LP3952 Datasheet, PDF (20/46 Pages) National Semiconductor (TI) – 6-Channel Color LED Driver with Audio Synchronization

LP3952
SNVS518A – JULY 2007 – REVISED MARCH 2013
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EN_AVG
MODE_CTRL[1:0]
SPEED_CTRL[1:0]
Bit 4
Bits 3-2
Bits 1-0
Audio_sync_CTRL2 (2BH)
0 – averaging disabled (not applicable in audio sync mode)
1 – averaging enabled (not applicable in audio sync mode)
See below: Mode control
Sets the LEDs light response time to audio input.
[00] = FASTEST (default)
[01] = FAST
[10] = MEDIUM
[11] = SLOW
(For SLOW setting in amplitude mode f_MAX= 3.8 Hz,
Frequency mode f_MAX = 7.6 Hz)
MODE CONTROL IN FREQUENCY MODE (1.65V ≤ V_DDIO ≤ V_DD1,2V) (unless otherwise noted)
Mode control has two setups based on audio synchronization mode select: the frequency mode and the
amplitude mode. During the frequency mode user can select two filter options by MODE_CTRL as shown
below. User can select the filters based on the music type and light effect requirements. In the first mode the
frequency range extends to 8 kHz in the secont to 4 kHz.
The lowpass filter is used for the red, the bandpass filter for the blue and the hipass filter for the green LED.
Higher Frequency Mode
MODE_CTRL = 00 and SYNC_MODE = 1
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
0
BANDPASS
LOWPASS
HIPASS
1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0
kHz
Lower Frequency Mode
MODE_CTRL = 01 and SYNC_MODE = 1
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
0
BANDPASS
LOWPASS
HIPASS
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
kHz
MODE CONTROL IN AMPLITUDE MODE (1.65V ≤ V_DDIO ≤ V_DD1,2V) (unless otherwise noted)
During the amplitude synchronization mode user can select between three different amplitude mappings by
using MODE_CTRL select. These three mapping options give different light response. The modes are presented
in the following graphs.
20
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