A6281中文资料3-Channel Constant Current LED Driver with Programmable PWM Control数据手册Allegro规格书

描述 Description

These parts are discontinued. Samples are no longer available. For new customers or new applications, please contact Allegro. Date of status change: December 2, 2014.

The A6281 is a 3-channel constant current LED driver that has a wide range of output currents. The A6281 controls LED brightness with a Pulse Width Modulation (PWM) scheme that gives the application the capability of displaying a billion colors in an RGB cluster. The maximum current is set by an external resistor.

The LED brightness is controlled by performing PWM control on the outputs. The brightness data of the PWM signal for each LED is stored in three 10-bit registers. The peak value for each LED can be adjusted (dot-corrected) to compensate for mismatch, aging, and temperature effects. All the internal latched registers are loaded by a 32-bit shift register. One address bit controls whether dot correction/clock divider ratio or brightness data is loaded into the registers. The remaining bits are used for the data.

The A6281 is designed to minimize the number of components needed to drive LEDs with large pixel spacing. A large number of A6281s can be daisy chained together and controlled by just four control signals (clock, serial data, latch, and output enable). Each of these inputs is buffered to drive the next chip in the chain. Also, VIN can be tied to the LED voltage supply bus, thus eliminating the need for a separate chip supply bus or an external regulator.

The A6281 is supplied in a 3 mm × 3 mm 16-terminal QFN (suffix ‘ES’) package, with 0.75 mm nominal overall height. The package is lead (Pb) free with 100% matte-tin leadframe plating.

Applications Colored, large-character LED signs Scrolling, colored marquees Architectural lighting High intensity monochrome displays Large video and graphic displays

特性 Features

• 3 × 10-bit PWM brightness settings
• 3 × 7-bit dot correction current settings
• 5 to 17 V operation
• Wide output current range, 10 to 150 mA per channel
• Internally generated PWM clock
• Serial port operates at up to 5 MHz
• Data and clock logic architecture allows single microcontroller control of large quantities of serially-connected A6281s at fast data transfer rate
• Buffered logic outputs to drive cables
• Thermal shutdown and UVLO protection
• Power-On Reset

简介

A6281属于集成电路（IC）的LED驱动器。由制造生产的A6281LED 驱动器器件属于 LED 驱动器电源管理集成电路 (PMIC) 系列，可通过标称固定电压的电源为负载（通常为发光二极管）提供电流，并且电流可控。它与用于电压调节的类似产品的主要区别在于，这类器件提供较低的反馈电压（以提高系统能效），而且通常可对器件工作点进行外部控制，可在照明应用中用于实现调光功能。