High Efficiency 8-CH LED Backlight Driver with Dual LCD Bias Power

Description

KTZ8869 is the ideal power solution for LED backlighting and LCD bias power of medium size panels. It integrates two step-up converters for LED backlighting, a step-up converter with LDO and inverting charge pump for LCD bias power, resulting in a simpler and smaller solution with fewer external components. High switching frequency allows the use of smaller inductors and capacitors. Its input operating range is from 2.7V to 5.5V, accommodating 1-cell lithium-ion batteries or 5V supply.

The LED driver has two step-up converters, and each converter drive four current sinks with total eight current sinks. Each current sink can regulate up to 30mA/32.4mA with its maximum boost output voltage up to 40V. 12-bit linear or Gamma 2.2 ILED resolution can be obtained over I2C or PWM dimming. For additional flexibility, PWM dimming offers wide range frequency and duty cycle to support Content Adaptive Brightness Control (CABC).

The LCD bias power section includes a step-up converter, LDO and an inverting charge pump to generate dual outputs, OUTP and OUTN, whose voltages can be programmed via an I2C interface. By integrating synchronous rectification MOSFETs for the step-up converter and charge pump, the KTZ8869 maximizes conversion efficiency up to 85%.

Various protection features are built into KTZ8869, including inductor current limit protection, output short circuit protection, output over-voltage protection, LED fault (open or short) protection and thermal shutdown protection.

KTZ8869 is equipped with I2C interface for various controls and status monitor.

KTZ8869 is available in RoHS and Green compliant WQFN55-32 (5mm x 5mm, 32 Lead).

Features

  • Backlight LED Driver
    • Wide input range: 2.7V~5.5V
    • High efficiency step-up LED driver with 8-Ch current sinks, up to 40V boost voltage.
      • Up to 30mA/Ch or 32.4mA/Ch
      • ±1.2% current matching at 20mA
      • ±2.2% current accuracy at 20mA
    • I2C/PWM dual dimming control scheme
      • High resolution I2C 12-bit linear or Gamma 2.2 dimming
      • Wide range PWM dimming.
        • 100Hz to 100kHz frequency
        • 0.2% to 100% duty cycle at 20kHz
    • Programmable current sink turn on/off ramp time/shape and transition ramp up/down time.
    • 1.0MHz typical boost switching frequency
    • Programmable input PWM hysteresis to minimize jitter at low PWM duty cycle.
    • Programmable OVP and current limit
    • LED open/short protection
    • Optional external PMOS control to isolate boost output from input during shutdown
  • LCD Panel Bias
    • Wide input range: 2.7V~5.5V
    • Programmable dual output Bias regulator using a single inductor.
    • Programmable ramp time for OUTP and OUTN
    • Charge pump PFM mode at light load
    • LCD Bias efficiency: up to 85%
    • Wide dual output voltage range ±4.0V to ±6.3V (50mV/step) and output current up to 300mA at VIN ≥ 3.2V and VHR_LCD=0.5V
    • Active output discharge function
    • Current limit and short protection
  • Others
    • System level input UVLO
    • Thermal shutdown protection
    • Low shutdown current <1µA
    • Flexible I2C interface
    • Pb-free Packages:
    • WQFN55-32 (5mm x 5mm, 32 Lead)
    • RoHS and Green Compliant
  • -40°C to +85°C Temperature Range

Applications

  • Tablet Backlight and Bias

Packaging Information

Package Dimensions Package Code
WQFN55-32 5.00mm x 5.00mm x 0.75mm UAD

Technical Documentation

Description Documents Type
DatasheetKTZ8869-04aPDF
Package Outline DrawingWQFN55-32 UAD PODPDF

Purchase

Purchase Options
Buy from Digi-Key
Buy from Mouser