The general linear LED driver provides 360mA output current

Linear Technology Corporation (Linear Technology Corporation) launched inductorless, low noise, high efficiency LED driver LTC3220/-1, the device for cellular phone screen and other programmable lighting applications. The device provides 18 separate configurable LED current sources that are completely flexible when programming multiple screens. The display current is set by an accurate internal current reference. Universal current source can be controlled in a digital way, with independent dimming, brightness, flicker and gray control, can be programmed through a simple two wire I2C serial interface; LTC3220 and LTC3220-1 each has a unique I2C address. The 2.9V to 5.5V input voltage range of the LTC3220/-1 has been optimized for single-cell Li ion / polymer battery applications. Lithium ion battery (nominal value of 3.6V) drive, the efficiency of up to 91%, quiescent current as low as 500uA, to maximize the battery working hours. In addition, the slew rate limited switch reduces the conduction and radiation noise (EMI).

LTC3220/-1 multi mode charge pump operates at low noise and constant frequency, based on LED current source voltage optimization efficiency. The device is powered by the 1x mode and automatically switches to the boost mode (1.5x) when any of the start-up LED current sources are in fast differential pressure, and the subsequent voltage drop switches the device to the voltage doubler (2x) mode. The internal circuit prevents inrush current and excessive input noise when starting and mode switching. In addition, the device has short circuit and over temperature protection.

LTC3220/-1 uses ultra thin (0.55mm) 28 lead QFN (4mmx4mm) package, available from stock. The integrated circuit requires only 5 small capacitor LED power supply can be composed of tiny, complete and current controller solution. To buy 1000 units in bulk, each price of $2.35.

Performance summary:

* 18 20mA configurable universal current sources with 64 linear brightness control levels

Each current source can be independently controlled by two wire I2C interface ON/OFF, brightness level, flicker and gray

Multi mode (1x/1.5x/2x) low noise charge pump delivers up to 91% efficiency

Conversion limited switching to reduce conduction and radiated noise (EMI)

Total output current of up to 360mA

* 2.9V to 5.5V input voltage range for Li ion / polymer applications optimized

Internal current reference

A single reset pin is used for asynchronous shutdown and all data register reset

Provides two I2C addresses (LTC3220:0011100; LTC3220-1:0011101)

Automatic or forced mode switching

Internal soft start limits inrush current

Short circuit / overheat protection

Ultra thin (0.55mm) 4mmx4mmQFN-28 package

Source: Electronic Engineering album