TDA7575B

Diagnostics functional description

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are recommended for their negligible acoustic impact and also to maximize the impedance

module's ratio between with tweeter-on and tweeter-off.

Figure 37 shows the Load Impedance as a function of the peak output voltage and the

relevant diagnostic fields.

This feature is disabled if any overloads leading to activation of the short-circuit protection

occurs in the process.

Figure 37. Current detection high: Load impedance |Z| vs. output peak voltage

Figure 38. Current detection low: Load impedance |Z| vs. output peak voltage

7.5

Multiple faults

When more misconnections are simultaneously in place at the audio outputs, it is

guaranteed that at least one of them is initially read out. The others are notified after

This is true for both kinds of diagnostic (Turn on and Permanent).

The table below shows all the couples of double-fault possible. It should be taken into

account that a short circuit with the 4

Ω speaker unconnected is considered as double fault.

12

34

5

6

7

8

1

2

3

5

10

20

30

50

Vout (Peak)

Load |z| (Ohm)

Iout (peak) <250mA

Iout (peak) >500mA

Low current detection area

(Open load)

D5 = 1 of the DBx byres

High current detection area

(Normal load)

D5 = 0 of the DBx bytes

IB2(D0) = 0

0.5

1

1.5

2

2.5

3

3.5

4

1

2

3

5

10

20

30

50

Vout (Peak)

Load |z| (Ohm)

Iout (peak) <125mA

Iout (peak) >250mA

Low current detection area

(Open load)

D5 = 1 of the DBx byres

High current detection area

(Normal load)

D5 = 0 of the DBx bytes

IB2(D0) = 1