TDA7563A

Diagnostics functional description

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Diagnostics functional description

3.1

Turn-on diagnostic

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

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.

CH-

CH+

Isource

Vs~5V

Isink

t (ms)

I (mA)

Isink

Isource

~100mS

Measure time