LM4970

Audio Synchronized Color LED Driver

General Description

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 I

user defined LED pattern, color, and intensity programmabil-

ity 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.

Key Specifications

V

42mA (2X setting)

1.5µA (typ)

Features

n

Audio synchronized color LED driver

n

User defined LED pattern, color, and intensity capability

n

Programmable:

LED Drive current

PWM frequency

High pass filter frequency select

Audio input signal gain

n

Eliminates external LED current limiting resistors

n

I

n

Ultra low shutdown current

Applications

n

Cell Phones

n

Portable MP3, CD, DVD, AAC players

n

PDA’s

Block Diagram

20121201

FIGURE 1. Block Diagram

February 2005

© 2005 National Semiconductor Corporation

DS201212

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