Tiny High Efficiency White LED Driver with Integrated Schottky Drives up to 10 LEDs

Mar 6 2007 - MILPITAS, CA
  • Linear Technology announces the LT3591, a high efficiency, constant current white LED driver packaged in a 2mm × 3mm DFN package. The LT3591 features an integrated Schottky diode on chip, eliminating both the added cost and space required by an external diode. A unique high-side LED current sense topology enables the LED cathode to be connected directly to ground, creating a single wire current source. The LT3591 is designed to drive up to 10 white LEDs from a single Li-Ion cell at efficiencies over 78%. It switches at 1MHz, allowing the use of a tiny inductor and capacitors while keeping switching noise out of critical RF frequency bands. The combination of the LT3591's high efficiency, low noise and extremely small total solution footprint makes it ideal for handheld applications requiring up to 10 white LEDs for backlighting.

    The LT3591 ensures uniform LED brightness by acting as a constant current source, delivering the same current to each white LED, regardless of fluctuations in the LED's forward voltage drop, which varies with temperature, manufacturing tolerances and age. The LT3591 also utilizes True Color PWM dimming to offer a wide dimming range of up to 80:1. Additional features include output voltage limiting when LEDs are disconnected and ±5% reference accuracy.

    The LT3591 is available from stock in an 8-lead 2mm × 3mm DFN package. Pricing starts at $1.40 each for 1,000-piece quantities.


    Summary of Features: LT3591

    • Drives Up to 10 White LEDs from a 3V Supply
    • High-Side Sense Allows "One Wire Current Source"
    • Internal Schottky Diode 
    • One Pin Dimming and Shutdown
    • 80:1 True Color PWM Dimming Range
    • 42V Open LED Protection
    • 1MHz Switching Frequency
    • ±5% Reference Accuracy
    • VIN Range: 2.5V to 12V
    • Low Profile 8-Lead DFN Package (3mm × 2mm × 0.75mm)

    Tiny LED Driver with Integrated Schottky Drives up to 10 White LEDs

     

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