Supertex HV9860升压电流模式LED驱动方案
Supertex公司的HV9860是电流模式控制的LED驱动器,采用峰值电流模式控制方案,包括采用跨导放大器来精确控制输出电流,使得输出电流精度高,内部电压源精度±2%,主要适合恒频模式下(内部开关频率100kHz)控制升压或反激LED驱动器,可用在DC/DC爱LED驱动器,RGB或白光LED背光应用,平板显示屏背光.本文介绍了功能方框图和典型应用电路图.
The HV9860 is a current mode control LED driver IC designed to control a boost or flyback LED driver in constant frequency mode. The controller uses a peak current-mode control scheme and includes an internal transconductance amplifier to accurately control the output current over all line and load conditions. The IC also provides a disconnect switch gate drive output, which can be used to achieve good PWM rise and fall times for the LED current using an external disconnect FET.
The HV9860 also has a DUTY pin which can be used to set the maximum duty cycle to either 90%(typ) or 75%(typ). The 75% duty cycle limit can be used for flyback applications.
The HV9860 also provides a TTL compatible, low-frequency PWM dimming input that can accept an external control signal with a duty ratio of 0-100% and a frequency of up to a few kilohertz.
The HV9860 includes a wiring fault detection function that sends a flag to the boost input power supply in case of an LED to wiring fault.
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