High Efficiency Backlight LED Driver


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The RT4501/A is a high-efficiency LED driver for backlight applications. An asynchronous boost converter with an internal Schottky diode and a current source driver are designed to support 6LED/channel with wide input voltage range from 2.5V to 5.5V.

An I2C interface can provide easy backlight control in fast and high speed mode. The RT4501 supports linear mappings with 256 steps to setup the brightness of backlight LEDs. It also supports PWM dimming to adjust the brightness.

For brightness dimming, the RT4501A supports 128 steps pulse dimming which determines the LED current, and RT4501 support 256 steps PWM dimming which determines the LED current.

The RT4501/A provides complete protection functions such as input under-voltage lockout, over-current, output over-voltage and over-temperature protection. The OVP threshold voltage can be set at 16V and 25.5V for different applications. The RT4501/A is available in the
WL-CSP-10B 0.87x2.07 (BSC) package.


  • Cellular Phones
  • Digital Cameras
  • PDAs and Smart Phones
  • Portable Instruments
Key Spec.
RT4501 RT4501A
Status Active Active
Vin (min) (V) 2.5 2.5
Vin (max) (V) 5.5 5.5
Vout (max) (V) 25.5 25.5
LED Channels 2 2
Topology Boost + Current Source Boost + Current Source
SW Freq (typ) (kHz) 1100 1100
Dimming Control I2C;PWM I2C;Pulse
Features Adjustable Frequency;Backlight;Cycle-by-Cycle Current Limit;Enable Input;OVP;SCP;UVP Adjustable Frequency;Backlight;Cycle-by-Cycle Current Limit;Enable Input;OVP;SCP;UVP
Package Type WL-CSP0.87x2.07-10(BSC) WL-CSP0.87x2.07-10(BSC)
  • Input Voltage Range : 2.5V to 5.5V
  • Internal Schottky Diode
  • Fast-speed mode I2C Compatible Interface
  • Drive Up to 7 WLEDs in 2 String
  • External PWM/Pulse Brightness Control
  • 550k/1.1MHz Switching Frequency
  • Built-in Internal Soft-Start
  • PWM Dimming/Pulse Dimming Resolution 256/128 Steps
  • I2C Programmable 256 Steps Linear Current Regulation
  • Up to 85% Efficiency with Small Magnetics
  • Programmable 16V/25.5V OVP
  • Current Accuracy ±5% and Current Balance ±3%
  • UVLO, OVP, OCP, OTP Protection
  • Shutdown Current : < 1μA
  • Temperature Range : -40°C to 85°C
  • RoHS Compliant and Halogen Free
TitleLast UpdateShareDownload
High Efficiency Backlight LED Driver2015/04/29
Part NumberPackage TypePackage Qty.Free SampleBuy From Authorized Distributor
RT4501WSCWL-CSP0.87x2.07-10(BSC)3000 Not available Buy from Distributor