The AL3158 is a low noise, constant frequency charge pump
DC/DC converter that uses a Dual mode load switch (1x), and (2x)
conversion for white LED applications. The AL3158 is capable of
driving three groups of three LED channels at 20mA from a 2.7V to
5.5V input. The current sinks may be operated using three simple
PWM dimming inputs individually or in parallel for driving highercurrent
LEDs. Low external part counts (one 1μF flying capacitor
and two 2.2μF capacitors at VIN and VOUT) make this part ideally
suited for small, battery-powered applications.
AL3158 PWM dimming inputs are used to enable, disable device
and dimming LED current with a fixed default current settings at
20mA or other factory programming options available.
Each output of the AL3158 is equipped with built-in protection for
VOUT short circuit and auto-disable for LED short conditions. Built-in
soft-start circuitry prevents excessive inrush current during start-up
and mode switching. A low-current shutdown feature disconnects
the load from VIN to reduce quiescent current less than 1μA.
The AL3158 is available in a lead-free, space-saving, thermally
enhanced 20-pin 3 x 3mm QFN package.