SY7704 - 4-string LED Driver with Build-in Boost Regulator


  • Programmable switching frequency to achieve best efficiency and EMI performance
  • Drive up to 4 strings of LEDs with up to 12 LED per string
  • Minimum on time: 80ns typical
  • Adjustable over voltage protection
  • Low Rdson of internal boost switch: 220mohm
  • PWM dimming control: 0%~100%
  • Dimming Frequency: 100Hz~30kHz
  • +/-2% current matching among strings guaranteed for above 10% dimming level
  • Programmable LED current: up to 40mA per string. +/-3% accuracy
  • Internal softstart
  • Compact packages: QFN3x3-16

Typical Application


SY7704 develops a high efficiency boost regulator with four matching current source to drive up to four strings of white LEDs in the backlight applications of LCD panels.
The device operates over a wide input voltage range of 4V to 24V. SY7704 has adjustable switching frequency from 300kHz to 2MHz. The LED current can be programmed from 10mA to 40mA. SY7704 also integrates PWM dimming function for accurate LED current control.
The SY7704 is available in QFN3x3-16 package.


  • Monitor Panel Backlight
  • TV Panel Backlight