The RT8561A is a 40V 8-CH LED driver capable of delivering 30mA to each channel with 10 LEDs (3.6V per diode), total of 80 LEDs with one driver. The RT8561A is a current mode boost converter operated at 1MHz, wide VIN range covers from 6V to 24V and the on-chip current switch is 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 RT8561A automati-cally detects and disconnects any unconnected and/or broken strings during operation from PWM loop to prevent VOUT from over voltage. The 1.5% matched LED currents on all channels are simply programmed with a resistor or a current sink. Both analog dimming and digitally controlled PWM dimming are supported by the RT8561A. Analog dimming is linearly controlled by an external voltage. With an on-chip output clamping amplifier and a 300kΩ resistor, PWM dimming signal is easily low-pass filtered to an analog dimming signal with one external capacitor for noise-free PWM dimming. A very high contrast ratio true digital PWM dimming can be achieved by driving ACTL pin with a PWM signal.Other protecting features include programmable output over voltage protection, LED current limit, PWM switch current limit and thermal shutdown.The RT8561A is packaged with a tiny footprint package of WQFN-24L 4x4 packages.
Applications
- UMPC and Notebook Computer Backlight
- GPS, Portable DVD Backlight
- Desk Lights and Room Lighting