The new Linear inductorless mobile phone LED/CAM driver

(Linear Technology Corporation) technology company recently launched inductorless, low noise, high efficiency LED/CAM driver LTC3207, the device for cellular phone displays and lighting. The LTC3207 provides 12 individually configurable current sources for primary, secondary, RGB, auxiliary or general purpose (GPO) display / Lighting / output, which also has the ability to drive a 400mA high current LED camera lamp. The universal current source has a digital controller with independent dimming, brightness, flash and gray level control functions, which can be set by a simple two wire I2C serial interface. The camera flash (pulse) or flashlight (continuous) current level can be selected in real time via the CAMHL pin and can be controlled via the I2C port. The 2.9V to 5.5V input voltage range of the LTC3207 has been optimized for single-cell Li ion / polymer battery applications. When the lithium ion battery (nominal value of 3.6V) is driven, the efficiency is 92%, and the quiescent current is only 500uA, so as to prolong the working time of the battery. Slew rate limited switching operation reduces conduction and radiated noise (EMI).

Multi mode charge pump LTC3207 with low noise constant frequency operation, automatic optimization based on VIN and LED positive voltage. The device is powered up in the 1x mode and automatically switches to the boost (1.5x) mode when either of the enabled LED current sources is in the state of a voltage drop, and the subsequent voltage drop switches the device to the voltage doubler (2x) mode. The internal circuit prevents inrush current and excessive input noise during start-up and mode switching. In addition, the device also has short circuit protection and thermal protection function.

By LTC3207 (4mm x QFN flat 24 lead 4mm package), off the shelf. The integrated circuit requires only 5 small capacitors, LED power supply can be composed of tiny, complete and current controller solution. In 1000 pieces for the bulk purchase, each price starts at $1.95.

LTC3207 performance overview:

Multi mode 1x/1.5x/2x charge pump delivers up to 92% efficiency

Transfer rate limited switching operations reduce conduction and radiated noise (EMI)

Total output current up to 600mA

12 independently configurable 28mA current sources with 64 linear brightness control stages

400mA CAM LED current source with 16 stage linear brightness control and a two second high current safety timer

Using two wire I2C interface for each current source for independent on / off, brightness, flicker and gray control

Automatic or manual mode switching

Low noise, constant frequency operation

Internal soft start limits inrush current

Short circuit protection

2.9V to 5.5V input voltage range

Flat 4mm 4mm x QFN-24 x package (0.75mm)