AL3158 (Not Recommended for new design)

Description

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 higher-current LEDs. Low external part counts (one 1µF flying capacitor and two 2.2µF capacitors at V_IN and V_OUT) make this part ideally suited for small, battery-powered applications. AL3158 enable inputs are used to enable, disable device and dim the LED current with a fixed DC current of 20mA. Each output of the AL3158 is equipped with built-in protection for V_OUT 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 V_IN 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.

Feature(s)

• V_IN Range: 2.7V to 5.5V
• Up to 93% Max Power Efficiency
• 1% Current Matching Accuracy Between Channels
• Drives up to 9 Channels of LEDs in 3 x 3-Channels combinations
• Versatile 3-wire logic decoding of °C current control
• Short circuit, Thermal and UVLO Protection

Application(s)

• Mobile Phone White LED Backlighting and Indicators
• RGB LED driving
• PDA White LED Backlighting
• Battery-operated Phone Main and Sub Screen White LED Backlighting