安森美NCP3065高亮LED SEPIC 方案 设计, 开关, designed, regulate, average

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安森美的NCP3065是单片开关稳压器，能为高亮度LED提供恒定电流，集成了1.5 A开关，输入电压从3.0 V到 40 V。
       本文介绍了NCP3065的主要性能，典型应用电路图，以及带外接开关的降压演示板应用电路图；同时还介绍了单端初级电感转换器（SEPIC） 设计原理，计算公式等设计要点。

        The NCP3065 is a monolithic switching regulator designed to deliver constant current for powering high brightness LEDs. The device has a very low feedback voltage of 235 mV (nominal) which is used to regulate the average current of the LED string. In addition, the NCP3065 has a wide input voltage up to 40 V to allow it to operate from 12 Vac or 12 Vdc supplies commonly used for lighting applications as well as unregulated supplies such as Lead Acid batteries. The device can be configured in a controller topology with the addition of an external transistor to support higher LED currents beyond the 1.5_A rated switch current of the internal transistor. The NCP3065 switching regulator can be configured in Step-Down (Buck) and Step-Up (boost) topologies with a minimum number of external components.