RT8561D Datasheet | Richtek

® High Voltage 8-CH LED Driver General Description The RT8561Dis a 40V 8-CH LEDdriver capable of delivering 30m A to each channel with 10 LEDs (3.6V per diode), for a total of 80 LEDs per driver. The RT8561D is a currentmode Boost converter that operates at 1MHz, with a wide VIN range from 4.5V to 24V and an on chip current switch rated at 2.5A. The PWM output voltage loop regulates the LED pins to 0.6V with an auto adjustment circuit allowing voltage mismatches between LED strings. The RT8561D automatically detects and disconnects any unconnected and/or broken strings during operation from the PWM loop to prevent VOUT from over-voltage. The 1.5% matched LED currents on all channels can be simply adjustable with a resistor or a current sink. A very high contrast true digital PWM dimming can be achieved by driving the PWM pin with a PWM signal. Other protections including adjustable programmable output over-voltage protection, LED current limit, PWM switch current limit and thermal shutdown are provided. The RT8561D is available in the WQFN-24L 4x4 package. Features z High Voltage : VIN up to 24V, VOUT up to 40V z Adjustable Channel Current from 10m A to 30m A z 1.5% Channel Current Matching z Current-Mode PWM 1MHz Boost Converter z Easy and High Accuracy Digital Dimming by PWM Signal z Adjustable Soft-Start z Automatic Detection of Unconnected and/or Broken Channel z Adjustable Over-Voltage Protection z Disconnect Adjustable LED in Shutdown z No Power Sequence Concern z VIN Under-Voltage Lockout z Over-Temperature Protection z Current Limiting z Small 24-Lead WQFN Package z Ro HS pliant and Halogen Free Applications z UMPC and Notebook puter Backlight z GPS, Portable DVD Backlight z Desk Lights and Room Lighting Simplified Application Circuit VIN C1 R4 L1 RT8561D VCC C6 R5 5V EN LED1 PWM Signal R6 ACTL VC LED2 LED7 LED8 C8 R1 CREG C2 C3 SS RISET C4 GND ... ... VOUT...