Practical information

STA541SA

18/26

Doc ID 16988 Rev 2

7.4

Built–in protection

7.4.1

Diagnostic facilities (pin 10)

The STA541SA is equipped with diagnostic circuitry that is able to detect the following

events:

●

clipping of the output signal

●

thermal shutdown

●

output fault:

–

short circuit to ground

–

short circuit to supply

–

soft short circuit at turn-on

The event is signalled when the open collector output of pin 10 (DIAG) begins to sink

current.

7.4.2

Short-circuit protection

Reliable and safe operation in the presence of all kinds of output short circuit is assured by

speaker, there is a soft short-circuit condition which is signalled on pin DIAG during the

turn-on phase to verify output circuit integrity in order to ensure correct amplifier operation.

As mentioned previously, it is important to limit the external current driving pin STBY

to 5 mA, the reason being that the associated circuitry is normally disabled with currents

greater than 5 mA.

7.4.3

Clipping detection

Figure 17.

Clipping detection waveforms

A gain-compression function is initiated whenever the amplifier is overdriven. When a

certain distortion level is reached at each output, pin 10 starts to sink current.

Audio output signal

Clipping detector output current

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