Allegromicro A8514 multi-output white LED driver solution

The A8514 is a multi-output white LED driver for small-size LCD backlighting. It integrates a current-mode boost converter with internal power switch and four current sinks. The boost converter can drive up to 48 LEDs, 12 LEDs per string, at 80 mA. The LED sinks can be paralleled together to achieve even higher LED currents, up to 320 mA. The device operates from a 5V-40V supply, has a switching frequency of up to 2.3MHz, and has a current matching accuracy of 0.7% - 0.8% for each LED string. It also has PWM and analog dimming inputs. It is mainly used in automotive infotainment systems, automotive instrument panels,

and automotive center consoles. This article introduces the main features and advantages of the A8514, a block diagram, and a variety of application circuits. from 5 to 40 V, which allows the part to withstand load dump conditions encountered in automotive systems.

The A8514 can drive an external P-FET to disconnect the input supply from the system in the event of a fault. The A8514 provides protection against output short and overvoltage, open or shorted diode, open or shorted LED pin, shorted boost switch or inductor, shorted FSET or ISET resistor, and IC overtemperature. and protects the internal current switch against high current overloads. The A8514

has a synchronization pin that allows PWM switching frequencies to be synchronized in the range of 580 kHz to 2.3 MHz. V DMOS • Sync function to synchronize boost converter switching frequency up to 2.3 MHz, allowing operation above the AM band • Excellent input voltage transient response • Single resistor primary OVP minimizes VOUT leakage • Internal secondary OVP for redundant protection • LED current of 80 mA per channel • Drives up to 12 series LEDs in 4 parallel strings • 0.7% to 0.8% LED to LED matching accuracy • PWM and analog dimming inputs • Provides driver for external PMOS input disconnect switch • Extensive protection against: ▫ Shorted boost switch or inductor ▫ Shorted FSET or ISET resistor ▫ Shorted output ▫ Open or shorted LED pin ▫ Open boost Schottky ▫ Overtemperature (OTP) A8514 application: LCD backlighting or LED lighting for: ▫ Automotive infotainment ▫ Automotive cluster ▫ Automotive center Figure 1. A8514 block diagram Figure 2. A8514 application circuit diagram using P-MOSFET detection and VIN ground short protection Figure 3. A8514 design example circuit diagram Figure 4. A8514 SEPIC configuration application circuit diagram using precision input current detection and VSENSE ground protection For more information, please see:

























































http://www.allegromicro.com/en/Products/Part_Numbers/8514/8514.pdf