TDA7360 Datasheet, PDF (9/22 Pages) STMicroelectronics – 22W BRIDGE / STEREO AUDIO AMPLIFIER WITH CLIPPING DETECTOR

Figure 21: Power Dissipation & Efficiency vs.
Output Power (Bridge)
TDA7360
TO MINIMIZE THE OUTPUT NOISE AND OP-
TIMIZE SVR
SILENT MUTE/ST-BY FUNCTION FEATUR-
ING ABSENCE OF POP ON/OFF NOISE
HIGH SVR
STEREO/BRIDGE OPERATION WITHOUT
ADDITION OF EXTERNAL COMPONENT
AC/DC SHORT CIRCUIT PROTECTION (TO
GND, TO V_S, ACROSS THE LOAD)
LOUDSPEAKER PROTECTION
DUMP PROTECTION
ESD PROTECTION
Figure 22: Power Dissipation & Efficiency vs.
Output Power (Bridge)
BLOCK DESCRIPTION
Polarization
The device is organized with the gain resistors di-
rectly connected to the signal ground pin i.e. with-
out gain capacitors (fig. 23).
The non inverting inputs of the amplifiers are con-
nected to the SVR pin by means of resistor divid-
ers, equal to the feedback networks. This allows
the outputs to track the SVR pin which is suffi-
ciently slow to avoid audible turn-on and turn-off
transients.
SVR
The voltage ripple on the outputs is equal to the
one on SVR pin: with appropriate selection of
CSVR, more than 60dB of ripple rejection can be
obtained.
AMPLIFIER ORGANIZATION
The TDA7360 has been developed taking care of
the key concepts of the modern power audio am-
plifier for car radio such as: space and costs sav-
ing due to the minimized external count, excellent
electrical performances, flexibility in use, superior
reliability thanks to a built-in array of protections.
As a result the following performances has been
achieved:
NO NEED OF BOOTSTRAP CAPACITORS
EVEN AT THE HIGHEST OUTPUT POWER
LEVELS
ABSOLUTE STABILITY WITHOUT EXTER-
NAL COMPENSATION THANKS TO THE IN-
NOVATIVE OUT STAGE CONFIGURATION,
ALSO ALLOWING INTERNALLY FIXED
CLOSED LOOP LOWER THAN COMPETI-
TORS
LOW GAIN (20dB STEREO FIXED WITHOUT
ANY EXTERNAL COMPONENTS) IN ORDER
Delayed Turn-on (muting)
The CSVR sets a signal turn-on delay too. A circuit
is included which mutes the device until the volt-
age on SVR pin reaches ~2.5V typ. (fig. 25). The
mute function is obtained by duplicating the input
differential pair (fig. 24): it can be switched to the
signal source or to an internal mute input. This
feature is necessary to prevent transients at the
inputs reaching the loudspeaker(s) immediately
after power-on).
Fig. 25 represents the detailed turn-on transient
with reference to the stereo configuration.
At the power-on the output decoupling capacitors
are charged through an internal path but the de-
vice itself remains switched off (phase 1 of the
represented diagram).
When the outputs reach the voltage level of about
1V (this means that there is no presence of short
circuits) the device switches on, the SVR capaci-
tor starts charging itself and the output tracks ex-
actly the SVR pin.
During this phase the device is muted until the
SVR reaches the ”Play” threshold (~2.5V typ.), af-
ter that the music signal starts being played.
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