TDA8564Q Datasheet, PDF (4/15 Pages) NXP Semiconductors – 2 x 24 W BTL or 4 x 12 W single-ended car radio power amplifier

Philips Semiconductors
2 × 24 W BTL or 4 × 12 W single-ended car
radio power amplifier
Preliminary specification
TDA8564Q
Diagnostic output (pin 16)
DYNAMIC DISTORTION DETECTOR (DDD)
At the onset of clipping of one or more output stages, the
dynamic distortion detector becomes active and pin 16
goes LOW. This information can be used to drive a sound
processor or DC volume control to attenuate the input
signal and thus limit the distortion. The output level of
pin 16 is independent of the number of channels that are
clipping (see Figs 4 and 5).
approximately 20 ms. After that time it is checked during
approximately 50 µs to see whether the short-circuit is still
present. Due to this duty cycle of 50 µs/20 ms the average
current consumption during this short-circuit condition is
very low (approximately 40 mA).
During this short-circuit condition, pin 16 is LOW for 20 ms
and HIGH for 50 µs (see Fig.6).
The power dissipation in any short-circuit condition is
very low.
SHORT-CIRCUIT PROTECTION
When a short-circuit occurs at one or more outputs to
ground or to the supply voltage, the output stages are
switched off until the short-circuit is removed and the
device is switched on again, with a delay of approximately
20 ms after removal of the short-circuit. During this
short-circuit condition, pin 16 is continuously LOW.
When a short-circuit across the load of one or more
channels occurs the output stages are switched off during
TEMPERATURE DETECTION
When the virtual junction temperature T_vj reaches 150 °C,
pin 16 will be active LOW.
OPEN-COLLECTOR OUTPUT
Pin 16 is an open-collector output, which allows pin 16 of
more devices being tied together.
handbook, halfpage VO
0
MGA705
V16
VP
0
t
Fig.4 Distortion detector waveform; BTL application.
handbook, halfpage ^VO
0
MGA706
V16
VP
Fig.5
0
t
Distortion detector waveform; single-ended
application.
handbook, full pagewidth^current
in
output
stage
V16
VP
short-circuit over the load
20 ms
February 1995
50 µs
Fig.6 Short-circuit waveform.
5
MGA707
t
t