HT7L4091 -- Universal Step-Down PWM Control For High Brightness LED Lighting Control

General Description

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.

Features

  • Input supply AC voltage range: 100V~240V
  • Ultra Low Power-on Start-up current < 30uA
  • 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
  • Efficiency > 85%
  • 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

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