The RT8560 is a 60V 4-channel LED driver capable of delivering 30mA to each channel with 15 LEDs (3.6V per diode) total 60 LEDs with one driver. The RT8560 is a current mode boost converter opearated at 1MHz switching frequency, wide VIN range covers from 7V to 40V and the on-chip current switch is rated at 1.5A.The PWM output voltage loop selects and regulates the LED pin with the highest voltage string to 0.9V allowing voltage mismatches between LED strings. The RT8560 automatically detects and disconnects any unconnected and/or broken strings during operation from PWM loop to prevent VOUT from over voltage. The 3% 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 RT8560. Analog dimming is linearly controlled by an external voltage. With an on-chip output clampping amplifier and a 200kΩ 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 EN pin to PWM shutdown the chip or by driving ACTL pin.Other protecting features include programmable PWM output over voltage protection, LED curren limit, PWM switch current limit and thermal shutdown. The RT8560 is packaged with a tiny footprint package of WQFN-20L 4x4 packages.
Applications
- UMPC and Notebook Computer Backlight
- GPS, Portable DVD Backlight
- Desk Lights and Room Lighting