NS公司的RD-173 - MR16 和PAR38 参考设计采用LM3429多功能高压控制器和LM2841/42 PWM DC/DC 降压稳压器. LM3429的输入电压可从4.5V到75V,具有快速(50kHz) PWM 调光特性;而LM2841/42的输入电压从表面上看4.5V到42V,输出电流300mA或600mA可选择.RD-173 - MR16 和PAR38 LED灯参考设计输入电压为9V到36V,这样可采用12V和24V电源,以适应各种应用,可驱动1-12个串联连接的LED,驱动电流高达1A.本文介绍了LM3429和LM2841/42的主要特性以及典型应用电路.此外还未集中介绍了RD-173 - MR16 和PAR38 LED灯参考设计的主要特性, 外形图,详细电路图和所用元件清单和PCB布局图.

LM3429: N-Chann Controller for Constant Current LED Drivers

The LM3429 is a versatile high voltage LED driver controller. With the capability to be configured in a Buck, Boost, Buck- Boost (Flyback), or SEPIC topology, and an input and output operating voltage rating of 75V, the LM3429 is ideal for illuminating LEDs in a very diverse, large family of applications.

Adjustable high-side current sense with a typical sense voltage of 100 mV allows for tight regulation of the LED current with the highest efficiency possible. Output LED current regulation is based on peak current-mode control with predictive Off-Time Control. This method of control eases the design of loop compensation while providing inherent input voltage feed-forward compensation.

The LM3429 includes a high-voltage startup regulator that operates over a wide input range of 4.5V to 75V. The internal PWM controller is designed for adjustable switching frequencies of up to 2.0MHz, thus enabling compact solutions. Additional features include: precision reference, logic compatible DIM input suitable for fast PWM dimming, cycle-by-cycle current limit, and thermal shutdown.

The LM3429 comes in a low profile, thermally efficient TSSOP EP 14-lead package.

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来源：NS