43V Asynchronous Boost WLED Driver


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The RT8511B is an LED driver IC that can support up to 10 WLED in series. It is composed of a current mode boost converter integrated with a 43V/2.2A power switch running at a fixed 500kHz frequency and covering a wide VIN range from 2.7V to 24V.

The white LED current is set with an external resistor, and the feedback voltage is regulated to 200mV (typ.). During operation, the LED current can be controlled by the PWM input signal in which the duty cycle determines the feedback reference voltage.

For brightness dimming, the RT8511B is able to maintain steady control of the LED current. Therefore, no audible noises are generated on the output capacitor. The RT8511B also has programmable over voltage pin to prevent the output from exceeding absolute maximum ratings during open LED conditions. The RT8511B is available in WDFN-8L 2x2 package.


Key Spec.
Status Active
Vin (min) (V) 2.7
Vin (max) (V) 24
SW Freq (typ) (kHz) 500
Number of LEDs (max) (pcs) 10
Iq (typ) (mA) 0.725
Dimming Control PWM
Topology Boost
Features Cycle-by-Cycle Current Limit;OCP;OVP
Package Type WDFN2x2-8
  • Wide Input Voltage Range : 2.7V to 24V
  • High Output Voltage : up to 43V
  • Direct PWM Dimming Control and Frequency from 100Hz to 8kHz
  • Internal Soft-Start and Compensation
  • 200mV Reference Voltage
  • PWM Dimming with Internal Filter
  • Programmable Over Voltage Protection
  • Over Temperature Protection
  • Current Limit Protection
  • Thin 8-Lead WDFN Package
  • RoHS Compliant and Halogen Free
TitleLast UpdateShareDownload
43V Asynchronous Boost WLED Driver2015/05/19
Technical Documents
TitleLast UpdateShareDownload
Power IC Solutions for IoT/Portable/Wearable/Battery-Powered Applications2020/12/30
Richtek Selection Guide [Oct., 2020]2020/12/30
Part NumberPackage TypePackage Qty.Free SampleBuy From Authorized Distributor
RT8511BGQWWDFN2x2-82500 Not available Buy from Distributor