DATASHEET
ISL97635A FN6564
Rev.3.00
Sep 26, 2017 SMBus 6-Channel LED Driver
The ISL97635A is a digitally controlled LED driver that controls
6 channels of LED current for LCD backlight applications. The
ISL97635A is capable of driving typically 54 (6x9) pieces of
3.5V/30mA or 60 (6x10) pieces of 3.2V/20mA LEDs. The
ISL97635A contains 6 channels of voltage controlled current
sources with typical currents matching of В±1%, which
compensate for the non-uniformity effect of forward voltages
variance in the LED stacks. To minimize the voltage headroom
and power loss in the typical multi-strings operation, the
ISL97635A features a dynamic headroom control that
monitors the highest LED forward voltage string and uses its
feedback signal for output regulation.
The LED dimming control can be achieved through a SMBus,
an external PWM, or a variable DC (analog light sensor) input.
SMBus controlled dimming allows 256 levels each of PWM
and DC current adjustments. The SMBus PWM dimming
frequency can be adjusted from 100Hz to 5kHz by an external
capacitor. External PWM input allows up to 20kHz audio noise
free PWM dimming. The SMBus PWM setting and an external …