DESCRIPTION

The PT6911 is ideally suited for AC/DC buck LED drivers. Since the PT6911 includes an 8V-450V linear regulator which allows it to work from a wide range of input voltages without the need for an external low voltage supply. Besides, the PT6911 operates in hysteretic control mode, the controller achieves good output current regulation without the need for any loop compensation. The PT6911 delivers constant current within high accuracy to a wide variety and number of series connected LEDs.

The PT6911 includes PWM dimming and linear dimming functions. The PWM dimming input can accept an external control signal with a duty cycle of 0~100% and a frequency between 100Hz and a few KHz. Output current to LED string can be programmed to any value between 0 to its maximum value by PWM dimming. Also, a 0~1.2V linear dimming input can be used for linear dimming of the LED current.

FEATURES

• 8V to 450V input range

• Hysteretic controller

• High accuracy output current

• Low stand-by power dissipation

• Soft start

• PWM low-frequency dimming and linear dimming

APPLICATIONS

• AC/DC LED driver

• Backlight LED driver

• Constant-Current driver