LP3950 Datasheet, PDF (1/38 Pages) National Semiconductor (TI) – Color LED Driver with Audio Synchronizer

LP3950
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SNVS331C – NOVEMBER 2004 – REVISED APRIL 2013
LP3950 Color LED Driver with Audio Synchronizer
Check for Samples: LP3950
FEATURES
1
•2 Audio Synchronization for Color LEDs with
Two Modes: Amplitude and Frequency
• Programmable Frequency and Amplitude
Response with Tracking Speed Control
• Automatic Gain Control or Selectable Gain for
Input Signal Optimization
• RGB Pattern Generator Similar to
LP3933/LP3936
• Magnetic DC-DC Boost Converter with
Programmable Boost Output Voltage
• Selectable SPI or I²C Compatible Interface
• One Pin Default Enable for Non-Serial Interface
Users. One Pin Selector for Synchronization
Mode
• Space Efficient 32-Pin TLGA Package
APPLICATIONS
• Cellular Phones
• MP3/CD/Minidisc Players
• Toys
DESCRIPTION
The LP3950 is a color LED driver with a built-in audio
synchronization feature for any analog audio input
such as polyphonic ring tones and MP3 music. LEDs
can be synchronized to an audio signal with two
methods - amplitude and frequency. Also several fine
tuning options are available for differentiation
purposes. The chip also has an unique AGC
(Automatic Gain Control) feature which tracks the
input signal level and automatically adjusts the gain
to an optimal value.
The LP3950 has a high efficiency magnetic DC/DC
converter with programmable output voltage and
switching frequency. The converter has high output
current capability so it is also able to drive flash LEDs
in camera phone applications.
The LP3950 is similar to LP3933 and LP3936 in that
the color LEDs (or RGB LEDs) can also be
programmed to generate light patterns
(programmable color, intensity, on/off timing, slope
and blinking cycle).
All functions are software controllable through a SPI
or I²C compatible interface but the device also
supports one pin control for enabling predefined
(default) audio synchronization mode.
Typical Application
2.8V
V_IN
C_VDD1
C_VDD2
C_VDDA
C_IN
L₁
4.7 PH
D₁
100 nF
100 nF
100 nF
10 PF
SINGLE-ENDED
AUDIO SIGNAL
DIFFERENTIAL
AUDIO SIGNAL
C₁
10 nF
C₂
10 nF
C₃
10 nF
4
MICROCONTROLLER
C_{VDD_IO}
100 nF
V_DD1
ASE
V_DD2
V_DDA
SW
FB
AD1
R1
G1
AD2
LP3950
SERIAL
INTERFACE
NRST
PWM_LED
IF_SEL
V_{DD_IO}
DME AMODE
B1
R2
G2
B2
RT
VREF
GNDs
R_R1
R_G1
R_B1
R_R2
R_G2
R_B2
R_T
82k
C_VREF
100 nF
C_OUT
10 PF
1
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2
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2004–2013, Texas Instruments Incorporated