摘要：  本文介绍了HV9971主要特性，功能方框图和典型应用电路图。

关键字：  LED驱动器，  元件，  电路，  照明

 Supertex公司的 HV9971是不连续导通模式（DCM）反激LED驱动器，可以工作满负荷100kHz开关频率，通用80-264VAC输入电压，±3% LED电流精度，自适应于外部元件误差和寄生参数，输出开路和短路保护，主要用在低功耗照明。本文介绍了HV9971主要特性，功能方框图和典型应用电路图。

 The HV9971 is a primary-side control IC for driving a discontinuous conduction mode (DCM) flyback LED driver. The IC is optimized for operation at a constant full-load switching frequency of 100kHz and the universal input AC voltage range of 80-264VAC. It maintains 3% variation of the LED current setting， and features tight line and load regulation. The proprietary primary-side output current control employed in the HV9971 makes the output current setting insensitive to most component tolerances and parasitics without use of an opto-feedback.

 The HV9971 LED driver is fully protected against output open and short circuit conditions and input under-voltage. It also offers a logic input for dimming the LED light output by means of pulse-width modulation of the output current.

The HV9971 is ideally suited for driving high-brightness LEDs in low-power lighting fixtures such as incandescent bulb retrofits.

HV9971主要特性：

Programmable true constant current operation

±3% LED current accuracy

Adaptive to external component tolerances and parasitics

Primary-side current sensing

Output open circuit protection

Output short circuit protection

Input under voltage lockout

PWM dimming / enable

Universal 80-264VAC operation

Fixed frequency operation

HV9971应用：

Low power lighting fixtures

图1。路图HV9971功能方框图

图2。HV9971典型应用电路图