TDA8922 PHILIPS [NXP Semiconductors], TDA8922 Datasheet - Page 10

• Manufacturer Part Number: TDA8922
• Description: 2 x 25 W class-D power amplifier
• Manufacturer: PHILIPS [NXP Semiconductors]

Philips Semiconductors
8.3.4
If the supply voltage drops below 12.5 V, the
undervoltage protection circuit is activated and the system
will shut down correctly. If the internal clock is used, this
switch-off will be silent and without plop noise. When the
supply voltage rises above the threshold level, the system
is restarted again after 100 ms. If the supply voltage
exceeds 32 V the overvoltage protection circuit is
activated and the power stages will shut down. They are
re-enabled as soon as the supply voltage drops below the
threshold level.
An additional balance protection circuit compares the
positive (V
is triggered if the voltage difference between them
exceeds a certain level. This level depends on the sum of
both supply voltages. An expression for the unbalanced
threshold level is as follows: V
Example: With a symmetrical supply of 30 V, the
protection circuit will be triggered if the unbalance exceeds
approximately 9 V; see Section 16.7.
2003 Mar 20
handbook, full pagewidth
2
25 W class-D power amplifier
S
DD
UPPLY VOLTAGE ALARM
) and the negative (V
th(unb)
V in
SS
Fig.6 Input configuration for mono BTL application.
) supply voltages and
0.15
IN1
IN1
IN2
IN2
(V
DD
+ V
SS
).
10
power stage
8.4
For a high common mode rejection ratio and a maximum
of flexibility in the application, the audio inputs are fully
differential. By connecting the inputs anti-parallel the
phase of one of the channels can be inverted, so that a
load can be connected between the two output filters.
In this case the system operates as a mono BTL amplifier
and with the same loudspeaker impedance an
approximately four times higher output power can be
obtained.
The input configuration for a mono BTL application is
illustrated in Fig.6; for more information see Chapter 16.
In the stereo single-ended configuration it is also
recommended to connect the two differential inputs in
anti-phase. This has advantages for the current handling
of the power supply at low signal frequencies.
Differential audio inputs
OUT1
OUT2
MBL466
SGND
Objective specification
TDA8922