Supertex HV9861A 21W通用AC输入高亮LED驱动方案

Supertex公司的HV9861A是平均模式恒流控制的LED驱动器,从而大大地改善了LED电流的精度,线路和负载调整精度而不需要回路补偿或高边电流检测,LED输出电流精度±3%.主要用在DC/DC或AC/DC LED驱动器,LCD屏的LED背光驱动,通用恒流源,LED显示屏,建筑和装饰照明以及LED街道照明.本文介绍了HV9861A主要特性,方框图,典型应用电路以及21W通用AC输入电压LED驱动器演示板主要指标,电路图,材料清单和PCB布局图.

The HV9861A is a patented, average-mode, constant current control LED driver IC operating in a constant off-time mode. Unlike the HV9910B, this control IC does not produce a peak-to-average error, and therefore greatly improves the accuracy, line and load regulation of the LED current without any need for loop compensation or highside current sensing. The output LED current accuracy is ±3%.

The IC is equipped with a current limit comparator for hiccup-mode output short circuit protection. Internal over-temperature protection is provided. The internally regulated voltage (VDD) for the HV9861A is 7.5V.

The IC can be powered from a 12 - 450V supply. A PWM dimming input is provided that accepts an external control TTL-compatible signal. The output current can be programmed by an internal 270mV reference, or controlled externally through a 0 - 1.5V dimming input.
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