In addition to the overload protection described
above, the device features a thermal shutdown
circuit which initially puts the device into a muting
state (@ Tj = 150
o
C) and then into stand-by (@
Tj = 160
o
C).
Full protection against electrostatic discharges on
every pin is included.
3) Other Features
The device is provided with both stand-by and
mute functions, independently driven by two
CMOS logic compatible input pins.
The circuits dedicated to the switching on and off
of the amplifier have been carefully optimized to
avoid any kind of uncontrolled audible transient at
the output.
The sequence that we recommend during the
ON/OFF transients is shown by Figure 4.
The application of figure 5 shows the possibility of
using only one command for both st-by and mute
functions. On both the pins, the maximum appli-
cable range corresponds to the operating supply
voltage.
APPLICATION INFORMATION
HIGH-EFFICIENCY
Constraints of implementing high power solutions
are the power dissipation and the size of the
power supply. These are both due to the low effi-
ciency of conventional AB class amplifier ap-
proaches.
Here below (figure 6) is described a circuit pro-
posal for a high efficiency amplifier which can be
adopted for both HI-FI and CAR-RADIO applica-
tions.
1N4148
10K
30K
20K
10
µ
F
10
µ
F
MUTE
STBY
D93AU014
MUTE/
ST-BY
Figure 5: Single Signal ST-BY/MUTE Control
Circuit
PLAY
OFF
ST-BY
MUTE
MUTE
ST-BY
OFF
D98AU817
5V
5V
+Vs
(V)
+40
-40
VMUTE
PIN #10
(V)
VST-BY
PIN #9
(V)
-Vs
VIN
(mV)
IQ
(mA)
VOUT
(V)
Figure 4: Turn ON/OFF Suggested Sequence
TDA7293
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