DocID14407 Rev 5

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TDA7563A

Diagnostics functional description

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Diagnostics functional description

3.1

Turn-on diagnostic

It is activated at the turn-on (standby out) under I2C bus request. Detectable output faults

are:



Short to GND



Short to Vs



Short across the speaker



Open speaker

To verify if any of the above misconnections are in place, a subsonic (inaudible) current

pulse (Figure 19) is internally generated, sent through the speaker(s) and sunk back.The

Turn On diagnostic status is internally stored until a successive diagnostic pulse is

requested (after a I2C reading).

If the "standby out" and "diagnostic enable" commands are both given through a single

programming step, the pulse takes place first (power stage still in standby mode, low,

outputs = high impedance).

Afterwards, when the amplifier is biased, the PERMANENT diagnostic takes place. The

previous Turn On state is kept until a short appears at the outputs.

Figure 19. Turn-on diagnostic: working principle

Figure 20 and 21 show SVR and OUTPUT waveforms at the turn-on (standby out) with and

without TURN-ON DIAGNOSTIC.