HT7943 -- White LED Backlight Driver

General Description

The HT7943 is a high efficiency DC-DC controller for driving a number of WLEDs connected both in series and parallel configurations. The device has a wide input voltage range from 4.5V to 26V and an adjustable 15mA to 30mA WLED current, setup using an external resistor. In total, the device can drive up to 66 WLEDs.

In addition, six current sink regulators provide ±1.5% high precision current matching between strings. Brightness can be adjusted by an external PWM signal up to 20kHz. If an open/short string is detected, the string is disabled while the other strings operate normally.

Other protection features include soft-start, under voltage lockout, programmable over voltage protection, switch current limit and thermal shutdown.

The device is supplied in a tiny 20-pin 4mm x 4mm QFN package.

Features

  • Max input voltage: 26V
  • Integrated Power Mosfet
  • Output voltage up to 40V driving 11 series
    LEDs – LED Vf(max)=3.5V per string – absolute max rating up to 44V
  • Channel Phase Shift PWM Dimming
  • Drives up to 12 LED strings under Vf(max)=3.3V condition
  • Low string feedback voltage: 0.8V at 20mA LED current
  • Switching frequency: 500kHz/1MHz
  • 6-string constant current output
  • LED current adjustable from 15mA to 30mA
  • ±1.5% current matching between strings
  • PWM dimming control
  • 1% minimum dimming duty-cycle at 2kHz
  • Integrated soft start function
  • LED failure detection: open and short circuit
  • Capacitor type: ceramic
  • Protection: OVP, OTP, UVLO, SW current limit
  • Small 20-pin outline package: 4mm x 4mm,
    thin QFN type

Technical Document

Other Information