Austria Micro Systems always has some really interesting new chips that they manufacture. This one is an all-in-one breathing LED driver chip with I2C (for pattern generation) and audio-sync in.
The AS3668 is a 4-channel LED driver designed to produce lighting effects for portable devices. A highly efficient charge pump enables LED driving over full Li-Ion battery voltage range. The device is equipped with an internal program memory, which allows control of LED patterns even without processor control. This helps the whole system to save power and extend for example battery life time in every mobile application. The AS3668 maintains excellent efficiency over a wide operating range by automatically selecting the best charge pump gain based on the LED forward voltage requirements and the device input voltage. Furthermore the chip supports an automatic power-save mode which gets active when LED outputs are not active. The special powersave mode has a extremely low current consumption below 10µA.
The AS3668 has an I2C-compatible control interface which supports two slave address without having a dedicated address selection pin. For fancy lighting effects synchronized with an audio signal the device supports special digital filter modes in order to make music literally visible on the 4 independent configurable current sources.