TDA75610DLVPD
Diagnostics functional description
4.2
Permanent diagnostics
Detectable conventional faults are:
Short to GND
Short to Vs
Short across the speaker
The following additional feature is provided:
Output offset detection
The TDA75610DLVPD has 2 operating status:
1. RESTART mode. The diagnostic is not enabled. Each audio channel operates
independently of each other. If any of the a.m. faults occurs, only the channel(s)
interested is shut down. A check of the output status is made every 1 ms (Figure 28).
Restart takes place when the overload is removed.
2. DIAGNOSTIC mode. It is enabled via I2C bus and it self activates if an output overload
(such as to cause the intervention of the short-circuit protection) occurs to the speakers
outputs. Once activated, the diagnostics procedure develops as follows (Figure 29):
– To avoid momentary re-circulation spikes from giving erroneous diagnostics, a
check of the output status is made after 1ms: if normal situation (no overloads) is
detected, the diagnostic is not performed and the channel returns active.
– Instead, if an overload is detected during the check after 1 ms, then a diagnostic
cycle having a duration of about 100 ms is started.
– After a diagnostic cycle, the audio channel interested by the fault is switched to
RESTART mode. The relevant data are stored inside the device and can be read
by the microprocessor. When one cycle has terminated, the next one is activated
by an I2C reading. This is to ensure continuous diagnostics throughout the car-
radio operating time.
– To check the status of the device a sampling system is needed. The timing is
chosen at microprocessor level (over half a second is recommended).
Figure 28. Restart timing without diagnostic enable (permanent) - Each 1 mS time, a
sampling of the fault is done
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M3
M3
M3 M3
M3
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