency Adjustment 14 Phase Shift Control 14 Switching Frequency . 15 5V Low Dropout Regulator 15 IC Protection Features and Fault Management . 15 2 C Communications 19 SMBus/I Write Byte 19 Read Byte 19 Slave Device Address 19 2 SMBus/I C Register Definitions 19 PWM Brightness Control Register (0x00) 21 Device Control Register (0x01) 21 Fault/Status Register (0x02) 22 Identification Register (0x03) . 23 DC Brightness Control Register (0x07) 23 Configuration Register (0x08) . 24 Output Channel Mask/Fault Readout Register (0x09) . 24 Phase Shift Control Register (0x0A) 25 Secondary Boost Oscillator Register (0x7F) 25 Component Selection . 25 Input Capacitor 25 Inductor 25 Output Capacitors . 26 Output Ripple . 26 Schottky Diode 26 Applications . 26 High Current Applications . 26 Low Voltage Operations 26 16-Bit Dimming . 27 Field Sequential RGB LED Backlighting . 27 Compensation 27 Revision History 28 About Intersil 28 Package Outline Drawing 29 FN8602 Rev.1.00 Page 2 of 29 Oct 20, 2017