E-TDA7375V Datasheet, PDF (10/15 Pages) STMicroelectronics – 2 x 35W dual/quad power amplifier for car radio

TDA7375V
vice 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 present between the output and GND. As the involved circuitry is nor-
mally disabled when a current 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 capacitor
is shared between two outputs (see fig. 24). Supposing that the output capacitor Cout for anyreason is
shorted, the loudspeaker will not be damaged being this soft short circuit condition revealed.
Figure 24. Single ended configuaration circuit
5.7.1 Diagnostics Facility
The TDA7375 is equipped with a diagnostic circuitry able to detect the following events:
■ Clipping in the output signal
■ Thermal shutdown
■ Output fault:
– short to GND
– short to VS
– soft short at turn on
The information is available across an open collector output (pin 10) through a current sinking 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.
5.7.2 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.
Figure 25. Clipping Detection Waveforms
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