RT8511AGQW Richtek

RT8511A 43V Asynchronous Boost WLED Driver General Description Features zz z zz Wide Input Voltage Range : 2.7V to 24V The RT8511A is an LED driver IC that can support up to 10 zz z zz High Output Voltage : up to 43V WLED in series. It is composed of a current mode boost zz z zz Direct PWM Dimming Control and Frequency from converter integrated with a 43V/1.2A power switch running 100Hz to 100kHz at a fixed 1MHz frequency and covering a wide VIN range zz z zz Internal Soft -Start and Compensation from 2.7V to 24V. zz z zz 200mV Reference Voltage The white LED current is set with an external resistor, and zz z zz PWM Dimming with Internal Filter the feedback voltage is regulated to 200mV (typ.). During zz z zz Programmable Over Voltage Protection operation, the LED current can be controlled by the PWM zz z zz Over Temperature Protection input signal in which the duty cycle determines the zz z zz Current Limit Protection feedback reference voltage. zz z zz Thin 8-Lead 2x2 and 8-Lead 3x3 WDFN Packages For brightness dimming, the RT8511A is able to maintain zz z zz RoHS Compliant and Halogen Free steady control of the LED current. Therefore, no audible noises are generated on the output capacitor. The RT8511A Applications also has programmable over voltage pin to prevent the z UMPC and Notebook Computer Backlight output from exceeding absolute maximum ratings during z GPS, Portable DVD Backlight open LED conditions. The RT8511A is available in WDFN-8L 2x2 and WDFN-8L 3x3 packages. Pin Configurations (TOP VIEW) Ordering Information RT8511A OVP 1 8 EN Package Type FB 2 7 PWM 3 6 DIMC VIN QW : WDFN-8L 2x2 (W-Type) 4 9 5 LX GND QWA : WDFN-8L 3x3 (W-Type) Lead Plating System WDFN-8L 2x2 / WDFN-8L 3x3 G : Green (Halogen Free and Pb Free) Note : Marking Information Richtek products are : RoHS compliant and compatible with the current require- RT8511AGQW 14 : Product Code ments of IPC/JEDEC J-STD-020. W : Date Code Suitable for use in SnPb or Pb-free soldering processes. 14W RT8511AGQWA 22= : Product Code YMDNN : Date Code 22=YM DNN Copyright 2013 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. DS8511A-04 August 2013 www.richtek.com 1 GNDRT8511A Typical Application Circuit V L OUT 10H D V IN 4.2V to 24V RT8511A R2 6 5 : : : 3.3M VIN LX : : : WLEDs C IN : : : C OUT 1F x 2 1 : : : OVP 1F x 2 Chip Enable 8 R1 EN 100k 2 FB PWM 7 PWM R 100Hz to 100kHz SET 4, 9 (Exposed Pad) 3 GND 3.3 DIMC C DIMC 1F Figure 1. Typical Application Circuit of Normal Operation V OUT L 10H D V LED 2.7V to 24V C LED 1F x 2 RT8511A R2 5 : : : 3.3M LX 6 V IN : : : WLEDs VIN : : : 2.7V to 4.2V C C IN OUT 1 : : : 1F OVP 1F x 2 Chip Enable 8 R1 EN 100k 2 FB 7 PWM PWM R 100Hz to 100kHz SET 4, 9 (Exposed Pad) 3 DIMC GND 3.3 C DIMC 1F Figure 2. Typical Application Circuit of Low Voltage Operation Functional Pin Description Pin No. Pin Name Pin Function 1 OVP Over Voltage Protection for Boost Converter. The detecting threshold is 1.2V. Feedback Pin. Connect a resistor between this pin and GND to set the LED 2 FB current. 3 DIMC PWM Filter Pin. Filter the PWM signal to a DC voltage. 4 GND Ground Pin. 5 LX Switch Node for Boost Converter. 6 VIN Power Supply Input. 7 PWM Dimming Control Input. 8 EN Chip Enable (Active High) for Boost Converter. The exposed pad must be soldered to a large PCB and connected to AGND for 9 (Exposed Pad) GND maximum power dissipation. Copyright 2013 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. www.richtek.com DS8511A-04 August 2013 2