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TDA7562

As for SHORT TO GND / Vs the fault-detection thresholds remain unchanged from 30 dB to 16 dB gain setting.

They are as follows:

Concerning SHORT ACROSS THE SPEAKER , the threshold varies from 30 dB to 16 dB gain setting, since

different loads are expected (either normal speaker's impedance or high impedance). The values in case of 30

dB gain are as follows:

If the Line-Driver mode (Gv= 16 dB and Line Driver Mode diagnostic = 1) is selected, the same thresholds will

change as follows:

OUTPUT DC OFFSET DETECTION

Any DC output offset exceeding ± 2V are signalled out. This inconvenient might occur as a consequence of ini-

tially defective or aged and worn-out input capacitors feeding a DC component to the inputs, so putting the

speakers at risk of overheating.

This diagnostic has to be performed with low-level output AC signal (or Vin = 0).

The test is run with selectable time duration by microprocessor (from a "start" to a "stop" command):

– START = Last reading operation or setting IB1 - D5 - (OFFSET enable) to 1

– STOP = Actual reading operation

Excess offset is signalled out if persistent throughout the assigned testing time. This feature is disabled if any

overloads leading to activation of the short-circuit protection occurs in the process.

MULTIPLE FAULTS

When more misconnections are simultaneously in place at the audio outputs, it is guaranteed that at least one

of them is initially read out. The others are notified after successive cycles of I2C reading and faults removal,

provided that the diagnostic is enabled.

The table below shows all the couples of double-fault possible. It should be taken into account that a short circuit

D01AU1253

S.C. to GND

x

S.C. to Vs

0V

1.8V

VS-1.8V

VS

x

Normal Operation

1.2V

VS-1.2V

S.C. across Load

x

0V

1.5

Ω

Infinite

Normal Operation

0.5

Ω

D01AU1254mod

D01AU1252mod

S.C. across Load

x

0

Ω

4.5

Ω

infinite

Normal Operation

1.5

Ω