The LT3591 is a high side LED current sense Li-Ion driver that can drive up to 10 white LEDs in series. The device only requires one external capacitor, has a high switching frequency and accurate LED dimming.
The LT3591 is a fixed‑frequency step‑up DC/DC converter designed to drive up to ten white LEDs from a 3 V supply. It features a high‑side current‑sense pin for one‑wire dimming, an integrated Schottky diode, and a low‑profile 8‑lead DFN package (3 mm × 2 mm). The device operates with a switching frequency of up to 1.2 MHz and provides true‑color PWM dimming over an 80:1 range.
Typical applications include cellular phones, PDAs, handheld computers, and digital cameras. The datasheet provides absolute maximum ratings, electrical characteristics, pin functions, recommended component selections, and detailed operation diagrams.
| Minimum Operating Voltage | 2.5 V |
|---|---|
| Maximum Operating Voltage | 12 V |
| Switching Frequency | 0.75 – 1.2 MHz |
| Maximum Duty Cycle | 92 % – 94 % |
| Switch Current Limit | 500 – 800 mA |
| Supply Current (typ) | 4 – 5 mA |
It can drive up to ten white LEDs in series.
A 22 µH inductor is recommended for most applications.
Pin 8 (CTRL) is the dimming and shutdown pin.
The device is supplied in an 8‑lead plastic DFN (3 mm × 2 mm) package.