NATIONAL Semiconductor, represented in Australia by Arrow Electronics , has released a Boomer audio-synchronized light emitting diode (LED) driver that does not require programming.
Previous designs required preprogrammed I2C-compatible code to control lighting patterns. The LM4970 gives designers the option of using I2C-compatible pattern control or choosing automatic audio-synchronised pattern generation. If the automatic mode is used, no software or memory storage is needed for pattern control, freeing up memory storage space for other features.
The I2C-compatible control bus is also used to turn each driver on or off, provide flexibility for controlling the brightness of the LED as well as the ability to change the high and mid-range frequency bands. The internal control features reduce the number of external components, optimising board space in small form factor applications such as mobile phones, MP3 players, PDAs and other portable devices.
The LM4970 is an audio-synchronised LED driver that eliminates the need for real-time software processing for LED lighting effects. The audio-synchronisation mode allows three audio inputs to be mixed and filtered into three frequency bands, with each frequency band assigned to a specific pulse width modulated (PWM) LED driver. It includes three individual PWM color LED drivers that provide up to 42mA of current drive for each LED output. The drivers can also be directly programmed through an I2C compatible interface for applications where user-defined LED pattern, colour, and intensity is required.
The LM4970 also has a brightness control that allows the user to set the intensity of each LED to the desired level. When used in portable systems with one of National's Boomer audio subsystems, such as the LM4857, users will experience high-quality stereo audio in 3D and lighting that moves with the music.