View Full Version : NEW Audio Synchronized Color LED Driver Chip LM-4970

Bruce Bates
06-07-2005, 12:03 AM
Stampers -

On numerous occasions we've seen Stamps used as programmable drivers for LEDs and LED arrays. There have also been Stampers who have used Stamps in audio applications in various ways. Also there have been Stampers who've used the Stamp in MIDI applications. Sometimes these applications are for display purposes, and others are more in the line of artistic endeavors. Regardless of the application or purpose, if you are interested in using an audio source to selectively drive an LED display (or individual LEDs) you may be interested in taking a look at a new chip that has just been announced by National Semiconductor. Here is a brief description, followed by a link to the National Semiconductor product page for the LM-4970:


The LM4970 is a LED driver with an audio synchronization mode that virtually eliminates the need for real time software processing for LED lighting effects. The LM4970 includes three individual PWM color LED drivers that provide up to 42mA of current drive for each PWM LED output.

The LM4970 features an audio synchronization mode where the audio input signal that is mixed in from three audio inputs is filtered into three frequency bands, with each frequency band assigned to a specific PWM LED driver. The PWM LED drivers can also be directly programmed through an I2C compatible interface for applications where user defined LED pattern, color, and intensity programmability is a priority.

The LM4970 also features an audio input gain control which allows the user to increase the gain if the audio input signal does not create a bright enough effect on the LEDs. The LM4970 is a feature rich LED driver that is available in a space saving 14 pin non-pullback LLP package.

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As noted: The LM4970 uses an I2C control interface, so it can be easily controlled by most Stamps.

Further information, and the datasheet can be found here:
иии http://www.national.com/pf/LM/LM4970.html

Forum administrators: Feel free to cross post this to the StampEFX forum or anywhere else where it might be appropriate.


Bruce Bates