AL3050 SMALL PANEL BACKLIGHT LED DRIVER Description Pin Assignments The AL3050 is a current mode Boost-type LED driver with programmable brightness dimming control for portable devices. With (Top View) a 30V rated integrated MOSFET and power diode, the AL3050 can support up to 8 LEDs in series. The small solution size, advanced SW dimming features and high efficiency are suitable for LED backlight 1 6 CTRL solutions for single cell Li-ion based equipment. The boost converter Thermal runs at 750kHz fixed switching frequency to reduce output ripple, 2 5 GND VIN Pad improve conversion efficiency, and allows for the use of small external components. 4 FB 3 VOUT The default LED current is adjustable by an external resister at FB pin and the feedback voltage is regulated to 200mV typically. The U-DFN2020-6 (Type S) AL3050 provides PWM dimming mode and single wire digital dimming mode for accurate LED current control from CTRL pin. In PWM dimming mode, the feedback reference voltage is changed with the Applications PWM duty cycle proportionally and the available PWM frequency Feature Phones range is from 20kHz to 100kHz. In single wire digital dimming mode, it Smart Phones provides a programmable 32-step brightness dimming function with Portable Media Players the CTRL pin setting. Ultra Mobile Devices GPS Receivers The AL3050 provides protection functions including Under Voltage Backlight for Small and Media Form Factor LCD Display Lockout, Over Voltage Protection, Over Current Protection and Over Temperature Protection to protect the circuit. The AL3050 is available in U-DFN2020-6 (Type S) packages. Features 2.7V to 5.5V Input Voltage Range 28V Open LED Protection (Up to 8 LEDs) Integrated 0.7A/30V Internal MOSFET and Power Diode 200mV Reference with 3% Accuracy 750kHz Switching Frequency Flexible Digital and PWM Brightness Control Single Wire Control Interface PWM Dimming Control Interface Up to 100:1 PWM Dimming Ratio Integrated Loop Compensation Built-in Soft-Start Built-in OTP Built-in OCP Tiny Package with U-DFN2020-6 (Type S) Package Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2) Halogen and Antimony Free. Green Device (Note 3) Notes: 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant. 2. See AL3050 Typical Applications Circuit L 2.7V to 5.5V 22H Up to 8 LEDs V BAT C C OUT IN 1F 2.2F VIN SW PWM or single wire VOUT CTRL Dimming Control GND FB R FB 10 W Pin Descriptions Pin Number Pin Name Function Control pin of the boost converter. It is a multi-functional pin which can be used for enable control, PWM and 1 CTRL digital dimming. Supply input pin. A capacitor should be connected between the VIN pin and GND pin to keep the DC input 2 VIN voltage constant. 3 VOUT Output of the boost converter. 4 FB Feedback pin for current. Connect a resistor between this pin and GND to set the current. 5 GND Ground. 6 SW This is the switching node of the IC. Connect the inductor between the VIN and SW pin. The thermal pad should be soldered to the analog ground plane. If possible, use thermal via to connect to - Thermal Pad ground plane for ideal power dissipation. Functional Block Diagram VIN SW VOUT UVLO Gate Driver Control OVP Detection Ramp OSC Generator + Current + + Sensor Comp - - Soft - FB Error Start-up Amp V REF + GND PWM & EasyScale CTRL Reference Control 2 of 16 AL3050 July 2016 Diodes Incorporated www.diodes.com Document number: DS38578 Rev. 2 - 2 AL3050