LT3474

• Product Introduction

LT3474 step-down 1A LED driver

peculiarity True Color PWM provides constant color and a dimming range of 400:1 Wide input range: 4V to 36V LED current up to 1A Adjustable switching frequency from 200kHz to 2MHz Adjustable control of LED current Integrated boost diode High output current accuracy is maintained over a wide range of 35mA to 1A LED Open Circuit (LT3474) and Short Circuit Protection High-end detection allows the negative electrode to be grounded Small inductors and ceramic capacitors are used The LT3474-1 drives LED strings up to 26V Compact 16-pin TSSOP thermally enhanced surface-mount package

description

®The LT 3474/LT3474-1 is a fixed-frequency step-down DC/DC converter designed to be used as a constant current source. An internal sense resistor monitors the output current for accurate current regulation, making it ideal for driving high-current LEDs. High output current accuracy is maintained over a wide range (35mA to 1A), providing a wide dimming range.

The unique PWM circuitry achieves a 400:1 dimming range, thus avoiding color drift common in LED current dimming operations.

高开关频率提供了诸多优点，并允许采用小电感器和陶瓷电容器。小电感器与 16 引脚 TSSOP 表面贴装封装相结合，使得占用空间和成本均低于替代解决方案。而恒定开关频率与低阻抗陶瓷电容器的组合将产生低and可预测的输出纹波。

With its wide input range of 4V to 36V, the LT3474/LT3474-1 can be regulated for a wide range of power supplies, from 5V logic rails to untuned wall transformers, lead-acid batteries, and distributed power supplies. The current-mode PWM architecture provides fast transient response and cycle-by-cycle current limiting capabilities. Frequency foldback and thermal shutdown features provide additional protection.

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• 汽车和航空照明
• 建筑物局部照明
• 显示器背面照明
• 恒定电流源