The A8509 is a multi-output white LED driver for backlit LCD panels. It integrates a current-mode boost controller and four individual current absorbers.
This boost controller architecture allows for greatly expandable boosts to optimize solutions for the number of LEDs required per string. The FSET/SYNC pin sets the desired boost switching frequency or synchronizes the value over the range of 300 to 800 kHz.
The LED pour current value can be set via an external ISET resistor (see Figure 1). The four LED sink currents can also be combined to achieve higher currents for each LED string.
The A8509 provides output short-circuit and over-voltage protection, LED pin open-circuit or short-circuit protection, and over-temperature protection. The two-stage pulse-by-pulse current limiting feature provides soft start and protection against high current overloads on external current switches. As an option, the A8509 drives a P-FET connected to the FAULT pin to disconnect the input power from the system in the event of a ground short circuit in the boost converter.
Package options are available in 24-pin TSSOP (suffix LP) and SOICW (LB) packages. The TSSOP has an exposed heat sink mounted, while the SOICW has four pins with internal fuses for better heat dissipation. Both packages are lead-free and feature 100% matte tin-plated pin frames.
-
用于 LED 串的四个集成的高电流吸收器；可绑定在一起，实现更高电流
-
具有栅极驱动器/升压控制器的固定频率电流模式控制；可驱动外部 N 通道 MOSFET 的强大栅极驱动器可极大扩展每串的 LED 数
-
可与一个主升压控制器和最多三个额外从控制器并行运行；在仅装载一个主升压稳压器的同时最多可运行 16 个 LED 串
-
LED 串之间的电流自主均流共享可实现 0.7% 的精确度与 0.8% 的匹配率
-
较宽的输入电压范围：9 至 40 V
-
为单电源操作提供内部偏压供电（一般 VIN = 12 或 24 V）
-
单独的 Enable 和 PWM 引脚，作为实现 Enable 和 PWM 调光功能的接口
-
可设置升压转换器开关频率或在 800 kHz 时进行同步的 Fset/Sync 功能
-
保护功能
-
开路或短路 LED 引脚保护
-
开路 Schottky 保护
-
逐脉冲电流限制
-
过温保护 (OTP)