RT8560GQW

RT8560 High Voltage 4 Channel LED Driver General Description Features zz z zz High Voltage : V up to 40V, V up to 60V, Driving IN OUT The RT8560 is a 60V 4-channel LED driver capable of up to 60 x 3.6V LEDs (15 each channel) delivering 30mA to each channel with 15 LEDs (3.6V per zz z zz Channel Current Programmabe 4mA to 30mA and diode) total 60 LEDs with one driver. The RT8560 is a Matched to 3% Accuracy current mode boost converter opearated at 1MHz switching zz z zz Current Mode PWM 1MHz Boost Converter frequency, wide V range covers from 7V to 40V and the IN zz z zz Easy Analog and Digital Dimming Control on-chip current switch is rated at 1.5A. zz z zz Programmable Soft Start The PWM output voltage loop selects and regulates the zz z zz Automatic Detecting Unconnected and/or Broken LED pin with the highest voltage string to 0.9V allowing Channel voltage mismatches between LED strings. The RT8560 zz z zz Programmable Over Voltage Protection automatically detects and disconnects any unconnected zz z zz Disconnects LED in Digital Dimming : Providing and/or broken strings during operation from PWM loop to High Accuracy Digital Dimming by PWM at ACTL prevent V from over voltage. OUT Pin or EN Pin The 3% matched LED currents on all channels are simply zz z zz V Under Voltage Lockout IN programmed with a resistor or a current sink. Both analog zz z zz Over Temperature Protection dimming and digitally controlled PWM dimming are zz z zz Current Limiting Protection supported by RT8560. Analog dimming is linearly zz z zz Small 20-Lead WQFN Package controlled by an external voltage. With an on-chip output zz z zz RoHS Compliant and Halogen Free clampping amplifier and a 200k resistor, PWM dimming signal is easily low-pass filtered to an analog dimming Applications signal with one external capacitor for noise-free PWM z UMPC and Notebook Computer Backlight dimming. A very high contrast ratio true digital PWM z GPS, Portable DVD Backlight dimming can be achieved by driving EN pin to PWM z Desk Lights and Room Lighting shutdown the chip or by driving ACTL pin. Ordering Information Other protecting features include programmable PWM RT8560 output over voltage protection, LED curren limit, PWM Package Type switch current limit and thermal shutdown. The RT8560 QW : WQFN-20L 4x4 (W-Type) is packaged with a tiny footprint package of WQFN-20L Lead Plating System 4x4 packages. G : Green (Halogen Free and Pb Free) Note : Pin Configurations Richtek products are : (TOP VIEW) RoHS compliant and compatible with the current require- ments of IPC/JEDEC J-STD-020. Suitable for use in SnPb or Pb-free soldering processes. 20 19 18 17 16 1 15 LED4 GND GND 2 14 VC Marking Information 13 GND 3 GND SS 4 12 OVP SW 21 For marking information, contact our sales representative 11 SW 5 EN 7 6 89 10 directly or through a Richtek distributor located in your area. WQFN-20L 4x4 DS8560-01 April 2011 www.richtek.com 1 GND VCC2 VCC1 GND LED1 RISET LED2 ACTL LED3 DCTLRT8560 Typical Application Circuit V IN C OUT3 7V to 40V 1F V OUT 60V MAX L 10H D C VIN 15 LED String 10F : : : : : : : : R C VCC1 C OUT1 OUT2 : : : : RT8560 10 C2 : : : : R4 4, 5 SW 18 7 LED1 VCC1 17 LED2 C R3 VCC1 1k 1F 16 11 LED3 5V EN 15 LED4 R1 12 V R OUT OVP ISET 5.36k I =LED 20mA 5.36k 8 R R2 ISET RISET R VCC2 R5 10 6 V VCC2 1k IN 9 ACTL C VCC2 PWM Signal 1F 10 DCTL 14 VC 1, 2, 3, 19, 20, Exposed Pad (21) 13 R GND VC SS 1.8k C1 C VC 0.1F 3.9nF Figure 1. 1MHz, 20mA Full Scale Current Digital PWM Dimming Control V IN C OUT3 7V to 40V 1F V OUT 60V MAX L 10H D C VIN 15 LED String 10F : : : : : : : : R C C VCC1 OUT1 OUT2 : : : : RT8560 10 : C2 : : : R4 4, 5 SW 18 7 LED1 VCC1 17 R3 LED2 C VCC1 1k 1F 11 16 LED3 5V EN 15 R1 LED4 12 V OUT OVP R ISET 5.36k I =LED 20mA 5.36k 8 R2 R ISET RISET R VCC2 10 6 V R5 IN VCC2 1k Analog 9 ACTL C VCC2 Dimming 1F 10 DCTL 14 VC 1, 2, 3, 19, 20, Exposed Pad (21) 13 GND R VC SS 1.8k C1 C VC 0.1F 3.9nF Figure 2. 1MHz, 20mA Full Scale Current Analog Dimming Control www.richtek.com DS8560-01 April 2011 2