AS3490 - ams

AS3490 Highly Efficient 2-6 LEDs Backlight Driver

The AS3490 is an inductive highly efficient DCDC boost converter. The DCDC converter operates at a fixed frequency of 2MHz and includes soft startup to allow easy integration into noise sensitive RF systems. A predictable startup is guaranteed even with very low duty cycle PWM input signals. The voltage on the output capacitor is controlled to minimize rippl.

Features

2 MHz DCDC Boost converter - Small 4.7µH external coil - Very high system efficiency of 86% (DCDC and current sources combined) - Very low voltage changes on output to avoid acoustic noise on output capacitor even with PWM - Smooth startup even under low duty cycle PWM conditions
Three Current sources up to 25mA - Low voltage compliance (150mV) - High side current source to simplify layout and thermal management of the LEDs - Automatically detect and disable failing or not used LEDs to keep efficiency high - Current matching <4% - Current accuracy <7.5%
Excellent LED current output rippl.