NXP Semiconductors TDA8560Q - Manual (Page 5)

1996 Jan 08 5
Philips Semiconductors Product specification
2
×
40 W/2
Ω
stereo BTL car radio
power amplifier with diagnostic facility
TDA8560Q
S HORT - 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 12 is continuously low.
When a short-circuit across the load of one or both
channels occurs the output stages are switched off during
approximately 20 ms. After that time it is checked during
approximately 50
µ
s to see whether the short-circuit is still
present. Due to this duty cycle of 50
µ
s/20 ms the average
current consumption during this short-circuit condition is
very low (approximately 40 mA).
During this short-circuit condition, pin 12 is low for 20 ms
and high for 50
µ
s (see Fig.4).
The power dissipation in any short-circuit condition is
very low.
T EMPERATURE DETECTION
When the virtual junction temperature T
vj
reaches 150
°
C,
pin 12 will become continuously low.
O PEN COLLECTOR OUTPUT
Pin 12 is an open collector output, which allows pin 12 of
more devices being tied together.
Fig.4 Short-circuit waveform.
handbook, full pagewidth
MGA722
short-circuit over the load
20 ms
µ
50 s
t
t
VP
current
in
output
stage
V12