TDA7563PD

12/21

– START = Last reading operation or setting IB1 - D5 - (OFFSET enable) to 1

– STOP = Actual reading operation

Excess offset is signalled out if persistent throughout the assigned testing time. This feature is disabled if any

overloads leading to activation of the short-circuit protection occurs in the process.

5

MULTIPLE FAULTS

When more misconnections are simultaneously in place at the audio outputs, it is guaranteed that at least one

provided that the diagnostic is enabled. 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 ohm speaker unconnected is considered as double fault.

Table 5.

S. GND (so) / S. GND (sk) in the above table make a distinction according to which of the 2 outputs is shorted

to ground (test-current source side= so, test-current sink side = sk). More precisely, in Channels LF and RR, so

= CH+, sk = CH-; in Channels LR and RF, so = CH-, sk = CH+ .

In Permanent Diagnostic the table is the same, with only a difference concerning Open Load(*) , which is not

among the recognisable faults. Should an Open Load be present during the device's normal working, it would

be detected at a subsequent Turn on Diagnostic cycle (i.e. at the successive Car Radio Turn on).

6

FAULTS AVAILABILITY

period of time. If the fault is stable throughout the whole period, it will be sent out.

To guarantee always resident functions, every kind of diagnostic cycles (Turn on, Permanent, Offset) will be

but the read data will come from the previous diag. cycle (i.e. The device is in Turn On state, with a short to Gnd,

7

THERMAL PROTECTION

Thermal protection is implemented through thermal foldback (fig. 27). Thermal foldback begins limiting the audio

input to the amplifier stage as the junction temperatures rise above the normal operating range. This effectively

limits the output power capability of the device thus reducing the temperature to acceptable levels without totally

interrupting the operation of the device. The output power will decrease to the point at which thermal equilibrium

is reached. Thermal equilibrium will be reached when the reduction in output power reduces the dissipated pow-

er such that the die temperature falls below the thermal foldback threshold. Should the device cool, the audio

level will increase until a new thermal equilibrium is reached or the amplifier reaches full power. Thermal fold-

back will reduce the audio output level in a linear manner.

Double fault table for Turn On Diagnostic

S. GND (so)

S. GND (sk)

S. Vs

S. Across L.

Open L.

S. GND (so)

S. GND

S. GND

S. Vs + S. GND

S. GND

S. GND

S. GND (sk)

/

S. GND

S. Vs

S. GND

Open L. (*)

S. Vs

/

/

S. Vs

S. Vs

S. Vs

S. Across L.

///

S. Across L.

N.A.

Open L.

////

Open L. (*)