SUPERTEX HV9985三路RGB LED驱动方案
SUPERTEX 公司的确HV9985是三路峰值电流模式PWM控制器,能用来驱动RGB LED或多路白光LED. HV9985具有40V线性稳压器,提供5V电源给IC供电,三个转换器的开关频率由外时钟信号或内部振荡器控制.三路有120度的相位差,以降低输入电流波纹.LED串间电流精度为±2% ,线性和PWM调光,PWM调光比高达5000:1,输入电压10-40V,主要用在RGB背景光,升压,降压和SEPIC转换器,多串白光LED驱动应用.本文介绍了HV9985的主要特性,方框图,典型应用电路以及PCB布局指南
The HV9985 is a three-channel peak current mode PWM controller for driving single switch converters in a constant output current mode. It can be used for driving either RGB LEDs or multiple channels of white LEDs.
The HV9985 features a 40V linear regulator, which provides a 5.0V supply to power the IC. The switching frequencies of the three converters in the IC are controlled either with an external clock signal (the channels operate at a switching frequency of 1/12th of the external clock frequency) or using the internal oscillator. The three channels are positioned 120°out-of-phase to reduce the input current ripple. Each converter is driven by a peak current mode controller with output current feedback.
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