The A8435, a high-efficiency charge-pump white LED driver IC, has its sights set on portable electronics display applications. Crafted by Allegro MicroSystems Europe, the chip uses a proprietary 1×/1.5× control scheme to match up to four output currents to within 0.5% LED.
A low 1× /1.5× transition voltage threshold maintains optimum operation in the 1× mode for higher overall efficiency, helping to prolong the operating life of the lithium-ion batteries typically used in these applications. The A8435 operates over an input range of 2.7 V to 5.5 V, and delivers up to 30 mA for each of the four regulated current sources.
It can supply a total output current of 120 mA, meeting the requirements of most lithium-ion-powered, white LED backlight applications. Outputs can also be combined for flash or torch applications.
The device offers flexible options for LED-current driving. The LED current can be set by one of four different methods: choosing an appropriate setting-resistance value; two-bit parallel control with three levels; PWM control; or one-wire serial pulse input to enable the part and set up to 11 dimming levels from 100% down to 5%.