TDA7382 Datasheet, PDF (8/10 Pages) STMicroelectronics – 4 x 22W FOUR BRIDGE CHANNELS CAR RADIO AMPLIFIER

TDA7382
signed in order to obtain a virtually pop-free tran-
sition has to be slower than 2.5V/ms.
CLIPPING DETECTOR
The CLIPPING DETECTOR acts in a way to out-
put a signal as soon as one or more outputs
reach or trespass a typical THD level of 10%.
As a result, the clipping-related signal at pin 25
takes the form of pulses, which are syncronized
with each single clipping event in the music pro-
gram. Applications making use of this facility
usually operate a filtering/integration of the pulses
train through passive R-C networks and realize a
volume (or tone bass) stepping down in associa-
tion with microprocessor-driven audioprocessors.
The maximum load that pin 25 can sustain is
Figure 12: Diagnostics circuit.
25
R
VREF
1KΩ.
Due to its operating principles, the clipping detec-
tor has to be viewed mainly as a power-depend-
ent feature rather than frequency-dependent.This
means that clipping state causing THD = 10%
typ. will be immediately signaled out whenever a
fixed power level is reached, regardless of the
audio frequency.
In other words, this feature offers the means to
counteract the extremely sound-damaging effects
of heavy clipping, caused by a sudden increase of
odd order harmonics and appearance of serious
intermodulation phenomena.
Figure 13: Clipping Detection Waveforms.
VO
AUDIO
O UTPUT
SIGNAL
Vpin 25
TDA7382
D97AU810
Figure 14: Diagnostics Waveforms.
ICLIP
0
CLIPPING
DET.
OUTPUT
CURR.
D97AU811
time
ST-BY PIN
VOLTAGE
t
MUTE PIN
VOLTAGE
t
Vs
OUTPUT
WAVEFORM
t
Vpin 25
WAVEFORM
8/10
CLIPPING
t
D97AU812A