Reliable and safe operation, in presence of all

kinds of short circuit involving the outputs is as-

sured by BUILT-IN protectors. Additionally to the

speaker, a SOFT SHORT condition is signalled

out during the TURN-ON PHASE so assuring cor-

rect operation for the device itself and for the

loudspeaker.

This particular kind of protection acts in a way to

avoid that the device is turned on (by ST-BY)

when a resistive path (less than 16 ohms) is pre-

sent between the output and GND. As the in-

volved circuitry is normally disabled when a cur-

rent higher than 5mA is flowing into the ST-BY

pin, it is important, in order not to disable it, to

have the external current source driving the ST-

BY pin limited to 5mA.

This extra function becomes particularly attractive

when, in the single ended configuration, one ca-

pacitor is shared between two outputs (see fig.

21).

reason is shorted, the loudspeaker will not be

damaged being this soft short circuit condition re-

vealed.

Diagnostics Facility

The TDA7375 is equipped with a diagnostic cir-

cuitry able to detect the following events:

Clipping in the output signal

Thermal shutdown

Output fault:

– short to GND

– soft short at turn on

The information is available across an open

collector output (pin 10) through a current sink-

ing when the event is detected

A current sinking at pin 10 is triggered when a

certain distortion level is reached at any of the

outputs. This function allows gain compression

possibility whenever the amplifier is overdriven.

Thermal Shutdown

In this case the output 10 will signal the proximity

of the junction temperature to the shutdown

threshold. Typically current sinking at pin 10 will

start ~10

°C before the shutdown threshold is

reached.

HANDLING OF THE DIAGNOSTICS INFORMA-

Figure 21.

Figure 22: Clipping Detection Waveforms

Figure 23: Output Fault Waveforms (see fig. 24)

TDA7375

TDA7375

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