The LTC3217 is a low noise charge pump DC/DC converter designed to power four high current LEDs. The LTC3217 requires only four small ceramic capacitors and two current set resistors to form a complete LED power supply and current controller. Built-in soft-start circuitry prevents excessive inrush current during start-up and mode changes. High switching frequency enables the use of small external capacitors. Independent high and low current settings are programmed by two external resistors. Shutdown mode and current output levels are selected via two logic inputs. The current through the LEDs is programmed via ISET1 and ISET2. In addition, the brightness can be controlled by pulse width modulation of the EN2 pin. The charge pump optimizes efficiency based on the voltage across the LED current sources. The part powers up in 1x mode and w
The LTC3217 is a charge‑pump DC/DC converter designed to power four high‑current LEDs for camera flash and multi‑LED lighting applications. It operates from a low input voltage and uses only four small ceramic capacitors and two programming resistors to provide a complete LED driver solution. The device features automatic mode switching (1x, 1.5x, 2x) to maintain efficiency as LED voltage drops, and includes built‑in soft‑start, over‑current, short‑circuit, and thermal protection.
The part is supplied in a 16‑lead 3 mm × 3 mm plastic QFN package and offers PWM brightness control via the EN2 pin, low shutdown current (4 µA), and a typical clock frequency of 0.85–1.415 MHz. Electrical characteristics such as operating voltage (2.9 V–4.5 V), total LED output current (up to 600 mA), and shutdown current are detailed in the datasheet.
| Operating Voltage | 2.9 V to 4.5 V |
|---|---|
| Total LED Output Current | Up to 600 mA |
| Shutdown Current | 4 µA |
| Package | 16‑lead 3 mm × 3 mm plastic QFN |
| Clock Frequency | 0.85 MHz to 1.415 MHz |
The LTC3217 can deliver up to 600 mA total across its four LED channels.
Brightness can be adjusted by PWM on the EN2 pin; the minimum pulse width is 50 µs and the maximum low time is 1 ms when EN1 is low.
The LTC3217 draws a low shutdown current of 4 µA.
It is supplied in a 16‑lead 3 mm × 3 mm plastic QFN package.