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

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Description

KTZ8868 is the ideal power solution for LED backlighting and LCD bias power of medium size panels. It integrates a step-up converter 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 a smaller inductor and capacitor. Its input operating range is from 2.7V to 5.5V, accommodating 1-cell lithium-ion batteries or 5V supply.

The LED driver’s eight regulated current sinks can regulate up to 30mA with its maximum boost output voltage up to 40V. 11-bit linear or exponential 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 KTZ8868 maximizes conversion efficiency up to 85%.

Various protection features are built into KTZ8868, including inductor current limit protection, output short circuit protection, output over-voltage protection, LED fault (open or short) protection and thermal shutdown protection.

KTZ8868 is equipped with I2C interface for various controls and status monitor.

KTZ8868 is available in a RoHS and Green compliant WQFN55-32L (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 in backlight mode
      • ±0.7% current matching at 20mA
      • ±2.2% current accuracy at 20mA
    • I2C/PWM dual dimming control scheme
      • High resolution I2C 11-bit linear or exponential dimming
      • Wide range PWM dimming.
        • 100Hz to 100kHz frequency
        • 0.2% to 100% duty cycle at 20kHz
    • Programmable current sink turns 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 limitation
    • LED open/short protection
  • 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 200mA at VIN ≥ 2.9 V.
    • Active output discharge function
    • Current limitation and short protection
  • Others
    • System level input UVLO
    • Thermal shutdown protection
    • Low shutdown current <1µA
    • Flexible I2C interface
    • Pb-free Packages:
    • WQFN55-32L (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 Bumps Package Code
WQFN55-32L 5.00mm x 5.00mm x 0.75mm 32 UAD

Parameters

VCC VGD (Max) Bus Voltage (Max) ADC (bit) Control Interface Control Topology Operating Temperature Package
3.0~5.0V 18V 100V 12 I2C PWM Analog Sensorless FOC -40°C to 125°C WQFN88-72

Technical Documentation

Description Documents Type
DatasheetKTZ8868-04aPDF

Purchase

Part Number Marking Operating Temperature Package
KTZ8868EUAD-TR KTZ8868
aaaaaaaa
-40°C to +85°C WQFN55-32

Purchase Options Coming Soon