TDF8555J NXP Semiconductors, TDF8555J Datasheet - Page 14

• Manufacturer Part Number: TDF8555J
• Description: The TDF8555J is one of a new generation of complementary quad Bridge-Tied Load(BTL) audio power amplifiers with full I²C-bus controlled diagnostics, multiple voltageregulator and two power switches intended for automotive applications
• Manufacturer: NXP Semiconductors

NXP Semiconductors
TDF8555J
Product data sheet
7.4.5 Thermal pre-warning and thermal protection
7.5 Diagnostics
If the average junction temperature reaches one of the adjustable levels set via the
I
selected) and can be read via the I
is IB3[D4] = 0, setting the warning level at T
If the temperature increases further, the temperature-controlled gain reduction is activated
for all four channels to reduce the output power; see
average junction temperature, all four channels are switched off at the absolute maximum
temperature T
Diagnostic information can be read via the I
pin DIAG. This information is seen at pin DIAG as a logical OR. In case of a failure,
pin DIAG remains LOW and the microcontroller can read the failure information via the
I
When the failure is removed, pin DIAG is released.
If the clip information is not needed, it can be removed from pin DIAG, enabling pin DIAG
to be used as an interrupt input for the microprocessor.
Table 4.
Diagnostic information
Power-on reset
Low battery
Clip detection
Temperature pre-warning
Short-circuit outputs to battery,
ground or across the load
Speaker fault detection
Offset detection
Load detection
2
2
Fig 7.
C-bus, selected with IB3[D4], pre-warning is activated resulting in pin DIAG LOW (if
C-bus; pin DIAG can be used as a microcontroller interrupt to minimize I
Temperature controlled amplifier gain
Diagnostic information on pin DIAG
off
All information provided in this document is subject to legal disclaimers.
.
Rev. 1 — 15 September 2011
(dB)
G
30
20
10
0
140
4 45 W power amplifier with multiple voltage regulator
Pin DIAG
after power-on reset; pin DIAG will remain LOW until amplifier
has started
yes
can be enabled if IB4[D2] = 0
yes
yes
yes
no
no
150
2
C-bus. The default setting for the thermal pre-warning
160
2
j(AV)(pwarn)
C-bus, but can also be made available at
170
Figure
= 160 C.
180
001aam696
T
j
(°C)
7. If this does not reduce the
190
TDF8555J
© NXP B.V. 2011. All rights reserved.
2
C-bus traffic.
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