4-String White LED Driver with Boost Regulator


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The RT8575 is a high efficiency LED driver with 40V I/O support. It is designed for LCD panel that employs an array of LEDs as the lighting source. An integrated switch current mode Boost controller drives four strings in parallel and supports up to 18 pieces of LEDs per string. The internal current sinks support typical ±1% current mismatching 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 RT8575 has a wide input voltage operating range from 4.2V to 24V and provides adjustable 50mA to 150mA LED current. The internal 150mΩ, 60V power switch with current-mode control provides cycle-by-cycle over current protection. RT8575 also integrates PWM dimming function for accurate LED current control. The input PWM dimming frequency can operate from 120Hz to 1kHz without inducing any inrush current in LEDs or inductor. The switching frequency of RT8575 is adjustable from 150kHz to 500kHz, which allows the trade-off between efficiency and component size.

The RT8575 is available in WDFN-16L 5x5 and DIP-16 (BW) packages to achieve optimized solution for PCB space.


  • White LED Backlighting
Key Spec.
Status Active
Vin (min) (V) 4.2
Vin (max) (V) 24
SW Freq (typ) (kHz) 280
Number of LEDs (max) (pcs) 18
Iout (max)/channel (mA) 600
Iq (typ) (mA) 3.3
Dimming Control PWM
Topology Boost
Features Adjustable Frequency;Current Mode Control;Cycle-by-Cycle Current Limit;Enable Input;OCP;OVP;Stable with Ceramic Capacitor;UVP
Package Type WDFN5x5-16
  • Input Operating Voltage Range 4.2V to 24V
  • 60V Maximum Output Voltage
  • Adjustable Switching Frequency : 150kHz to 500kHz
  • Support Up to 4 LED Strings
  • 50mA to 150mA LED Current Per Channel
  • 1% Typical LED Current Accuracy
  • 1% Typical LED Current Matching
  • Programmable Over Voltage Protection
  • Built-in Soft-Start, OTP
  • LED Short/Open Detection
  • RoHS Compliant and Halogen Free
TitleLast UpdateShareDownload
4-String White LED Driver with Boost Regulator2013/09/11
Title Last Update ShareDownload
4-String White LED Driver with Boost Regulator 2015/05/19
Technical Documents
TitleLast UpdateShareDownload
Richtek Selection Guide [Oct., 2020]2020/12/30
Part NumberPackage TypePackage Qty.Free SampleBuy From Authorized Distributor
RT8575GQWWDFN5x5-161500 Not available Buy from Distributor