The RT8543 is a high efficiency white LED driver. It is designed for LCD panel that employs an LED array as the lighting source. An integrated switch current mode Boost controller drives six strings in parallel and supports up to 10 pieces of LEDs per string. The internal current sinks support maximum ±2% current matching for excellent brightness uniformity in each LED string. To provide enough headroom for the operating of current sink, Boost controller monitors the minimum voltage of feedback pins and regulates an optimized output voltage for power efficiency.

The RT8543 has wide input voltage range from 2.5V to 24V and provides adjustable 5mA to 50mA LED current. The internal 200mΩ, 43V power switch with current-mode control provides cycle-by-cycle over-current protection. The RT8543 also integrates PWM and analog dimming functions for accurate LED current control. The input PWM dimming frequency can operate from 100Hz to 20kHz without inducing any inrush current in LED or inductor.

The RT8543 is available in thin WQFN-20L 4x4 and UQFN-20L 4x4 packages.

应用

UMPC and Notebook Computer Backlight

关键特性

Wide Input Voltage : VIN 2.5V to 24V

High Output Voltage : VOUT up to 43V

Current Mode Boost Regulator

600kHz to 1.2MHz Switching Frequency

Up to 85% High Frequency

Adjustable Full Channel Current from 5mA to 50mA and Matched to 2%

Channel Current Regulation with ±3% Accuracy

Dimming Controls

Direct PWM Dimming up to 20kHz and Minimum On-Time to 500ns

PWM to Analog Dimming up to 20kHz with 8 bit resolution

Built-In Soft-Start to Prevent Inrush Current without External Capacitor

Disconnects LED in Shutdown

Protection

Strings Open Detection

Current Limit Protection

Adjustable Over-Voltage Protection

Over-Temperature Protection

20-Lead WQFN and UQFN Package

RoHS Compliant and Halogen Free