ALT80600 LED Driver with Pre-Emptive Boost for Ultra-High Dimming Ratio and Low Output Ripple FEATURES AND BENEFITS DESCRIPTION The ALT80600 is a multi-output LED driver for small-size Automotive AEC-Q100 qualified LCD backlighting. It integrates a current-mode boost converter Wide input voltage range of 4.5 to 40 V for start/stop, with internal power switch and four current sinks. The boost cold crank, and load dump requirements converter can drive up to 44 white LEDs, 11 LED per string, Fully integrated LED current sinks and boost converter at 120 mA (V = 3.3 V max). LED sinks can be paralleled with internal power MOSFET F together to achieve higher currents up to 480 mA. Operate in Boost or SEPIC mode for flexible output Drives up to 11 series white LED in 4 parallel strings, at The ALT80600 operates from single power supply from 4.5 to up to 120 mA per string (V = 3.3 V max). F 40 V once started, it can continue to operate down to 3.9 V. Programmable boost switching frequency or sync This allows the part to withstand stop/start, cold crank, and externally from 200 kHz to 2.3 MHz load dump conditions encountered in automotive systems. Clock-Out feature for internal switching frequency The ALT80600 can control LED brightness through external Adjustable boost frequency dithering to reduce EMI PWM signal. By using the patented Pre-emptive Boost Advanced control allows minimum PWM on-time down control, an LED brightness contrast ratio of 15,000:1 can be to 0.3 s, and avoids MLCC audible noises achieved using PWM dimming at 200 Hz. A higher ratio of LED contrast ratio: 15,000:1 at 200 Hz using PWM 150,000:1 is possible when using a combination of PWM and dimming alone, 150,000:1 when combining PWM and analog dimming. analog dimming Continued on next page... Continued on next page... PACKAGE: APPLICATIONS 24-Pin 4 mm 4 mm QFN Automotive infotainment backlighting with Wettable Flank Automotive cluster Automotive center stack Not to scale Automotive exterior lighting V = 4.5 to 40 V IN V 40 V OUT *optional 10 H 0.024 Q1 C in 383 187 k GATE SW OVP 4.7 F 4.7 F Vsense Vin V c PGND 1 F VDD 10 k LED1 FAULT ALT80600 LED2 Up to 11 WLEDs in series EN Enable Up to 120 mA/channel LED3 PWM PWM t 0.3 s ON LED4 APWM CLKOUT COMP AGND ISET FSET DITH PEB APWM 100 kHz 0-90% 845 8.25 k 100 pF 40.2 k 10 k 68 nF 9.09 k 10 nF Figure 1: Typical application diagram showing ALT80600 in Boost mode ALT80600-DS March 20, 2018 MCO-0000393LED Driver with Pre-Emptive Boost ALT80600 for Ultra-High Dimming Ratio and Low Output Ripple FEATURES AND BENEFITS (continued) DESCRIPTION (continued) Excellent input voltage transient response even at lowest Switching frequency can be either above or below AM band. PWM duty cycle A programmable dithering feature further reduces EMI. A Gate driver for optional PMOS input disconnect switch synchronization pin allows switching frequency to be synchronized Extensive protection against: externally between 200 kHz and 2.3 MHz. A Clock-Out pin allows Shorted boost switch, inductor or output capacitor other converters to be synchronized to the ALT80600s switching Shorted FSET or ISET resistor frequency. Open or shorted LED pins and LED strings The ALT80600 provides protection against output short, overvoltage, Open boost Schottky diode open or shorted diode, open or shorted LED pin, and overtemperature. Overtemperature A cycle-by-cycle current limit protects the internal boost switch against high current overloads. An external P-MOSFET can optionally be used to disconnect input supply in case of output to ground short fault. 1 SELECTION GUIDE Part Number Package Packing Leadframe Plating 24-pin 4 4 mm wettable flank QFN ALT80600KESJSR 1500 pieces per reel 100% matte tin with exposed thermal pad and sidewall plating 1 Contact Allegro for additional packing options. 2 ABSOLUTE MAXIMUM RATINGS Characteristi Symbol Notes Rating Unit LEDx Pin V x = 1..4 0.3 to 40 V LEDx OVP pin V 0.3 to 40 V OVP VIN V 0.3 to 40 V IN Higher of 0.3 V , SENSE VSENSE, GATE and (V 7.4) to V IN V GATE V +0.4 IN Continuous 0.6 to 50 V SW V t < 50 ns (repetitious, <2.5 MHz) 1.0 to 54 V SW 3 Single-event in case of Fault 1.5 to 60 V FAULT V 0.3 to 40 V FAULT APWM, EN, PWM, CLKOUT, COMP, 0.3 to 5.5 V DITH, FSET, ISET, VDD, PEB Operating Ambient Temperature T Range K 40 to 125 C A Maximum Junction Temperature T (max) 150 C J Storage Temperature T 55 to 150 C stg 2 Stresses beyond those listed in this table may cause permanent damage to the device. The absolute maximum ratings are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the Electrical Characteristics table is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. 3 SW DMOS is self-protecting and will conduct when VSW exceeds 60 V. THERMAL CHARACTERISTICS: May require derating at maximum conditions see application information 4 Characteristic Symbol Test Conditions Value Unit Package Thermal Resistance R ES package measured on 4-layer PCB based on JEDEC standard 37 C/W JA 4 Additional thermal information available on the Allegro website. Allegro MicroSystems, LLC 2 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000 www.allegromicro.com