Holtek HT7L4091通用高亮LED照明控制方案 - 消费电子 - 电子工程网
HT7L4091 ：Universal Step-Down PWM Control For High Brightness LED Lighting Control
The HT7L4091 device provides a low-cost solution for active current mode PWM controls of High Intensity LED drive systems supplied by either AC or DC line power lines. The device operates in constant off-time mode which is suitable for buck LED drivers. The low start-up and operating currents provides flexible power requirements for high efficiency or low cost applications. The switch frequency off-time can be programmed using an external resistor. The peak current mode control achieves good output current regulation without requiring loop compensations for a wide range of input voltages.
Included in the device is a PWM dimming input which can accept an external control signal with a duty ratio from 0 to 100%. The output current can be programmed from 0 to 250mA by applying an external control voltage on the linear dimming control input.
The device includes a frequency jitter function which helps to reduce EMI power supply emissions. from damage should the LEDs be short circuited. .
The device requires a minimum number of external standard components and is available in an 8-pin NSOP package for small area PCB applications.
●●Input supply AC voltage range: 100V~240V
●●Ultra Low Power-on Start-up current 30μA
●●Integrated 25V Zener diode internally connected to VIN pin
●●5V LDO output voltage with 6mA driving current for external components
●●Frequency jitter function for enhanced EMI performance
●●Under Voltage Lockout Function - UVLO
●●Current mode operation with cycle-by-cycle current limiting
●●Over Temperature Protection Function
●●High-current FET Drive Output
●●Linear and PWM Dimming Function
●●Enhanced Short Circuit Protection Function
●●AC/DC and DC/DC Power control For High Power LED Lighting
●●RGB back lighting LED driver
●●Flat Panel Displays Back Lighting
●●General Purpose Constant Current Source
●●Signage and Decorative LED lighting