RT8543
RT8543 is 6-String 43V White LED Driver manufactured by Richtek.
Description
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 5m A to 50m A 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 20k Hz without inducing any inrush current in LED or inductor.
The RT8543 is available in thin WQFN-20L 4x4 and UQFN20L 4x4 packages.
Applications
- UMPC and Notebook puter Backlight
Features
- Wide Input Voltage : VIN 2.5V to 24V
- High Output Voltage : VOUT up to 43V
- Current Mode Boost Regulator
600k Hz to 1.2MHz Switching Frequency Up to 85% High Frequency
- Adjustable Full Channel Current from 5m A to 50m A and Matched to 2%
- Channel Current Regulation with ±3% Accuracy
- Dimming Controls Direct PWM Dimming up to 20k Hz and Minimum On-Time to 500ns PWM to Analog Dimming up to 20k Hz 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
- Ro HS pliant and Halogen Free
Simplified Application Circuit
L1
D1
Enable
LX VIN EN RT8543 OVP
PWM Signal
CC RP CP
RISET
RFSW
ISET...
