TDA7561

Diagnostics functional description

Doc ID 8326 Rev 6

15/27

4.3

Output DC offset detection

Any DC output offset exceeding ±2 V are signalled out. This inconvenient might occur as a

consequence of initially defective or aged and worn-out input capacitors feeding a DC

component to the inputs, so putting the speakers at risk of overheating.

This diagnostic has to be performed with low-level output AC signal (or Vin = 0).

The test is run with selectable time duration by microprocessor (from a "start" to a "stop"

command):

●

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.