RT8491

® RT8491 High Voltage 6-CH LED Driver Controller General Description The RT8491 is a 6-CH LED driver controller that delivers well matched LED current to each channel of LED string. With external current sources, the number of LEDs per string is only limited by the current source and the VIN/ VOUT conditions. The current mode PWM boost type controller operates at a programmable switching frequency of up to 1MHz, with a wide VIN range covering from 9V to 32V. The switch driver is designed to drive industrial grade high power MOSFETs. The PWM loop selects and regulates the LED string with the highest voltage string to 0.9V, thus allowing voltage mismatches between the LED strings. The RT8491 automatically detects and excludes any open and/or broken strings during operation from the PWM loop to prevent VOUT from over voltage. The RT8491 also provides LED short protection. If LED short occurs and causes any LEDx but not all LEDx pin voltage greater than 8V, the CAP pin is charged up by internal 10μA. If the LED short condition lasts longer than the CAP pin voltage reaches 3.5V, the FLAG pin will go high and the GATE pin will be kept low immediately until the CAP pin voltage drops below 3.5V. The delay time is programmable by the capacitor at the CAP pin. Features  Wide Operation Voltage Range : 9V to 32V  Programmable Channel Current  3% Current Matching Accuracy between Channels  Programmable Switching Frequency  Easy Analog and Digital Dimming Control  Programmable Sof...